1975 18' sf

[dave s]

Finally got the extension/bracket mold finished; with all the rain and mess ups it took me a lot longer than I thought.
It is definitely a ton more work than closing the transom and making a separate mold for the bracket.
You can't see in the pics but I had to fully support the mold and hull, so there would be no movement between them. Every time I got in the hull or leaned on the mold it would separate!

Oh well, I wanted a project and of course picked a most difficult one!
I learned a lot esp. what to do differently and simpler- next time!


Waxed the mold three times and tried to spray Pva with PreVail sprayer- well that didn't work, so I brushed on the Pva. It came up with lots of fish eyes and streaks. It was ugly, which I could have lived with, even with a bit more fairing work, but there were areas that weren't coated. And finally with all this rain , the layer of Pva just lifted off by itself!

So reading on the West Systems site, they used hairspray as a mold release! Which is water based and the aerosol spray can made it easy to get an even coat on the mold. Two cans covered about 8 coats; trick is to spray light coats, esp. the first tack coat.

After using the stuff, I recommend the extra hold, unscented! Too bad it's clear- makes it harder to see the coats.

Decided to do a test batch first before committing to glassing the mold; sprayed some hairspray on the outside of the melamine board and brushed on some plain epoxy, CSM matt, and 1708 samples to see if it will separate cleanly.
Will see tomorrow if it's a go for glassing or I may have to add wax- again!

Lots of pics, in case it helps anyone else.