Instead of mold release wax???

kloudie1 · Feb 16, 2009

non-stick spray like Pam or Crisco is fine.. Mist it on lightly. Floor paste wax will work too and not leave a liquid mess to deal with..

CalebD · Feb 16, 2009

Hermit,
There are some plastics that epoxy will not stick to - I am not sure about vinyl ester but it is also likely as I keep hearing that epoxy has the highest adhesion of all the resins.
Empty gallon plastic milk/water/OJ jugs and even some plastic take-out food containers can be cut up and used to make (more or less) reusable molds using some duct tape at the seams. In fact, any material that will flex once your resin hardens can be used but thin 1/8" plywood will leave some pieces of wood attached to the resin. The advantage of using something like 1/8" ply or plastic is it can be shaped to conform more closely with the inside slope of the hull.
I know that epoxy will release from the plastic mixing buckets I use to make it in once it cures.
The best way to figure out how to get away without mold release agent is to try a few small samples with the resin you have, let it cure and see how easily it will detach from the mold.
RichH knows the chemical names of the plastics that resist a bond with epoxy and might even be able to suggest a substitute material to use.
Good luck. I enjoyed reading all the responses to your C30 to the Bahamas thread. Thanks for that.

Steve Dion · Feb 16, 2009

Why not just take plywood plates and over size the thru hull hole. Then you can either epoxy or glass the wood. I have never had a boat that did not have a plywood backing plate, so while I understand they get a little moldy, they have worked for many years without a problem.

Ross · Feb 16, 2009

Cereal box liners are good, thick polyethylene sheeting works. do you have an air roller? that is the little roller with grooves about an eighth inch apart that works the resin into the cloth and gets the air bubbles out when you aren't vacuum bagging. Yes 24 ounce roving is hard to wetout and white spots are dry spots. I like to use CSM between layers of roving, the gaps in the weave in the roving are big/little holes and the CSM helps to fill those and increase the contact area between plies.

Maine Sail · Feb 16, 2009

Hermit Scott said:
I need to start my fiberglass backing plates tonight for my through hulls, but I didn't order any mold release wax. I don't want to put this off another week and there are no places in San Antonio I know of that would have it.
Does anyone know of a common land lubber store like Home Depot would carry it or maybe it's there under a different name?
Is there an alternative I can use? I have a 2'x2' thick piece of glass to build it on, gallon of vinyl ester, and 10 yards of 24 oz. roving cloth. Is that thickness of cloth hard to wet out? Are there anythings I should watch out for doing this?
Messing around with this is going to be practice for a dinghy also.

Wax paper works fine. Be careful with automotive waxes as they often contain silicone which can contaminate the glass work..

Where did you find vinylester in one gallon sizes??

Maine Sail · Feb 16, 2009

Hermit Scott said:
Lowes-styrene monomer same thing I repaired the blisters with. It's $35 a gallon. And it was easy to work with.

Steve- I need some practice with fiberglass, since my goal is to work on my boat in exotic locations.

Hermit,

If you bought it at Lowes for $35.00 a gallon it's likely not going to be vinylester but rather polyester. This will be perfectly fine for backing blocks, but Lowes at least up here, sells Elmer's resin which is polyester not vinylester.

The going rate for a gallon of vinylester is usually between $75.00-$90.00 per gallon. Styrene monomer on it's own is a reducer / thinner you can buy for polyester resin to make it wet out better. It is also an ingredient in BOTH polyester resin & vinylester resin.

If you actually found vinylester for $35.00 a gallon I know a LOT of folks who would want to buy some including myself!!:dance:

Vinylester is essentially a styrene modified epoxy resin, hence the fiberglass smell, and is why the price point is closer to that of epoxy..

jibes138 · Feb 17, 2009

Couple comments

After using it countless times building boats, I have found Saran Wrap to be the best mold release. It is thin, can be stretched and adheres nicely since it electrostatically clings to anything. What is great is to use it on top of the repair to get a really smooth finish to eliminate or minimize sanding. Just lay it down smooth it out and duct tape it in place, Do your layup and let it cure. Remove it and peel off the saran wrap, no greases or waxes to try to remove.
Check out Merton's fiberglass supply in Springfield Ma. to see if you can get 1 gallon cans of vinylester. He is an old friend from high school and specializes in this kind of thing.

jibes138 · Feb 17, 2009

Maine Sail Check this out

My old buddy Merton has this on his web site. You can get 1 gallon cans for 45 bucks. He advertises in Soundings. Good guy, helped me out when I needed to glass the bottom of my dinghy when it started leaking from the plywood checking.

Home :: Vinylester Resin (promoted)

Ashland Aroguard 45
Vinylester Resin (promoted)

Resilient corrosion resistant bisphenal epoxy vinylester, particularly, suited to high stress/fatigue and thermal cycling situations where optimum structural properties are desired. Provides the best high temperature physical properties and corrosion resistance.
1 to 4 Gallons$ 45.00 each5 or More Gallons $ 42.75 each5 Gallon Pail*$198.00 each*Customer pickup or motor freight only.

Prices include catalyst. (2 fluid ounces per gallon)

BobM · Feb 17, 2009

Thanks for the tip about Merton's...plus he's local to boot.

And in answer to Hermit's question...yes there are chemists on this site...but there are many types of chemists. So if you are losing sleep over your thu-hull project I can assure of the chemical purity and stability of the sleep drug Lunesta, which my company Sepracor sells ;-)

Maine Sail · Feb 17, 2009

Great price

jibes138 said:
My old buddy Merton has this on his web site. You can get 1 gallon cans for 45 bucks.

Great source!! That is the best price I've ever seen on vinylester, of course the shipping is what kills you.

As I said above the Elmer's is fine for laminating backing blocks and you could also use polyester to bond it to your hull if you are through bolting the seacocks. If you are tapping the backing block and not through bolting I'd personally feel much more comfortable with thickened epoxy..

Maine Sail · Feb 17, 2009

Hermit Scott said:
I ordered the bolts to through bolt the flanges from fastenal. Looking at prices of resins, I can't see elmers being vinyl.
I think I would prefer to use CSM in between the fiberglass backing plate and the hull. Maine Sail- is there a reason you use kitty hair instead of anything else?
BobM-how are the secondary bonding charachteristics of Lunesta?

Sorry for the late response but I'm away this week, currently in Texas, for business. The simple reason was because I was through bolting and wanted to finish the project same day. It should be noted that both the backing block and hull were really scuffed up with a brass brush on a drill and washed with Solvent 202 before installation. While kitty hair is nothing more than CSM, some filler and polyester resin it does offer considerably less adhesion strength than that of epoxy so if not through bolting I would not have used it.

Maine Sail · Feb 18, 2009

Hermit Scott said:
Where were you in Texas Maine?

Still in Dallas but leaving for the airport soon to head to Philly..

Mike B · Feb 18, 2009

Hermit, I think Bob M. is going to have to sleep on it before giving you an answer