removing undercoating

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moparmat2000

moparmat2000

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hi y'all

i am working on my 67 cuda restification, i plan on removing all the old undercoating from the body but most specifically in the wheel wells, i am going to strip, reprime, and repaint the undercarriage with dupont GM chassis black,

i plan on using a friends pressure pot sandblaster to clean the metal up with low pressure to reduce or prevent the metal from warping prior to repriming and repainting, but what i'm dealing with is chunks of undercoating. i have removed some of the factory stuff by warming it up with a bernsomatic torch, and scraping it with a paint scraper. is there an easier way, or do i just have to put the time in? plus theres a bunch of aftermarket undercoating sprayed in spots under the car. this stuff is uber nasty, and sticky, heating it up and scraping it wont work as heating it just makes it more liquid and sticky.

any ideas on removing this stuff

thanks
matt
 
I used a steam cleaner and took everything down to bare metal without hurting the factory zinc coating. It was messy but melted it off to a clean surface then I treated it inside and out with Rustbullit
 
I used my Harbor Freight heat gun with a scraper and an straight edge razor gasket scraper.
 
I faced the same dilemma as you last Fall. I used one of these on my project. I used it for all four wheel wells. I followed up (not finished) with naptha to get the last of it off. I used a 60 gal compressor and the air tank could recharge while it was being used (not a real high air volume pig). I think that the fron aprons took me about 1-1/2 hour each. I found mine on sale and thought I'd give it a try and it was slick. Another member referred to a multi-tool..........pretty much the same thing, but not electric. L8r

http://www.harborfreight.com/6-piece-pneumatic-scraper-kit-95826.html
 
The only undercoating I have ever removed was when I re-did my '68 GTX in 1981. It was in the dead of winter on LI when I did that part of the job in the wheelwells. I mostly used a flexible putty knife with a hammer. The undercoating mostly just chipped off.

Now that I am working on my '68 'Cuda in Texas, there is no hope of having that freezing weather way down here. I will have to resort to the heat gun, which I recently purchased el-cheapo at Harbor Freight tools for around $8 on sale.
 
I'm trying to figure the best way my self thinking of renting a high power pressure washer 1st see how well that works. I wouldn't sand blast I did that to a 86 Laser I put a 360 in sand was still coming out years later.
 
You need a hi pressure steam cleaner. Didn't have one and didn't want the mess it makes.
 
I used a hand held propane torch, leather gloves and some brass scrapers. It is pain in the butt! It comes off with heat easy, then I wiped it down with lacquer thinner. Cleans up easy with lacquer thinner.
 
SAND BLASTER , COST ME $30 IN SAND . TOOK ME A COUPLE OF WEEKENDS . DID THE ENGINE COMPARTMENT AND UNDERNEATH , WHEEL WELLS AND ALL. GETTING ALL THE SAND OUT AFTER IS KIND OF A PAIN BUT IT CAN BE DONE WITH AIR AND A VAC.. :glasses7:
 
Torch it 'til its crispy and then scrape it off with a putty knife.

Needless to say, BE CAREFUL if you use this method.
 
ok Y'all

heres what is did. i tried the bernsomatic torch and scraper on one front fenderwell side. it worked ok i did my main floor pan i took from my donor 74 dart before installing it about a year ago the same way so yes its messy, and a pain.

i also tried something else on the other fenderwell that works really well. you will need some butcher paper to put on the floor if you dont want your shop floor all messy, and use clothes you wont mind throwing in the trash once your done doing this job.

get a can of WD-40 and soak the undercoating really well. you may have to recoat it a few times over the 2 or 3 days you need to let it sit to loosen up the undercoating (i would let it sit a week). after that a good sharp paint scraper will take most of it off very easily. then i used some throwaway shop cloths and laquer thinner to remove the rest down to clean painted metal and some small steel wire brushes to clean up in the nooks and crannies. the laquer thinner will take some of the paint off too, but who cares since its getting stripped and repainted anyways. this is a little messier, but in a way easier than the torch and scraper method.

one fenderwell took me 6 hours of hard labour with torch and scraper, and is still not finished. the other fenderwell took me 2.5 hours with WD-40 and mild labour and is ready for a soap n water wash n dry before blasting

in the end i think i am going to strip the rest of the cars undercoating with WD-40, a scraper, wire brush, and laquer thinner with a rag. i will then clean everything up with power clean or simple green straight up and rinse with water, then i will let it all thoroughly dry in the west texas 103 degree heat, and start my sandblasting.

end result both methods really suck, but i think the WD-40 sucks less since your not grinding all that undercoat into breathable dust, so if your not in a hurry to git er done soak it with WD-40 and let it sit for about a week, spraying it down once a day and letting it sit. after you scrape it off the remainder will mostly come off with a rag soaked in laquer thinner.

so there it is 2 methods, each do work, i just think one works better.

hope this helps
matt
 
moparmat2000 said:
ok Y'all

heres what is did. i tried the bernsomatic torch and scraper on one front fenderwell side. it worked ok i did my main floor pan i took from my donor 74 dart before installing it about a year ago the same way so yes its messy, and a pain.

i also tried something else on the other fenderwell that works really well. you will need some butcher paper to put on the floor if you dont want your shop floor all messy, and use clothes you wont mind throwing in the trash once your done doing this job.

get a can of WD-40 and soak the undercoating really well. you may have to recoat it a few times over the 2 or 3 days you need to let it sit to loosen up the undercoating (i would let it sit a week). after that a good sharp paint scraper will take most of it off very easily. then i used some throwaway shop cloths and laquer thinner to remove the rest down to clean painted metal and some small steel wire brushes to clean up in the nooks and crannies. the laquer thinner will take some of the paint off too, but who cares since its getting stripped and repainted anyways. this is a little messier, but in a way easier than the torch and scraper method.

one fenderwell took me 6 hours of hard labour with torch and scraper, and is still not finished. the other fenderwell took me 2.5 hours with WD-40 and mild labour and is ready for a soap n water wash n dry before blasting

in the end i think i am going to strip the rest of the cars undercoating with WD-40, a scraper, wire brush, and laquer thinner with a rag. i will then clean everything up with power clean or simple green straight up and rinse with water, then i will let it all thoroughly dry in the west texas 103 degree heat, and start my sandblasting.

end result both methods really suck, but i think the WD-40 sucks less since your not grinding all that undercoat into breathable dust, so if your not in a hurry to git er done soak it with WD-40 and let it sit for about a week, spraying it down once a day and letting it sit. after you scrape it off the remainder will mostly come off with a rag soaked in laquer thinner.

so there it is 2 methods, each do work, i just think one works better.

hope this helps
matt
Click to expand...
Be sure to clean that WD with an aggressive cleaner before you start grinding/sanding. That "Penetrating Oil" will soak in and give you fits when its time to paint.
 
Thanks for the tip, moparmat. I'll give that a try first.
 
I used mineral spirits. Mineral spirits are pretty cheap. Get a good spray bottle, couple of scrapers, stiff brush, bunch of rags and cardboard or plastic for on the ground and have at it.
 
CUUDAK said:
Be sure to clean that WD with an aggressive cleaner before you start grinding/sanding. That "Penetrating Oil" will soak in and give you fits when its time to paint.
Click to expand...


i plan on using some castrol superclean straight up and a scrub brush before i use my buddies blaster to strip the rust and paint away, then rinse thoroughly with hot water and let it dry in the west texas sun for a day. the superclean stuff works great, but if you dont use rubber gloves it will strip a layer of skin of your hands. dont use it on anything aluminum since it is caustic and will start to eat away and discolor the metal.

matt
 
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