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heavy oxidization gelcoat
Posted by Keith Boyer
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heavy oxidization gelcoat March 22, 2005 11:57AM |
Registered: 17 years ago Posts: 141 |
<HTML>I have come acroos a few boats that are mid to late eighties, mostly carvers and the type, that have heavy oxidation from a lack of proper care. I have been using 3M's one step gelcoat compound in the one gallon can. I apply with a high speed buffer with a singel strand wool pad until it falshes off. One of two things happens either it rains a few days later or we get a really heavy dew and the boat looks the same as it did the day before i detailed it. Or if I use a sealant or wax the same thing happens the gelcoat just immediately goes back to that chalky look and feel. Is the gelcoat beyond repair or would I have to look at wet sanding a boat to remove all the oxdization? Any suggestions or product recommendations? Brian does your manual cover this subject? This is the one thing that is holding me up in boats. Thanks.</HTML>
Keith
Details on Demand Inc.
Mobile Auto and Boat Detailing
Keith
Details on Demand Inc.
Mobile Auto and Boat Detailing
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Re: heavy oxidization gelcoat March 22, 2005 04:10PM |
Registered: 17 years ago Posts: 641 |
<HTML>Keith,
The indications, following the finishing of the work, are this.
1. The oxidized gel was never completely removed in the compounding process.
Or
2. The gel coat is so serverly compromised by UV degradation that there is very little of the actual "film former/binder" portion of the resin system left.
Once this most important part of the gel is attacked or removed, you are dealing with a "sponge", and as you know, it is not possible to produce a long term gloss on a sponge.
Normal industry standards for gelcoat application in the tooling mold is 16 to 20 mils wet, which then compacts as it cures down to 12 to 15 mils of hard, cured gelcoat.
The top portion, (that which one sees) of the gelcoat, is the dense portion, for as stated earlier, a sponge will not shine, one must have density to have gloss.
The dense portion is usually 5 to 6 mils of the total gelcoat cured film build.
Below that, is the "sponge", must the same as shown on our website, of the modern clearcoat paint system, highly magnified cross section.
In my years of experience of dealing with the FRP industry, gelcoats, etc, I have to give you the bad news.
The only way a long term gloss may be attained is through the use of the special "gelcoat" paints available for marine use.
Ketch</HTML>
Do it right or don't do it at all!
The indications, following the finishing of the work, are this.
1. The oxidized gel was never completely removed in the compounding process.
Or
2. The gel coat is so serverly compromised by UV degradation that there is very little of the actual "film former/binder" portion of the resin system left.
Once this most important part of the gel is attacked or removed, you are dealing with a "sponge", and as you know, it is not possible to produce a long term gloss on a sponge.
Normal industry standards for gelcoat application in the tooling mold is 16 to 20 mils wet, which then compacts as it cures down to 12 to 15 mils of hard, cured gelcoat.
The top portion, (that which one sees) of the gelcoat, is the dense portion, for as stated earlier, a sponge will not shine, one must have density to have gloss.
The dense portion is usually 5 to 6 mils of the total gelcoat cured film build.
Below that, is the "sponge", must the same as shown on our website, of the modern clearcoat paint system, highly magnified cross section.
In my years of experience of dealing with the FRP industry, gelcoats, etc, I have to give you the bad news.
The only way a long term gloss may be attained is through the use of the special "gelcoat" paints available for marine use.
Ketch</HTML>
Do it right or don't do it at all!
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Re: heavy oxidization gelcoat March 22, 2005 06:52PM |
Registered: 17 years ago Posts: 1,838 |
<HTML>Keith,
Couple questions first:
Does the compounding and polishing produce a glossy clean shine when done? Usually if you're in the sponge layer like Ron stated, the gel's color show a tint of yellow or beige and won't produce a gloss -- but more of a blotch look.
If the boat is still chalky then enough oxidized gel wasn't removed. After long research on gelcoats I learned that waxing on top of oxidiation -- even just a little -- can create more damage since you're sealing in the problem rather than fixing it.
I have noticed that older (mid-80s) Carvers and Jeffersons oxidize within weeks after a complete oxidation removal, polishing and sealant.
It could be a number of things and hopefully we can help you out. My manual covers this problem but the worst case scenario fix only lasts a year.
Do you know how to wet-sand?</HTML>
Take care,
Brian
Precision Auto & Marine
Learn to detail boats! Visit www.detailtheboat.com
Couple questions first:
Does the compounding and polishing produce a glossy clean shine when done? Usually if you're in the sponge layer like Ron stated, the gel's color show a tint of yellow or beige and won't produce a gloss -- but more of a blotch look.
If the boat is still chalky then enough oxidized gel wasn't removed. After long research on gelcoats I learned that waxing on top of oxidiation -- even just a little -- can create more damage since you're sealing in the problem rather than fixing it.
I have noticed that older (mid-80s) Carvers and Jeffersons oxidize within weeks after a complete oxidation removal, polishing and sealant.
It could be a number of things and hopefully we can help you out. My manual covers this problem but the worst case scenario fix only lasts a year.
Do you know how to wet-sand?</HTML>
Take care,
Brian
Precision Auto & Marine
Learn to detail boats! Visit www.detailtheboat.com
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Re: heavy oxidization gelcoat March 22, 2005 08:22PM |
Registered: 17 years ago Posts: 641 |
<HTML>Another item to consider, but hard to determine, is what was the grade of the gelcoat?
Some boat manufacturers, chose to go with the best price for gel.
Quality gelcoat cost about the same, no matter who supplies it.
Cheaper gel's are loaded with styrene, IE, why it costs less.
Gelcoats with high percentages of styrene, tend to do two things, one the white turns yellow, and no buffing is going to change that, two, the gel oxidizes very quickly and loses it's density.
Ketch</HTML>
Do it right or don't do it at all!
Some boat manufacturers, chose to go with the best price for gel.
Quality gelcoat cost about the same, no matter who supplies it.
Cheaper gel's are loaded with styrene, IE, why it costs less.
Gelcoats with high percentages of styrene, tend to do two things, one the white turns yellow, and no buffing is going to change that, two, the gel oxidizes very quickly and loses it's density.
Ketch</HTML>
Do it right or don't do it at all!
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Re: heavy oxidization gelcoat March 23, 2005 04:59AM |
Registered: 17 years ago Posts: 141 |
<HTML>Brain and Ketch thanks for the insight. Those dmaned Carvers just seem to be oxidation monsters. One thing I have used in the past is a product from Star_Brite called Glas-Cote it's an acrylic that goes on with a sponge it also last about a year. Techincally when I use this per the instructions I have grat result with a long lasting shine that last about a year as well. I feel like Iam 'cheating'somehow when i use this product but hey my customers like it. And yes Brain thanks to the good folks at Paint Bull and my local marina customers I have learned the fine art of wet sanding. Thanks again if your e book is available on your web site I'll buy ti today, thanks again!</HTML>
Keith
Details on Demand Inc.
Mobile Auto and Boat Detailing
Keith
Details on Demand Inc.
Mobile Auto and Boat Detailing
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