Gelcoat Question

[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

[Stephen W.]

Re: Gelcoat Question

Good point about repo glass products. Sounds like they are well aware of a proplem that exists with their glass products and the "fix" is the use of the Gelcoat as a barrier coat to prevent any solvents being absorbed into the voids in their glass. I've worked with SMC and oem pressed glass without issue but have not experienced using the aftermarket suppliers of replacement parts.
if thats what they recommend it's for a reason and I would follow thos directions to the letter.

[Stephen W.]

Re: Gelcoat Question

Good point about repo glass products. Sounds like they are well aware of a proplem that exists with their glass products and the "fix" is the use of the Gelcoat as a barrier coat to prevent any solvents being absorbed into the voids in their glass. I've worked with SMC and oem pressed glass without issue but have not experienced using the aftermarket suppliers of replacement parts.
if thats what they recommend it's for a reason and I would follow thos directions to the letter.

[Terry F.]

Re: Gelcoat Question

It makes me wonder what might be going on because I believe the 68 panels they produce are nealy identical in composition to original GM. I will say that I have ordered panels from them in the past and they felt like they still needed to dry a bit more. I am not in a hurry so the one on my 68 has been sitting for over a year now. Maybe they are worried the part will vent off the solvents that are naturally found in the resin. Maybe GM/Rockwell/etc dried the panels longer or used infra red heat to speed the process of drying.

Thanks, Terry

[Terry F.]

Re: Gelcoat Question

It makes me wonder what might be going on because I believe the 68 panels they produce are nealy identical in composition to original GM. I will say that I have ordered panels from them in the past and they felt like they still needed to dry a bit more. I am not in a hurry so the one on my 68 has been sitting for over a year now. Maybe they are worried the part will vent off the solvents that are naturally found in the resin. Maybe GM/Rockwell/etc dried the panels longer or used infra red heat to speed the process of drying.

Thanks, Terry

[John H.]

Re: Gelcoat Question

The male and female steel molds used in huge hydraulic presses to make the original panels were heated to 160*F or so by hot oil circulated through drilled galleries in the molds; the molds for the press-molded reproduction panels are neither steel nor heated.

[John H.]

Re: Gelcoat Question

The male and female steel molds used in huge hydraulic presses to make the original panels were heated to 160*F or so by hot oil circulated through drilled galleries in the molds; the molds for the press-molded reproduction panels are neither steel nor heated.

[Terry F.]

Re: Gelcoat Question

Interesting and may explain some of the issues with reproduction panels. I would suspect they would like to keep there inventories at reasonable small levels.

What about eckler's, they show a great big machine in their catalog and claim to have original manufacturing equipment as I recall. Or do they just buy from the two guys that I know of that are making black glass parts? Terry

[Terry F.]

Re: Gelcoat Question

Interesting and may explain some of the issues with reproduction panels. I would suspect they would like to keep there inventories at reasonable small levels.

What about eckler's, they show a great big machine in their catalog and claim to have original manufacturing equipment as I recall. Or do they just buy from the two guys that I know of that are making black glass parts? Terry