a question on polyester resin safety

[issac]

ok, here's the thing I've finally finished the fake rock backdrop for my viv and have applied the first coats of polyester resin, when I find this website http://www.garf.org/140.gallon.html#PAINT it states that polyester resin is not safe for aquarium (in my case viv) use, however I have read elsewhere that it is safe. so now I am not sure if I have to start over, proceed as planned, or can I seal the whole thing polyester and all with an epoxy for portable water tanks (which I had no idea even existed, and neather did the sherwin williams rep that I consulted) thanks for any help

[Kyle Barker]

here is the thing. there are many types of poly resins. So while some are excellent for animals, some are not. Some take very long times to off gas and the air inhibited ones often always have some amount of the final product not completely cured.

The advantage with epoxies is it is strong, more durable and doesnt shrink while it cures. In most cases it does take longer to cure than poly resins. It also sticks to everything!

There are many types of resins used in fibreglass. Polyester and epoxy are just the easiest to work with and more common ones. Some others are silicone, phenoloc melamine and thermplastics. These really would help you in this case, but gives you some names to read up on. These are all considered "families" , just like animals there are a bunch of things in a family. So keep that in mind, a poly resin could mean any number of things. Look at things like cure time, temps air pressure etc.

that site is refering to "epoxy paint". That name alone sounds to me like a really crappy way of doing it. It makes me think of people using "bondo" on their cars instead of using anything remotly decent. I stay away from anything that says its ready to go and doesnt take any or almost any prep work. There are almost always at least a couple steps in using resins and fibreglass. If it were me using a poly (which i often prefer over epoxy) i would be sure to use a poly resin that cures very hard and rigid (for the purpose you need it for).

People also tend to look past the fact that all different resins cure differently. Some poly's need temps over 400 degrees to cure, while others need heat and high air pressure. I think thats the reason people say its unhealthy for animals due to off gas, because they didnt cure it properly. If you get a nice low temp low air pressure curing poly and give it time you wont have any problems.

Read the can, contact the company. Ask what EXACTLY that particular resin needs to FULLY cure. Anyone can write up a web site and say its good or bad, but the company is probably one of the few people you will get any concrete info from. After all they could be sued if they are wrong.

EDIT: If you do decide to put something over the poly resin also be sure to use something that will stick. Lots of resins have a film that comes to the surface and therefor anything over that will just come off. That is why when people lay up their boats they do it really fast (coat before the previous coat starts to cure). if they wait too long they have to wait a day or three adn sand it down to do the next coat. Doing 20 coats liek that will begin to piss you off. anyway be sure to sand it a bit before adding another coat, unless you know the resin you used doesnt do this.