How to remove spray on sound deadener or undercoating

[rennie]

I've combed the forums and couldn't find anything specifically addressing removal of old, dried, and crusty SPRAY ON sound deadening (not adhesive mat)... the black, rough surfaced stuff, similar to this pic:

I saw the thread on cleaning an engine: https://www.thesamba.com/vw/forum/viewtopic.php?t=475553, but it doesn't mention removing the nightmare spray on material.

What started as a carb leak fix has lead to re-doing the fuel tank and possibly a freeway flyer... and while in there, why not try to scrape out the engine bay, which currently looks like below (spray on deadener on top of OG paint):

In the forums, these items were mentioned for paint removal: Citrus Strip, Easy Off, purple degreaser, gas on a rag, Simple Green, Lifter-1 Bug/Tar Remover, lacquer thinner, kerosene, etc.

Has anyone used any of these to successfully remove hardened, decades-old, crusty, black spray on sound deadener? …or know of any other affective method?

[jason]

I have used undercoater remover from FLAPS with ok success. The spray on paint remover works good also. Get it wet and let it sit, when it dries reapply. Comes right off.

[rennie]

Flap discs are a good thought but two things I should have mentioned are that the entire engine bay needs doing, and I'd like to preserve the OG paint if possible, though I may be dreaming. I think flap discs would destroy the OG paint right away.

[Hokie87]

Eastwood Pre works well, too. It takes some elbow grease and a lot of rags but won't hurt the paint underneath. http://www.eastwood.com/eastwood-pre-painting-prep.html

[nlorntson]

Warm an area up with a heat gun and use a plastic putty knife to get the big stuff off then one of the chemical products mentioned.

[rennie]

Thanks, will check out Eastwood, and heat is a good idea, too.

Rang two decent body shops today. They said they just use paint remover, but they aren't trying to preserve OG paint underneath.

I'll let you know results when/if I find something that works well.

[hitest]

[rennie]

About 3 hrs work (thick in places!). Support pillar is how clean it eventually comes and now serves as motivation to keep going. I'm committed to the long haul...

Bought/using a heat gun and plastic scrapers, which tend to heat up but need to stay cool for efficient scraping (no flexing).

2 sq ft done, 20 to go... I'll be the tortoise on this one, not the hare...

[oldbusboy]

I know some guys who have used cans of compressed air, the kind you use for blowing dust off electronic parts. This is for stock VW undercoating. I believe they inverse the can while spraying, or shake the can and by doing so the air that comes out is extremely cold. Once the area you spray becomes brittle you can use a very stiff plastic putty knife to start chipping away.

Worth a shot. The cans of air aren't expensive and there are no fumes unlike heating the tar with a heat gun.

https://www.amazon.ca/Emzone-Air-Duster-284g-10Oz-...ressed+air

Trevor
_________________
1968 porsche

[Erik G]

[rennie]

[BarryL]

[rennie]

[rennie]

Progress pics after about 19 hrs.

Using heat gun with firm plastic scrapers to get the bulk off, then reheating and wiping off excess residue with rags, then using clean rags with off-the-shelf acetone for the final clean up (decided not to by Eastwood PRE after I rang them and they said the California version has a very high acetone content... and I've learned straight acetone is working just fine). No luck with paint remover, and didn't want to risk using oven cleaner with OG paint preservation in mind.

Anything other than plastic or teflon scrapers (ie: bamboo/wood) scratches the nice OG paint hiding underneath. Some areas, like by the battery, have very hardened black deadener that heat doesn't affect. Using a metal 'wood chisel' there at a very careful/light pressure/consistent angle to slowly scrape it off without scratching the OG paint.

Cleaning the calked seams is tricky as the paint wants to come off more easily than paint on metal, but fine and focused light scraping and light rag wipes is working out okay. Sometimes I feel like I'm going at an archaeologist's pace!

I've come across no rusty areas, and still have fingers crossed on that front. My chosen method is slow going but it's coming along, and the hours of later enjoyment will far exceed the hours of work to remove this dreadful stuff.

I've almost got the other side done, too, and this weekend hope to move to the 'roof'...

[ronjonlasvegas]

Nice job. Keep at it. The area you have finished looks fantastic.

I am in the process of removing four layers of old paint off my DC so I know it is not easy. I also need to remove the spay bomb paint off my interior for all areas that will not be covered with panels. The prior owner used trunk splatter black paint on mine and it is not too bad to remove. I am really glad they did not use sound deadner.

I commend you on your patience and persistence.
_________________
September 1964 Standard Sunroof walk through SWR/BG original paint.

[rennie]

Thanks ronjon. I've seen your thread, which along with others helped inspire me to dive in and do it. Impressive how much you're doing to save your postal yellow!

Left side progress pic below, after about 23 hrs on that side.

Am having to scrape gently yet firmly with the chisel on the flat tray area... while using light heat so as not to soften the paint too much. The tar there has hardened to a crust and nothing penetrates the bulk well enough to scrape it off. Left side is taking more hours than the right.

Pic also shows the aft side wall and how clean it gets when reheating it after the bulk is removed and just using a rag without acetone. Lower on the sidewall, and tray, you can see where the acetone rag was used for final clean up... matching the forward sections. I'll detail out the seam calk and vents more later.

[BarryL]

Epic task you are tackling.

In retrospect it seems so ridiculous to have that stuff applied in there. Plus, imagine what the applier person looked like after that job. One good thing is it sure protected the original paint.

[rennie]

[motofly196]

You're pretty far into this project, but I also had to deal with the same thing on my Single Cab behind the seat and dash. What works great and doesn't harm the original paint....bug and tar remover. It literally MELTS the undercoating! If it's thick in areas, you might need to spray it a few times, but it was melting off as I was spraying on the bug and tar remover. Good stuff!

[Malokin Martin]

People have had relatively good success with an air needle sander. Never done it myself though. I think it may pock mark the paint though. One idea.