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Building Tips and technical articles. => Paint and finishing => Topic started by: Dennis Toth on February 24, 2022, 03:19:43 PM
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Guys,
I'm getting ready to do a top block and have carved and shaped it from pink foam. The pink foam is very light, carvers well (you need to use a very shape knife to slice smoothly to remove chips) and sands nice (if you don't overheat it in one place). The fuse is balsa sides and bottom with cross bracing on the top under the block for stiffness. The block is there just to give it shape. The plan is to cover it with 1oz/yd^2 fiberglass cloth using finishing resin. The question is do I wrap the whole fuse and give it one coat of resin then final fill with primer or two coats of finishing resin? Anyone know what is lighter? Could also use polyester resin if it is lighter.
Best, DennisT
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Istvan covered his blue foam plane in this fashion.
Apply a thinned first coat to the foam and wood. Allow to dry and lightly sand. Then apply another coat of resin and apply the fibreglass. Sand and paint.
I have been finishing my balsa models this way. Sand down to 400. Apply 1/2oz cloth with thinned finishing resin. Lightly Sand. Spray with primer and sand off. Paint your colours.
I would finishing the whole plane in fibreglass, no dope.
All the best.
Craig
Ps. Finishing this way us courtesy of Philly Skip👍
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Maybe the white glue/CF or light glass?
Best, DennisT
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Craig,
If you tried your resin/paint/coat on blue or pink foam if it is harmful, or not,
if not harmful, please, let us know its brandname.
It would be common interest, since I can advise only the CIBA/Huntsman Araldite LY-5052 with its hardener.
It is coming from the aerospace industry, pretty expensive, and I am not sure, if it is obtainable in small quantities.
Istvan
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That is a fair question Istvan.
I have only used Zap and Bob Smith finishing resin on balsa and blue foam, at this stage. No issues so far, but blue foam stabiliser and elevators only.
You are correct, LY-5052 is expensive and not readily available in, "Trial", quantities.
I am going to trial West systems 105 with H206 hardener in the next months.
Craig
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Motorman,
It sounds nice!
Did you experience, is this Minivax Polycrylic methanol-resistant after drying/hardening?
If is, this material is the "Holy Grail" for me, since I never-ever found any water based paint/lacquer etc. being fully methanol-resistant.
And I do not want to turn on electric...
Istvan
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I'm crying,
Just like John Lennon, when he was the "Walrus"... :)
Istvan
(All the coats must be methanol-resistant, since the vapour of it can diffund thru the top coat, and from inside begins to destroy the painted system. No mercy. Naturally it begins not in days or weeks, but within 1-2-3 years... )
Istvan
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I'm crying,
Just like John Lennon, when he was the "Walrus"... :)
Istvan
(All the coats must be methanol-resistant, since the vapour of it can diffund thru the top coat, and from inside begins to destroy the painted system. No mercy. Naturally it begins not in days or weeks, but within 1-2-3 years... )
Istvan
I know everyone likes "light."
Block under coatings with a two part auto primer.