FG & Gelcoat Stuff I don't understand....

[VRaptor SpeedWorks, LLC]

Ok....been doing this for 20 years now. This is the 40th GTM I've worked on here. I wish someone could explain to me how this sort of thing is even possible? In the first photo, I have some arrows drawn. The blue arrow points to the top surface of gelcoat. The 2 orange arrows point to a layer of fiberlass/resin. The green arrow is another thick layer of (uncured) gelcoat that has the consistency of chewing gum. The 3rd orange arrow is another layer of fiberglass/resin. The other photo is another area where I see the same thing. I've made quite a few fg parts here from moulds, and I'm still trying to figure out how you end up with something like this? You coat the mould with gelcoat, wait for it to cure and then fg over the top and then pop the finished part out of the mould. So how in the heck do we end up with gelcoat, and then fg and then gelcoat and then fiberglass? In the 3rd photo, you can see that the uncured gelcoat is still soft and sticky and wraps itself around the dremel bit. It is really close to something like slightly dried chewing gum....the dremel digs it out in big chunks and you can roll it between your fingers and create a ball like silly putty or play-dough.

This is the hood latch pocket area and also the area right in front of the latch pockets. There is about a 3/16" mis-match in the mould here, so the plan was to dremel the seam down, rough up the low side and use some fiberfill to blend the mis-match in the mould.....just like I've done dozens of times before. Once I started grinding the seam, I kept finding all of these areas of soft gelcoat and just kept dremelling until I finally got to something solid.


Screenshot_20240610-134044_Gallery.jpgVoid.jpgDremel.jpg

[VRaptor SpeedWorks, LLC]

Started working on the opposite latch pocket....

https://www.youtube.com/shorts/deE5S7L1oHw

[Shoeless]

Damn, that's ugly.

Do you see this on every GTM you have worked on or just some?

I know the owner appreciates getting that mess all cleaned up and addressed in the best manner possible , but damn what a headache.

[VRaptor SpeedWorks, LLC]

Definitely don't see this on every GTM....or even most. It seems to vary pretty wildly. I've had some GTM bodies that required very little work (as far as the basic mould alignment and lay-up is concerned)....very few soft spots, very few pinholes, very few thin spots. I've had some that had so many voids and pinholes (not necessarily soft spots like above) that I never thought I'd stop finding and fixing them.....particularly around the side scoop area it seems. I haven't really touched any of the body seams yet on this car except for the latch pockets...because I'm trying to get the hood hinged and latched and can't mount the latches until I get these latch pockets smoothed and leveled out so the latch sits flat and is in it's final position so that all of my adjustments will stay before and after bodywork/paint. So hopefully all of this uncured gelcoat crap is isolated to just this area? I just wish I could understand how it got this way in the first place. I completely understand that making a GTM body is not an easy thing and nothing is going to be perfect in life......but I'm just trying to figure out how you get the outer layer of cured gelcoat, then a layer of fg/resin, then an uncured layer of gelcoat and then more fg/resin over top of that? I can see going around the mould after the fg lay-up, finding thin spots and adding more fg/resin to those areas to "fix" them.....but how does another layer of gelcoat get in there?

[Peter Ross]

It depends how the gel coat was applied.
If it was shoved through a gel coat system chances are the mekp container ran dry.
If gel coat was brushed in the mold it was not fully mixed in the cup.
It doesn't look like old gel coat with polystyrene issues caused by air and age.
If you have any mekp on hand, try to cure some of that goo you're pulling out. If it sets up it had no hardener in it to begin with. There is no cure for uncured gel coat except removal.
Typically "odd lot" or in other words, out of date gel coat loses it profile/depth of shine but age doesn't really prohibit cure (in my experience. )

[Peter Ross]

Definitely don't see this on every GTM....or even most. It seems to vary pretty wildly. I've had some GTM bodies that required very little work (as far as the basic mould alignment and lay-up is concerned)....very few soft spots, very few pinholes, very few thin spots. I've had some that had so many voids and pinholes (not necessarily soft spots like above) that I never thought I'd stop finding and fixing them.....particularly around the side scoop area it seems. I haven't really touched any of the body seams yet on this car except for the latch pockets...because I'm trying to get the hood hinged and latched and can't mount the latches until I get these latch pockets smoothed and leveled out so the latch sits flat and is in it's final position so that all of my adjustments will stay before and after bodywork/paint. So hopefully all of this uncured gelcoat crap is isolated to just this area? I just wish I could understand how it got this way in the first place. I completely understand that making a GTM body is not an easy thing and nothing is going to be perfect in life......but I'm just trying to figure out how you get the outer layer of cured gelcoat, then a layer of fg/resin, then an uncured layer of gelcoat and then more fg/resin over top of that? I can see going around the mould after the fg lay-up, finding thin spots and adding more fg/resin to those areas to "fix" them.....but how does another layer of gelcoat get in there?

Tap the suspected areas and listen for the thud. Tap the rest of the car and listen for that dead thud.

[VRaptor SpeedWorks, LLC]

The adventure continues. The one constant is that every place I find a soft spot of uncured gelcoat and start grinding, I see the exact same thing......cured gelcoat, then a layer of fg, then soft gelcoat, then more fg.......

https://www.youtube.com/watch?v=SQqIbvNK5C0

[Shoeless]

Damn, what a mess. FF did a number on this one.

At least you have some good music in the background

[crash]

What Peter Ross said. I suspect there was not proper hardener in the second layer of gel. No idea why there would be two layers. Guessing that if some person actually put in that second layer then it is likely they did not understand what they were doing in the first place, so the lack of proper hardener is not a total surprise.

I have had one instance where I mixed wrong amounts in a build up primer and thought I would have to strip it all off, but left it for a month or so and it did harden to where it was sandable. I was relieved about that.

The problem I see with what you have there is that it may have NO hardener in that layer mix, and/or because it is covered with a properly mixed and cured layer of FG that there may be little or no ability for the uncured gel layer to outgas and therefore may never cure even if it has any hardener.

If I had that in my shop I think the options to the customer would be to 1) put the bodywork outside in the sun for a month or two and see if it sets up, 2) use that body for a mould and build an entirely new body, 3) cover it up as best you can and tell the customer..."Here is the exact problem. There is no replacement bodywork available. Just remember it is a kit car and they are never production car quality".

Tough problem for sure. That body probably should not have gotten out into circulation.

[wallace18]

Unfortunately I have seen this on a few of the last FFR kits I built. 3 MK4's and 2- 33's. Part of the reason I gave up doing them.

[bil1024]

Contact FFR let them know so that they are aware