MIG welding gas supplies.

[Pugglt Auld Jock]

You'll all be relieved to know I'm actually going to talk about gas supplies now!

As the weather was so lousy I spent some of the afternoon ringing round the three suppliers of "rent free" cylinders I've found near me for prices and conditions.

Their conditions of supply seem similar in most respects. To get myself set up I have to pay a deposit on the bottle. This is quite hefty but refundable in full (keep your receipt - no refund without paperwork!) if you decide to hand it back. So a nice wee bonus for Mrs J if I unexpectedly pop my cloggs. All she's got to do is hand the cylinder back and she's got money for drinks at the wake! Then you pay for your gas fill. When the cylinder is empty you just take it back and exchange it for a full one, paying just for the gas.

I'm intending to start with the 10 litre size cylinder which I think will give me plenty of "run time" but there are larger, more expensive, options if I need them. So, the three suppliers I've contacted so far pan out like this for 10 litre bottles of 5% argon CO2 mix:

For Hobby Weld:
Deposit on bottle £65 and gas fill £38 total set up cost:- £103.00

For "Unknown brand" supplied by wee local company:
Deposit on bottle £72 and gas fill £39.59 Total set up cost:- £111.59

For SGS:
Deposit on bottle £ not known yet and gas fill £ not known yet Total set up cost:- £137.55

When I rang about the SGS bottles the lad who answered the phone didn't know much about it as the main business is motor spares but he was able to find a price sheet which had only that "all in" price on it. These are people I know very well so I'll ring back and get a proper break down on it. Also worth mentioning that the service pressure quoted on a full bottle is 137 bar for the first two and 200 bar for the SGS bottles.So although more expensive you get more gas with the SGS option. I like the idea of that as it means you will be needing a fill less frequently. Might be worth it even if slightly more expensive. I'm still trying to understand what difference, if any, the "wee sniff" (2% I think) of oxygen in the hobbyweld makes. I feel I should probably disregard it for my pretty rough welding ability if it weren't for the fact that the BOC product I've been using for years has it and the welds are very nice using that gas. I'm going to have a chat with the chap at NIA (Northern Industrial Alloys) - local BOC distributor - when I hand the big BOC bottle back. He should know surely? I have to have the bottle back at their depot before the 20th of this month to avoid another years rental (£70.00) However it's about 3/4 of an hour drive away into West Lothian. Think I'll get away with it? We haven't been "released" yet like you folk down south. I won't be stopping anywhere and it's just a depot - big yard - so social distancing should be easy. The car's in very good nick too so a breakdown is unlikely. Think I'll have to try it!

 

[Pugglt Auld Jock]

Just back in the door from returning the BOC bottle. Glad to say no problems with the drive. Saw several police vehicles but none showed any interest in me. The traffic was generally light but there were more vehicles about than I expected out on the open road.

The actual handing back of the bottle went very smoothly and I was surprised to find the man who dealt with me was the chap who worked in their Gorgie branch many years ago when I used to buy rods etc there. He made me feel very welcome and we had a few chuckles about "the old days". Gorgie has been closed for many years. He was amused to see my bottle which was the oldest one he'd seen in some time! The BOC accounts are kept on one computer and the shop business is on another. He needed to get the shop computer to "talk" to the BOC computer in order to give me a hard copy reciept. Guess what? the one computer wouldn't talk to the other! However he showed me the entry on the BOC computer which plainly shows my bottle returned and no new bottle issued. He's going to send me an email reciept later today but I think I'll ring BOC themselves tomorrow just to be sure it's all gone through Ok.

By the way, if anyone in our area - west Edinburgh/Livingston - is looking at anything to do with welding I can thoroughly recommend these people who I've known for years: Northern Industrial Alloys, Broxburn. The shop/warehouse is a good old "commercial" type with lots of stuff on display. Although clearly aimed at the professional welder they also have a good selection of less expensive gear suitable for the enthusiast. I also noticed a fair few offers on power tools. ie drills, grinders etc.

So the deed is done. I am now "bottless" - until I decide which rent free deal I'm going for.

 

[Pugglt Auld Jock]

Been gardening all morning. Quite pleased with the outcome. Pretty much all nice and neat now although there is a large weigela and my shaped cotoneaster needing trimmed back. They're almost finished flowering so I'll be doing that in maybe a fortnight. Now in the living room with a cup of coffee and listening to Michael Gove going on about how we have to leave the EU as soon as possible. Hence why I'm writing this - as a distraction!

Being the "doubting Thomas" that I am and feeling "nervous" about having no paperwork from yesterday, I have just rung BOC to get confirmation that they acknowledge my returned bottle and cancellation of my contract. All seems fine and they are forwarding confirmation paperwork - might take a few days to arrive as they are working from home. So that's a good outcome.

So, feeling full of enthusiasm, I thought I'd complete my investigations into which rent free bottle system I am going to buy into. The result is, I think, quite interesting so here we go. I decided for security of supply I'll be going with the "big names" so I'm not going to enquire further of the "wee guy" out in East Lothian I've heard of. I've just rung my local factor about the SGS gas price breakdown. Luckily I got a chap on the 'phone who I know very well and who has, in the past, been exceptionally helpful. I think I'll get on fine with the 10 litre size which is about half the size of my old "Y" size BOC bottle. (a 20 litre size is available if needed. The all in price for the 10 litre bottle and fill of gas is £137.53p which breaks down into £53.53p for the gas fill and a one off £70.00p deposit (fully refundable on return with receipt) for the bottle. From then on you only pay for the gas fill when exchanging your empty bottle for an full one.

The conditions are basically similar for the Hobbyweld but, at first sight their prices seem quite a bit cheaper. All in setup price £103.00p which breaks down to £38.00p for gas and £65.00p for the cylinder. However there is a return charge of approximately 15% if you return the cylinder for refund. SGS give you all your money back!

Then there are a few other things to factor in. For me it's no small consideration that the SGS agent, being my local factor, is just round the corner (5 mins in the car) whereas the Hobbyweld folk are on the other side of the town, a good half hour in the car and more in heavy traffic which might be frustrating if I ran out of gas half way through a job. So the fact that the SGS gas costs more was disappointing. But, hang on, when you look at it in the cold light of day is it? Well, yes you are going to lay out £34.53p more for your initial set up but, are we comparing "apples" with "apples"? I don't think so! The SGS bottle describes itself as 10 litre capacity whereas the Hobbyweld is 9 litres. Ok, that's cutting hairs, but pretty "thick hairs" when at 137 or 200 bar? Talking about cylinder pressures, and by the way they all seem to talk about the pressures they "hope" to achieve on a full fill - no doubt to allow for a very small variation? The Hobbyweld target pressure is 137 bar whereas the SGS claims 200 bar. This is no small difference and must account for a big difference in the actual quantity of gas they get into their cylinders? I Emailed both companies day before yesterday and got an almost instantaneous reply from SGS , still none from Hobbyweld, but could be covid induced problems? I told them both that I was comparing their products and on the subject of gas quantity the SGS chap told me you can more or less say that if you decompress the contents of one of their 200 bar 10 litre bottles it contains approx 2,000 litres of gas. He went on to say the same comparison at 137 bar gives 1,370 litres. I'm guessing that as the Hobbyweld bottle is slightly smaller it's possibly a bit less than that. So you are probably getting about 450 litres, or thereabouts, more gas in the SGS cylinder for £15.53p more. I figure this gives the hobbyweld a small advantage on price. However, looking on line, I haven't come across anyone selling the Hobbyweld as cheaply as the one on the other side of town from me. For instance: https://www.ebay.co.uk/i/3612070292...pjMo9kYf1oFu4yBR1Sjo9mrA7iZc1lmQaArChEALw_wcB In which case the SGS would be a definite winner. You would need to look at local pricing if you were thinking of aquiring a bottle. Wonder if my local Hobbyweld guy has reduced his price to "win" SGS customers? The final variable for me is that the Hobbyweld has 2% oxygen (like the BOC gas I've been using and the SGS does not). I raised this with the SGS chap in my email. His reply was that a large number of their bottles are in use in small garage businesses and they've never had this issue raised ever and he went on to say they have over 100,000 bottles in circulation at this time. You'd think someone would have raised it if it were a problem wouldn't you?

So, my mind is made up. It's going to be an SGS bottle for me. The factor tells me he has stock on the shelf all the time as quite a few local garages are buying from him, so I can just walk in the door and out again with my bottle whenever I want. On that basis I'll just wait 'till the first time I need the MIG - Want to bet it'll be a Sunday?

Oh happy days! Mrs J is just back from dropping unneeded baby clothes at the charity shop. (she's been clearing out during lockdown) and she's come back with a loaf of Olive Bread from the baker next door to the shop. Smells wonderful so I'm off to cut myself a slice right now!

Kindest regards and stay safe all
Jock

 

[Pugglt Auld Jock]

Another wee interesting finding which supports my choice of SGS bottles. I just used the Hobbyweld and SGS's dealer search engine and there are four factoring organizations here doing SGS bottles with 2 locations very nearby and 4 others easily reached whereas the Hobbyweld only gives me one outlet on the other side of town and 2 more quite inconveniently further away.

Oh, and according to my friend, the police are far too busy watching the crowds down on Portobello beach and in the Royal Park and others to be worried about me taking my welding bottle out to Broxburn!

 

[Pugglt Auld Jock]

Hey, I'm not as brain dead as I thought. Taking the two expanded gas figures of 2,000 and 1,370 litres and working out the cost per litre - did it long division! The SGS works out at 2.676 pence per litre whereas the Hobbyweld (lets say H/W from here on in?) comes in at 2.774 pence per litre. So I'm saving 0.098 pence per litre - £1.96p per bottlefull? - with SGS! Really not worth thinking about is it?

However it becomes a bit more worth factoring in if your H/W supplier is charging prices nearer to the one I found on line and you have to remember you're going to get all your bottle deposit back from SGS but loose some of the H/W (£10.00p plus VAT I saw on their website today for the 10L bottle). I suppose for me there would be a petrol cost in getting right across the city too. None of it amounts to a lot of money, but, on the other hand I could buy the grandchildren quite a few ice creams with it!

Go on now all you clever clogs with calculators, tell me my maths is wrong?

 

[s130]

Wow!

This has rolled a little.

So if we cut to the chase and look at gas supplies for mig welders where are we actually at?

 

[Pugglt Auld Jock]

Wow!

This has rolled a little.

So if we cut to the chase and look at gas supplies for mig welders where are we actually at?

From my point of view and in my particular situation there isn't much to choose between either of the rent free options. I've going with the SGS option because their supplier is virtually on my doorstep and I have a good working relationship with them (the supplier). I'm also attracted by the fact that the SGS cylinder actually contains more gas so will not require exchanging so often. There's very little in the price of the gas but, I think, the H/W bottle will end up costing more at the end of the day because of that "admin" charge when you return it.

If you are only a very occasional user maybe disposable canisters will do you but they run out pretty quickly and are, pro rata, an expensive way to go.

The other option is to go with the "big boys" The likes of Air Products, BOC, Air Liquide, AGA gas, any I've missed? If you are using a lot of gas, like I was with the evening classes whilst also doing "stuff" at home I thought it was a good option and some will do you a "Low Volume User" agreement, like BOC did with me after I stopped doing the classes. Even so though they were wanting £70.00p off me just for cylinder rental this year and the rental is payable every year!

In my opinion therefore going with the rent free option is the way to go if you are an "enthusiastic", but intermittent, user like me. - Not sure if that helps? Please ask away if I can answer any questions.

 

[s130]

Well I came to the SGS conclusion when I posted about them and prices for similar reasons to you my local SGS supplier all about the products and could supply everything together wish "cash trade" as opposed to having to have an account.

Mind you next time I have to use the welder I'm going to try gassless fluxed core welding wire and see how I get on. This would be a near zero cost option as well.

 

[Pugglt Auld Jock]

and could supply everything together wish "cash trade" as opposed to having to have an account.

Mind you next time I have to use the welder I'm going to try gassless fluxed core welding wire and see how I get on. This would be a near zero cost option as well.

I didn't mention the "cash purchase" aspect and I strongly agree with you that for me this is also an attraction. I'm still waiting to see what BOC finally send me by way of paper work. Apparently because they have already issued me with an invoice for the payment, payable by 20th June, they will now issue me with a refund statement for the amount which cancels the invoice, or so they say. I'm waiting with interest to see what comes in the post and what the bottom line shows, seems like a complicated way to do a simple thing? At least they acknowledge that I've handed back the bottle and now have a bottle holding of zero.

It's going to be so simple just to walk into SRS and pay the one off charge for the new bottle.

I've briefly tried a couple of No-Gas machines which people brought in to the evening classes I used to do. They worked well enough, especially on slightly thicker materials, and you can certainly weld bodywork if you don't try to lay down a continuous bead - mind you it's often not possible with a gas machine either although I think the gas helps to cool things a bit. I found I just didn't like it so much though, but then I had been using the gas machine for years and only "played" with the flux cored one. I suppose also that I was used to my machine - the Cebora - and most of the machines people bought up here were Clarke brand (local big Machine Mart store) which were just slightly different to use. So, for me, I would go for the gas machine every time even if there's a wee bit extra cost involved.

 

[jimboy]

Aye Jock, this is a thread that has loads of information.
Do you do a lot of welding? My days of the electrode manipulating control are long gone as I said before. You never loose the knack, it’s like riding a bike, you just never forget. Interested what welding projects you are at.

 

[Pugglt Auld Jock]

Aye Jock, this is a thread that has loads of information.
Do you do a lot of welding? My days of the electrode manipulating control are long gone as I said before. You never loose the knack, it’s like riding a bike, you just never forget. Interested what welding projects you are at.

Yes Jim, it's been very interesting tracking down all the info I needed and then breaking it down into a form where I was comparing "apples" with "apples. I'm still just a little concerned about the 2% oxygen "thing" so have decided to go and have a word with the fellow down at Newhaven harbour who runs A G Autos because he uses the SGS bottles as supplied through SRS ("my" factor). The good thing is that I'm in no hurry.

Present welding project? None As I've always been more into the mechanical guts of cars, bikes and horticultural machinery. The welding has usually "spun off" from something I've been mending - like a crack found in a pedal cluster/bulkhead whilst renewing a master cylinder for instance. I doubt if it'll be all that long without though because many of my friends and acquaintances know I weld as do my children's friends, many of whom run around in old wrecks. I am becoming a bit more selective now with what I'll take on though as this old body doesn't like bending into strange shapes so much any more. The good thing is that I have the MOT welder John, who I met a few years ago when he welded up some very corroded bits on Felicity. So I pass the "nasty" stuff on to him for which he's very greatful which in turn stands me in good stead when I need him to do something for me! It's what makes the world go round!

One of the most ambitious things I ever made was my mobile engine gantry:



You can see from this why I can't get a car into the garage! The gantry is like a very big inverted "L" with the long leg welded to a "U" shaped base with a small wheel at each corner - like an engine crane - so you can wheel it around. The only bit my welder really couldn't manage was the gusset plate you can see at the top bend. Luckily the chap who taught me to use my wee MMA welder took the whole thing into work with him (that was a whole story in itself) and put the bend into it and welded the gusset in for me. getting it home was a little easier because it was now shorter! The rest of it was all joined using the SIP TOPWELD MMA welder (the yellow one I've shown on here before. In use you slide the front legs of the "U" base under the front of the car and lift the engine out using the block and tackle. Then, because the base has wheels you simply wheel it away and let the engine down onto the floor. The block and tackle makes it a bit slow to use but it's massively strong and I've never even seen it begin to bend. I haven't used it in some years now so, as you can see from the picture, it's become a bit of a "coat hanger" of late, I couldn't possibly get rid of it though, took too much effort to build it and several packets of hacksaw blades! It does have one major flaw though, spotted it? the damn thing is too tall to get out of the garage door! How did I manage that? because I was trying to get as much lift as possible so if I had something up on stands to disconnect drive shafts etc I could still clear the front panel with the bottom of the engine. Ah well!

Then when I was heavily into Hillman Imps I built an engine stand which is an integral part of the gantry using it's main upright to carry it:



It just unbolts when you are using the rig to lift out engines. Remember the old two position BL mini engine lifting bracket anyone? Can you spot it?

Probably the project I'm proudest of is my half ton 5x3 ft trailer which I built in the late '80s It's still got my old Cordoba's no plate on it:



If you look to the left side of the picture showing the gantry you can just see the upright bars of it's ladder rack sticking up with my old Barbour hanging over the left one. It's resting just now as I don't have a towbar on either Twink or Becky and my boy replaced his Fabia Scout with the Kia. All the old cars had towbars but now there's none! The trailer was mostly used for transporting garden machinery and you can see it's full of them right now. When I was thinking of making it I was down at Johansens yard in Leith (now Daltons) looking for car parts when I mentioned it to them. "Got just the thing for you son - Bed irons! Keep them specially for people making trailers" I'd no idea what he was talking about but he explained he was talking about the angle iron which old type beds - like prison/hospital beds - were made from. According to him they are thinner and lighter than traditional angle iron but much stronger. I bought 4 leangths and some 2" square heavy section square tube from Blakes metal centre. Two heavy duty German made suspension units and an unbraked hitch from the trailer centre in Tranent, three wheels from a Reliant Robin (one for spare) and I already had two mini rear wheel hubs lying about complete with bearings. Tail light units from Pilrig Motors and some plugs and wires completed the purchases. Couple of weeks of evening and weekend working and I had a trailer. It's done a lot of miles and never even suffered a puncture let alone a failed weld. All the main welds get the once over every year for cracks "just to be safe".

I made a very handy wee stand with storage for my pressure regulator and air tools. It also allows me to have the pressure regulator near to where I'm working:





I found two solid rubber wheels in the scrap at work and made them into a sack barrow - boy has that been useful:



Reinforcing welds in horticultural stuff is common cracks in chassis especially. This is on my, somewhere around 70 year old, Merry Tiller Major cultivator:



I have also made shed door security bars for all our garden sheds:



Look to the right and you can see I've extended the original shed which I did to accommodate a lot of the Imp spares - engines, gearboxes, suspension parts etc - which I couldn't get into the garage. Mrs J used to joke (I think she was joking wasn't she?) when we are at social events that everyone else in the street has an extension or conservatory on the back of their house, we have an extension to the shed! I succumbed and let her have a wee conservatory a few years back though.

Of course there have been a lot of car related stuff but I don't have pictures of them. Oh and I made a trolley for my tool boxes - top and extension box - out of an old hospital tea trolley. That was actually quite involved as the whole thing had to be cut and rewelded to fit with bits of angle iron let in. Sprayed it all up with a Lidl red paint can and it matches the tool boxes perfectly! Then there were trolleys for both the welding plants.

Jim, this could just go on for ever. So I'm going to stop now in the hope that it'll give you some idea of the sort of stuff I've been up to over the years. I'm not going to get a new gas bottle until I have a job to do with it but I have a feeling that may not be so long!

Keep safe
all kindest regards
Jock

 

[s130]

Hillman Imp

Font memories had a Singer Chamois.

Metal work a tough as old boots. Never needed to weld. Just keep on top of any rust that did start to dig in.

When the car went to the car sky I removed the engine and transaxle and built a Dexian carriage on casters. Put the engine/transaxle, instrument cluster etc. All designed to take Mecc Alte 240V alternator.

With not so fond memories of the coal minors strike and power cuts I called my creation "The Aurther Scargill" buster.

 

[Pugglt Auld Jock]

Hillman Imp

Font memories had a Singer Chamois.

Metal work a tough as old boots. Never needed to weld. Just keep on top of any rust that did start to dig in.

When the car went to the car sky I removed the engine and transaxle and built a Dexian carriage on casters. Put the engine/transaxle, instrument cluster etc. All designed to take Mecc Alte 240V alternator.

With not so fond memories of the coal minors strike and power cuts I called my creation "The Aurther Scargill" buster.

I had several Imps but my favourite was an estate. The load bay was a bit compromised by the engine being under the floor but I really loved that car.

I think I've done everything possible on an Imp except rebuild a gearbox - I had 3 spare gearboxes and 5 engines at one time - I believe setting up the crown wheel/pinion clearance was difficult, with a capital D. King pin bushes were a regular feature I remember.

What I was always looking out for was one of the old Coventry Climax engined fire pumps but I never did get one.

 

[s130]

OH! The luxury of maintenance of the estate.

No.4 spark plug accessible. End thermostat housing accessible .....

Fond memories of hated maintenance tasks!

 

[jimboy]

The last homer type job I did welding was a friend who was a plumber, and he won a contract for a major hotel in Inverness to redo the piping for the heating and hot water. I was welding pipe joints in the basement, 6 and 8 inches. My friend paid me thirty quid a joint and there were quite a few. That was in the 90s I was fit in those days and the positions tested you. A good earner.

 

[F123C]

Hey, I'm not as brain dead as I thought. Taking the two expanded gas figures of 2,000 and 1,370 litres and working out the cost per litre - did it long division! The SGS works out at 2.676 pence per litre whereas the Hobbyweld (lets say H/W from here on in?) comes in at 2.774 pence per litre. So I'm saving 0.098 pence per litre - £1.96p per bottlefull? - with SGS! Really not worth thinking about is it?

However it becomes a bit more worth factoring in if your H/W supplier is charging prices nearer to the one I found on line and you have to remember you're going to get all your bottle deposit back from SGS but loose some of the H/W (£10.00p plus VAT I saw on their website today for the 10L bottle). I suppose for me there would be a petrol cost in getting right across the city too. None of it amounts to a lot of money, but, on the other hand I could buy the grandchildren quite a few ice creams with it!

Go on now all you clever clogs with calculators, tell me my maths is wrong?

Hi Jock,

What's this' long division' of which you speak?
Reminds me of my time teaching evening auto. tech. classes, I used to get stuck with the classes that the fulltime lecturers didn't want, e.g. maths & craft calculations to 1st year apprentices - many of whom couldn't wait to get out of academic education, so started in a trade, thought they were going to work hands-on on cars etc. and would never have to study maths again. For the majority of those I taught, it was like trying to row a boat uphill, on my own, while the 'students' in the stern (why do the troublesome students always sit at the back?) continuously dropped the anchor overboard.....

I've noticed that other types of gas cylinders e.g. butane, propane are marked with what I assume is the net? weight (i.e. the weight of the contents), this way, there's no need to compare pressures and cylinder size or do any calculations - just weigh the cylinder and subtract the weight of an empty cyl. to see if the cyl. is full. This way you're paying for the mass (weight) of gas supplied.

Maybe a small point, but don't forget that any change in temperature will affect the cylinder pressure. When the cylinder is being refilled, the temperature of both the gas and cylinder will rise, until the refilling process is stopped when the pressure has reached the required figure. As the cylinder cools, the internal pressure will drop a little, but the mass of gas inside stays the same. Maybe this is why the cylinder refillers/agents say they 'aim' to fill to a particular pressure, probably hoping to avoid any comebacks, if upon installation, the contents gauge pressure indicates a lower figure...

I've often wondered if the cylinder valves, especially on high pressure oxygen cylinders actually seal well (given their construction) or do they lose pressure over time. I well remember one of the safety precautions was not to hang a coat or similar over the cylinders, oxygen or acetylene (for different reasons).

Have you read 'Science for Motor Vehicle Technicians' by S.J.Zammit (a Longman Technical Series book, ISBN 0 582 42016 4)? It used to be a standard textbook for those studying the science behind motor vehicles.
This book has a chapter on Gases. Do you remember Boyle's Law (the relationship between pressure and volume of a gas), Charle's Law (the relationship between volume and temperature of a gas), or combining these two, giving you 'the gas equation', not forgetting S.T.P. (Standard temperature and pressure, not the engine oil additive). Reminds me of my time teaching evening auto. tech. classes (again). Except, I also got to teach Heat Engines & Applied Mechanics to senior apprentices and those older mechanics who had returned to college to obtain better qualifications in order to advance themselves - what a great bunch of guys (no gals), highly motivated, keen to learn, no messing, asked intelligent/relevant questions, really kept me on my toes.

I used to put a felt tip mark on the regulator 'contents' gauges when I installed new oxygen and acetylene cylinders to see if 1) I had been supplied with 'full' cylinders (the 'porta pac' sized ones could vary quite a bit...) and, 2) to monitor usage.

I've heard of some people refilling small gas cylinders from larger ones...
I could see it working for oxygen but not for acetylene (the acetylene is dissolved in acetone held in a porous material, as you probably already know). Personally, I wouldn't mess with any type of gas, will just stay safe by relying on the experts, who hopefully know what they're doing.
Sorry, I digress...

On the question of cost? cylinder deposit, refilling charge etc.
Have you considered simply and deliberately adding a small charge on each welding job you do for others, so that over time the cylinder effectively has cost you nothing? It took me a while to adopt this approach, as I always preferred to do someone a favour (for free) or at as low a cost as possible, it took me a while to figure out why I never had much money, despite always seeming to be working, one reason was because I was buying consumables etc. and then giving them away for free, or buying a workshop manual or a special tool (never to be used again) to do a job for someone and paying for these myself.

P.S.
Jock, I'm not criticising your calculations, they seem a good-enough way of trying to achieve a comparison of apples with apples, even if the cyl. suppliers makes it feel like you're trying to compare eating with cooking varieties..

Regards,

Al.

 

[F123C]

Hi Jock, you mentioned earlier using 2.5mm rods.

I got 2.0 and 2.5mm welding rods from Lidl recently. Just looking at the specs, I noticed something interesting (see the Amperage figures) :-

2.0mm rod > welding material thickness= 2 - 4 mm, Amperage=35 - 60 Amps

2.5mm rod >welding material thickness= 2 - 6 mm, Amperage=70 -100 Amps.

Both these rods have the same tensile strength and the same ignition voltage (70 volts). My little, recently purchased, Inverter welder's No-Load Voltage is only 68 volts....

Al.

 

[Pugglt Auld Jock]

Hi Jock, you mentioned earlier using 2.5mm rods.

I got 2.0 and 2.5mm welding rods from Lidl recently. Just looking at the specs, I noticed something interesting (see the Amperage figures) :-

2.0mm rod > welding material thickness= 2 - 4 mm, Amperage=35 - 60 Amps

2.5mm rod >welding material thickness= 2 - 6 mm, Amperage=70 -100 Amps.

Both these rods have the same tensile strength and the same ignition voltage (70 volts). My little, recently purchased, Inverter welder's No-Load Voltage is only 68 volts....

Al.

Aye Al, bit puzzling isn't it - the lower recommendation on the 2.0mm rod especially? I can only guess that it's a function of the thickness of material being welded (and so heat input required?) But then why the 70 amp recommendation for the 2.5?

It bothered my "little grey cells" enough that I decided to dig out almost my entire stock of rods to compare them, although I didn't include the half pack of 3.2 because I don't really use them as the machine struggles to burn them so I stuck them up on the top shelf out of the way:



Here's the recommended amperages on the packets that are still legible:







Really quite similar to what you have?

I have to say also that although I got very tied up with manufacturer's recommended settings (both for rods and what the machine's manufacturer recommended) It wasn't long before I learned that they are only rough - and I would say very rough - guides. These days although I know roughly where I'm going to set the pointer on my machine for most thicknesses of metal, I tend to stick a rod in the handle and do a wee burn on a bit of the job, or an offcut, and "tweek" it up or down depending on the outcome. I probably couldn't actually tell you what amperage I set on the scale. Probably too high if the whole rod starts glowing red hot though? Ha Ha.

As a last "parting shot" it may be worth mentioning that I have found quite a noticeable difference between makes of rod. My definite favourites are made by FRO. Unfortunately they are difficult to find, but I've got a pack and a half still so it'll be some time before I need to face that and I'll be surprised if NIA can't get them if I ask.

The worst rods I have just now are the ones in the white pack. They have very little info on the pack, not even manufacturer or supplier and no specification info at all. When I started doing the evening classes I had to order through the official suppliers and that's where these ones came from - Later I was entrusted to source my own materials and bill them, which was much better. If you compare my FRO rods to these ones there is very little to see, both even have the same "E" number, The ones from the white pack are themselves rather lighter in colour perhaps when compared to my favourite FROs - more on that in a minute:



The difference when in use is significant though. They are very very difficult to "light up". Even when you successfully get the arc struck it can mysteriously extinguish for no obvious reason. They caused me lots of trouble on the night we first tried to use them. I've given up with them. I suppose I should just bin them. The only thing I find slightly suspicious is their colour, Many years ago, before I knew better, I had problems with coatings deteriorating due to damp from where I stored them. I now keep all my spare rods in the airing cupboard with the hot water tank and I find they last for ages like this. I did notice the contaminated rods tended to take on a whitish powdery surface. Maybe a factor in the whiteness of the poor quality rods? But then again they are very uniform in colour so I'm not convinced this is the problem.

 

[Pugglt Auld Jock]

Oh yes, thermostat access on all the saloon/coupe models was an absolute b***h wasn't it. I only did a few when I was earning my living repairing cars because I worked for DAF or later BL dealers so didn't see many Imps in the shop. (plus I learned to hide until some other poor sod landed the job! Then when I became obsessed with Imps I would automatically fit a new one whenever the engine was out. In fact the engine came out so easily I wonder if it would have been quicker - certainly easier - to just whip the whole engine out to do a thermostat?

This in reply to S130 (I forgot to tick the box for quote)

 

[Pugglt Auld Jock]

(why do the troublesome students always sit at the back?)

Maybe a small point, but don't forget that any change in temperature will affect the cylinder pressure.

I've often wondered if the cylinder valves, especially on high pressure oxygen cylinders actually seal well (given their construction) or do they lose pressure over time. I well remember one of the safety precautions was not to hang a coat or similar over the cylinders, oxygen or acetylene (for different reasons).

Have you read 'Science for Motor Vehicle Technicians' by S.J.Zammit (a Longman Technical Series book, ISBN 0 582 42016 4)? It used to be a standard textbook for those studying the science behind motor vehicles.
This book has a chapter on Gases. Do you remember Boyle's Law (the relationship between pressure and volume of a gas), Charle's Law (the relationship between volume and temperature of a gas), or combining these two, giving you 'the gas equation', not forgetting S.T.P. (Standard temperature and pressure, not the engine oil additive). Reminds me of my time teaching evening auto. tech. classes (again). Except, I also got to teach Heat Engines & Applied Mechanics to senior apprentices and those older mechanics who had returned to college to obtain better qualifications in order to advance themselves - what a great bunch of guys (no gals), highly motivated, keen to learn, no messing, asked intelligent/relevant questions, really kept me on my toes.

I used to put a felt tip mark on the regulator 'contents' gauges when I installed new oxygen and acetylene cylinders to see if 1) I had been supplied with 'full' cylinders (the 'porta pac' sized ones could vary quite a bit...) and, 2) to monitor usage.

I've heard of some people refilling small gas cylinders from larger ones...
I could see it working for oxygen but not for acetylene (the acetylene is dissolved in acetone held in a porous material, as you probably already know). Personally, I wouldn't mess with any type of gas, will just stay safe by relying on the experts, who hopefully know what they're doing.
Sorry, I digress...

On the question of cost? cylinder deposit, refilling charge etc.
Have you considered simply and deliberately adding a small charge on each welding job you do for others, so that over time the cylinder effectively has cost you nothing? It took me a while to adopt this approach, as I always preferred to do someone a favour (for free) or at as low a cost as possible, it took me a while to figure out why I never had much money, despite always seeming to be working, one reason was because I was buying consumables etc. and then giving them away for free, or buying a workshop manual or a special tool (never to be used again) to do a job for someone and paying for these myself.

Afternoon Al.

Why do they sit at the back? I recon, despite all their bluster and indifference it's because they are basically insecure and unsure so need people in front to hide behind.

Leaky cylinder valves? Often an abused component. I've watched, more than once, someone with a length of pipe over the cylinder key forcing it tightly shut. I always leave my gauge attached and backed off when not in use. That way I'll get a reading showing on the operating pressure gauge if the cylinder is leaking.

Regarding the books, our two "bibles" were Hillier and Pittuck Fundamentals of Motor Vehicle Technology, at present residing somewhere in my loft and this one which was still in my bookcase:



My personal preference though would be for books like these:



We used to do short, subject specific, in depth courses which were for qualified mechanics wanting to look at a particular subject in detail and came under the heading of "Full Trade Training" to differentiate them from the basic course we more usually ran. They lasted typically a week or fortnight full time depending on subject. I only taught a few of these but I loved them because the students were so well motivated. In fact, because these were guys working on the shop floor in their dealerships every day they always had something interesting to discuss during tea breaks/lunch times/etc. I found they always knew something I didn't.

I've actually seen a link pipe specifically for refilling from larger bottles, usually mig gasses - especially CO2. I've never seen it done though and with pressures as extreme as these I don't think I'd want to have any truck with it myself.

Dissolved Acetylene? Yes I learned very early on about that and how a new cylinder should not be used unless it's stood up for a while to let the Acetone settle away from the valve. - Can't remember how long the recommended time is? I seem to remember that there's also a maximum "draw" rate before the acetone starts to bubble out, Probably only of interest to people using cutting torches or maybe if the bottle is part of a manifold supply system? I remember being absolutely horrified watching a torch being used in a scrap yard, probably in the late '60s when I was green behind the ears, with both cylinders lying separately on their side in the mud. I was too young and unsure of myself to say anything to the tattood bear of a man who was wielding the torch!

Cost? That was one of the main reasons I took up the evening classes. It enabled me to enjoy my hobbys and pay for quite a bit of annual holiday costs. I've only very occasionally made any charge for a job I've done at home. I prefer to build up a store of "good will" that I can call on later. This has worked well for me. even if I can't call the favour back in It wins such good will I value that more than the money.

All best wishes
Jock