General Removing underseal

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General Removing underseal

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Not a Stilo questione as such, but there may be some hoary old DIY mechanics on here who might have some experience, compared to the other forums which are full of girls or young blokes who don't know how to remove facial hair, never mind old underseal.

I'm currently cleaning up the under-floor of the Younger Mrs S's Cinquecento since it failed an MOT with some rusty chassis rails (now welded up). While I'm there (subframe out, fuel-tank out, brake lines out etc.) I decided it might be a good idea to repaint the whole underfloor and wheel arches etc. in a new shiny uniform yellow (n.b. the Cinq' is yellow ... but you probably guessed :D ).

The underbody Shutz coating is in good nick apart from the odd rusty patch which I've repaired.. but over the years and previous owners, the car has also acquired several areas (inner sills etc.) of underseal. I've poked about and it seems to be solid unerneath.. so it seems the underseal has been put on there as additional protection and done a good job. In other areas, it covers a rust blister or some other minor blemish... and I'm unpicking those and repairing them.

But the underseal is a) horrible b) not overpaintable and c) sticky.. so caught a load of dust and grit.

I want to remove it all, so I have either painted metal (body primer grey or yellow) or the rubbery Schutz stuff, which I can repaint in the shiny yellow.

What's the best way to remove underseal? Degreaser kind of works.. paraffin kind of works... but they don't shift it easily.. I have to scrub/agitate it with the missus' dish brush and apart from she notices when she uses it for the washing up, I get covered in underseal spatter and fumes. They also don't rinse off with water very well... (even the degreaser). I have to get detergent on it to lift it off the metal and that's just another faff, lying in the wet from having rinsed it, scrubbing it some more.

I've done about 1/4 of the rear floorpan (so about 1/8 of the rear area I want to clean up) and it's taking ages. What's a better way to do it?


Ralf S.
 
Other then get it soda blasted costly or sing heat not a good on anything other then a shell with nothing inside to burn you'd probably have to keep doing what your doing solvent and scrubbing
 
Is it original underseal you're trying to get rid off ?
Try supercold then, get some dry ice, place it on the spot you want to remove coating, wait 2-3 minutes and bang with hammer it's the easy wai of doing it .
Other option sandblasting , you can make a sandblaster yourself it doesn't cost that much , but you have to have a good compressor with good airflow.
Third and final option if other two is take a lot of cloth put it in the area where you want to remove the coating , spray petrol on top and wait a little.
I've used to do lor of reataurations few years ago and i find these three methods best for it ;)
Good luck mate ;)
 
I might give petrol a go. (y) When I removed the tank I had quite a few litres in there, so I filled up all the old fuel cans I could find with it.

The underseal I'm trying to remove is after-market black stuff. It looks like grease mixed with old oil when it's in the tin but it semi-dries out to be black and waxy. I've used it myself in the past, to cover up rust spots or scabs until I can get round to fixing it properly (some which I did and some which I never got round to).

On the Cinq' it's been applied to the inner sill panel (around the space where the petrol tank goes) and the area between the chassis rails and the spare wheel well. The sills get sprayed with road grime from the wheels, so it's probably a good idea to have it there (although I'm going to remove it, refurbish the surface, "primer" it with stone-chip paint and then paint it body colour). In the wheel well area, it just gets splashed, so it doesn't need the extra protection. It already has the factory rubber Schutz and I'm going to re-new the paint finish too.

The car is pretty much going to be semi-retired, not used as a daily driver any more, so it'll get wet more from being washed than being used. I can afford to have it clean underneath rather than being covered in an all-weather proof coating. It'll also be easier to see any new problem areas (e.g. the rear wheel arches, which is already a job for later).


Ralf S.
 
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