Technical Dreaded removal of old Undercoating.

I'm working on getting the underside of my 55 Bird cleaned up decent Not show quality but hopefully better. About 30 years ago I removed all of it from just the wheel wells. Then I had to have it plastic media blasted to get it cleaned up well enough for paint. At that time I use a butane torch and a putty knife. Worst job ever. And pretty damn dangerous as well. Fires yaknow, and not to mention one can burn the paint on the good side.
Jump to 2023 and I'm 71 years into things and decide I need to do the rest of the underneath of my baby. Much better success and speed with an oscillating tool. I used a wood cutting blade on it and pushed it like a putty knife. It cuts right thru it and peels 1/8" to 1/4" heavy tar undercoating off. It also generates some heat which helps to get thru the heavy stuff. Not super fast but thorough. Then I clean it up with mineral spirits. If I don't try to get in any hurry, it works slow and sure. I don't have a hard deadline and no rotisserie. I just jack the car up high enough that I don't have to reach so far as the tool gets heavy pretty quick. I try to run about an 18" area and then walk away for awhile to not get burnt out. I checked into dry Ice blasting and it was 1000 bucks estimate to start, and I almost went for it. But I have more time than money (may!). Once I get it scrapped down I will take it to a truck wash to give it a final solvent wash and then a pressure wash. Then hopefully I can paint it myself and detail things out. Any other suggestions would be appreciated.



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Have you seen these scraper blades for your Sawzall? Work pretty dang good for a lot of things. I don't envy what you're into, pain in the royal sphincter lol

 

with a heat gun......don't know how many bags I filled......

 

Definitely not a expert, on my vehicle I pre-heated with a torch. Used a scrapper, and went back over with a wire wheel. At work we use a snap-on air operated scrapper which works well. Like previous stated though, I'm sure there are cheaper solutions out there, that do the same.

 

I like to use the heat method whenever possible. The oscillating tool left little marks in the steel whenever I tried it, a bit of heat and a clean scraper and I was able to scrape the metal off clean without leaving any marks.

I really only do it if it's an area that I have to do welding on. Factory applied undercoating, especially whatever they were using in the 50's, is really good at it's job of preserving the metal underneath. Unless it's failing/falling off in sheets, or I have to weld up the steel in that area, I prefer to just leave it alone.

 

That's such a nasty job. I just finished doing the underside of my '50 and not all that long ago the underside of the black '63 in my avatar, which was a real chore. It had an aftermarket rust-proofing all over the underside that was cracked and peeling and very thick where it was still stuck.

A job like that makes a person want to drink enough to forget the sore hands and the crap in your hair and eyes. Nasty job !!

 

I cleaned the underside of a 50 ford that had been undercoated when new, was not a easy job. Used a air chisel with a flat blade, then sanded smooth.

 

^^^. Yep, this is the bottom line I guess. One's face is right in the middle of it. I plan on getting some of the spray head socks. Already wearing a 3m respirator, welding cap and safety glasses for now. Still is barely enough. Also found I may as well take out my contact lenses, they don't get along with dust!
I forgot to mention, I'm not taking the car off the road, so this isn't going to be be a full-blown restoration project. I want to do what I can as I go along.
Thanks, for all the good advice.

 

THIS^^^^^^^^^^^^^^ is perfect! We used to have an attachment for our Watervleit planishing hammer that did this. The trick is not heat but COLD. Do it in the dead of winter or use canned cold.



You zap an area and hit it with the scraper. Most times the stuff flakes off leaving little to no residue

 

Yeah, I'm sure this is true. Makes it brittle. Still have to protect yourself from all the crap flying around. That is my main issue I think.
I'll have to check in to where I can get some of this to try. Would work on the dry ice principle.

 

I saw a thing online somewhere where the dude used dry ice and the thick undercoat just popped right off and left the metal clean as a whistle. You would have to turn your car upside down though. Mitch

 

With no carpet or sound deadening you can use crushed dry ice on the floor boards to get the under coating cold.

 

Arctic in January??

 

Dry Ice blasting. The only "clean" way I am aware of.

 

Yes, I've checked into Dry Ice blasting. Estimate was 1000 bucks minimum. I really like that process but don't want to dump that kind of money all at once.
If the car was upside down, I could do it easy!, in an afternoon. haha.
The single spray cans that have been mentioned would work I think but are 20-39 bucks a piece. Nearest dryce blaster is about 4.5 hours away.
I can do this just have to take my time and keep cleaning up the mess.

 

Dirty job, and really slow. But making progress. Definitely getting it all off. Although I've not reached the hard to get places yet. Contemplating removing the mufflers and pipes. (Ugh) and will remove the fuel tank. Which leads me down the path of replacing mufflers with a different style.

 

I highly recommend a 3M full face respirator. While the lens is rated to stop a shattered cut off wheel from piercing it, it give much more eye protection (and provides a much better full face seal) that the half-face respirators. It makes many less enjoyable jobs only slightly less enjoyable, but it also eliminates the need to wear separate safety glasses (in some situations), too.

 

HF hand-held needle scaler does a pretty good job.

 

These are all really good suggestions guys. Keep 'em comin.
In_The_Pink, I have checked into this very mask and will get it for when I get around to pressure washing everything. This and a waterproof disposable suit. This is going to get really messy.
283john I agree on the needle scaler, Would work best I think with the cold application too.
I spot painted an area of the frame and floor pan to try and see what colors are going to work for me. I am brushing on rustoleum semi-gloss on the frame and structure and using Rustoleum hammered gray on the pans. This is a black car and this seems to work without bringing to much attention to the flaws but still adding some more light underneath. I'll get some pics of how it looks soon. Pretty pleased all things considered.

 

did a 49 Dodge 20 years ago the old fashioned way , scrapping , wire wheel , paint thinner then Rustoleum red rusty metal primer, brushed on and still looks great today....

 

When I was working on Plan II, we cut out the rear floor section to alter the wheelbase, I cleaned the undercoating off that while it was apart. I used a propane torch and putty knife, then a rag dipped in gasoline to wipe off the remaining residue.



Then after it was welded back in, flipped the car on it's side and got rid of the rest of the undercoating.



The thing about it is that the undercoating was on there well, and did it's job, and was still doing it's job in most places. I removed it because I built a race car, and any extra weight needed to be removed. If I were building a "normal" car, I would have been happy to leave it in place.

 

Been there done that ! You haven't lived until you've done a couple full size Chevy wagons. This was 20 years with a cotton mask and safety glasses on. I don't miss those days.

 

Yes! Squirrel, if I only had my car flipped over! Got to do this on my back while still able drive it. I know, Definitely NOT ideal. Admittedly, this is an OCD thing of just trying to get things more presentable, fix some pinholes and patches without going whole hog show car. Most folks will never see it and sure won't care. I will. And someday when someone else gets this car they MAY appreciate it.

Yup, Milwscruffy, I know this guy.

 

Why not look on facebook for a used Carbon Dioxide tank or rent one for a month? Then lots of the cold stuff that you can freeze the undercoating with.

 

ekimneirbo, I'll give it a shot. Altho so far I haven't had any luck finding anything that is affordable and or anywhere near convenient. Not to mention I'm getting closer to the hard part being done.
Again it's the hard to reach parts that are making it tough now.
Thanks for your suggestion!

 

We have a rotisserie so it makes the job easier. Use a squirt bottle filled with gasoline and burn till coating starts to bubble, scrape and sand blast with fine sand. Gas will burn at a constant temperature while a torch can overheat areas. Diesel burns too hot. One CAN NOT burn where heat is trapped; like the underside of a fender when car is right side up. Pics of a 55 Nomad floor pan.

 

FYI, Here's what I am running into with Liquid Nitrogen and Carbon Dioixde. First issue is I have to own a cylinder and I can't seem to find one to buy or rent in a convenient size. Full-size truck sure. Then I have to sign a waver since both are extremely hazardous to use. Those hand held spray cans are still an option gonna go grab a couple to test.

 

Coilover, yep that definitely gets the job done. I just don't have access to those facilities now. And if I did I don't have my car apart.

So, today Picked up the only remaining can of FREEZE-off at a local shop. 10 ounces for just a tad over 36 bucks! Well, It worked just about like you said Tman. But, with only 10 ounces I was only able to get about 15" of panel done. Fell off clean like glass in a 3" pieces! If I could only get my hands on some liquid nitrogen it would really come off clean and easy. I need a Hamb member who is a dermatologist.

 

Rotisserie is the best way. Frame off and nothing in the way but you still want to drive it. I have used all above mentioned and all work but none are easy and clean when you are on your back under it. In the one picture I see some rust pinholes. Do you plan to repair them by cutting them out and repairing or were they overlayed from the opposite side?