Fiberglass hood repair questions

[69clone]

Hey guys so I picked up a pretty nice fiberglass lift off hood for my 69' the only problems with it are some stress cracks around the scoop along with a small chip in the back, oh and on one side I guess he hinged it but forgot to switch the springs so it stressed one side. I was wondering what would you guys do to repair the stress cracks? I sanded one area pretty good til I couldn't feel nor see the cracks and repainted it but the cracks showed up again... So I bought some fiberglass repair stuff along with body filler and whatnot. Id like to hear what you guys did before I go out and start sanding.
Thanks,
~Nick
Btw I'll post some pictures later.

 

[alleyoopmgv]

Fiberglass needs to be repaired with fiberglass matting to be fixed the proper way. Cloth has no structural strength at all. You need to V out the crack, then use matting, then bondo, etc... to be done correctly. Otherwise the crack will just keep coming back.

 

[69clone]

Fiberglass needs to be repaired with fiberglass matting to be fixed the proper way. Cloth has no structural strength at all. You need to V out the crack, then use matting, then bondo, etc... to be done correctly. Otherwise the crack will just keep coming back.

Thanks alley, There not big cracks just hair line stress cracks? Those will need to be widen so that the matting can fill them in? Also what is matting? I bought a bag of fiber cloth and a can of resin.
Thanks for the help.

 

[696pack]

The fiberglass cloth IS the matting. and it DOES have strength because it is cross woven. As said above grind the crack out with a grinder in a V. Cut mat to fit down in the V and then mix resin and hardner and satuate the cloth you have cut. It is a messy job best done with thin rubber gloves. You have to work quickly as the resin begins hardnening quickly and then you can no longer work it. If you get air in any folds of the cloth/resin mix it will dry as a void. After drying you then need to open up the hole and put more resin in it. If the cracks are large you need to drill holes at the ends of them to keep them from running later. You have to fill these holes with resin. You can tape wax paper over the back side to keep the resin in the hole.

 

[Ron 73]

If you use any kind of what they call "bondo" to cover anything or touch up even small things Use Duro-glass, much stronger And adheaves to fiber glass better then Bondo harder to sand but is better IF you have to do it when done. The fiberglass cloth/mat is strong but has to be done right. Which i think has been covered good here, no pun intended! You wont get away with loosing those small cracks unless it is repaired, they will come back, Even pulling it apart and putting bondo in the cracks will not seal it.. To be honest what 696pack told you about the holes at each end and fill? Its a good safe guard to do it anyway, Just to be sure that it doesn't spread out like spider cracks in A windshield... Fiberglass do lots of rock-in n Rollin, especially on a hood.. VI-BER-RATION dancin... my pennies worth.

 

[alleyoopmgv]

The fiberglass cloth IS the matting. and it DOES have strength because it is cross woven.

That is not true, cloth is for cosmetic purposes only, matting is for structural strength. That is a lot of peoples misunderstandings, cloth provides no structural strength whatsoever. Fiberglas Matting is what you need.

This is what it looks like.

 

[alleyoopmgv]

This is what you do not want to use. This is the cloth, you don't want to repair a crack with it. It is for cosmetic purposes only.

 

[alleyoopmgv]

If you use any kind of what they call "bondo" to cover anything or touch up even small things Use Duro-glass, much stronger And adheaves to fiber glass better then Bondo harder to sand but is better IF you have to do it when done. The fiberglass cloth/mat is strong but has to be done right.

Duraglas is made with fiberglass, so if you already repaired the crack with fiberglass matting, then you would not have to use Duraglas, unless you still have a lot leveling to do.
Duraglas is stronger then plastic body filler (bondo) as Ron 73 has pointed out, but is not as strong as fiberglass matting.
It is a messy job for sure, and you have to make sure there are no air bubbles in the repair, or it wont last.

 

[alleyoopmgv]

Thanks alley, There not big cracks just hair line stress cracks? Those will need to be widen so that the matting can fill them in? Also what is matting? I bought a bag of fiber cloth and a can of resin.
Thanks for the help.

Even hair line stress cracks should be repaired this way but,

If the hair line cracks are not that deep, you can V them out, and get a quart of Tigerhair to repair your hood, and not even mess with matting at all.
You would use the Tigerhair with the hardener, and then go straight to body filler,etc.....

 

[wannadrag]

I do a fair amount of vintage snowmobile hoods and always add a layer of mat on the bottom side of the crack also.

 

[SUPERSTOCKRACER]

If you use any kind of what they call "bondo" to cover anything or touch up even small things Use Duro-glass, much stronger And adheaves to fiber glass better then Bondo harder to sand but is better IF you have to do it when done. The fiberglass cloth/mat is strong but has to be done right. Which i think has been covered good here, no pun intended! You wont get away with loosing those small cracks unless it is repaired, they will come back, Even pulling it apart and putting bondo in the cracks will not seal it.. To be honest what 696pack told you about the holes at each end and fill? Its a good safe guard to do it anyway, Just to be sure that it doesn't spread out like spider cracks in A windshield... Fiberglass do lots of rock-in n Rollin, especially on a hood.. VI-BER-RATION dancin... my pennies worth.

duroglass is the bomb. my 65 dodge hood has it and works the best and not messy.

 

[69clone]

Thanks for all the help, I guess there is alittle more work then I hoped... I figured if I put a layer of resin over then entire top, that it would fall into the cracks and problem solved oh well... So I guess a file or dremil are the best tools to v the cracks?

 

[Ron 73]

Duraglas is made with fiberglass, so if you already repaired the crack with fiberglass matting, then you would not have to use Duraglas, unless you still have a lot leveling to do.
Duraglas is stronger then plastic body filler (bondo) as Ron 73 has pointed out, but is not as strong as fiberglass matting.
It is a messy job for sure, and you have to make sure there are no air bubbles in the repair, or it wont last.

Didn't mean it be stronger, then matting/cloth. BUT as you pointed out IF you have any leveling to do, whats the difference in any meaning as you take it when i said "to cover anything or touch up even small things Use Duro-glass, much stronger And adheaves to fiber glass better then Bondo harder to sand but is better IF you have to do it when done." i believe you said its stronger then "BONDO" yourself... What part are you missing i said in correctly, or what am i missing. Cover up small parts any finishing, ect is that something like "leveling off"? as you put it? Thank you for pointing this out.. not good in mornings, i do hope he understands what to do now, i hate drawing pictures and i hate more to argu over the same thing said just took wrong, which i will take that mistake here myself for under explaining what i meant by finishing or small area touch ups..

 

[69clone]

One other question is it better to v out the cracks now while I'm sanding it down, or wait til I'm done removing the paint?

 

[Ron 73]

Nice looking car SSR I did a hood like that once not quite that tall. Using the fiberglass you can blend that scoop into the hood and you would swear its part of the hood, maybe you do not like that type of look but i myself thought it was better then the spaces. Its all ones idea of what we like as our ride, which im not going to say to anyone it should be this or should not be. It is a nice looking car. Ron

 

[696pack]

That is not true, cloth is for cosmetic purposes only, matting is for structural strength. That is a lot of peoples misunderstandings, cloth provides no structural strength whatsoever. Fiberglas Matting is what you need.

This is what it looks like.

Well, I guess you are right. When I commented on cloth I meant mat. I did not know they made anything different and have never seen CLOTH.

 

[alleyoopmgv]

Didn't mean it be stronger, then matting/cloth. BUT as you pointed out IF you have any leveling to do, whats the difference in any meaning as you take it when i said "to cover anything or touch up even small things Use Duro-glass, much stronger And adheaves to fiber glass better then Bondo harder to sand but is better IF you have to do it when done." i believe you said its stronger then "BONDO" yourself... What part are you missing i said in correctly, or what am i missing. Cover up small parts any finishing, ect is that something like "leveling off"? as you put it? Thank you for pointing this out.. not good in mornings, i do hope he understands what to do now, i hate drawing pictures and i hate more to argu over the same thing said just took wrong, which i will take that mistake here myself for under explaining what i meant by finishing or small area touch ups..

I just wanted to make it clear to 69clone what is stronger. You didn't say anything wrong at all. I just want 69clone to get his hood repaired properly.

 

[alleyoopmgv]

One other question is it better to v out the cracks now while I'm sanding it down, or wait til I'm done removing the paint?

I would do it before you remove the rest of the paint just so you know where the cracks are, but it really doesn't matter.

 

[alleyoopmgv]

Well, I guess you are right. When I commented on cloth I meant mat. I did not know they made anything different and have never seen CLOTH.

No problems whatsoever on my end. Were all on the same team here. I just want for 69clone to get his hood fixed. Hell, I would do it for him if he was close enough to me.

 

[69clone]

No problems whatsoever on my end. Were all on the same team here. I just want for 69clone to get his hood fixed. Hell, I would do it for him if he was close enough to me.

Thanks I really appreciate your help and offer. its all a learning experience for me. I rather ask before I do something and do it right then do twice...