by JETMORE » Aug 13, 2012 9:20 am
We are all budget minded, and epoxy is not needed unless the smell of styrene drives you crazy, on a boat that sits outside of the water more than in the water. End-grain balsa is great. 1/2 inch will do the trick on the entire bottom. it couldn't hurt to glass a layer of plywood in the pad, also, and ill only add another 15 pounds or so. i like using 1208 biaxial, if this is not enough glass for you, put two layers down. it wets and lays easier than 1708 but 1708 is great, too. if you want affordable but good enough for fillets, mix some polyester resin with cabosil, or milled fibre, whatever is in the shop, just not talc. it is strong enough, almost no matter what you mix with it. some guys will tell you to spend $400 on fillet material, but, the vast majority of stress is in the skins, inner and outer, not the core, which is precisely why balsa and foam work just fine.
a little trick to stay on top of water migration; when you are done glassing with polyester, whether inside the hull, or outside, "chase" the surface with a circular wire brush on the end of a drill, then brush a coat of vinylester, or epoxy over the entire surface. you will barely use any material in doing this as it is a simple coating. then when you are done finishing the bottom of the boat, same thing, scratch is up and roll a few coats of epoxy. once is hardens, scrub off the amine blush, sand with 180 or 220, put a filler primer down, and paint. the idea is, you are sealing the surfaces, since the "core" is not already sealed by using an epoxy, or good quality vinyl. its a little more work, but will save you a lot of money.
if you use polyester for the job, use nice long 12:1 bevels, or "aeronautical" bevels. this helps combat the peeling issues of poly. Howard told me he never had a come back on a repair done with poly. prep the stuff properly, get all the dust off, and be sure the rags you use don't have any fabric softeners and that they are entirely cotton.
my 2 pesos.
ronny
We are all budget minded, and epoxy is not needed unless the smell of styrene drives you crazy, on a boat that sits outside of the water more than in the water. End-grain balsa is great. 1/2 inch will do the trick on the entire bottom. it couldn't hurt to glass a layer of plywood in the pad, also, and ill only add another 15 pounds or so. i like using 1208 biaxial, if this is not enough glass for you, put two layers down. it wets and lays easier than 1708 but 1708 is great, too. if you want affordable but good enough for fillets, mix some polyester resin with cabosil, or milled fibre, whatever is in the shop, just not talc. it is strong enough, almost no matter what you mix with it. some guys will tell you to spend $400 on fillet material, but, the vast majority of stress is in the skins, inner and outer, not the core, which is precisely why balsa and foam work just fine.
a little trick to stay on top of water migration; when you are done glassing with polyester, whether inside the hull, or outside, "chase" the surface with a circular wire brush on the end of a drill, then brush a coat of vinylester, or epoxy over the entire surface. you will barely use any material in doing this as it is a simple coating. then when you are done finishing the bottom of the boat, same thing, scratch is up and roll a few coats of epoxy. once is hardens, scrub off the amine blush, sand with 180 or 220, put a filler primer down, and paint. the idea is, you are sealing the surfaces, since the "core" is not already sealed by using an epoxy, or good quality vinyl. its a little more work, but will save you a lot of money.
if you use polyester for the job, use nice long 12:1 bevels, or "aeronautical" bevels. this helps combat the peeling issues of poly. Howard told me he never had a come back on a repair done with poly. prep the stuff properly, get all the dust off, and be sure the rags you use don't have any fabric softeners and that they are entirely cotton.
my 2 pesos.
ronny
