Seeking Advice for Gelcoat Correction on Kit Car

[DaveBa]

I'm looking for some advice on my next project. It's a kit car from Classic Roadsters Inc, of Fargo ND, built in 1988. It is gelcoated fiberglass.

While the gelcoat is in decent condition (driven only in good weather, and garaged), there is significant oxidation on horizontal surfaces. Vertical panels have virtually no oxidation. There are swirl marks and scratches throughout, but none are deep. The worst damage seems to be some bird-bombs which were cleaned incorrectly, leaving dull spots. The color is dark blue.

For buffers, I have a Flex 3401 VRG, a Rupes mini LHR75E, and a GG6. I have a variety of foam, wool and microfiber pads.

I've been reviewing the Boating and RV forum sections. They're very helpful, but I still have a few specific questions.

First, should I buy Marine 31 Captain's Compound (which Mike Phillips recommends very highly)? I already have several aggressive compounds - Sonax CutMax, and Rupes Zephyr Coarse (with blue pads), plus M105 and Meg's Ultimate Compound. Would any of these do?

Second, is there any way to tell (or has anyone had experience with) how thick the gelcoat is? I assume it won't be as thick as on a boat, since they are subject to far tougher conditions.

Lastly, the client has yet to decide whether to go with a coating or a sealant. I typically apply either GTechniq Crystal Serum Light or Blackfire Wet Diamond. Will either of these suffice, or are there products more suited for gelcoat - - maybe a marine product?

Thanks,
Dave

 

[Mike PhillipsMike Phillips is verified member.]

Seeking Advice for Gelcoat Correction on Kit Car

I'm looking for some advice on my next project. It's a kit car from Classic Roadsters Inc, of Fargo ND, built in 1988. It is gelcoated fiberglass.

We need a picture! Sounds like a cool project.

While the gelcoat is in decent condition (driven only in good weather, and garaged), there is significant oxidation on horizontal surfaces. Vertical panels have virtually no oxidation. There are swirl marks and scratches throughout, but none are deep. The worst damage seems to be some bird-bombs which were cleaned incorrectly, leaving dull spots. The color is dark blue.

For buffers, I have a Flex 3401 VRG, a Rupes mini LHR75E, and a GG6. I have a variety of foam, wool and microfiber pads.

Pigmented Gel-coat likes HARD foam pads, not soft pads. In my boat detailing class we hold here once a year, we "polish" using either the FLEX 3401 or RUPES BigFoot 21 using the RUPES blue and green hard, sharp foam cutting pads with either the Marine 31 Captain's Compound or RUPES Diamond Ultra Fine Polish - just depends on how far we want to take the finish on the boat.

I've been reviewing the Boating and RV forum sections. They're very helpful,

I taught this class, processed these pictures and the results completely impress me.... (I didn't do the work though, my class did it)


Pictures: 2018 Boat Detailing Class at Autogeek with Mike Phillips

but I still have a few specific questions.

First, should I buy Marine 31 Captain's Compound (which Mike Phillips recommends very highly)? I already have several aggressive compounds - Sonax CutMax, and Rupes Zephyr Coarse (with blue pads), plus M105 and Meg's Ultimate Compound. Would any of these do?

I would think one of those would work very well on pigmented gel-coat. Wouldn't hurt to try. The RUPES Zephyr Coarse is like it says, very coarse but finished out like a polish. The SONAX CutMax uses great abrasive technology too, not as much initial cut as the RUPES (I think). The Megs UC is also a great compound, here's my article on this particular product, part of Car Wax History.

Meguiar's Ultimate Compound History

Second, is there any way to tell (or has anyone had experience with) how thick the gelcoat is? I assume it won't be as thick as on a boat, since they are subject to far tougher conditions.

If you can find a place where the gel-coat is "chipped" you can visually see the thickness of the layer of gel-coat. Besides that not really. From my experience, sprayed gel-coat is usually in a realm of 20 to 30 mils. Buffing through it would be my last worry... assuming you're working intelligently and you are.

Lastly, the client has yet to decide whether to go with a coating or a sealant. I typically apply either GTechniq Crystal Serum Light or Blackfire Wet Diamond.

Will either of these suffice, or are there products more suited for gelcoat - - maybe a marine product?

Thanks,
Dave

For the last 2 boat detailing classes we've been applying Gtechniq C1 Crystal Lacquer. Check out this recent article I wrote - I'm completely impressed.


BEFORE & AFTER - EXTREME Gelcoat Oxidation Removal + Ceramic Coating


Hope that helps... I have not tested the Crystal Serum Light on gel-coat which is a completely different material than car paint but I'm sure it would work. The key is always in the chemical stripping and I have lots of articles on this topic.

My boat class is a very good class, it always sells out.... just and fyi

 

[DaveBa]

Thanks for weighing in, Mike. This *IS* a cool project! I've been anticipating the arrival of this car for weeks!


Here are some pics...
View attachment 65118

View attachment 65119

View attachment 65120

View attachment 65121

After giving it a pretty good cleaning, I see that the first thing I need to do is to give it a more thorough cleaning! There are lots of crevices, angles and bolted on items that need more attention. I'll remove items where possible.

The work that your class did on those boats is great! I'll be glad if my work can come out close to that. Especially because the color on that Rinker looks close to what I'm working with!

Also, cleaning revealed a couple of spots where it looks like the owner used a gelcoat touch-up. (The original documents say it is provided.) These were not smoothed down, so it looks like I have some wet sanding to do, first. I'll definitely read up on that! (I've cleaned up headlights often enough, so I'm not completely unacquainted with the process.)

I'm glad to hear that I can use my existing supplies! Besides the Rupes, my pads are LC. I have three each of Force Hybrid gray and orange.

I have a couple more 'Q's.

Regarding your use of Rupes blue/green pads with ultra fine polish, do you mean that the class started with the UFP, or that you finished with it as the last of multiple steps?

Regarding your comment about the chemical stripping as prep for the coating, are there any chemicals that I shouldn't use on gelcoat? My usual steps for clearcoat are: Wash, Iron-X, rinse, Tar-X, Wash, Clay/Nanoskin, Wash, Correction, Wash, Panel Wipe coat/seal. Considering that gelcoat is porous, I'm sure more thorough rinsing is required.

The coating pics in your link look terrific! But is Gtechniq C1 significantly more difficult to apply than Crystal Serum Light? I chose CSL because it harder to make a mistake. But now that I have the technique for applying CSL, maybe I can work with the more professional (and more durable) product.

I agree with you about Meg's UC. I have gone to that more often than I thought I ever would, considering all the specialized products that are around! It far outperformed CutMax and Menzerna heavy cut 400 on a ridiculously heavy water spotted truck I did recently. I hadn't seen that article on UC.

Finally, Mike, Thank You for taking the time, and for making the considerable effort, to share what you learn with the rest of us. We're all the better for it! I've paid a lot of attention to your posts on techniques and how best to use products. For example, ever since I saw it, I've adopted your surface prep method of using Gtechniq Panel Wipe - especially the extra, 'insurance' step. It's not in the original directions, but it just makes sense. Why do all that prep work, and then fail right at the finish line?!

Dave