Gelcoat Question

[Stephen W.]

Re: Gelcoat Question

Joe... As a formed paint rep I will make one comment. Never mix products.... period. Always use a paint system from start to finish for best results. I know everybody has some thing they find works for them but its never a good idea to mix. I have used the PPG system as was mentioned earlier in this thread and had excellent results that were long lasting. Actually it was a friends '63 that was painted in 1995 using all PPG including their Black lacquer. Went to a lot of shows and other than some stone chips and sandblasting from highway driving still looks good. That car was a driver that was recycled after an 80 year old man missed the stop sign and cleaned the front of it off just in front of the rad support. That car had SCM upper surround NOS pressed glass panels and even one good used panel. None of the repairs ever showed back through. I'm a big fan of Glasurit products especially using their epoxy primers and High fill primers. I have also used a lot of GelCoat... But I limit that use for boat repairs... The wax is added so it will cure. Remember when the boat hull is built the gel is sprayed first into a mold so its designed to cure without oxygen. The wax rises to the surface to seal it off.

[Stephen W.]

Re: Gelcoat Question

Joe... As a formed paint rep I will make one comment. Never mix products.... period. Always use a paint system from start to finish for best results. I know everybody has some thing they find works for them but its never a good idea to mix. I have used the PPG system as was mentioned earlier in this thread and had excellent results that were long lasting. Actually it was a friends '63 that was painted in 1995 using all PPG including their Black lacquer. Went to a lot of shows and other than some stone chips and sandblasting from highway driving still looks good. That car was a driver that was recycled after an 80 year old man missed the stop sign and cleaned the front of it off just in front of the rad support. That car had SCM upper surround NOS pressed glass panels and even one good used panel. None of the repairs ever showed back through. I'm a big fan of Glasurit products especially using their epoxy primers and High fill primers. I have also used a lot of GelCoat... But I limit that use for boat repairs... The wax is added so it will cure. Remember when the boat hull is built the gel is sprayed first into a mold so its designed to cure without oxygen. The wax rises to the surface to seal it off.

[Terry F.]

Re: Gelcoat Question

Some of the gellcoats have a parfin type substance built into them that floats to the surface and seals the product from air. That alows it to cure correctly. Some products will go off on their own but still need to be sealed for a couple of days with another product to cure correctly. You then wash it off and start sanding. Terry

[Terry F.]

Re: Gelcoat Question

Some of the gellcoats have a parfin type substance built into them that floats to the surface and seals the product from air. That alows it to cure correctly. Some products will go off on their own but still need to be sealed for a couple of days with another product to cure correctly. You then wash it off and start sanding. Terry

[Dick G.]

Re: Gelcoat Question

A good friend of mine has done over 30 56-57 corvettes. He has used gel coat always. He is 67 years old. He also uses the original nitro-cellulose lacquer paint. Yes, it is still obtainable. He also quit using sealers, with great results. Yes he mixes products, because PPG and Dupont do not make gel coat to my knowledge. PPG DP epoxy is now lead free and not as durable as the the old epoxy. His cars are national top flite beauties. If you go to the nationals you have probably seen his cars. As far as the earlier statement sealing the bare glass, so the paint will not lift. Sealers have always been intended to be used in the paint booth the day you shoot the color, applied just before the color. In my opinion, to think that applying an epoxy (PPG DP)(thinned down) over bare glass may be a waste. If the glass below has solvents or other contaniments trying to get to the surface, the epoxy (in sealer form) will also move, moving everything else above. The gel coat will probably do a better job. I have read that some pros will use a medium temp. lacquer thinner or acetone to wipe the entire bare glass car before begining any bodywork. Claiming it will push out the contaniments as long as the under side of the body is also clean of any paint/undercoating. Let the glass breath,wipe clean,do all topcoat bodywork, gel coat/prime body, topcoat with color, then at last spray the underside of the body. I applied a high quality poly-primer (very user friendly) over my bare body after my bodywork was complete. I am now blocking/guidecoating to get it straight. On paint day, I will use a reduced (DP) epoxy primer over the primed body and apply color. I have never used gel coat. Gel coat is a cousin to poly-primer and uses the exact same catlyst also the same used in resin for all fiberglass repairs.

[Dick G.]

Re: Gelcoat Question

A good friend of mine has done over 30 56-57 corvettes. He has used gel coat always. He is 67 years old. He also uses the original nitro-cellulose lacquer paint. Yes, it is still obtainable. He also quit using sealers, with great results. Yes he mixes products, because PPG and Dupont do not make gel coat to my knowledge. PPG DP epoxy is now lead free and not as durable as the the old epoxy. His cars are national top flite beauties. If you go to the nationals you have probably seen his cars. As far as the earlier statement sealing the bare glass, so the paint will not lift. Sealers have always been intended to be used in the paint booth the day you shoot the color, applied just before the color. In my opinion, to think that applying an epoxy (PPG DP)(thinned down) over bare glass may be a waste. If the glass below has solvents or other contaniments trying to get to the surface, the epoxy (in sealer form) will also move, moving everything else above. The gel coat will probably do a better job. I have read that some pros will use a medium temp. lacquer thinner or acetone to wipe the entire bare glass car before begining any bodywork. Claiming it will push out the contaniments as long as the under side of the body is also clean of any paint/undercoating. Let the glass breath,wipe clean,do all topcoat bodywork, gel coat/prime body, topcoat with color, then at last spray the underside of the body. I applied a high quality poly-primer (very user friendly) over my bare body after my bodywork was complete. I am now blocking/guidecoating to get it straight. On paint day, I will use a reduced (DP) epoxy primer over the primed body and apply color. I have never used gel coat. Gel coat is a cousin to poly-primer and uses the exact same catlyst also the same used in resin for all fiberglass repairs.

[Kurt B.]

Re: Gelcoat Question

Jim,
Yes, I was going to ask whoever ends up painting it to use base coat clear coat. I know it is not factory originla but have been told lacquer is not available or desireable to use. Car will only be driven on weekends.
This is the most stressful part of this 8 year restoration and I am having regrets I ever went down this road but the paint was so bad that I had to do something and one thing led to another until I was restoring the entire car.
The thought of sticking it into a body shop for a year or even several months does not sit well with me. This car has to much sentimental value for me to have it out of my sight/care.
Kurt

[Kurt B.]

Re: Gelcoat Question

Jim,
Yes, I was going to ask whoever ends up painting it to use base coat clear coat. I know it is not factory originla but have been told lacquer is not available or desireable to use. Car will only be driven on weekends.
This is the most stressful part of this 8 year restoration and I am having regrets I ever went down this road but the paint was so bad that I had to do something and one thing led to another until I was restoring the entire car.
The thought of sticking it into a body shop for a year or even several months does not sit well with me. This car has to much sentimental value for me to have it out of my sight/care.
Kurt

[Donald T.]

Re: Gelcoat Question

For a solid color, I prefer single stage urethane over Base/Clear. If it is metallic and you want the option to color sand, then base/clear would be a better option.

[Donald T.]

Re: Gelcoat Question

For a solid color, I prefer single stage urethane over Base/Clear. If it is metallic and you want the option to color sand, then base/clear would be a better option.

[Steven S.]

Re: Gelcoat Question

Theere are very few gel coat manufacturers in the United Sates. I work for one of them. The materials that you get from Eklers and others are made in drums and no less than 5 gallon pails. All these gel coats are originally made to be used in a mold. Gel coats are air inhibited cured products meaning that they cure from the mold side out. They remain sticky on the back side so the resin will cross link with it. When used as a primer, the gel coat must be sprayed at least 11 thousands of an inch thick to cure properly. It is mixed with a catalyst that is MEKP - Methyl Ethyl Ketone preoxide at the rate of 1.5% by weight to a max of 3.0 percent. Higher percent for cool conditions but no cooler than 60 degrees. Wax and styrene can be added to thin and make it more sprayable and cure on the surface so it can be sanded easily. The materials that you buy from the various parts suppliers may be made into a sprayable version to be used for a primer. That question needs to be asked so that you know what you are dealing with. Only major companies making gel coat in US are CCP in Mo., Ashland Chemical in Ohio, InterPlastics in Mn., Alpha Owens Corning in Tn., HK Products in NC, Valspar in Indiana.

Steve

[Steven S.]

Re: Gelcoat Question

Theere are very few gel coat manufacturers in the United Sates. I work for one of them. The materials that you get from Eklers and others are made in drums and no less than 5 gallon pails. All these gel coats are originally made to be used in a mold. Gel coats are air inhibited cured products meaning that they cure from the mold side out. They remain sticky on the back side so the resin will cross link with it. When used as a primer, the gel coat must be sprayed at least 11 thousands of an inch thick to cure properly. It is mixed with a catalyst that is MEKP - Methyl Ethyl Ketone preoxide at the rate of 1.5% by weight to a max of 3.0 percent. Higher percent for cool conditions but no cooler than 60 degrees. Wax and styrene can be added to thin and make it more sprayable and cure on the surface so it can be sanded easily. The materials that you buy from the various parts suppliers may be made into a sprayable version to be used for a primer. That question needs to be asked so that you know what you are dealing with. Only major companies making gel coat in US are CCP in Mo., Ashland Chemical in Ohio, InterPlastics in Mn., Alpha Owens Corning in Tn., HK Products in NC, Valspar in Indiana.

Steve

[Stephen W.]

Re: Gelcoat Question

Steve... intersting and informative. I worked with a local Chris*Craft dealer to repair a few scratched (gouged) boats. He had it in Gallon cans that were white label with "prof use only" and a sticker taped across the top saying "wax added" only other marking was the color "snow white" . I was trying to remember the manufacturer but it was a long time ago. I thought it was Glidden Industrial coatings. The solvent used to thin it was for hot temps and they supplied a retarder for spraying large areas. I would have about 15 minutes at the max from the time I "kicked" it to spray it out and then it was a mad rush to clean the gun. I understand the hardness and barrier capabilities it can provide but I just don't think it's necessary unless its very poor condition glass your working with.I find that by using a good epoxy primer will do an excellent job without unnecessary film build and a lot easier to work with.

[Stephen W.]

Re: Gelcoat Question

Steve... intersting and informative. I worked with a local Chris*Craft dealer to repair a few scratched (gouged) boats. He had it in Gallon cans that were white label with "prof use only" and a sticker taped across the top saying "wax added" only other marking was the color "snow white" . I was trying to remember the manufacturer but it was a long time ago. I thought it was Glidden Industrial coatings. The solvent used to thin it was for hot temps and they supplied a retarder for spraying large areas. I would have about 15 minutes at the max from the time I "kicked" it to spray it out and then it was a mad rush to clean the gun. I understand the hardness and barrier capabilities it can provide but I just don't think it's necessary unless its very poor condition glass your working with.I find that by using a good epoxy primer will do an excellent job without unnecessary film build and a lot easier to work with.

[Terry F.]

Re: Gelcoat Question

One of the pieces of lit I have from Corvette Image says, "Please DO NOT, I repeat, DO NOT use urethane and epoxy primers on reproduction bare glass parts." They go on to say that these substances contain heavy solvents that will soak into the pores and fibers of the fiberglass panel only to migrate out later and cause blisters.

I believe the polyester gel coat they sell actually cross links to the suface of the bear fiberglass panel. I think that sort of chemical bond is hard to beat and nearly impossible to lift if properly applied. It also forces anything that is absorbed into the panel to take the path of least resistance which will be the back side of the panel.

I think you can have success without gel coat but I believe your chances are better with it. Interesting topic! Terry