Epoxy over polyester resin

Thanks for the tips fellas. release is not really an issue as I intend to gouge out the styrofoam afterwards. Just protecting the styrofoam from melting is the issue and looks like plenty of options to sort that out. Just getting to the stage where serious hours needs to be spent sorting the console and locking in the design before I move any further with the boat build

 

To turn unwaxed resin into waxed simply dissolve some paraffin wax (used for sealing jars of jam) in styrene and add to the resin.

This will give you a hard tack free surface but it will require sanding before it is re-coated with anything.
I would use peel ply fabric.

 

You don't need a heat gun to melt the styro-foam. All you do is introduce a little bit of acetone to the area and close it off with piece of plastic drop-cloth and some tape.

 

Interesting that about acetone. I have used petrol previously with polystyrene foam but never thought of using acetone. I do know that with heat gun and and petrol the foam melts back to a solid layer providing a fair bit of structure. Better rigidity then gouging out the foam and leaving only the laminates behind

Sadly I have measured out the blocks of polystyrene I have remaining and it falls way short of using for this project. About a quarter of a cubic metre short. I am now resigned to making the structure from ply and use kerfing and such techniques to get the nice curves I am after. I am still going to use the polyester resin as budget constrains do not allow sourcing more epoxy. I have to use what I have and hope it works out

Hope to hit a nice methodology to integrate the glass and polyester buildup with the ply former and avoid the delaminating pitfalls. Which brings me back to the bonding of polyester with epoxy question. Has anyone tried applying polyester resin over a still green epoxy layer? Would appreciate learning about your results

 

Epoxy will bond to poly but not vice versa.
While poly has been used over ply for generations it is generally frowned upon now epoxy is so widespread.
But what we used to do was;
Sand the ply area to be bonded with 80 grit to remove any surface gloss/contaminant.
When taping in bulkheads etc we would score the ply with a sharp tool (tile scorer chisel corner etc.) with a series of x's along the edge to provide more grip.
Paint the ply area to be glassed with acetone with a bit of promoter (cobalt) in it, when dry, laminate.

 

I figured that be the case from reading up various things online about polyester and ply. That's why I am interested in sealing he ply first with epoxy. I have enough to paint once. I do not have access to acetone here in Fiji. That and other regular solvents are not on sale to public due to sniffers. Only products like auto paint thinners are available and sold with discretion to genuine painters and hobbyists

I did pick up a Stanley Sureform when in Sydney, thought it might come in handy for fast material removal and scouring duties

 

Fingernail polish remover is acetone.
http://en.wikipedia.org/wiki/Acetone