Getting undercoat off fiberglass.

[Jeff K]

I want to get rid of the undercoat from the bottom rails and wheel wells.

I know the procedure for the frame, but some of the chemicals (and needle scaler) can hurt fiberglass.

Any suggestions?

Thanks
Jeff

[sdg3205]

I want to get rid of the undercoat from the bottom rails and wheel wells.

I know the procedure for the frame, but some of the chemicals (and needle scaler) can hurt fiberglass.

Any suggestions?

Thanks
Jeff

The lame, ugly, sticky black stuff? Could you post a how to on this when you're done Jeff? I'm sure it's not rocket science but I'd like to do it right without damaging anything.

[Patrick C]

Try lacquer thinner on a rag.

[Jeff K]

I tried Acetone, that is a product people use on boats with gel-coat. It seems like a tiny bit flakes off each time. So slow.

Maybe I will just re-coat with a rubber undercoat. At least it will match and look new.

[David T]

Go over to Eastwood.com. They sell an aerosol can of stuff that softens and loosens undercoating and is not as dangerous as Lacquer thinner. I agree you have to be careful with what mechanical methods you use so as not to damage the fiberglass.
David Teitelbaum

[sdg3205]

Damn, I just got an order from Eastwood last week. Ill check it out!

[DMC5180]

I'm fairly sure most of the old under coatings are a TAR like petroleum base. I would think Mineral spirits and hard plastic scrapers would get the stuff off.

[john 05141]

That will be an impossible job to do. You'll need some machinery. But even if you "damage the surface"of the fibreglass, you can add a new layer of fibreglass over the old one, and than add a new layer of rubber as a protection.
If you have scraped the bottom before that would be wide to do. If the underside is still intact I'd just add a new layer of rubber undercoat.
I have some cracks in the rubber layer only, but it does not bother me and it is hard to see anyway.

I'd like to see pics of that if you will do this.
Jan

[David T]

There is a pneumatic tool with a belt that has long finger-like scrapers to chip off the old, hard undercoating. It is meant to be used on metal frames, it would damage the fiberglass. The aerosol Eastwood sells soaks in and softens the old undercoating so you can scrape it off. Old undercoating can get rock hard and difficult to remove. Gasoline also works well but is very flammable. Even the stuff from Eastwood is dangerous so you should take the standard precautions, eye, face, skin protection, a fire extinguisher nearby, a fan for ventilation. Keep the fire extinguisher nearby in the path you would take to escape a fire, not right next to where you would expect a fire to occur. It would do you no good if you had a fire and the fire extinguisher was right in the middle if it!
David Teitelbaum

[painterdave72]

I just used lacquer thinner on my wheel wells and it takes it right off.. most of it flakes off now because it is so old...lacquer thinner does not hurt cured fiberglass.if you want to shine it up after just use some sort of armor all like product in the wheel wells. it looks nice and clean when done..

[jawn101]

...if you want to shine it up after just use some sort of armor all like product in the wheel wells. it looks nice and clean when done..

Scrubbing Bubbles!! If there is a single member on here who hasn't tried this on their fiberglass yet they are crazy.

Either this stuff: http://www.scrubbingbubbles.com/Products/Pages/Bathroom-Cleaner.aspx

Or this stuff: http://www.kaboomkaboom.com/products/kaboom-foam-tastic-fresh-scent.aspx

You will be amazed.

[Jeff K]

I just used lacquer thinner on my wheel wells and it takes it right off.. most of it flakes off now because it is so old...lacquer thinner does not hurt cured fiberglass.if you want to shine it up after just use some sort of armor all like product in the wheel wells. it looks nice and clean when done..

I'm going to try Thinner and Acetone this weekend. Maybe gently use a putty knife too. I especially want to clean up the bottom rails. They are pretty visible and from what I was able to do so far look good.

I was considering carefully putting a new rubber undercoat too. That should protect the fiberglass and maybe deaden a little sound.

[David T]

I would not put undercoating back. Only the '83's have it. It really isn't necessary for "protecting" the fiberglass and it just adds weight. As for sound deadening, you get better results with some kind of padding inside under the carpet.
David Teitelbaum

[john 05141]

I have a 81 and I indeed do not hink I have this rubber coating.
I have Dynamat, but the sound diverence is also 0, do not waist money on that.

Jan

[Jeff K]

Scrubbing Bubbles!! If there is a single member on here who hasn't tried this on their fiberglass yet they are crazy.

Either this stuff: http://www.scrubbingbubbles.com/Products/Pages/Bathroom-Cleaner.aspx

Or this stuff: http://www.kaboomkaboom.com/products/kaboom-foam-tastic-fresh-scent.aspx

You will be amazed.

Did that help actually remove undercoat Jon or clean the stock fiberglass real well?

Good idea too..

Jeff

[jawn101]

Did that help actually remove undercoat Jon or clean the stock fiberglass real well?

Good idea too..

Jeff

I didn't have the undercoat, thankfully - but it makes the black fiberglass look like a million bucks. Spray it on and let it do its work. Hose it off or wipe it down after it's completely turned white or vanished entirely and you will be shocked at how much filth comes off. Eats road grime and leaves the fiberglass clean and looking like it's supposed to. Even works on my textured pontoons!

FWIW, I did use it to remove the old carpet padding in the car. I just soaked the padding with the Kaboom version of this stuff and left it for a half hour. When I came back the whole mess just wiped out - glue, padding, cleanser and all.

[sdg3205]

I had lots of luck today using good old brake clean. Spray it on let it soak or a minute and it comes right off. Thicker spots need a scrub and I used an scouring pad similar to the ones we use for graining.

I did a rinse with simple green and a rag.

[Jeff K]

Ok, I can painfully remove the undercoating from the metal chassis, but the fiberglass won't budge.

I've used acetone, thinner and brake cleaner. Pretty much Zero!

I googled Marine barnacle cleaner... here is a link

http://www.auroramarine.com/aurora/catalog/algaestrip/index.php?cat=1

It's designed for Gelcoat. Algae Strip

Anyone try this or something similar?

Jeff

[Patrick C]

Ok, I can painfully remove the undercoating from the metal chassis, but the fiberglass won't budge.

I've used acetone, thinner and brake cleaner. Pretty much Zero!


I wonder if we are dealing with two different chemicals...undercoating should come right off with lacquer thinner or brake cleaner. If they used truck bed lining instead of undercoating, that is very difficult to remove.

[Jeff K]

I wonder if we are dealing with two different chemicals...undercoating should come right off with lacquer thinner or brake cleaner. If they used truck bed lining instead of undercoating, that is very difficult to remove.

That's a good guess and it makes sense. That stuff will barely flake off my fiberglass.

[bdmiko]

I know this is an old thread but thought I would add my 2 cents. WD-40 works as well as brake cleaner, if not better, for removing my undercoating. Bought a gallon of it and put it in a spray bottle. Thoroughly soaked down the undercoating and then scraped off with a plastic scraper. Once most of the undercoating was gone I wet it down again with WD-40 and then wiped clean with paper towels. As a final clean I used acetone to remove any lingering tar and WD-40 residue.

Worked on the frame too. Cheaper than brake cleaner and less carcinogenic.