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-   -   Fiberglass hood work. (http://www.hotrodders.com/forum/fiberglass-hood-work-226245.html)

Javelin69 11-18-2012 05:56 PM

Fiberglass hood work.
 
Hi gang,

First off I'd like to wish everyone a great holiday season! Ok, I have a 69' Javelin and recently purchased a fiberglass hood for it. Now the Javein hood has a couple indentions that were ment for the faux hood scoops, but I'd like to fill them in to make the hood a smooth one. Now how should I go about that? should i just slowly build it up with body filler, or should I build it up with resin and mat? Any help would be greatly appreciated! Thanks...

NEW INTERIORS 11-18-2012 06:01 PM

Post a picture of the hood and we can better help you..

mr4speed 11-18-2012 07:38 PM

I am familiar with the javlin hood and the recesses your talking about. Since this is not a structual repair on the glass hood I do not see the need for any fiberglass reinforced matting. Although it will be a fairly thick amount of filler needed to smooth out these areas, you could mix some fiberglass resin in with your bodyfiller and block away. The added resin will help the filler to level out some as your filling a pretty long area. When your filling such a long slope on a pretty long hood, try to mix up a large amount of filler in one shot and when you apply it to the hood lay down some big globs of filler every 4 or 5 inches then come back and do one sweep down the whole hood, it just makes for a more even layer of filler on such a long flat hood. Also make sure you scuff up that whole hood before you do any kind of bodywork to it getting rid of that shiny gel coat surface. I would D/A the whole thing with 180 then 80 in those recess areas that will be filled.

NEW INTERIORS 11-18-2012 07:47 PM

To thick of a body filler on a hood will crack over time.. (When you shut the hood):nono:

69 widetrack 11-18-2012 08:06 PM

The recesses are for a type of hood louver that AMC came out with, similar to the 68 Camaro with the chrome pieces on the hood. For strength and durability I feel your best bet is to use fiberglass mat with the proper resin and hardner...Rough out the opening with minimum 80 grit paper and apply your matting and resin. Sand as smooth as you can and apply a minimal amount of filler over top for leveling purposes. I would then block the entire hood with 180 grit (aftermarket fiberglass parts have tendency to be fairly wavy, especially any AMC parts I've bought, not as big a market as the big three). After you have the hood straight, prime the entire hood and finish blocking with whatever grit (320 400) the paint manufacturer recommends.

I have several AMX's and I have found anything aftermarket fiberglass AMC is questionable at best.

Hope this helps
Ray

mr4speed 11-18-2012 08:15 PM

Never had any problems with filling fiberglass hoods, and even in one extreme case on a 10 second drag car by the time this thing was at top speed (around 130 mph) the whole hood completly changed shape by probably 5 to 6 inches from the wind trying to rip it right off the car. Guess what not a single crack anywhere on this hood and this has been done at least 6 to 7 years ago, racing every year.

NEW INTERIORS 11-18-2012 08:18 PM

1 Attachment(s)
I'm guessing this is the hood he has..

I agree on the glass.. If you had to go with the filler.. I would do it with Kitty Hair short strand reinforced body filler..Ruff it up with 36 use the short strand and level it out with rage... But I also say the glass is your best bet..

69 widetrack 11-18-2012 08:24 PM

[QUOTE=mr4speed;1612986]Never had any problems with filling fiberglass hoods, and even in one extreme case on a 10 second drag car by the time this thing was at top speed (around 130 mph) the whole hood completly changed shape by probably 5 to 6 inches from the wind trying to rip it right off the car. Guess what not a single crack anywhere on this hood and this has been done at least 6 to 7 years ago, racing every year.[/QUOT

I'm sure you haven't had a problem and the race car did all you said it did...That doesn't make it a proper repair...The best repair for anything is to use the same material on whatever it is that your repairing that whatever your repairing is made of....That's why rust holes should be repaired with the same type of metal, (people used to braze steel patches in with brass and it didn't hold up well) holes in tires are repaired with rubber plugs or patches, rips in vinyl are repaired with vinyl. To me it stands to reason that fiberglass should be repaired with fiberglass, wouldn't you agree.

Filler should be used to fill imperfections, not to sculpt, that's why they use granite for that.

mr4speed 11-19-2012 06:02 AM

Ray, you are 100% correct on the fact that fiberglass should be repaired with fiberglass, metal with metal and vinyl with vinyl and so on. I am currently doing a shelby with a glass nose. There was a repair done right behind the front bumper that was cracking and repaired only using filler not glass. Obviously that repair was done incorrectly and did not hold up, so I repaired it the correct way with fiberglass strands layered in resin. That is the key word here "repair", this instance we are dealing with a hood that has no cracks, no weak spots , and no damage, it should not have it is BRAND NEW. Now when you get a hood that we all know are as wavy as an ocean, what do you do to get that hood straight? I am pretty sure you would not "resculpt" the hood with fiberglass reinforced filler or layered coats of fiberglass stranded resin. I am sure we can agree that you will most likely skim coat that whole thing to make it straight with bodyfiller. Sure you are bound to have areas that are pretty thick in the real low spots, but you and I both know that will not be a problem. Can we agree on that? Your way to fill this hood will for sure work, as will mine. After all isn't bodyfiller a resin as is fiberglass, both do use a hardener that will work on either. The example I gave was an extreme one to prove a point as to the cracking issues that were mentioned, if this way was a sure failure, it sure would have happened in this case.

NEW INTERIORS 11-19-2012 06:21 AM

I wasn't try to say your way won't work.. I'm saying it isn't the best way to fix it... One of the worstest places to build up filler is on a roof or a hood.. You should know that... Them spots on that hood are pretty deep and slapping a bunch of filler to build it up isn't the way.. Sorry !!! And he isn't trying to ''skim coat that whole thing to make it straight with bodyfiller''

Skim coating and building something up is two different things... Why would anyone go through the time to fix it Knowing one day it could crack.. And they do.. You may have gotten away with it.. But it doen't say he will.. If it was just to get the low spot's out.. I would say go for it.. But that isn't what he's doing..Yet !!

I guess the Question he needs to answer for us is how thick will this end up..

69 widetrack 11-19-2012 07:08 AM

[QUOTE=mr4speed;1613094]Ray, you are 100% correct on the fact that fiberglass should be repaired with fiberglass, metal with metal and vinyl with vinyl and so on. I am currently doing a shelby with a glass nose. There was a repair done right behind the front bumper that was cracking and repaired only using filler not glass. Obviously that repair was done incorrectly and did not hold up, so I repaired it the correct way with fiberglass strands layered in resin. That is the key word here "repair", this instance we are dealing with a hood that has no cracks, no weak spots , and no damage, it should not have it is BRAND NEW. Now when you get a hood that we all know are as wavy as an ocean, what do you do to get that hood straight? I am pretty sure you would not "resculpt" the hood with fiberglass reinforced filler or layered coats of fiberglass stranded resin. I am sure we can agree that you will most likely skim coat that whole thing to make it straight with bodyfiller. Sure you are bound to have areas that are pretty thick in the real low spots, but you and I both know that will not be a problem. Can we agree on that? Your way to fill this hood will for sure work, as will mine. After all isn't bodyfiller a resin as is fiberglass, both do use a hardener that will work on either. The example I gave was an extreme one to prove a point as to the cracking issues that were mentioned, if this way was a sure failure, it sure would have happened in this case.[/QUOT

It seems like we are having a technical banter on several different post here and the last thing I want to do is make things personal, all I want to do is give out correct information.

Body filler is more talc based and very different from fiberglass, You only use the same hardner on either a can of short or long strand fiberglass filler, Fiberglass matting is an actual fiberglass mat with resin and a liquid catalyst. If you read the label on a can of quality filler I believe that the manufacturers don't recommend a filler be applied more than 1/4 of an inch thick. The recesses in a Javelin hood are Deeper than that.

What I do to get the hood straight is block the gel coat until I come close to the actual fiberglass and skim the areas that are still low. Then I like to use a product like Evercoat Featherfill as a primer (2K will work as well but the Evercoat product is resin based).

When you say "if this way was a sure failure, it sure would have happened in this case.", not necessarily. I've seen work done on vehicles that should't have lasted 6 months that lasted several years...it doesn't make it a proper repair and I think everyone would agree that when people come to this site want to learn how to do a proper repair. I haven't been here that long but have yet to see anybody put up a post that asked what is the wrong way to do this. You yourself said "Ray, you are 100% correct on the fact that fiberglass should be repaired with fiberglass". So I hope we agree.

As far as if a hood or any part is that bad that I had to push a product way past it's limits I wouldn't use the part. In the past I actually threw out a fiberglass fender for an AMC. I wouldn't put my name on the part or the repairs it needed to be straight.

Ray

302 Z28 11-19-2012 07:25 AM

No way would I use traditional body filler, it would have to be too thick. I would use polyester resin mixed with either micro balloons or chopped cotton fiber to form a thick paste. Use that thick paste to build up the low area then fill any small imperfections with just catalyzed polyester resin.

Vince

NEW INTERIORS 11-19-2012 07:35 AM

Quote:

Originally Posted by 302 Z28 (Post 1613112)
No way would I use traditional body filler, it would have to be too thick. I would use polyester resin mixed with either micro balloons or chopped cotton fiber to form a thick paste. Use that thick paste to build up the low area then fill any small imperfections with just catalyzed polyester resin.

Vince

Vince..Resin by it's self is very brittle..

302 Z28 11-19-2012 07:53 AM

Quote:

Originally Posted by NEW INTERIORS (Post 1613117)
Vince..Resin by it's self is very brittle..

Yes I know the resin would be very thin less than 1/16". Any thicker and I would use the same mixture as I did for filling.

Thanks
Vince

69 widetrack 11-19-2012 07:57 AM

Quote:

Originally Posted by 302 Z28 (Post 1613124)
Yes I know the resin would be very thin less than 1/16". Any thicker and I would use the same mixture as I did for filling.

Thanks
Vince

Like Evercoat's Featherfill, resin based.

Ray


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