fiberglassing floats

[battlestu]

Hello all,

Looking for some advice on to fiberglass my floats. I've done some fiberglass work in the past but nothing this big.

Which resin should i use on foam? (in the past i would use 30min epoxy with a bit of alcohol mixed in to thin it out)
How do i get a nice smooth finish?
Should i use a heaver cloth on the bottom of the floats?

Thanks
Greg

[piker]

Are the floats cut from blue/pink foam?

My Sandringham has 1.4oz cloth everywhere except on the bottom ahead of the step where I think I have three layers of 4oz.

I find the bottom to be more than strong enough for water, but a little delicate for flying from land, especially from the Bramalea, limestone "fuselage rasp" runway    I find the nacelles (blue foam) to be delicate... they dent easily.

So based on that, for the floats I think you're asking about (for a 3 or 4 pound plane) I'd simply use 4oz. overall.

For Resin... DON'T use polyester resin.  It melts foam.  Use a finishing epoxy and thin as you like (I've never thinned epoxy.  I have low viscosity, long pot life stuff from years ago).  You want it thin enough to wet out the dry cloth while in place.  Try to overlap at the keel to add extra thickness there, and remove all the excess epoxy you can while wetting out.  A squeegy (sp?) and paper towels work well for this.  For shapes like floats, I use a foam brush to apply the epoxy.  When cured, sand the rough seams, spot putty the deep grooves, and spray with high build Motomaster primer.  Sand (with 320-400 wet sand paper) and repeat until you have a nice, smooth surface.  Ideally, you don't want any weave showing through your paint.  i like Canadian Tire Krylon paint as it goes on lightly, so the weight can be controlled.

Robert

[battlestu]

Thank you for the advice... sounds like i'll be busy sanding for next little bit

Yes they are made from pink foam

[Bobmic]

How is water based Varathane compared to finishing epoxy for this type of job?
It is significantly easier (and cheaper...) to apply in thin coats, It is not as strong as epoxy but I think it should be good enough for covering foam.

[piker]

I don't personally have a lot of experience with water based polyurethane, but I know people have used it a lot.  Laddie Mikulasko is a prime example.  I agree, it probably won't be a tough, but it might be easier... unless multiple coats / days are required.

Robert