Epoxy as undercarriage and suspension final coat

E

Evil_Fiz

Promoted Users
crashtech said:
...Epoxy only will be the most chip resistant, and probably the most chemical resistant as well, once full cure is achieved.
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I plan to spray everything but the car's exterior in 3 - 4 coats of custom mixed ~25% Grey SPI epoxy, for visibility reasons, since I am visually impaired and night blind. The exterior will be Black SPI epoxy for sanding contrast. This is on an air-cooled VW and I plan to paint the chassis/pans and suspension in the same Grey. The car will not be completed for a few years.

Will SPI epoxy that cures for 2 -3 years be rugged enough to stand up to the underside and wheel well abuse? If not, what would be a suitable and durable topcoat, other than a tintable bedliner, that can be had in a light color?

Cheers,
Emil
 
I am not sure what you mean by "custom mixed -25%"?

I have used black epoxy mixed 1:1 with activator for frames, axles, control arms and other parts that are not exposed to direct sunlight for years now.

As an experiment, I painted the frame of a horse trailer with 2 coats of epoxy and after a couple of months I tried to scratch it with a screw driver. It was so tough and scratch resistant that I was amazed. Hence my using it on my signature car and many other projects.
 
'68 Coronet R/T said:
I am not sure what you mean by "custom mixed -25%"?

I have used black epoxy mixed 1:1 with activator for frames, axles, control arms and other parts that are not exposed to direct sunlight for years now.

As an experiment, I painted the frame of a horse trailer with 2 coats of epoxy and after a couple of months I tried to scratch it with a screw driver. It was so tough and scratch resistant that I was amazed. Hence my using it on my signature car and many other projects.
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Thanks for the feedback. It is what I was hoping for.
The "custom mix" will be, for example:
[3 parts white epoxy] + [1 part black epoxy] = 25% Grey
Once I achieve the desired shade of Grey I will mix the epoxy 1:1 with the activator.

I failed to ask in my original post, what is the chemical resistance of epoxy? Can it resist brake fluid?
I doubt it but it doesn't hurt to ask. I am mainly concerned about the area around the master cylinder since it is mounted directly to the chassis and is a known trouble spot on VWs.

-----
Emil
 
Evil_Fiz said:
This just keeps getting better. Now I just need to figure out a shade I can live with and spray it.

Thanks, guys
Emil
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Since time is on your side and you mention not painting for a few years--You might want to get a 24"x 24" so piece of sheet steel and do a spray-out both sides. Let it cure and slop brake fluid on it and put it outside in the sun with the brake fluid side down and the other side up to the weather. See what happens where you live for a year. Same with gasoline, saline solutions, greases, mild acids (vinegar etc....) etc................... Then place it on the dirt or earth where you live and see what happens on that side. Such a test will give you an idea of any soil minerals present where you live that might detract from the epoxy's ability to withstand staying on the test piece. That should give you your answer for the undercarriage of your VW where you live and what the finish is apt to look like in use on your car in a few years. My experience with sand abrasion with epoxies has been good.
 
D.A.T. said:
Since time is on your side and you mention not painting for a few years--You might want to get a 24"x 24" so piece of sheet steel and do a spray-out both sides.
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I was thinking of doing a test with just the brake fluid but I like your idea better. I have cutout pieces of OE VW sheet metal so I will blast and epoxy those and then do the tests you suggest. It may prove useful to others, and that lets me feel like I am contributing to the forum rather than just asking for help all the time.

Thanks,
Emil
 
If your braking system is going to be new, or if you want to flush out the old DOT fluid, you could use DOT 5 silicone.

DOT 5 does not harm paint.
 
Evil_Fiz said:
I was thinking of doing a test with just the brake fluid but I like your idea better. I have cutout pieces of OE VW sheet metal so I will blast and epoxy those and then do the tests you suggest. It may prove useful to others, and that lets me feel like I am contributing to the forum rather than just asking for help all the time.

Thanks,
Emil
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Maybe let the epoxy reach a full cure over a couple of months before starting the torture testing. Some time in the sun would be good too.
 
MJM said:
If your braking system is going to be new, or if you want to flush out the old DOT fluid, you could use DOT 5 silicone.

DOT 5 does not harm paint.
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I was reading up on that but have seen conflicting reports on pedal feel. Something that stood out was a comment on how DOT-5 is harder to bleed because it likes to hold on to air in the fluid. More research is needed but I like the idea. I plan on using all-new Wilwood front and rear disc kits so no issues with contamination.

dhutton01 said:
Maybe let the epoxy reach a full cure over a couple of months before starting the torture testing. Some time in the sun would be good too.
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Noted.
I'm thinking of duplicating the test pieces. One set kept outside but out of the sun and the other in the garage where the car will be stored. That way I can more closely replicate the possible conditions the epoxy would be subjected to.

Thanks again,
Emil
 
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