Plastic Covering Materials

[Sakura Maru]

Hi all, before I do this, I was wondering if any of you have tried covering materials such as Monokote as a hull finish, particularly on balsa and plywood. I've seen it done once so far, but I'm wondering about long term maintenance and water intrusion. I'm considering pre-finishing the hull with Balsarite so the film sticks better to the wood and offers some measure of fuel proofing. I figure if float plane pontoons are done this way, why not a whole hull? Your thoughts on this matter are appreciated. When it comes to using fiberglass for a finish, I'm rather lazy.

[pompebled]

Go ahead, be lazy.

Cover a hull this way and keep us posted how it keeps up.

My major concern would be the fact that a floatplane only spends a short time on the water, so minor scuffing or pinholes wouldn't do much damage to the wood underneath.
On a 'normal' boat the exposure to water is permanent and damage would result in more swelling of the wood, rendering the hull useless.

That's why I always cover a wooden hull in epoxy (and glasscloth if the need arises).

Regards, Jan.

[Sakura Maru]

Ah, so I'm the trail blazer today, eh?

[pompebled]

Yep.

[CG Bob]

No, you're not the first to try it. I've seen several racing sailboat models that used Monokote or similar products for the main deck covering. This stepped hydro pool racer (http://rcstore.com/ME2/dirmod.asp?sid=521FEB3C003A47F1B2FD524B47FF0DF7&nm=Test&type=EcomBB&mod=E%2DCommerce%3A%3AProduct+Catalog&mid=D30FB4BBE3764A5694C4972616B7262A&tier=3&id=2ED7AAE6050B41E597901CA37D5D26BC&ntier1=Plans&ntier2=Boats&ntier3=&ntier4=&ntier5=) is made mostly from insulation foam that is covered with Monokote.

[Brooks]

Monocoat is tough, but not invincible - pinholes and tears would be inevitable I think. While pinhole leaks though Monocoat applied over foam would not cause permanent damage, I would not trust balsa under the same conditions. But, if you waterproof the balsa before covering with Monocoat, then that concern would be covered.

Possible problem - When covering large areas of balsa, in a wing, for instance, air trapped between Monocoat and the balsa causes bubble problems. The WoodPecker was designed to put pinhole slices in balsa to give the air & adhesive gasses a place to go. But pinholes in your hull's balsa would defeat the waterproofing. The pinholes from the Woodpecker don't go all the way through the balsa, but they would break the waterproof barrier you applied to the balsa before covering.

Upshot - try Monocoat technique on a scrap hull-like object before committing to your final hull.
Woodpecker info:
http://www.monokote.com/accys/topr2190.html

[mfr02]

Back in the elder days it was cellulose dope and tissue. Thinned dope to proof the balsa, tissue applied and doped on. No bubbling problems, but you do get that vintage modelling aroma. I would assume an extra layer of fuel proofing for that type of motor.
As Brooks says, whatever you try, test on scrap first to check out any problems.

[Stu :)]

I skinned my current tug boat project in dope and tissue... It's quick to work with, I skinned the whole hull with 8 coats plus sanding in one night, bet that epoxy. However the overall cost was higher and I'm not to sure on the strength yet, a resin coated balsa hull feels like you could hurt someone with it :eek: But the doped hull does have that same feeling to it.

I think a fly-boy plastic wrap hull sounds a bit dodgy to me, but I could be wrong. I use resins not only for waterproofing, but strength as well.

Stu :)

[785boats]

I tried Solarfilm once. It pulled away from the concave sections of the hull as it shrunk. More than likely bad technique on my part ( I was young & foolish ) so I gave it away & used the time honoured tissue & dope. Now that I'm old & foolish, I would give it a try on the right type of hull ie no concave bits.
Think of all the great colors with no painting required.
Paul.

[spacephrawg]

I would say just stick with brush or spray on sealants. They'd be more durable than the proposed methods discussed here IMHO, but then again I havn't tried it myself.