Quote:
Originally Posted by ian_upton
Bly - good to see you hear. I rarely participate on this board because I have a Bertram20 project, not a Seacraft, but the restorations here are outstanding.
I exclusively used Coosa board on my Bertram for transom and sole replacement.
One thing I found I needed to do was clean the coosa very well or lightly scuff sand then clean with solvent and put a nice flood coat of resin to make sure I got a good bond.
Curious if you have any tips on proper preparation. I also used vinyl ester exclusively, although next time I think I will save some cash and only use vinyl for secondary bonding and not for panel layups.
Looking forward to the progress.
I think I posted this link before, but here is a link to me stalled project.
http://simplifying.net/phpbb/viewtopic.php?t=1028 |
I did do some test even tho my supplier had a lot of hands on experience before being talked into opening a small whole sale supply shop. I was also told by others that some of the best new england old school custom boat builders were incorporating his use and techniques into their builds of coosa and penske board. Many of them have molds to very pretty new england lobster style boats. were building the hull in glass and almost everything else in plywood with epoxy. Now many switching away from wood. The wood process does need a hot coat because it is very pourus and if you lay up the glass normally and just wet out the wood with normal layup resin it will be soaked into the wood pours and possibly cause a dry layup under the first layer. Most that use epoxy, use only a standard west system that is so thick that the primary epoxy bonding is doing most of the work. I use a thin epoxy and thicken mine when needed for any use. On my penske coosa board I have been using vinylester resin because of its superior properties compared to GP polyester resin. For less then $10 dollars a gallon more then GP. No I do not buy it in gallon cans. So it pays in my thoughts for the small increase. On the wet out coat.or hot coat. and letting that dry first and sepparately? It is not needed like wood. A fact is that No boat builders that use normal low density divinycel foam for cores do a hot coat. that foam is very pourus also. penske coosa is not pourus. the resin will not be absorbed into the board and cause a dry coat underneath. It can only absorb less then 5% of its weight in liquid in the best situation because of the uniformity density. I will reiterate one more time that the hot coat is so your resin does not run out of the glass into the wood and cause a later delamination of the glass because of lack of resin directly under it. It wont happen with penske coosa. I see no reason not to use polyester resin if you want. Me I will stay with vinylester resin. I may try some here and there on a console type work only for personal testing incase vinylester resin was not available or rose in cost? On prep the dust is a pain in the arse and I usually cut my board in front of a high speed fan in front of the open garage door. Or i put the horses outside when nice and use the wind to blow the dust away from me. Then I usually blow the dust off the board before using or bringing back in. That is my prep. Ian I just re reviewed your progress. . Great work you did. I never realized the 20 bertrams had a curved transom and that small pie sliced bumpout for the out drive. What a pain huh.