Let’s talk vinyl-ester resin and SMC
 

So I have been talking to a local shop that specializes in composites about purchasing the material to do the repairs to my 1976 C3. Their eBay store says, “Our business is everything Fiberglass, Carbon fiber and composites. For over 15yrs our store in Glendale, AZ has been manufacturing and selling all of the professional products and raw materials required for any fiberglass or composite project.”

Anyways, I call and talk to them about what it is I plan to do repair-wise and they recommend just using a vinyl-ester (VE) with MEKP and mat for all my repairs. I guess it is what marine guys use on their boats. So I call my cousin who builds fiberglass drag boats and he says the same exact thing: it’s not hard to use, it bonds great to EVERYTHING, and it is super strong.

I have done some reading and everything I see say that epoxy is a little easier to work with and a little more forgiving whereas the vinyl ester creates a stronger bond but the MEKP is finicky and requires a little more of a controlled environment. With VE the temp has to be just right, it needs to be covered up (sealed) after putting on the mat so the vinyl-ester will cure properly with no air, the shelf life isn’t very good, the MEKP is not the safest material to deal with, yada yada yada…

So, my questions to you body guys with years of fiberglass and SMC experience: have you used it before? Did you like it? CAN it be used on SMC bodies? Is it best to just stick with an epoxy resin? Why do you think the boat guys using it and recommending it? As with anything, there are a million opinions out there about every little thing and VE is no different. I just can’t find and corvette specific info on VE and why it should or should not be used. Let me know what you guys think. Your advice and experiences are appreciated!

ve is basically a modified epoxy, but works more like polyester. Polyester and ve are both styrene based. Ve will cure a lot faster than epoxy, but it does stay taky without wax. One advantage I can see with ve over epoxy is that if you are gelcoating over it ve would be the way to go because the styrene in the gelcoat can attack the epoxy. I think ve is more forgiving with tempature than epoxy. If you laminated with ve and 12 hours later the tempature drops below below 50 degrees it will be ok. If you do the same with epoxy it will STOP curing and will never cure properly. Another advantage to the ve over epoxy, is as long as you stay within the chemical Bond window, you can keep adding more. Most Epoxy however have a blush that rises to the surface and must be removed before redcoat. It will bond as well as any other styrene based resin for smc, must make sure you use .925 mekp and catalyze at 2 percent though.

Using ANY product and knowing how it works and cures is important. How it can link to another product and all that important stuff. And then what can be sprayed on it to also provide a good link so paint can be applied.

I use polyester and epoxy resin (where needed) due to THAT is what I use and I have never had ANY failures. So no need for me to implement in another product that.....may or may not...improve my repairs that are not failing currently.

I cure out my laminations AFTER the initial cure has been successful....and IF the temps are really low....I use infra red heat lamps to get the panel to be maintained at a specific temperature when I am laminating. So if the panel is at 40 degrees F...I can get it to a constant 70 degrees F ( for example).

I have always thought of using VE resin.....but....why tempt fate. I might get some and do some test panels and give them time to see how it works. I am not so pig-headed that I am stuck in my ways....but In have to be convinced it will hold up.

As I have been told by my guy who also does major fiberglass fabrication...the VE 's main advantage is corrosion resistance....and might be over kill. It is also stronger but as he put it...is more brittle....thus depending on how thick it is being applied...in regards to thickness of the lamination.

So even though VE resin is being used...those that use it and swear by it have figured out HOW they need to use it so it works for them. Kind of like the concrete you used to make a sidewalk leading up to your front door is NOT the product you use to build you brick house with. You would use mortar for the brick lay up.

Knowing what products to use and how to use them is always the 'trick'.

DUB