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Old 15-07-2011, 20:29   #1
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Restoring Old Gelcoat

Hi all,

We just completed a haul-out where we failed to get our gelcoat shiny with the buffer. I had expected that and we did the following procedure:

1 - acid wash with On & Off
2 - rinse
3 - wet sand with 2000 grit sand paper
4 - rinse
5 - machine buff using 3M rubbing compound
6 - repeat 5
7 - wash with Dawn dish-washing detergent to remove any wax residue
8 - bring on a single coat of RejeX

result:

The gelcoat looks like new again. RejeX is a polymer coating (with UV filters IIRC) from the same company that sells CorrosionX. I had used RejeX to coat Lexan windows since a couple of years and was impressed enough by that to import 2 gallons of the stuff from the USA. We only needed 0.5 gallon for the complete hull (64' but not very high freeboard)

The sanding is done until the color of the gelcoat turns bright white again.

The wash with Dawn (which is a base) is to remove wax so that the RejeX is put on the gelcoat instead of a wax layer.

This coating is expected to last 3-6 times as long as wax (3 times as long as top quality wax). It is much like AwlCare. Time will tell how it lasts but if it's anything like on Lexan, I will re-apply one coat every 6 months, hoping to stay ahead of UV damaging the gelcoat again.

ciao!
Nick.
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Old 15-07-2011, 21:02   #2
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Re: Restoring Old Gelcoat

I'm surprised that you got it to shine with the rubbing compound only, seems like without using a polishing compound it leaves a lot of swirl marks. Looks good.
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Old 15-07-2011, 21:08   #3
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Re: Restoring Old Gelcoat

Must have taken a long time if you hand wet-sanded your hull. I like to guide coat and then machine sand with 3M film. You can use it wet or dry.

3M
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Old 16-07-2011, 07:20   #4
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Re: Restoring Old Gelcoat

Quote:
Originally Posted by jrd22 View Post
I'm surprised that you got it to shine with the rubbing compound only, seems like without using a polishing compound it leaves a lot of swirl marks. Looks good.
I had the Finesse II to follow up the Super Duty rubbing compound but it wasn't needed. Last time I did a small gelcoat repair I went from 330 grit to rubbing compound and it looked great after that. I did use a polishing compound after that to see what happens... nothing. With gelcoat you can get away with things that aren't possible with a paint system

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Originally Posted by minaret View Post
Must have taken a long time if you hand wet-sanded your hull. I like to guide coat and then machine sand with 3M film. You can use it wet or dry.
I'm in Panama... effective procedures get replaced by cheap labour. I had 3 guys hand sand the complete hull in 7 hours at a cost of $210.- incl. materials.

Guide coat... believe me, I had one in the form of yellowed gelcoat

ciao!
Nick.
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Old 16-07-2011, 09:18   #5
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Re: Restoring Old Gelcoat

I have had Proguard+ applied to my hull. It is a polymer made by DuPont. They compound the hull first, wash it, then apply the polymer and buff it again. The hull looks like new at 8 years of age but it has a great gel coat to start with. Unfortunately, the appiliers are ony in Spain and Sint Maarten but the polymer can be bought for self application. It cost me about 1k for the application on a 60 ft boat.
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Old 16-07-2011, 09:22   #6
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Re: Restoring Old Gelcoat

Nice shine on that nice boat Jedi.
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Old 16-07-2011, 09:39   #7
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Re: Restoring Old Gelcoat

Curious. How many times can you do this before you actually need to repaint? This is good tip
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Old 16-07-2011, 10:44   #8
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Re: Restoring Old Gelcoat

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Originally Posted by speciald@ocens. View Post
[...]polymer made by DuPont. They compound the hull first, wash it, then apply the polymer and buff it again. The hull looks like new at 8 years of age but it has a great gel coat to start with.
That's the same process and a very similar product to what I used. Compounding wasn't enough for us, hence the wet sanding followed by double compound.

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Nice shine on that nice boat Jedi.
Thank you

Quote:
Originally Posted by SaltyMonkey View Post
Curious. How many times can you do this before you actually need to repaint? This is good tip
Watch out, this is gelcoat, not paint. Every time you polish or sand you take material away, so it's really a matter of how thick your gelcoat layer is and how much it's polished etc. I think my gelcoat is below standard and now, after 17 years of tropical sun, I see some fairing compound shining through the gelcoat in one spot. This is the first time the gelcoat is sanded but it has been compounded many times. Next time I need to paint the boat.

I would never re-gelcoat the boat... paint is so much nicer with virtually no maintenance compared to gelcoat. Remember that gelcoat is used because it's a cheap way for a hull that comes from a mold, not because it's the best way.

ciao!
Nick.
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Old 16-07-2011, 11:00   #9
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Re: Restoring Old Gelcoat

A friend of mine had his 15yo Taswell 49 re-gelcoated in Trinadad two winters ago. He said it was chaeaper than having it painted.
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Old 16-07-2011, 11:05   #10
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Re: Restoring Old Gelcoat

Jedi - yes...gel coat...thats my concern. What makes me nervous is not only the number of times you can perform this, but also over-compound or 'sanding'...or using cheap labour which might take off waaay too much.

Yikes!
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Old 16-07-2011, 11:32   #11
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Re: Restoring Old Gelcoat

Quote:
Originally Posted by speciald@ocens. View Post
A friend of mine had his 15yo Taswell 49 re-gelcoated in Trinadad two winters ago. He said it was chaeaper than having it painted.
Yes it is cheaper. The labour is cheaper because a paint system needs a much better job of fairing, meaning that a gelcoat boat that gets painted the first time needs significant fairing. Next thing is the gelcoat itself which is much cheaper than a high performance PU paint system.

But the difference is more than just price. I have seen two boats in Trini that got painted (one) and re-gelcoated (the other one). They both looked marvelous. A year later I saw both boats again in Grenada: the one with paint looked as beautiful as the day it got painted and the one with gelcoat looked like a boat that needs a good polish job.

Also, nasty stuff like soot from exhausts etc. you can just wash away from paint but it's a hell of a job to clean it off gelcoat. Optimal maintenance of gelcoat in the tropics means it needs to be waxed 4 times a year. Higher lattitudes 2 times a year. Paint? 0 times a year.

Quote:
Originally Posted by SaltyMonkey View Post
Jedi - yes...gel coat...thats my concern. What makes me nervous is not only the number of times you can perform this, but also over-compound or 'sanding'...or using cheap labour which might take off waaay too much.
Working with cheap labor is an art. Think of it as them being extra hands and muscles of you, you're the brain controlling it all. First, you need to know every detail of the work that must be done yourself. Second, you must show them how you want it done and explain every step in detail, when it's time to start doing that step (don't ever try to explain it all beforehand). While showing them how it's to be done, you grunt and spit and make it look tough while acting much the same as them. Third you must supervise them every second of the complete job. In this case I did other projects around the hull while keeping an eye on them and when I was done with that I started compounding the blue waterline that they were not allowed to touch (bring blue stuff onto white gelcoat and tools). You working besides them makes them respect you and that is more important than money to get a good job done... they don't get much money anyway.

ciao!
Nick.
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