Getting satisfactory results with MonoKote

[NatefromOgden]

Hi all. I'm a new builder, built a tissue covered rubber powered plane winter before last, have built a couple FT foamboard planes and now am trying to finish up a Hobbyking Sunbird sailplane. This is my first foray into ironing on coating. I've done the fuselage and tail pieces with no trouble.

It's the wing that is giving me fits. I've intended to make the front portion of the wing- from the spar forward white and I'm having trouble getting the Kote to stick to the spar. It tries to pull off when I go to shrink it. I've done each wing half in 4 pieces (2 top & 2 bottom) because my first attempt to do it in 2 failed at the bend point.

Would I be better off changing my scheme to get 1 color from leading edge to trailing edge? Maybe making the contrasting colors split front to back instead of down the spar? I realize now I couldn't have picked a more difficult wing to cover for a first attempt.

Would love advise from minds immeasurably smarter than mine.

 

[Joker 53150]

One thought would be to attach the two pieces of covering to each other BEFORE putting them on the wing. You'd make sure that they are bonded well, and don't use too much heat in this process. When you later shrink the covering be careful to not apply too much heat to the area where the colors overlap.

Are you trying to shrink the first covering before applying the second? That could also be a problem as the cover sticks better to more covering than it does to balsa.

Also, be careful when shrinking the covering on that wing! The SunBird's wing could be easily warped or broken by over-shrinking. Warpage can be removed, but broken balsa needs surgery to fix.

 

[NatefromOgden]

Joker, thanks for the response. In pondering it last evening, and not having a trim tool, trying to join the 2 colors together on the bench seems like a pretty advanced trick for a first attempt. I think I'm just going to change my scheme and make the wing 1 color with the wingtips in white. That way I can cover from leading to trailing edge with 1 piece. I think I'll still have to piece it where the wing tapers to avoid the Kote pinching and folding I suppose but will give it a try as 1 piece.

 

[bicyclemonkey]

It may sound obvious (and I don't mean to offend) but if it's your first time to monokote, did you peel the back off the film? Even at the lowest iron setting, if the iron has been heating for 10+ minutes, it'll activate the adhesive and should stick. A little warmer temp and it'll start to shrink. Don't go too hot or it'll shrink too much and warp the wing.

 

[GT6mark3]

Nate, I finished my Sunbird in a similar scheme to the one you first described using HK white and translucent yellow film. I applied the yellow first then overlapped the white onto it. Before applying the film I use a product called Clearcoat marketed by Solarfilm in the UK. It's main use is as a non yellowing fuel proofer and to improve film adhesion. You simply brush a thin coat onto the perimeter of the area being covered by the film and allow 15 minutes to dry. After a light sanding with 600 grade abrasive paper you can tack the film into place with your iron. Where the White overlaps the colour you also need to brush a thin coat. The heat from the iron seems to make the Clearcoat tacky and causes the two film laminations to bond together really well. Whilst this product might not be readily available in the US I'm sure there must be an equivalent that you can use.
I don't regularly use Monokote (because of the price!), but the HK film is very easy to use, doesn't sag when left in bright sunlight, and is much cheaper (in the UK). The photo shows my sunbird, with a couple of changes to the fuselage to make it match the elegant wing profile. They comprise rounded balsa blocks at the nose and a pair of 1/8th balsa stringers glued to each face of the fuselage. When covered in film it gives a faceted circular cross section to the fuselage.

 

[Joker 53150]

Looks like we've got pretty similar design taste for the SunBird!

 

[willsonman]

http://www.sigmfg.com/IndexText/SIGSX001.html

or

http://www.coverite.com/accys/covr2500.html

I actually have 3 cans of the balsarite. If you need some I can ship you a can. I'm not doing that much balsa building anymore and what I have will probably go bad by the time I get around to using it.

 

[NatefromOgden]

To each of you that has commented, thank you. Your wing covering designs are beautiful and your advice well received. I think my biggest frustration has been with the green colored cover that I bought that was a few years old and rolled so tightly that getting it flattened out has been a challenge. I've tried leaving it on my table unrolled and held flat but it didn't seem to make much difference.

I've no pictures yet but I do have 1 wing finished and the other part way done and the 2nd seems to be going better than the first. I've tried to shrink as carefully as possible but still have some wrinkles that I'm not certain will come out unless I start over. I changed my plan and made my color run leading edge to trailing edge with a white band in the middle and white tips. I'll get some pictures in a day or two for your review and recommendation.

Wilsonman, if you'd care to share a can of balsarite, I'd love to use it on my next project or during repairs to this bird as no doubt will be required in the future. The address is 1527 Rushton St. Ogden, Ut, 84401.

And since I have you all, I need further advice about a motor. I purchased one upon the advice from 1 LHS that assured me it would be fine and the next LHS said I would burn it up so I purchased the Parkzone 480 and prop that powers the E-Flite Radian. I should have purchased a standard 480 but mistakenly thought I could use the B model that mounts from the front, hoping I could fit it inside the fuselage.

So, is the 480 too big? Should I just swap it for a rear mount or disassemble this one to make it a rear mount? I have a Goldberg Electra waiting for an upgrade so I can use this motor for that plane as it will require some carpentry to be upgraded and I can put it aside for now.

Thanks gents.

 

[Joker 53150]

I'm heading out your way in a couple months, but will everywhere in Utah except the SLC/Ogden area. Moab to Cannonville to St George, and everywhere in between both on and off road. I love the area, and get there as often as I can.

I can't offer any help with the motor question, but look forward to the pictures. As you probably know, it gets easier as you do it more often. Some covering is easier to work with than others, and there is certainly a difference in how they stick and shrink.

Are you shrinking with an iron or with a heat gun? My preference is the heat gun, although some people swear by the iron.

 

[NatefromOgden]

Joker, mostly I have been using the iron though I also have a heat gun which I have tried using gingerly. I'm nervous about applying too much heat and warping that fragile wing,

 

[Joker 53150]

You can get great results with the heat gun, just remember to keep it moving. I run back & forth over a small area and carefully watch the shrink. It is also great for getting warp out of a wing (as well as creating the warp). If my wing is warped I'll hold one wing tip between my knees while seated and twist the wing in the opposite direction slightly. You'll then see excess material bunch up showing where to shrink, effectively pulling the warp out of the wing. Again, you need to be careful to not over-do it, but it works great.