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Mar 14, 2011, 12:44 AM
Registered User
Thread OP
Discussion

fiberglass boat hull


Hello,

I've sculpted a nice big ship hull from the blue styrofoam and I'm going to lay on 2oz fiberglass. What is the best stuff to put on styrofoam so I can easily remove the mold after the glass is done curing?

I've google'd around for ways on how to save the mold (pop it out) and can't really find anything so I've accepted the fact this is going to be "lost foam", but I don't really want to work with hazardous materials such as acetone to burn out the styrofoam (have read somewhere it can possibly weaken the fiberglass) and cutting it out is tedious and probably won't look very nice on the inside of the hull when done.

Any tips?

Also, how many layers of 2 oz fiberglass should I use? The boat is 4ft long, 1ft wide. Last thing I want is poke a hole in the hull hitting a rock.

Thanks!
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Mar 14, 2011, 02:20 AM
USA'd ex Brit
toesup's Avatar
Quote:
Originally Posted by firefly_joe

I've sculpted a nice big ship hull from the blue styrofoam and I'm going to lay on 2oz fiberglass. What is the best stuff to put on styrofoam so I can easily remove the mold after the glass is done curing?
Parcel tape..

Or you need to do a lot more work to get a plug / mold / hull..
https://www.rcgroups.com/forums/show....php?t=1108150
Mar 14, 2011, 06:04 AM
Cheif Bottlewasher
more coffee's Avatar
Ive been pondering the same as you joe.

My thoughts..
acrylic primer..many coats to seal the foam, atleast three coats of flat paint on that..then atleast three coats of glossy paint on top of that.. let it set for a few days..then a few coats of carnuba wax to act as a release agent.

You didnt mention it ..but regular drywall compound can be used as spot putty to fill any pit's or gaps.
Mar 14, 2011, 07:17 AM
Registered User
You might try spraying it with PVC, we used that when making small parts .
The paint and wax seems like a good solution too
Cecil
Mar 14, 2011, 12:10 PM
Registered User
Thread OP
Awesome, thanks for the tips!
Mar 14, 2011, 01:53 PM
r/c ships and workboats
What medium are you looking at using for the resin--polyester or epoxy as that knowledge will also help prevent the loss of all the work you have done if you can answere that for us.
Mar 14, 2011, 10:37 PM
Registered User
Thread OP
I'll be using epoxy
Mar 14, 2011, 11:00 PM
Boats on the brain!!
green-boat's Avatar
I'm glad you said that you will be using epoxy. Spraying the mold with PVC then covering it with polyester resin will result in a gooey mess. Polyester resin will melt anything containing styrene. Foam molds usually are a lost cause because the resin sticking in all the nooks and crannies. You could leave it in and carve out the needed spaces leaving the rest for ballast. In place of Acetone, brake cleaner will also work.
Mar 15, 2011, 03:27 AM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
When you guys say spray with PVC, do you mean a plastic coating?

Or do you mean PVA?
Mar 15, 2011, 07:02 AM
Registered User
tghsmith's Avatar
if using epoxy, you could paint the foam with several coats of resin (the first coats with some filler added, wood flour or micro balloons) sand and finish to final shape, wax and pva before adding resin and cloth to make hull or mold for hull..
Mar 15, 2011, 08:43 AM
"day ain't over yet-"
der kapitan's Avatar
The input from many of the people on this thread is absolutely correct, Firefly Joe.

Using blue foam and polyester resin will result in a gooey mess, generally resembling nothing like you started with, and a lot of disappointment on your part---.
Mar 15, 2011, 03:14 PM
Registered User

PVA not PVC !


Quote:
Originally Posted by Umi_Ryuzuki
When you guys say spray with PVC, do you mean a plastic coating?

Or do you mean PVA?

Yes I did mean PVA, had a senior moment, thanks for the correction..........
Cecil
Mar 15, 2011, 05:08 PM
Registered User
Jerome Morris's Avatar
Question! I've been priming and fairing my hull and am curious what to put on it to make is shine. Once the hull is where I want it to be, do I just wax that or should I apply a high gloss top coat before waxing it?
And should I use a carnuba based wax or the mold release wax I have.
Thanks!


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