polyester resin or epoxy

[edmorales]

which is the preferred material for a homebuilt hull. what are the pros and cons? anybody wish to share info on their experiences handling or using these material?
ed morales

[awallin]

which is the preferred material for a homebuilt hull. what are the pros and cons? anybody wish to share info on their experiences handling or using these material?
ed morales

polyester is cheaper, less strong, smells and shrinks more when curing.

epoxy is more expensive(5x?), a little stronger, does not smell(but is toxic! wear gloves!) and does not shrink as much.

you can very easily adjust the curing speed of polyester by adding more or less of the hardener. this is not as easy with epoxies although some system have two different hardeners(slow/fast) that you can mix.

even when cured epoxy becomes soft when subjected to temperatures above some critical temp (usually 60-80 C). not so with polyester. special epoxies might have a high T_crit.

epoxies usually need to be post cured in a heater to obtain maximum strength. a cardboard box with a hot-air-fan works OK. Polyester cures in room temp(don't cure in your home though because of the smell!)

I am not an expert, use chemicals at your own risk !

[Greg Vasileff]

"Epoxy is toxic"

I am wondering it just what ways working with West Systems would be harmful to me if in deed it is. Is it to the touch or with breathing fumes? Just how much epoxy work would I have to do in order to start worrying about this?

Thanks,

[soeren_andresen]

Hi

I prefer epoxy to polyester, the simple answer is because it dos not smell (no toxic fumes).

Over time I have worked with both, and “feelâ€

[rémi brès]

epoxy is toxic
if you are curious, just have two complete blood analysis, before and after a all week working epoxy...
you'll be surprised, and you'll never work epoxy without a "chemicalproof " mask to stop styren and other rubishes
you do not feel sick, as well as allergy, but you may risk liver cancer or other bad diseases
so protect yourselves, wear gloves, of course (no direct contact) but also wear a mask
epoxy is toxic

[Jamestj]

Epoxy HAS to be mixed in the correct ratio otherwise it won't harden ever, it is not known to give off fumes unless you get thermal runaway (so mix up small quantities at a time or spread it out in a roler tray) and therefore is safe to use inside. Most forms of epoxy will deactivate if you mix some more resin and hardener with it (in the correct ratio) whereas polyester will only form lumps and go off even quicker. With most epoxies, you should not add solvents since thermal runaway will cause fumes and possibly a fire risk. Epoxy produces a protein-like metabolite to which some people are alergic so latex gloves can be worn (unless you are alergic to latex!)