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I have an 85 Vette, and the original fiberglass targa top is severely cracked. My Dad and I think it was either dropped, or maybe it even blew off of the car. Can someone give me step by step instructions for repairing the fiberglass? I would greatly appreciate any help you can give me
Zak
it would be SMC not glass and it would be hard for me to give you step by step but you first need to get the wax off it V out the cracks and make up small strips glass mat as you add a strip you want it to be just a bit bigger and wider than the first to put in the V out try finding fiber gell made by swiss that works good try to post heat it and let it cure
I think the last year for fiberglass Vettes was 1975. After that they wee made of SMC (sheet molded compound) With out seeing it I would guess it could be repaired with Panel Adhesive, it's the same stuff as they use when they glue them together.
Bob
no 75 was smc and vett bond is not to good for that kind of work with out a backer what i have seen i think late 60 for glass
Would it help if I posted pictures for you guys to see? The cracks are pretty bad, and I started to sand it down today. The previous owner already tried to patch it, but it will probably have to be replaced. Also, how far do I need to sand it down?
Quote:
Originally Posted by pat mccarthy
I'm sure the SMC started in75 or 6. Didn't the tin floors start in 74 or 5 ?
So what do I need to do to get this repaired? I can post pictures and you guys can take me through it. Just let me know what I need to do.
you want to lay it way out from the crack thickness less than 1/6 of a inch and V feather back. to build it back with mat this is the only way to make it strong mat or cloth makes the part strong on the gell or resin i use and 36 grit on a 3m 8inch soft pad
Do you want me to post some pics of it? how much do I need to sand?
the last one i work on was a 65 white glass?? mild year . 75/76 front rubber bumper all i know is i was thinking i work at a shop that did the a 75 i was thinking? and it was all smc and they used vett bond look good till they roll it out it the sun :eek: i have seen smc parts on mild years and header on the gm cars wer smc back past 75. 69 had glass foors???steel bumper car were glass ??Quote:
Originally Posted by Bob W
Do you want me to post some pics of it? how much do I need to sand?
well i would need to see it so post away:)Quote:
Originally Posted by Corvette85
On the outside of the panel, V out the crack, then rip up some matt into shreads, brush on some resin, and work the fibers deep into the crack. If the cracks are severe, or chunks missing, then grind the inside of the panel with 36 grit and put a layer of matt on the inside. Before laying matt on the inside, use the method of shredded matt to fill the holes. After this has all dried on the inside of the panel, scuff it again with 36 grit and apply a layer of cloth that extends beyond the area you placed the matt on. For large repairs on 'glass bodies, I use core matt, or kevlar matt to add a bunch of strength to the repaired area... Might not be the way the reps say to fix it, but it works for me!!!!!
Here are several pictures.
Here are a few more.
Yup, blew off the car all right.... Definitely gonna need some reinforcement (matt) on the inside to keep it together..... Make sure before you do any patching with resin and matt that you scuff the area thoroughly with 36 grit so you will get proper adhesion.....
Dave, what exactly do ya'll mean when you say "V out the crack"?
It's the same process for boats, look that up. When I do fiberglass repairs, I work with epoxy resins like those available from West System for many reasons. Epoxies bond to all other resisn, they are many times more flexible than polyester, and they are many times stronger. That way, you know the part will fail somewhere other than the repair.
If I were to do this repair, I would simply bevel the material back at least 8x the thickness of the top on both sides. Cut sheets of biaxial cloth to fill the bevel and prepare them to be stacked in the bevel. Less sanding is necessary if you start with the bottom sheet being the largest and reduce the size of each additional sheet. Work one side at a time so you can use gravity to your advantage. The great thing about West Systems is its versatility. Many fillers are available to make it do many things from glueing, filleting, to fairing. Use the low density filler to make a fairing compound like Bondo to reduce the amount of sanding and laminating you need to do. West Systems is available at West Marine and Boater's World. It costs about $45 for a quart of resin and a matching quanitity of hardener.
Grind out the edges of the cracks into a V-Pattern, this will allow more resin into the crack plus you will be able to work some of the shredded matt into the V giving increased strength in the cracked area...
That should be able to be repaired. Grind the inside with 24grit disc and apply resin and 1 piece of 1.5 oz. mat to the entire inside of the panel, push out the air and let dry grind again and apply second piece to the inside. This will give the panel back its strength and allow you to work on the outside with out the cracking continuing. V out each crack and follow Daves instructions. Make sure you push out the air when appling the mat and resin.
if you do not post cure it i think it on a black car your repair will shrink and air cure will move in the heat of the sun any thing poly or epoxies will move more then the MSC this stuff is thremal set in the long run it may be a much bettter finding a used lid . the west systems are good and made here in bay city :) BUT the msc is not made by west systems from what i have seen it work great on alot of stuff but not to sure i would use it on msc ?? boats are not made out of msc . msc is a different animal .but i know what works on the stuff .i work on trucks an have put many of them back to gether with fiber gell and mat:3dSMILE: in side out would be the way to fix it
Thanks for all of the help.
Zak
Here's a link, the third drawing shows the 'V' prior to rebuilding the material.
Fiberglass Repair by Don Casey
Oh, ok. Thanks.
West Systems also has a lot of how-to stuff on their website. There is a lot of discussion about whether or not to lay the biggest piece of fiberglass in first or the smallest when you are filling the bevel. Either way produces an acceptable repair, but from my experience if you start with the biggest piece, there is less sanding to be done when you are finished. There is also less of a chance of getting unreinfoced pockets of resin. Oh, don't forget to buy a resin roller.
Oh, ok. I'm going to go ahead and finish sanding it down, then I'll get back to you guys from there.
Another question...do I need to sand the whole thing down to the fiberglass, or just in the repair spots?
West systems is good, i have used it a lot. One thing, You cant use matt with epoxy, use only cloth.. The glue that holds the glass fibers together in the matt, needs the polyester resin to disolve it. Epoxy wont do it.
epoxy sticks to polyester, but polyester does not stick to epoxy.
I love glass work, but it makes me itch.
Jim
You can use most matt with epoxy. The epoxy won't dissolve the binder which makes it harder to wet out, but you can still use matt and it still works fine. I did suggest biaxial cloth for this reason, though.
Here is a fiberglass repair I did. I replaced a section of a boat stringer. I used 2 layers of 1.5 oz mat and 1 24 oz roven. I used West System epoxy and it wet the mat out just fine. In fact, you can still see the wood underneath all of the glass.
http://i24.photobucket.com/albums/c8...rfinished1.jpg
Just looking at that picture, I smelled the west system. I havent used it in a few years. Good point on the mat. I have done it but didnt think it was ok.Quote:
Originally Posted by 76GMC1500
Jim
That is one more good thing about epoxy, the fumes aren't nearly as bad if you are working in an enclosed area.
If you drill 3/16 holes up an down the crack not on the crack not to exceed1" ether driction grind to a 45 both direction an apply fiberglass