Vinyl ester vs polyester resins

Hopefully Bill Hough will chime in on this one. Bill helped my install my Gulf flares and I remember him telling me that he preferred to use vinyl ester resin instead of the more common (and more readily available) polyester resin for wet layup work. He also told me NOT to use the West Systems epoxy I have in my basement, although I don't recall why.

Anyway, I'm getting ready to install my Gurney bubble and I've stopped at a couple marine supply places looking for vinyl ester resin with no success. I was getting ready to make an order with Aircraft Spruce, but the description on their web site says, "Shelf life of promoted vinyl ester resin is short at only a few months." Given the rate at which I work it's entirely possible that the product would be beyond its shelf life before I even opened the bottle!

Anyway, I'm looking for information regarding which type of resin to use. Thanks.
 

Peter Delaney

GT40s Supporter
My Vette restoration expert has come to the conclusion that vinyl ester resin is way better than the old polyester - years of trial & error. He has found that it bonds a lot better to the somewhat dubious 30 year old glass on the older Vettes, shrinks back a lot less, and therefore has no "print through" on joints & raw glass fibres.

He also ran into the short shelf life problem, so just gets small quantities in as required.

Kind Regards,

Peter D.
 
West system has several different formulas and you need to be fairly precise in its use or you could get a surface that you cannot overcoat. Should not be an issue with the knowledge base here, but the average joe might have an issue.
 
Mark,
I use vinylester resin and have been using it since 1976. It has it's goods and bads! It works well for me in thin lay-ups. It holds up better in the hot sun. You still get print through, but not as much as polyester. Usually the print through problem can be made less of a problem by using a very fine woven fabrick next to the gelcoat in the lay-up process. That means; another step & material in the lay-up process and more money.
It's getting to the point lately , does the cost of the resin justify is use. My cost on a drum of vinylester resin went from $540.00 per 55 gallon drum to $1080.00 in one year. That $1080.00 was quoted today. It's getting like buying carbon fiber. I'm going back to best polyester I can get.
I have an original GT40 nose in my shop right now made with polyester, and it looks just fine for a forty year old piece of fiberglass. It does have some racing history, actually a lot of racing history, but the integrity of the lay-up is first class. It's held it's shape just fine.
Mark, if you really want to use vinylester to bond the Gurney bubble on, come on down and I'll give you some. BUT, I think it's over kill. If your body was made with vinylester, then you could be a purist. If you are mounting it on top with the perimiter flange, grind the flange to a feather edge, stick it on with 3M 5200 fast cure, then glass over the flange and smooth it in with my favorite stuff "bondo". Be sure you rough up all surfaces that are to be bonded together. Also, you could do just as well with that awfull West system epoxy. Epoxy will bond as well as the 3M5200, but it doen't work with chopped strand fiber. You would have to mix in the flocked cotton for the epoxy to work. I hope this helps!
 
Hi Guys
You have to be carefull when mixing Epoxy, Vinylester and Polyester resins

Vinylester and Polyester are a chemical bond where as Exoxy is a mechanical bond.

Vinyl and Polyester will etch themselves together and to Epoxy, but Epoxy will not give a good bond to Vinyl and Polyester and in time will delaminate from each other.

To reduce the rick of print through on your finished item double gell and back up with a tissue before using chop strand matt, any use of woven clothes will print though in time if they are a too heavy weave.

Happy laminating
Bud
 
There must be some more fiberglass guys out there, Lets see if we can get Mark totally confused!
 
3M makes a very good Filler with short strand fiberglass based on Vinyl ester Resin (High strength marine repair filler). This filler bonds very well and shrinks less than Polyester Filler.

I have learned that you have to use a Vinyl ester filler on a Vinyl ester body (e.g. the new “FactoryFive” Cobra bodies) but does it make sense to use this filler on a Polyester body or should there be used a Polyester based filler?

Regards Reinhard
 
Hey William, aren't you finding that all materials, including paint, are going through the roof on price! Surely the polyester is the same way.
 
Here in the UK the price of resin has almost doubled in the last 18-24 months, even though the cost of crude oil is going down, resin and such like is still on the increase.

Two years ago Acetone was £65-70 a barrel, now it cost £125 and you have to shop around to get it at that price.

Bud
 
We are seeing the same thing here. What I have learned is that benzene, which is a feed-stock for both coatings and plastic (pvc, etc.) has gone up more than 58% in cost this year. Producers then decide which business is more profitable that day, and sell where they see fit. Raw materials pricing for both coatings and plastic change minute-by-minute. After years of it being a buyers market, things have changed 180 degrees to a sellers market.
 

Fran Hall RCR

GT40s Sponsor
This is not limited to the petro-chemical industry...
The cost of the raw material (metal and fibreglass) in the RCR cars has risen by over 50% since Jan 1st 2005...
 
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