What are necessities and options in painting on fiberglass?

[Roddy O'Dee]

Hello! Newbie here.

I am an artist and I want to do a painting on the side of a fiberglass camper/trailer. I have researched the basics enough to know about the required surface prep. So far I have a cleaner (SEM's Scuff & Clean) and primer (a "bumper primer": SEM's Flexible Primer Surfacer). Recommendations from my local auto paint supplier seem to indicate that any coating to be done on that primer must be urethane-based (paint and clear coat) and it must be sprayed on.

The type of painting that I'd like to do is one done with artist's brushes, using whatever brushable paint will work with the "bumper primer" -and- be compatible with a durable automotive clear coat. I had thought that my usual artistic medium-of-choice (artist's acrylic paint) would work between any primer and a urethane clear coat. But now I have my doubts. This is beyond the paint chemistry I learned 30 years ago in getting my fine arts degree.

Any comments on the details described above will be appreciated. Thanks.

[jdmccright]

Sounds like mostly good advice. A good cleaning and light scuff with fine grit paper would provide a clean, ahderent "canvas" for you to work on. Too coarse a paper or too much sanding can start to reveal the glass fibers, making them poke up from the surface and ruin your work. The prep sealer is a good step to help close up any tiny holes that may make your work bleed into the glass mat or cause surface defects.

I'll also agree with the the urethane-based paint since it has better flexibility and impact resistance than acrylics do. Fiberglass isn't as rigid as steel when going over bumps. But you should be able to find an urethane-based paint for pinstriping or similar that will have the flow and brushability that you need. If not, then a acrylic should be good as well. I would be careful about layering it on too thick...3-5 coats max to avoid checking and cracking from repeated exposure to the sun.

If you can go all enamel-based paint, then that is what I suggest. Lacquers are more prevalent because they are easier to paint with but not as durable. That's not to say you shouldn't use them at all. But if you must, you can use the lacquer for the artwork then top coat it with a clear enamel. But you can't mix the two for the artwork, nor use urethane for the art and topcoat with lacquer.

I would not suggest using artist's acrylic paint not for the fact that the acrylic isn't suitable, but for the unknown fact of how the pigments will react to the sunlight. Automotive paints use pigments and resins that are more resistant to the sun's UV (epoxies are the exception but they are typically protected by a topcoat). While the pigments in your paint may be durable indoors, they may fade, chalk, yellow, etc., when exposed to the sun. It also tends to be thicker...as mentioned before, you shouldn't apply paint too thick in this application.

Please post a pic of your finished work here. We'd love to see the outcome...and welcome to AF!

[Roddy O'Dee]

Thanks for the welcome and for the advice, jdm!

It seems that acrylics (applied thinly, as per my usual technique) could work here. The artist's acrylics colors that I plan to use will be colors with pigments that have the highest lightfastness ratings that I can find. This, of course, will result in a limited palette; but I planned on using a limited palette from the start so as not to make the artwork too garish.

A urethane clearcoat (preferably UV-blocking, if such a thing exists) should be compatible on top of acrylic, yes? I'd like to do some tests, but getting my hands on some scrap fiberglass at this time is more difficult than I thought. (The stuff seemed to be laying around all over the place when I was a kid.)

I'll post my chemistry results and a pic of the final art. - Thanks again!

[jdmccright]

While you may not be able to test colorfastness on a fiberglass substrate, you could at least set some test samples out in the sun on a similar plastic board. Test some with and without the topcoat and with multiple coats. Then mask half of each sample so that the sunlight is blocked yet will allow water drainage and drying...a strip of opaque plastic or sheet aluminum would do. For maximum exposure, tilt your test sample rack so that it faces the sun's track during the day....also helps with drainage.

I used to perform paint testing, hence the supposed extravagance of what I'm suggesting. But now with it being summer (actually past the peak), this is when the sun's light output is at it's maximum intensity and you're more apt to get quicker results.

Urethanes are fairly resistant to UV though not as well as acrylics. But on the flip side, urethanes have better flexibility and impact resistance. This is why I suggested urethanes when painting on a more flexible fiberglass substrate. I see no problem overcoating acrylic with urethane as long as you adhere to the curing/drying times. To be sure, you can test that as well. I for one would be curious of the results.

An alternative I just thought of, and this will probably sound blasphemous to an artist, would be to paint the artwork on a conventional substrate and then have it scanned in to be printed on an adhesive car wrap and simply apply it to the trailer. It would eliminate many of these worries you may have regarding paint choice, color limitations, prep work, and would also allow you to change it fairly easily if need be or wished to sell the trailer. The scanning and printing software can even take into account the ridges and curves of the trailer's side so that the artwork looks normal. The down side might be how large you want to go and its cost. It's a thought to ponder....

[wayne d. Moore]

Has anyone taken a beloved ck 1500 ext. cab and turned it into a 10,000 lb hauling and stopping machine preferably four wheel drive . We need to haul a Cris Craft Constellation cruiser that clams to have a dry weight of 5,600 lbs. No way! I would love to keep the truck but keep everyone safe!

[jdmccright]

Welcome to AF, Wayne!

Sorry, but this post should really be its own new thread. It's subject is completely different than the title.

That being said, you could try to modify your truck to be a beast hauler, but honestly, it would be very costly and there would be no guarantee that it would be capable of the monster towing rig you envision...it's only as strong as the weakest link.

The strength is in the frame. Thus, turning a 2wd base truck into 4wd stump puller would require a frame swap. I'd find a K3500 rolling chassis truck (dually) with axles and start there...though you'd probably find a used K3500 ext cab for not much more (you don't mention a year, but I'm guessing in the '88-'98 model year).

The dual rears are pretty much required for towing over 10k. Axles would likely be 4.10 ratio, best for big-time towing. And either a turbo diesel or big block engine. If you can find all that in one rolling chassis you've got a good start.

trying to piecemeal parts and welding reinforcements onto your existing frame would be futile...it's just not designed for that much hard work and very easy to miss a weakness.

Hope this helps!