The vinylester I have experience with is indistinguishable from polyester as you work with it. So although the cured product may be more like epoxy the uncured stuff REEKS. 3M wanted to demo some to me one year at the Maine Boat Builders Show. They mixed about 1 pint of resin, within moments the whole building smelled. The smell did not disipate until the next day.

I would not use it in my basement or anywhere you want to spend time without a full respirator.

: It has been discussed a few times. It is not as widely distributed so
: probably fewer pople have played with it. Of the three "common"
: resins used with fiberglass, it is probably the least common. It costs
: about as much as epoxy, so there is no price advantage, unlike polyester,
: which can be found for considerably less.

: Handling wise it is similar to polyester. Like polyester resin it cures by
: adding small quantities of an accelerant or catalyst. At room temperature
: you would use under an ounce of catalyst for a gallon of resin, so careful
: measuring is important.

: I can't find any references to this material soakin into the wood pores and
: sealing the wood as epoxy resins do, so I am inclinded to think that this
: has the same characteristics as polyester. That is, it is probably
: slightly permeable to water vapor, so it does not prevent rot.

: I believe the same catalyst can be used for either polyester or vinylester
: resins. You have some control over the potlife and cure times of these
: resins by adjusting the amount of the catalyst added. On hot days you can
: slow down the process by using less, and on cold days you can speed up the
: reaction by using more -- all within certain limits, of course. The resins
: are a bit "thicker" than epoxy so they create fewer runs and
: take a bit longer to wet out the cloth.

: Fibreglast (www.fibreglast.com) has this for $52.95 a gallon, and it has a
: short shelf life. Polyester resin from these people is $37 to $38 a gallon
: by comparison. Here is their description of the material: General Purpose
: Vinyl Ester Resin
: Tough and Corrosion Resistant
: This vinyl ester resin is formulated for maximum corrosion resistance to most
: fuels, vapors, and both acidic and basic chemicals. It is also heat
: resistant and blended for toughness. These qualities make it perfect for
: repairing tank linings, blistering boat hulls, as well as fabricating
: tough all-around parts. Catalyze with 1.25% MEKP, Shelf Life Limited to 3
: months.

: - - - -- - - - -- -

: Hope this helps

: PGJ