Undercoating removal

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1974Monstee

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I have a 1974 Duster what is the best way to remove all the undercoating so I can POR the underside?

Thank you
 
High powered pressure washer does the same thing but doesn't remove the factory paint.
 
The torch n scraper is the best way Ive found. I prefer the MAPP gas. Burns hotter than the propane. If Your gonna use the little bottles with the screw on nozzle.
 
Instead of a small torch I used a cheap heat gun from Harbor Freight. It only cost about $8. Then as said before a scraper, wire brush, straight edge razor scraper and some sort of solvent to clean the residue off.
 
jefflock said:
Instead of a small torch I used a cheap heat gun from Harbor Freight. It only cost about $8. Then as said before a scraper, wire brush, straight edge razor scraper and some sort of solvent to clean the residue off.
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That's what I use too, the undercoating catches fire pretty easy and being under a car with a torch is awkward, unless it's on a hoist.

challengergary said:
BTW - you only need to use POR-15 if there is actually rust present. It does basically nothing on clean/rust free metal.
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Exactly, I'm in the process of doing this as well and will be spraying epoxy primer followed by SS flat paint, no POR unless it's in tough to get to areas.
 
I used steam cleaner on mine. Took it down to bare metal without damaging the factory zinc coating. Messy but worked good without danger of fire from torch,Joe
 
This stuff works really well at stripping paint and undercoating. Just don't get it on your skin. I wear rubber gloves for handling chemicals and a face shield.
 

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I just remove it where loose and it pops off with a putty knife. Usually it detached from an impact. There is always surface rust where unbonded. I wire-brush or sand-blast (messy), getting into the solid undercoat a bit to get to clean metal. For combined clean and rusted metal, I like Rust Destroyer (quarts and spray cans). Good to 800 F so I use even near exhausts.
 
Yeah wire wheel takes forever...only did the front wheel wells and that took 2 plus hours each side and killed my wrists from the vibration
 
4spdcuda66 said:
This stuff works really well at stripping paint and undercoating. Just don't get it on your skin. I wear rubber gloves for handling chemicals and a face shield.
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I don't know about the rustoleum version but I doubt it's much different than the type I use. You need a good respirator and a well ventilated area, underneath your car isn't typically well ventilated, breathing that stuff is not a good plan. Read the tech sheet on it before you keel over and die :eek:ops:
 
I used an oxy-acetyline torch. There were areas where I got it hot enough to discolor the paint an the other side of the metal. If you're not repainting those areas, be careful.
 
If soda blasting is not available you can heat the undercoating with a heat gun and scrape most of it away then wirebrush the rest after you scraped everything.
 
Use propane just long enough to soften it. Remove with scraper. Go over quickly with torch again. Remaining residue will come off easily with light wire brush and I still had paint where it wasn't rusted
 
Propane torch and a putty knife, it comes off like butter. Pressure washer? It better be a SUPER Heavy duty one or it wont do anything. I tried that when I first got my 67, no go on the standard home style pressure washer on a CA Car anyway. East coast car where it is half coming off already different story.
 
1974Monstee said:
I have a 1974 Duster what is the best way to remove all the undercoating so I can POR the underside?

Thank you
Click to expand...

This worked for me.......In a well ventilated area with NO OPEN FLAMES OR OTHER IGNITION SOURCE, use a pump up weed sprayer to apply a coating of kerosene to the entire underside of car. do this twice a day for about 4 days. By then, most of the undercoating with be softened and literally hanging off the metal surfaces. Most of it can then be removed with a plastic scraper and the rest will wipe off with a rag doing little if any damage to the existing paint. To contain the mess and protect the garage floor, I placed plastic tarps under the car before starting.

Good Luck,

Russ
 
Everyone has their favorite method. It's a messy job no matter how you cut it. I used a propane torch to soften and scrape with a putty knife - just sweep up the chunks. It really doesn't take a lot of heat. A gallon of Goof-Off or other solvent will remove the residue.

Factory undercoat is not as volatile to an open flame as some make it sound. Aircraft strippers are expensive and equally messy. I'd save that for paint removal. And, if you've gotten lucky with power washing the stuff off - more power to ya.
 
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