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Author Topic:   gel coat

ron3637 posted 02-01-2003 11:23 PM ET (US)
How thick is the gel coat on a whaler. and can it be reapplied if it has ben heavily sanded? thanks
j_h_nimrod posted 02-01-2003 11:34 PM ET (US)
The gel coat is only a few thousandths of an inch thick and yes, it can be re-applied. Re-application is fairly technical and (for best restuts!)should only be done by a knowledgeable person. If you are a mechanical minded person there is enough information on this site to do the job right.
ron3637 posted 02-01-2003 11:47 PM ET (US)
What is below the gel coat, and how thick is it? thanks
j_h_nimrod posted 02-02-2003 12:35 AM ET (US)
The thickness of the material varies and I really do not know what it is. It seems like a Bondo type material that seems to be thickest at the hard corners, but I have seen this to not hold true all the time. If anyone here can shed light on this I would be interested to know too.
j_h_nimrod posted 02-02-2003 01:56 AM ET (US)
Maybe the material is actually a very thick layer of gel coat? I know BW sprays the inside of the boat mold with gel coat and then chopper gun glass so maybe their gel coat is thicker...
T Party posted 02-02-2003 07:39 AM ET (US)
Below the gelcoat is the fiberglass.
I have some peeling paint on the bottom of my boat. I had the bright idea of knocking it off with a pressure washer. Mistake. Using the ultra-high pressure nozzle (1850psi), I managed to damage the gelcoat - little chips came off. I stopped using that nozzle and switched to one that's no so high-pressure and finished the job. My question now is whether I must repair the gelcoat damage.
The damaged area is below the waterline, and will be painted. There will be paint there for the rest of this boat's life. I will be using a high-quality non-ablative anti-fouling bottom paint (black).
Will the paint protect the fiberglass properly or should I repair the gelcoat before applying the new bottom paint?
JOHN W MAYO posted 02-02-2003 09:02 AM ET (US)
First, I am ...no expert in this area, I will tell you what I did on my Whaler. A boat repair shop told me the fiberglass would absorb water if i did not repair the gel coat that was slightly damaged on my keel from loading on a trailer. I used MARINE TEX to fill the area's the gel coat had been knocked off of. After several thin aplications, sanding it smooth, it looks pretty good. The color is white, just a little lighter than the whaler color. When you sand the Marine Tex is much hard than the gel coat and it is easy to sand throught the gel coat.
jimh posted 02-02-2003 09:50 AM ET (US)
As seen in their catalogue photographs, Boston Whaler finishes their mold surfaces with strong contrasting colors, like bright red. When the white, gray, or tan gelcoat is sprayed into the mold, the operator probably judges the thickness of the gel coat by how well it covers the contrasting color of the mold.
The strong color contrast helps the operator to see where he has sprayed the new gelcoat, making sure he gets good coverage.
I don't know how, other than operator skill and experience, the thickness of the gel coat could be measured while it is being applied.
I think the gel coat layer is typically about 0.020 thick. This is thick enough that small scratches and imperfections can be sanded out and the surface buffed to a smooth gloss.
You can always reapply gelcoat. See Taylor Clark's excellent article in the REFERENCE section.
http://continuouswave.com/whaler/reference/whalerRepair.html
ron3637 posted 02-02-2003 11:21 AM ET (US)
After reading Mr.clark's excellent article on fiberglass repair, i am amazed that any shop can properly repair a damaged whaler. It strikes me that no shop would take the time and effort to properly do the repair as described in Tom Clark's article. comments?
Tom W Clark posted 02-02-2003 12:38 PM ET (US)
Gel coat is typically applied in a thickness of 15 to 22 mils in boat construction. I do not know what the exact specification is for Whaler hulls but jimh's figure of 20 mils sounds about right. The thickness of gel coat can be monitored during its application with a tool called a "mil gauge" or something like that. I am not sure how it works.
Beneath the gel coat is the fiberglass, plain and simple. In smaller Whaler hulls, the fiberglass thickness is about 1/8" with the thickness increasing at the keel or chine to as much as 5/16". I suspect the larger hulls get a proportionately thicker lay up schedule but I have never cut a large Whaler hull up before so I do not know first hand.
Gel coat is easy to repair if the area is small. There is no magic involved. Any patient and diligent person can make a hull look good as new if you follow the repair instructions as can any fiberglass repair shop.
The repair article described above is Taylor�s, not mine.
jimh posted 02-02-2003 02:05 PM ET (US)
Well, ron3736, when I have peaked inside an old- fashioned mechanical wristwatch, I wonder how anyone could have ever put one together, too. I guess it is a good thing there are skilled people left around who can do something other than type on computer keyboards!
andygere posted 02-03-2003 06:55 PM ET (US)
Repairing a fiberglass boat like a Boston Whaler is not a lot different than doing bodywork on a car or fixing a ding in a surfboard. The materials are different and so are some of the tools, but the techniques are more or less the same. Wrecked cars are made to look like new every day, and even broken surfboards are restored, so I suppose there must be some folks out there with the skill and know-how to properly repair damaged boats as well.
ron3637 posted 02-03-2003 11:21 PM ET (US)
It appears from what i have read on this board that a whaler's construction would not lend itself to standard repair techniques. Rather it appears that a much more skillful and labor intensive proces is required.
j_h_nimrod posted 02-04-2003 02:15 AM ET (US)
In my previous post(s) I mentioned a material under the gel coat on top of the glass. From the answers this material is probably just a thick gel coat. I have used an 1983 classic commercial hull that has a few very deep (~1/8") gouges in the gel coat on the gunnels and other places on the chines where the gel coat has been chipped off exposing the glass. In both cases the gel coat is very thick, being about 125 mils. Is this just a typical variation in gel coat or have others seen this in their boats?
kingfish posted 02-04-2003 08:24 AM ET (US)
ron3637-
Fiberglass repair is fiberglass repair for the most part. If there is a need for structural repair blow the fiberglass on a Whaler, there are some considerations that are different from most other boats on occasion, but so far as surface repair is concerned, if the shop can do a good job on other boats, they can do a good job on a Whaler.
kingfish

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Author	Topic: gel coat
ron3637	posted 02-01-2003 11:23 PM ET (US) How thick is the gel coat on a whaler. and can it be reapplied if it has ben heavily sanded? thanks
j_h_nimrod	posted 02-01-2003 11:34 PM ET (US) The gel coat is only a few thousandths of an inch thick and yes, it can be re-applied. Re-application is fairly technical and (for best restuts!)should only be done by a knowledgeable person. If you are a mechanical minded person there is enough information on this site to do the job right.
ron3637	posted 02-01-2003 11:47 PM ET (US) What is below the gel coat, and how thick is it? thanks
j_h_nimrod	posted 02-02-2003 12:35 AM ET (US) The thickness of the material varies and I really do not know what it is. It seems like a Bondo type material that seems to be thickest at the hard corners, but I have seen this to not hold true all the time. If anyone here can shed light on this I would be interested to know too.
j_h_nimrod	posted 02-02-2003 01:56 AM ET (US) Maybe the material is actually a very thick layer of gel coat? I know BW sprays the inside of the boat mold with gel coat and then chopper gun glass so maybe their gel coat is thicker...
T Party	posted 02-02-2003 07:39 AM ET (US) Below the gelcoat is the fiberglass. I have some peeling paint on the bottom of my boat. I had the bright idea of knocking it off with a pressure washer. Mistake. Using the ultra-high pressure nozzle (1850psi), I managed to damage the gelcoat - little chips came off. I stopped using that nozzle and switched to one that's no so high-pressure and finished the job. My question now is whether I must repair the gelcoat damage. The damaged area is below the waterline, and will be painted. There will be paint there for the rest of this boat's life. I will be using a high-quality non-ablative anti-fouling bottom paint (black). Will the paint protect the fiberglass properly or should I repair the gelcoat before applying the new bottom paint?
JOHN W MAYO	posted 02-02-2003 09:02 AM ET (US) First, I am ...no expert in this area, I will tell you what I did on my Whaler. A boat repair shop told me the fiberglass would absorb water if i did not repair the gel coat that was slightly damaged on my keel from loading on a trailer. I used MARINE TEX to fill the area's the gel coat had been knocked off of. After several thin aplications, sanding it smooth, it looks pretty good. The color is white, just a little lighter than the whaler color. When you sand the Marine Tex is much hard than the gel coat and it is easy to sand throught the gel coat.
jimh	posted 02-02-2003 09:50 AM ET (US) As seen in their catalogue photographs, Boston Whaler finishes their mold surfaces with strong contrasting colors, like bright red. When the white, gray, or tan gelcoat is sprayed into the mold, the operator probably judges the thickness of the gel coat by how well it covers the contrasting color of the mold. The strong color contrast helps the operator to see where he has sprayed the new gelcoat, making sure he gets good coverage. I don't know how, other than operator skill and experience, the thickness of the gel coat could be measured while it is being applied. I think the gel coat layer is typically about 0.020 thick. This is thick enough that small scratches and imperfections can be sanded out and the surface buffed to a smooth gloss. You can always reapply gelcoat. See Taylor Clark's excellent article in the REFERENCE section. http://continuouswave.com/whaler/reference/whalerRepair.html
ron3637	posted 02-02-2003 11:21 AM ET (US) After reading Mr.clark's excellent article on fiberglass repair, i am amazed that any shop can properly repair a damaged whaler. It strikes me that no shop would take the time and effort to properly do the repair as described in Tom Clark's article. comments?
Tom W Clark	posted 02-02-2003 12:38 PM ET (US) Gel coat is typically applied in a thickness of 15 to 22 mils in boat construction. I do not know what the exact specification is for Whaler hulls but jimh's figure of 20 mils sounds about right. The thickness of gel coat can be monitored during its application with a tool called a "mil gauge" or something like that. I am not sure how it works. Beneath the gel coat is the fiberglass, plain and simple. In smaller Whaler hulls, the fiberglass thickness is about 1/8" with the thickness increasing at the keel or chine to as much as 5/16". I suspect the larger hulls get a proportionately thicker lay up schedule but I have never cut a large Whaler hull up before so I do not know first hand. Gel coat is easy to repair if the area is small. There is no magic involved. Any patient and diligent person can make a hull look good as new if you follow the repair instructions as can any fiberglass repair shop. The repair article described above is Taylor�s, not mine.
jimh	posted 02-02-2003 02:05 PM ET (US) Well, ron3736, when I have peaked inside an old- fashioned mechanical wristwatch, I wonder how anyone could have ever put one together, too. I guess it is a good thing there are skilled people left around who can do something other than type on computer keyboards!
andygere	posted 02-03-2003 06:55 PM ET (US) Repairing a fiberglass boat like a Boston Whaler is not a lot different than doing bodywork on a car or fixing a ding in a surfboard. The materials are different and so are some of the tools, but the techniques are more or less the same. Wrecked cars are made to look like new every day, and even broken surfboards are restored, so I suppose there must be some folks out there with the skill and know-how to properly repair damaged boats as well.
ron3637	posted 02-03-2003 11:21 PM ET (US) It appears from what i have read on this board that a whaler's construction would not lend itself to standard repair techniques. Rather it appears that a much more skillful and labor intensive proces is required.
j_h_nimrod	posted 02-04-2003 02:15 AM ET (US) In my previous post(s) I mentioned a material under the gel coat on top of the glass. From the answers this material is probably just a thick gel coat. I have used an 1983 classic commercial hull that has a few very deep (~1/8") gouges in the gel coat on the gunnels and other places on the chines where the gel coat has been chipped off exposing the glass. In both cases the gel coat is very thick, being about 125 mils. Is this just a typical variation in gel coat or have others seen this in their boats?
kingfish	posted 02-04-2003 08:24 AM ET (US) ron3637- Fiberglass repair is fiberglass repair for the most part. If there is a need for structural repair blow the fiberglass on a Whaler, there are some considerations that are different from most other boats on occasion, but so far as surface repair is concerned, if the shop can do a good job on other boats, they can do a good job on a Whaler. kingfish