Removing under coating

[panzerjunky]

Anyone have any ideas on how to remove the tar like undercoating from under the bed and inside the fenders as I am almost 100% positive paint will not stick to this stuff.
Just wondering if it would be best to just re undercoat the thing with some ruberized undercoating?
Thanks Jerry

 

[harry]

I would power wash and respray otherwise its scrap and chisle the old stuff off


Harry

 

[Oilleaker1]

Sandblasting would be a mess , expensive, and you have to protect wiring etc. Then you would have to paint and seal it. The best method is to warm it with a propane torch, ( not melt or burn it ) and scrape it off with a putty knife. Take your brain out and put it on a shelf. Do the miserable job. Put brain back in when done I'd paint it instead of undercoat. If you undercoat, don't buy the crappy canned rubberised stuff, it is worse than what you have now. They make good stuff called body shootz ( SP ?) that sprays on with a air nozzle that screws into cans. It dries hard and won't rub off on your hands. Good stuff. Talk to your local paint/auto parts guy.

 

[m16ty]

That stuff is a mess. I tried to remove some when I was welding on my bed for my dump conversion. Don't really know the best way to get it off to paint. I'm going to say it's going to take some sort of solvent to get it all off.

I'll tell you what not to do. Don't even try a wire wheel on a grinder. All it does is smear it and makes it worse than when you started. It also just clogs up the wire wheel and throws that gooey stuff all over you. I ended up heating it with a torch and scraping it (as said above) and got enough off of it to weld. There was still a little residue left though so I don't think it was clean enough to paint.

 

[wreckerman893]

No really good way to do it.....I had a Plymouth Duster that had that stuff on it.

Acetone will dry the petroleum out of the asphalt base and it can be scraped or wire brushed off....it will take a lot of acetone and patience....do it in a well ventilated area and remember that acetone is very flammable.

The best solution is the heat and scrape method (per above) and then use the acetone to remove the residue.

 

[HeadWizard]

I've owned an undercoating/rustproofing/etc business for more than 20 years. Unless you are into breathing solvents, scraping for many, many, many hours, and then still probably not being able to get paint to stick to whats left, DON"T BOTHER TRYING.

Probably best to powerwash away anything that's loose, scrape anything else loose, let it dry twice as long as you think it needs to dry, then have someone re-undercoat it with a professional product like you'd find at a body shop, car dealer, etc..

Just my .

 

[Ronbo]

Would airplane stripper work??? or put strippers to work !!nuk nuk But seriously I dont know if it will but sure removes paint right down to the metal and then wash t off !

 

[Gamagoat1]

A real steam cleaner works, the hotter the better. It melts the crap, and with a good soap additive it will leave no trace

 

[Chevyman_15237]

I'm in the process of restoring a '79 Chevy K10 that had a ton of undercoat on the frame and cab... the propane torch and putty knife work well; it will come off in big chunks. If you end up taking it down to bare metal, I suggest the Chassis Saver paint. About $35 a quart, works wonders on bare metal or a tight rusty surface............. WEAR GLOVES AND DON'T GET IT ON YOUR SKIN!

 

[panzerjunky]

Sandblasting would be a mess , expensive, and you have to protect wiring etc. Then you would have to paint and seal it. The best method is to warm it with a propane torch, ( not melt or burn it ) and scrape it off with a putty knife. Take your brain out and put it on a shelf. Do the miserable job. Put brain back in when done I'd paint it instead of undercoat. If you undercoat, don't buy the crappy canned rubberised stuff, it is worse than what you have now. They make good stuff called body shootz ( SP ?) that sprays on with a air nozzle that screws into cans. It dries hard and won't rub off on your hands. Good stuff. Talk to your local paint/auto parts guy.

Thanks Guy's
My 1st thought was to heat and scrape then being tar I was going to wipe down with mineral spirits and finally clean that mess up with acetone. But wasn't sure as to the possibility of making a roman candle out of the old deuce. and yes I did try the 4" grinder with a wire cup and i ended wearing tar chunks in my ears for a week. I have been scrapping and sanding with a healthy acetone wash got a couple areas clear and painted let dry a week and tried to scrape off the new paint it held well very hard to remove almost like stock paint. I would leave the under coat but it is horribly spotty none in some areas and 1/4 inch thick in others so we will see what happens.
Thanks Jerry

 

[mkcoen]

I know this is an old thread but...

I've spent most of the last 2 days removing what I thought was undercoating but now am more inclined to believe was road tar from the front end parts I'm going to replace on the wife's M37. Most of that time was simply with a putty knife then sanding what was left with a DA and 80 grit.

After yesterday's endeavor I decided to do a search and found this thread. I can confirm the heat/acetone combination (a little time between the open flame and acetone is best) works just as well on road tar (gasoline works too but can be REALLY messy).

The "well ventilated" work area is recommended as well. Otherwise you'll be accompanying Jim Stafford singing "take a trip and never leave the farm."

 

[x-ray]

A needle scaler may help. Guy on youtube shows how his cheap HF needle scaler removes undercoating from a VW.

 

[Akicita]

I have a thick coat of black undercoating on my Deuce, too. Does anyone know what that stuff actually is ? It is much thicker than any undercoating I've seen on cars over the years. They put it on "army strong". Mine is beginning to break and flake in a few small areas but it is still in good shape everywhere else. I live in PA where they use a lot of salt in the winter to keep the roads safer. For that reason, I'm glad to have it.

 

[mktopside]

Snap On used to sell a tool called the "Crud Thug" (they might still) that was specially designed to remove sound deadening and undercoating material from car bodies. It is also made by Wurth IIRC.

Back in my race car days, my partner and I would make our wives remove the sound deadening stuff from the cars, because it was a mindless job that they could do. It would take two of them about a week using a heat gun and a putty knife to do it. After picking up a crud thug, an entire car could be done in one night.

In my experience nothing works better.

It was an expensive tool, and someone eventually stole it from me.

However, when you take into account the opportunity cost of how long it would take you without this tool, it might actually save you money.

http://buy1.snapon.com/catalog/item.asp?saleType=All&group_ID=13078&Item_id=76499