Any thoughts on using polyester (boat resin) versus epoxy (West System) for a Jet A/kerosene fuel tank other than cost?

Roy

Personally I wouldn't even consider Polyester, for the smell alone and strength is another reason. The cost difference in a part that small is not significant.

Because of the structure of the Polymer chain of each and how they set, Polyester resin will shrink substantially more than an Epoxy.

As a short explanation, the catalist of a Polyester is an exciter and attracts the chains to each other, once it has done this it leaves a small amount of itself behind and moves on to the next chain, that is why Polyester resin only needs a small amount of catalist and has some substantial shrinkage issues, also in bulk it will produce substantial heat, but will set underwater if that is what you need, with an Epoxy the catalist becomes part of the chain and does not move on hence the reason to always mix Epoxies well and in most cases's at a strict ratio of about 50:50 by becoming part of the chain and not moving on the shrinkage is much less, but needs a temp above 5deg to set correctly.

Hope that helps.

Mike

Oh yes and another thing with Polyester resins they will melt most of the Polystyrene foams on the market today, so be carefull with what material you use for the plug.

Mike