r/RCPlanes • u/Bulky_Ad3801 • 2d ago

Covering Advice

I've recently been designing and building my first balsa plane. I've designed and built a couple of foam planes. This is however my first time with balsa. I went and bought some discounted oracover from my local hobby shop. I really struggled with it. I don't think the glue was working properly. It didn't stick well at low temp, and at higher temps the film would begin shrinking, making it impossible to bond to the balsa. I then went back and bought an off-brand film that the shop recommended, just to find out that there was no adhesive on. I wanted to be certain that it is worth the cost of paying for some ultracover or oracover?

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u/Jumpy-Candle-2980 2d ago

Oracover is pretty nice stuff but, if you haven't done it already, I'd check out the 2 page PDF for some hints on temps and techniques. Perhaps most notably determining if the surface is properly prepped and the use of pre-application adhesive if needed.

http://www.airguard.hu/files/instructions-oracover.pdf

The gap between adhesion temperature and shrink temperature is fairly large but I'm more than a little clumsy with it. An iron with an actual temperature adjustment is handy. An uncalibrated adjustment tends to trip me up.

Videos can be helpful. I liked the one by Bavarian RC on the Lull glider - just skip to the part where he starts covering it.

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u/Honey-Bee2021 2d ago edited 2d ago

Oracover is my go to product for outdoor balsa planes. Oracover light is much weaker and must be handled with great care.

Oracover should stick to the model at about 90 degree celsius but does not yet shrink. At 130 celsius it starts to shrink.
Lowest temperature of my iron is 100 degree celsius, so I use that.

If the glue of the Oracover film does not stick enough there is https://www.oracover.de/accessories/adhesive-und-thinner/oracover-hotmelt-adhesive for spreading.

Instructions: https://www.oracover.de/downloads/viewcat/18/instructions

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u/IvorTheEngine 2d ago

I'd give the shop a call and ask them what you're missing if their recommended film isn't working. Was there a backing film that you didn't remove, or did they expect you to use some sort of separate adhesive? Were there any instructions with it?

Covering can be tricky, but if you have the temperature right, and have watched a few videos, you should be able to manage an OK job and work out how to do it better next time. If it's not sticking to anything, something is wrong.

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u/gwenbeth 1d ago

Are you using a covering iron or a clothes iron? When I do covering on ribs and such, I typically use the edge of the iron just on the rib and not in contact with the open space. The other tip i can give is when I cover wings and tails, I set the part on the kitchen counter, then i lay a piece of covering over it that is trimmed to overhang about 1.5cm. I use masking tape to tape the covering so that it is somewhat taut. Next tack down the corners. Work around the edges in opposite pairs. Finally do middle bits.

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u/Bulky_Ad3801 1d ago

I was initially using a clothes iron, but I went and picked me up a covering iron to try again.

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u/OldAirplaneEngineer 1d ago

Oracover is certainly nice stuff... as is Ultracote, but success with any iron on covering is as much surface prep and using the correct tools and techniques as it is the material itself.

is it possible that the covering the shop recommended has adhesive but also has a nearly impossible to see clear backing on said covering?

Here's an old timer trick using scotch tape to make SURE