MonoCoat Finish

[Garry Finlay]

Has anyone finished a boat with MonoCoat - or similar iron on Mylar finish. I plan on building a simple rigger and hope to save a little wieght by using a basa prep (BalsaRite) and MonoCoat. I will seal up the corners and seams with CA.

I used to do this on all my planes and had good success keeping the exhast oil out of the wood. Hope to keep water out of the balsa with this one.

Let me know if someone has tried this. I may be all wet.

Garry

[Doug Forrester]

Welcome Garry
I have never personally used a plastic film on a boat. It is an interesting concept however. I think you would be smart to use a heat sealing balsa prep coat such as Balsarite as you suggest. This would increase film adhesion and also protect against water absorbsion by the wood. I would certainly arrange my seams so the film edges faced away from the direction of water travel.
I, also wonder whether the temperature differential, in and out of the water might eventually cause the Monokote to bubble.

I'd love to hear how it works out if you decide to try it.

[Otis]

If I recall correctly, Jay Turner used monocote to cover the foam sponsons of his XL cat (RCBM plans). He used Krylon on the center section, which was wood. I think he also used lexan for the riding surfaces in order to assure a light yet hard surface for the water to contact.

I've not tried this myself. It seems like it would work well. But, for a sport boat it seems like traditional paint would have a longer life. (??)

[Climate]

This is exactly how we finished our "Electron" sub micro rigger. See www.microhydros.com
We painted the original one and ended up making it twice as heavy so we opted for the film to save weight
We sealed the entire tub and sponsons with a layer of BalsaRite, and then ironed on the MonoCote.
The white that we used has not bubbled to date nor let one drop of water through. Follow Doug’s suggestion and work from the transom forward so that any joins are overlapped the correct way and will not peel back.
I would not recommend this method for anything much larger than a micro though as the film is pretty thin and not very abrasion resistant.

[AndyKunz]

I have used this several times extremely successfully. I use MonoKote (TM) (from Tower or Great Planes) which includes the glue on the film - no BalsaRite required.

There are a variety of films out there with different properties. Some (UltraCote) are low temperature, others (Solarfilm) are lighter weight, etc. MonoKote is the heaviest of them all, and needs a pretty good temperature to shrink down. It is also the toughest stuff I can find, and seems to have the best stick to wood. More than once I have taken home an airplane in a custom-fitting trash bag :eek:

Whenever you finish with the films, always keep in mind the it bonds better to itself than to the wood. You always need to overlap it onto the other surface by at least 1/4" for the best fit.

Also, when shrinking (particularly with MonoKote, as it pulls so hard) you need to work opposite sides immediately in order to reduce twisting. If you shrink it wrong, you can make yourself a banana pretty quickly.

One down-side of the films is that they are too smooth a finish. You need to scuff the stuff with a Brillo pad on the wet parts in order to improve the speed. The top-side finish can be left as shiny as you want.

No, you don't want to use the textured films like SolarTex.

The largest boat I ever finished this with as 22", but that's only because I haven't had time for more.

The stuffing box exit needs to be glued in place AFTER covering. You need to get the epoxy blob to hold down the edges of the finish where it sticks through the hull, or it will peel it back real quck!

Andy

[Garry Finlay]

This confirms my suspicions. Overlap the edges. Lap the seams away from the flow. Seal the edges well. Don’t do compound curves. Keep it to small hulls. And use common sense.

I’ll let you know how this goes on a simple 6-cell rigger that I am toying with.

Thanks gentleman, this is a great board.

Garry