Curing a Fiberglass Body??

[seadog]

My glass Deuce 5 window project is just about ready for paint and I need some advice on the best way to cure the body so that I don't get print through after the first hot summer day I'm on the road.  I've heard that mounting the body on the frame and letting it sit overnight in a paint booth is the way to go, but would like verification of this before I go forward.  At what temperature does the booth need to be?  How long does it need to sit?  Does it need to cool off and heat up over a number of cycles to fully cure?  I've also heard that all I need to do is to let it sit outside for a few hot days before painting.  Since winter is here this last is not much of an option.  Here are the basic facts...I've had the body for about three years.   It has never been out of the shop where the temperature is 70 degrees year round.  When I picked up the body it was in the dead of winter, so it didn't get exposed to much heat on the trailer on the way to the shop.  Thanks.

[unklian]

Is the body work finished ?

Heat is a natural byproduct of resin curing.

[Crosley.In.AZ]

I would think that after 3 yrs of being out of the mold , the body is cured.

This does not mean the body will not shift , move around or suffer with cold creep.

[Dave]

Tony is right if its been that long dont worry about it. New bodys work out better if they are bolted to the frame and shimmed so everything is right like door gaps etc then you can either throw it in a booth with heat or i just roll it out in the hot sun for a few days.. Print thru is gonna come mainly from possible wood or metal hitting the inside of the glass without a thick enuff glass barrier or from sanding thru the gel coat. Sanding thru the gel coat can be fixed by a little resin over the top or filler or ive found a good thick coat of epoxy primer seems to work also .. The only problem i had with my coupe was on the panel behind the rear window. Seems the filler or primer shrunk and there was 2 spots there that came back. Actually I think it was the primer. After looking at it one day it seems the whole paint job had shrunk..  I figure the way im doing the roadster the primer will prolly have a couple months cure time so no worrys..
Dave

[Bruce Dorsi]

Does it need to cool off and heat up over a number of cycles to fully cure?  
...I've also heard that all I need to do is to let it sit outside for a few hot days before painting.
...It has never been out of the shop where the temperature is 70 degrees year round.
...it didn't get exposed to much heat on the trailer on the way to the shop.

Take this for what it is worth.  ....It is only another opinion, but it sounds plausible to me.  

According to an article I read once, fiberglass is only stable to the highest temperature to which it has been exposed.  

If the internal temperature during the mixing/curing operation reached 110(?) degrees, the 'glass would be stable until that temp was exceeded.

Parking in the sun, up North, during the summer may exceed that temperature by a few degrees, making the 'glass unstable.  .....After any movement that may occur, the 'glass is now stable to the higher temperature.

Parking a dark-colored body in the South during the summer would very easily exceed that temperature, causing the 'glass to be unstable.  .....Again,  after any movement that may occur, the 'glass is now stable to the higher temperature.

The article suggested baking the body as a way to stabilize the 'glass before painting.   .....I can't recall the recommended temperature, but I think it was in the 200-225 degree range.  .....Maybe a 'net search can provide more info.

It is also suggested to ground a 'glass body while painting to eliminate static charge.  .....Some will say this is not necessary, but it certainly can't hurt.

[Dave]

Does it need to cool off and heat up over a number of cycles to fully cure?  
...I've also heard that all I need to do is to let it sit outside for a few hot days before painting.
...It has never been out of the shop where the temperature is 70 degrees year round.
...it didn't get exposed to much heat on the trailer on the way to the shop.

Take this for what it is worth.  ....It is only another opinion, but it sounds plausible to me.  

According to an article I read once, fiberglass is only stable to the highest temperature to which it has been exposed.  

If the internal temperature during the mixing/curing operation reached 110(?) degrees, the 'glass would be stable until that temp was exceeded.

Parking in the sun, up North, during the summer may exceed that temperature by a few degrees, making the 'glass unstable.  .....After any movement that may occur, the 'glass is now stable to the higher temperature.

Parking a dark-colored body in the South during the summer would very easily exceed that temperature, causing the 'glass to be unstable.  .....Again,  after any movement that may occur, the 'glass is now stable to the higher temperature.

The article suggested baking the body as a way to stabilize the 'glass before painting.   .....I can't recall the recommended temperature, but I think it was in the 200-225 degree range.  .....Maybe a 'net search can provide more info.

It is also suggested to ground a 'glass body while painting to eliminate static charge.  .....Some will say this is not necessary, but it certainly can't hurt.

All good points bruce.. when I did my 34 the body had to be like 5 to 10 years old. It had already been primed with an epoxy primer so i never gave it any thought really about curing the thing. It was a  * to get shimmed on the frame as any one that the floor is not glassed in on the frame thats gonna be used can be. I had the same problem on the roadster im working on now..  But once I got everything lined up i drove it with a fresh coat of black epoxy primer for a couple years then sanded that down and painted it. I dont remember any problems with that body and the paint didnt shrink either. The more I fool with hi fill primers and stuff the more i kinda like to give em a big window for cure time to avoid any shrinkage.. The thing is were hot rod builders not production paint shops so the only unhappy customers are ourselves when it comes to completion times..  
Dave

[jaybee]

Hope this isn't stealing the thread but it seems related to me, what's the best way to attach things to the back side of a fiberglass panel to avoid the print through problem?  As an example I met a guy here in IA who built a beutiful '38 Chevy 2 door sedan.  Gorgeous car but he was having problems with the Oak he glassed to the underside of the hood top as a mount for alligator style hinges.

[Dave]

Hope this isn't stealing the thread but it seems related to me, what's the best way to attach things to the back side of a fiberglass panel to avoid the print through problem?  As an example I met a guy here in IA who built a beutiful '38 Chevy 2 door sedan.  Gorgeous car but he was having problems with the Oak he glassed to the underside of the hood top as a mount for alligator style hinges.

They suggest a bit of foam between the part and the glass or just an air gap it if can be done.. Tex Smiths how to on glass cars has some good info in it. Ive had a copy for years and its setting right in front of me here at work ! If you could make an actual glass mount on the underside of the hood then mount the oak to that or the hinge to it id bet you wouldnt see it.
Dave

[jaybee]

I see what you're saying about the foam.  The last I saw him he was planning to cut out the oak and put a layer of foam between the oak ans the hood, glassing it all in as he had before.  Someone told him that should work but he had never done it personally so didn't know if it was going to solve the problem.

[seadog]

According to an article I read once, fiberglass is only stable to the highest temperature to which it has been exposed.  

If the internal temperature during the mixing/curing operation reached 110(?) degrees, the 'glass would be stable until that temp was exceeded.

Parking a dark-colored body in the South during the summer would very easily exceed that temperature, causing the 'glass to be unstable.  .....Again,  after any movement that may occur, the 'glass is now stable to the higher temperature.

The article suggested baking the body as a way to stabilize the 'glass before painting.   .....I can't recall the recommended temperature, but I think it was in the 200-225 degree range.  .....Maybe a 'net search can provide more info.

Bingo, that's what I've heard too.  Summers in the South, where I am, can get really hot and I'm worried that the body needs to be exposed to a level of heat greater than the triple digits that it will encounter when it's on the road.  Can anybody shed more light on the details here.  200-225 degrees in a paint booth sounds like it would certainly exceed the worst case scenario, but then again, maybe not?  Thanks.

[Dave]

Maybe check some manufactures web sites. I really cant answer the question but ive heard this mentioned before.. I thought the heat deal was just to make sure it was cured when it was fairly new. Thats all I know
Dave
ps: if you find out for sure please let me know cause i love glass bodys.. Did my time on rusty steel junk    

[Bugpac]

Actually the best way to attach anything to glass is not to attach it at all, whenever you attach in a big flat panel you likely will have problem, Like adding 1" of wood between hinges and jambs, best way is to bolt thru all three pieces, attach any steel infrastructure in corners etc, not in the large flat areas....

[Topsterguy]

Don't know who's body you're using but mine is a New Age Motorsports ( the old Flatlanders) and I had MAJOR problems with it from day one. My body guy had it perfect, but after it was painted for a couple of months  it shrunk on both sides of the rear window. Needless to say because it was finish painted etc  ( and my body guy died) I'm living with the shrink marks for now. I would say that your body is probably as cured as it's gonna get and should be good, but as a word of caution to future buyers ..............be VERY aware of New Age bodies overall, and make sure they're cured BEFORE you get them. Also, check ALL window garniches for fit and door jams for fit BEFORE you take them home. Between my body guy and my upholstery guy we've had MAJOR grief with my NA body, and even tho Ed , the owner, has assured me they've solved all the problems I would not buy another body from them unless I could check it out thoroughly, in person,  before I took posession of it.

[Crosley.In.AZ]

interesting comments...

A fellow local here had a glass body from a company  outside  of the USA.  He molded in a neat interior built with wood, finished it with paint.  The wood expands differently from the glass.  it cracked in a few joint spots.


From what I read here.... it is best to set the body on a frame , shim it , heat & cool  the body many cycles to help it to take a set?   Should the chassis be loaded with weight too?

[Dave]

interesting comments...

A fellow local here had a glass body from a company  outside  of the USA.  He molded in a neat interior built with wood, finished it with paint.  The wood expands differently from the glass.  it cracked in a few joint spots.


From what I read here.... it is best to set the body on a frame , shim it , heat & cool  the body many cycles to help it to take a set?   Should the chassis be loaded with weight too?

I wouldnt think you would need weight unless your chassis was prone to movement IE: weak .. Then your gonna have more problems down the road.. With mine the heat and cool cycles came from the summer sun . I had no problems except for the paint shrinkage and thats what it was..
Dave