The Stovebolt Site Forums The Shop Area Paint and Body Shop Tips on removing under coating

Looking for ideas on how to remove the under coating on my 54 3100. Its that nice thick tar like stuff up under the hood, fenders and under the cab. Any help is welcomed.

Hidiy deant54-

Is this "under coating" on your truck the commercially available chassis under coating similar to a line-x or Rust-Oleum product? Or is your "under coating" grease/oil/grime/engine residue? I understand your question, but I'm getting confused because I've heard the term used interchangeably.

A better way to ask: did somebody put it there on purpose, or is it 60 years of accumulated Stovebolt funk?

Either way, I would sandblast it off if I got to pick any method of removal. Glass beads as the blast media.

I'm right in the middle of cleaning up my 55.2 3100 frame, but I don't have the blasted media option. So, here's what all I've used (my enemy is 60 years of Stovebolt funk): pressure washer, strong laundry detergent, scrub brushes, a good USA-made paint scraper tool, various wire brushes, rifle chamber brushes, tooth brushes, Purple Power degreaser, more hose pipe water, baby bottle brushes, dish brushes, a wire cup brush on an angle grinder, and more spray degreaser... Rinsed, and repeated several times.

A big jar full of elbow grease probably helped the most.

If your hood is installed on your truck, and there's an engine still installed under it, use some caution as to what all you use chemical-wise. I have not tried my cleaning method on an assembled truck, but the principle is the same.

Hope this helps & have fun!
Brad

My guess is its plain old roofing tar.
Won't wash off...
Sand blast was only way I got the metal clean.
But it took forever to get thick layers off.
I waz able to get the worst off with a good dose of COLD weather to make the tar brittle and then using an assortment of scrapers and elbow grease chipped away at it till the majority was gone.
Then blasted what was left.
That was the "fastest" way I found.

Media blasting sounds like an interesting method. It all depends on what you want to achieve.
For me, I wanted to inspect the metal beneath my 1965 undercoating. I used a needle scaler in the corners where my grinder couldn't reach. The grinder with a Harbor Freight 4.5" poly carbide wheel took the majority of it off. I agree that cold weather will help it come off in chunks. Search YouTube and you will see people using needle scalers, grinders, oscillating saws and even dry ice. Nix the dry ice idea.
Check my Build thread in the signature below and look back a few months (Check archives 8/27/14 and newer) to see the results I got on my cab bottom. I cleaned off old undercoating, got the majority down to bare metal, primered and then sprayed on bed liner. I am very pleased with my results. It ain't perfection, but mine will be a daily driver.

Jay

Those electric oscillating multiple tools with the scraper blade attachment works well for this kind of work.
Carl

Eastwood sells an aerosol spray product that softens the undercoating, making it easy to remove with a scraper. It worked very well for me

Heat gun and a putty knife! Then use wax and grease remover.

It will work..................................................................................................................................................................................................................................................................................................eventually.

I can just see using the needle scalier (great on rust!) and a heat gun on the OP's "thick tar" problem now.
Maybe it could turn into some kind of new rat rod look...
A Car Tattoo.

Seriously though,
W&G remover doesn't work that well on tar.

Your better off if you use reducer to cut the tar and then clean up with W&G as normal.
And by 'better off' I mean one must be $pretty well off$ as well, to have enough money to use reducer (or the chem of your choice) to get an 1/8" of tar off the bottom of a cab.
And lots and lots of time.



Cold and a chipper of some kind (like 52Carl mentioned would work great if you had one) was the quickest/ easiest route I've found to remove the "old thick tar" undercoating I've come across.


Also as a word of caution: I strongly advise NOT to use a heat gun after applying Reducer to tar unless adequate Destructive Intent is being applied...

Thanks for the reply's Gents, looks like i have some options to choose from. It looks to me like it's factory undercoating, just lke 60 year old roofing tar. i don'thave the sand blasting option to try out so I'll give the heat gun chem method a try this weekend. I'll keep you all posted. thanks again, Dean

I used a degreaser or oven cleaner let that sit andwashed it off. That seamed to loosen up part of the funk. After that i used a putty knife and some heat like already stated above.

Enjoy the chipping!

If you are very careful, a pneumatic hammer with a chisel tip would work. VERY carefully. I use a 1-1/2" wide thick putty knife for this because I do not trust myself with the above.