Will fiberglass ever stop "wiggling"?

[mikeinatlanta]

Originally Posted by Tim7139

This issue is directly related to the quality of the resin, and the quality control in mixing the resin. If your body isn't stable after a year, you can pretty much bet on it never being stable. Without knowing the specific resin they used, there is no way to determine if your issue is a material defect, or just cheap materials that shouldn't have been used in the first place.


Is the inverse also true? If you have no issues over that year, are you likely to not develop any subject to proper finish and regular care?

That is a tough one to answer other than "it depends". For example, I work with and epoxy resin Hysol EA9390 ($375 per quart). Its tg is 350 Fahrenheit and requires a 200 degree cook to properly cure, however, it will harden at lower temperatures to include room temperature. The thing is, the only area where is will have problems if cured cool is that it can't take high temps. If cured at room temp it can sit for two years and as soon as you put it in the hot sun it goes back liquid.

Basic story is that as long as your body isn't exposed to temperature extremes beyond what it has already seen, you should be ok, but when it sees a higher temp than before, that's when you may have an issue. The best thing you can do with a fiberglass body is to take it to someone with a big oven like a powder coater and have the body cooked at 150 for a good four hours. EDIT: That would be BEFORE paint, not after.

All of this assumes that the body is made of a sufficient quality material to begin with. If it's made of a low quality resin that can't take normal underhood temps you are screwed no matter what you do. It doesn't require the best resin, just not the cheap junk resin.

[krausewich]

Obsessive... Another cause of the wavy navy, can be the result of brush applied gelcoat. I don't know that this is your case on a 4000 body, but too often lazy laminators will brush apply the gelcoat prior to the reinforcement layers. This will result in starts n stops, streaks, thick an thin spots. If you hold the part up to the light you will see what I mean. I've attached a photo I just took of a hood scoop I have here that came from a reputable accessories supplier several years back. You will also notice a few bright speckles from air bubbles. Compound this with the glass reinforcement not able to lay flush with the surface causing a 'wavy' layup and resin pockets... long story short, resin shrinks as the styrene evacuates; thicker unsupported resin will move more than the thinner and squibbly spooge you will have! Brush application.. tolerable for small interior stuff like foot boxes, air scoops trunk trays, etc... but on quality finish surfaces, spray application is the only way to go. Not a solution to your current issue, but I do hope it helps with the understanding for future investments.

Bernica, may I hijack the lovely lady in your avatar?? I promise to have her home by 10

https://www.dropbox.com/s/nkxq67k5b6..._5103.JPG?dl=0

Mike.