For all you guys out there restoring C3's which have SMC body panels, what materials have you been using to make your fiberglass repairs?

1) What type of resin have you been using?
2) What brand of fiberglass mat have you been using?
3) What have the results been like? Is this system working good for you?

I need to decide which materials I will buy to make my SMC body panel repairs. I need your guys' help. I was thinking about buying some Evercoat SMC Fiberglass Resin...but I need some reviews before I'll shell out the money.

Thanks in advance

 

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If you are using resin and matting, you need to use smc resin on smc parts. The regular type resin usually will peel off. Smc resin is very expensive though. At work, a gallon is $100. Evercoat and USC make good matting.

 

Thias was discussed in depth last week but the basic difference is EPOXY resin on SMC and polyester resin on older pre73 cars
I like epoxies from Fiber glass coatings inc in Florida. I have a long history with them from boat building and have had very good bond results with their opexy to SMC panels.
Basically go with a high quality epoxy. A good bit of the stuff marketed under various brand names is manufactured by either West Systems or FGC mentioned above.

my $.02

others will have different opinions

 

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When was the switch to SMC?

 

I've heard that some fibrglass matt contains styrene, which reacts with eposy resin, preventing it from curing. Is this true? If so, where Can I get fiberglass matt that doesn't contain styrene?

 

You heard correctly and styrene isn't the only ingrediant that can cause problems.
There are many, many, many types of glass fiber, all the way up to kevlar and beyond compatable for both polyester and epoxy.

If you have a boat manufacturing co near you or a taxidermist or a fishing pole manufacturer, They can explain the ins and outs of glassing and maybe supply your the materials.

There are many glass supply houses local to me because of boating industry but places such as this
http://www.mertons.com/
can help you out with everything. In other words a dedicated composite supply house is much more educated than a parts store that probably has aged cans sitting on the shelf and knows little about any of the thousands of products they sell. There are dozens of dedicated glass places like this.

You need the right epoxy and the compatable matt and compatable filler if you want to make your own bondo or adhesive. This is the best all corvettes smc panels or not.

 

I spoke to a tech at a chemical company that makes Epoxy resins (mostly for commercial use) and they said the same thing about fiberglass mat ..that it may contain styrene. The guy said fiberglass cloth, the woven stuff, does not contain styrene. Of course, you can use cloth (which is stronger than mat) on your lower areas of the repair, but you don't want to use cloth on your top layers becuase it will produce a checkerboard pattern on your finished product down the road, even if you cover it with filler (someone did that on a repair on my car, so I've seen it first hand).

Back to your original question, I finally bit the bullit and bought the Ecklers Epoxy resin repair kit (my car's an 81). I wasted a lot of time, psychoanalyzing which product to use, trying cheaper stuff that didn't workd ...scouring the internet for info. Finally I decided I needed to "Git 'er dun" and just ordered it. I use fiberglass mat by USC. It's worked great. Product code number on my bag is partially melted away (thinner), but the last 4 digits are 8075. It indicates it can be used with polyester or epoxy resins. It does not appear to have any styrene in it - the strands look exactly like the strands of the fiberglass cloth I use (by bondo). I personally wouldn't bother with the cloth unless you have major reconstruction to do. My repairs have turned out great. Any auto paint store should have USC products. Ecklers, I'm sure also has some mat. Also, if you haven't done much glass work, make sure you buy a fiberglass roller. I've done glass work in the past w/o the roller and in my opinion, the roller really makes the job a ton better. You'll get a better, stronger, repair, less messy.Ecklers also sell it, but I got mine from the auto paint store for about $10. I also use a heat lamp to help cure the epoxy a touch faster ..as epoxy seems to take longer to set-up than polyester resin.

One other note, the Ecklers Epoxy kit is only a qt, but, really, a quart really goes a long way. When you use the roller you don't use that much resin. Seems like I only need to mix up a few ounces at a time (a small amount in a paper cup) and I still have some left over. I've glassed up the whole main seam on 1 front fender, made a few repairs to the seam on the other front fender, hood repairs and some misc. repairs to cracks in the rear and I've only used about an 1" from the top of the can. There's no way at this rate I'm going to use even half the can (not interested in selling the xtra at this time). So, I suggest don't get fixated on the extra cost of epoxy over polyester resin, it's not likely you'll be using enough to dent your repair budget. The worst gouge for me is paying the hefty shipping.

Good luck,

Mark G

 

One other quick note: if you only have a small repair or two, I know the body shop supply stores sell syringe type repair kits. Personally, I wouldn't hesitate to go to Home Depot and get 4-5 epoxy repair kits in syringes for $3 ea, some fiberglass mat (the right stuff from an autobody store) and go to town. I bet it's the same stuff and would work just fine. There are lots of types and some list usage for wave runners and water craft, many which also use SMC. I fixed a wheel center cap using some plain epoxy in a tube and chopped up cloth. Worked great, strong repair.

Just a thought.

Mark G

 

Anyone know anything about Evercoat's fiberglas mat? They say it's 100% fiberglas, no styrene, kevlar or anything else that's odd. I picked up several of the #940 1 sq. ft. packages at an auction for very little money.

 

Batman

Just as an example and contains no binders (it is the binders in the matt that will dissolve in the stryrene, that is part of the polester resin, little of it in the matt)
.75 oz chopped matt @ 3.50/lin.yd. (yd=38"w)
1.5 oz chopped matt @ 4.50/ lin.yd.
Additionally, all of the "stitched products" contain no binders.

kevlar and carbon fibers are in lieu of glass fibers and at 10 times the cost. ie bulletproof vests etc.