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Old Dec 04, 2004, 09:32 PM
Balsa is love....
glue_sniffer's Avatar
Los Gatos, CA
Joined Aug 2004
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Then I use a straight edge and a exacto blade to cut my pieces out of my sheets - this also makes getting an even overlap on all your parts super easy - since the parts are trapped under the "tarp" the stay in place until they're fully cut away.

Another great thing about Doculam - trimming it around your pieces is WAY easier than Solite - it doesn't have nearly the same tendancy to tear or run that Solite does, it cuts very straight and easy, and doesn't require a brand new blade every hour or so the way that Solite does.
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Old Dec 04, 2004, 09:34 PM
Balsa is love....
glue_sniffer's Avatar
Los Gatos, CA
Joined Aug 2004
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then I just wrap my excess around to the other side, flip my pieces over and repeat! Easy right? Try it, you'll find it works great. this is one method that plays into one of the advanteges of Doculam - it's insanely cheap - there's definitely a lot of extra/waste using this method, but it's hard to care when I have 3000 square feet of the stuff for $50!!
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Old Dec 04, 2004, 09:42 PM
Balsa is love....
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Joined Aug 2004
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I got bold and gave my wings a shot in the same manner - and hey it worked! Below you see one of my "during" pics - I should have taken more, sorry. Anyway, the way I did it in the picture worked ok, but I've since come up with an even better method:

1. Place your wing on your table with the leading edge right on the edge of the table. You might want to consider keeping it in place with a few pieces of double sided scotch tape, just so it doesn't move when you're stretching the Doculam.
2. Prop up your trailing edge with some spare balsa. 1/4" will be just fine. (I did this on my wing in the pic, it keeps the Doculam nice and tight across the whole trailing edge. Use stick stock so the whole trailing edge will be supported.
3. Lay your Doculam over your wing - let the Doculam go an inch or so past the leading edge, down the side of your table/desk (it helps to have a reasonably thick table, or a desk with a solid side on it.
4. Now just follow the same procedure outlined in my previous posts, treat it just like your tail surfaces.
5. Depending on your wing shape, you may have to do the tips "by hand" once you have tacked down the rest of the wing. For my Bellanca I only tacked down to the last main wing rib since the tip rib is so much shorter, and it wasn't possible to get the wing and the tips wrinkle free. The tips were a breeze once I had the whole wing tacked/shrunk.

The idea of the trailing edge shims to raise it up will also help any parts that have significant taper - if you have super tapered tail feathers just prop them up a little so that the Doculam does not lose contact with the trailing edge.

Now, granted, the only thing you can't do with this method is a fuse, but hey, this gets about 3/4 of your covering knocked out in no time, with no hassles. Give it a shot, I think you'll find it's pretty cool!

Of course, this method also works with any covering material that's iron on, but I have to say.....I'm off the Solite wagon completely!! I LOVE how this stuff looks painted, and it's still very light, and WAY stiffer than Solite, so much more rigid too.
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Old Dec 04, 2004, 09:47 PM
Imagine That!
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Tularosa, New Mexico, United States
Joined Jan 2003
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Nice work, glue sniffer! That's a good trick that I'll try on my next bird.

I find that a heat gun works really well for getting the last of the wrinkles out of Doculam.

Tom
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Old Dec 04, 2004, 09:57 PM
Balsa is love....
glue_sniffer's Avatar
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Thanks Tom - And thanks for all your TurboCAD help in getting this project off the ground in the Builder's Workshop forum! I found with this method - doing a real proper "shrink" isn't even necessary - the parts come out so tight and nice just from my 250-300 degree tack, that turning up the iron and shrinking is totally not needed most of the time.

Along the same lines - something I noticed with Doculam is that "less is more" when it comes to shrinking. Don't shrink it any more than you absolutely have to - after I finished my tail feathers using this method, I turned up the iron to shrink them, even though they were already nice and tight. What I found was that shrinking one side lead to a few wrinkles on the other side. So I had to go back and forth between sides a few times to get things just right, and in the process deformed my rudder ever so slightly - remember Doculam may not shrink as much as other coverings, but its' pull is very strong! I've since learned to only shrink the parts that truly need to be shrunk, and have had no problems with this approach.
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Old Dec 05, 2004, 12:12 AM
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Gluesniffer,

Thanks for sharing the great tips, I'll have to try that method on the next suitable project I have to cover.

AmpAce
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Old Dec 05, 2004, 06:52 PM
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Gluesniffer, you need to send this one into the mags! Great idea and one tha prevents all the problems.

I have run into the 'multiple recurring wrinkles' issue as well. Never occurred to me the doculam was pulling the frame that tight. Here it is true that 'less is more'!

Since I am in the middle of covering my Bird Dog I will use your method on the wings. Will have to prop up quite a bit to preserve the dihedral and washout, but, that should work to my advantage.

THANKS!!!
charlie
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Old Dec 05, 2004, 07:37 PM
easily confused
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Nashville Metro, Tennessee, United States
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About the only thing I'd add to the technique is something I always do, on all sharp corners, be they acute or obtuse: I use a small separate piece to cover each of these first. For example, on the near corner of your wing at the TE, I'd use an 'L' shaped piece wrapped around it.

You don't need much at all, maybe 1/2" long, which gives 1/4" extending from the point of the corner on the edges, also allow at least 1/16" in width beyond the edges to lie on the upper & lower surfaces; obviously on the angled TE root rib it'd be a bit wider due to the taper, but you get the idea.

After ironing the covering to the edges just slide your iron over the 'tabs' to stick them to the upper and lower flat surfaces, kind of like taping a box. In these corners the material may fold over itself a bit but it'll stick, and besides, it'll be covered by your main piece of material.

This way you get super clean corners with no little odd shaped scraps of covering protruding...which look even worse when they get some paint on them.

Not just corners, either...control surface outlines benefit, like the faces at the TE where ailerons hinge using CA-type or hinge points; ragged edges here can look awful. It's a little more effort, but the clean looks are worth it to me.

Glenn
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Old Dec 05, 2004, 08:07 PM
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Have you tried a soldering iron instead? With some coverings, you can just iron it down, then run a soldering iron around the edge...it cuts the outline and seals the edges at the same time. Try it on doculam.
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Old Dec 05, 2004, 09:55 PM
Balsa is love....
glue_sniffer's Avatar
Los Gatos, CA
Joined Aug 2004
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Hey Charlie -
With this method, you don't have to worry about washout and dihedral quite as much as I'm thinking you're thinking (ha! does that make any sense.....anyhow) Since my iron is set to my tacking temperature(250-300), and not my true shrinking temperature(~375), you have a lot of room left in the materials shrinkage to correct problems or add washout.

Since we're talking about washout - Have you guys noticed that since Doculam is so stiff and rigid, that you have to put more washout in your wing when you're setting it/shrinking it? My Bellanca called for 1/8" of washout - I held down the egdes and put a 3/16" shim under the trailing edge in order to get my 1/8". I tried a 1/8" shim to start with, and it only put about 1/16" in there. Mind you, once it was set, it was SET. Hasn't budged a millimeter since then, which is nice. Anyone else experience the same thing?

Glenn - I settled on the Tamiya paint, it looks fantastic! I'm definitely hooked on painting models, can't believe I waited this long. Do you have any pics of your "super clean edges" method? I'm really visual, and trying to visualize in my mind how what you're proposing would create a cleaner corner.....and well I'm not getting it! Is the idea that you don't have to wrap your main piece around the corner since it's already covered? I have my own little tricks for keeping the egdes clean, but I would love to see exactly what you're talking about if you have a pic.

Viva Doculam!

-Sky
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Old Dec 06, 2004, 12:05 AM
easily confused
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Quote:
Originally Posted by glue_sniffer
Since we're talking about washout - Have you guys noticed that since Doculam is so stiff and rigid, that you have to put more washout in your wing when you're setting it/shrinking it? My Bellanca called for 1/8" of washout - I held down the egdes and put a 3/16" shim under the trailing edge in order to get my 1/8". I tried a 1/8" shim to start with, and it only put about 1/16" in there. Mind you, once it was set, it was SET. Hasn't budged a millimeter since then, which is nice. Anyone else experience the same thing?

Glenn - I settled on the Tamiya paint, it looks fantastic! I'm definitely hooked on painting models, can't believe I waited this long. Do you have any pics of your "super clean edges" method? I'm really visual, and trying to visualize in my mind how what you're proposing would create a cleaner corner.....and well I'm not getting it! Is the idea that you don't have to wrap your main piece around the corner since it's already covered? I have my own little tricks for keeping the egdes clean, but I would love to see exactly what you're talking about if you have a pic.

Viva Doculam!

-Sky
Hey Sky-

I think the extra washout holding is pretty common with any film, once the tension on it's released after you shrink the material, it's going to relax slightly. That said, Doculam does indeed stay right where you put it. When I covered my Stuka's wings I wasn't able to get to masking and painting them till a couple or three weeks later, and the washout I put in hadn't budged. Very stiff stuff!

As to covering the corners, I grabbed some scrap to demonstrate on. I would have preferred some tapered TE stock but I used it all up on the Halberstadt build, sorry...flat 1/16" will have to do. Hopefully it'll convey what I was talking about. It's fairly rough, the imperfections you'll see are pretty much due to the open grain...that's why it's scrap

Imagine this piece as, say, an elevator with an angled end. First, cut a piece of Doculam with the idea that it'll extend along each edge outwards from the corner you're doing by 1/4" or so..at least enough to comfortably grab with your fingertips. Not critical at all, though you want to be sure there's at least 1/16" past the top and bottom edges to lie on the flat surfaces.
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Old Dec 06, 2004, 12:08 AM
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Next, position your piece of covering centered on the edge and with the corner of the wood about at its midpoint. Iron the covering down on the edge. I cut the Doculam a bit wider than necessary to better show in the photo.
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Old Dec 06, 2004, 12:11 AM
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Smoothly iron down the excess. You could cut a slit right at the corner, but I usually don't bother; even when one side of the piece folds on top of the other, it's so thin you'll never see it...that's what I did here, and it doesn't look noticeable to me.

OTOH, be careful not to let the covering wrinkle as you iron it to the flat parts; that you WILL see! This bit did OK.
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Old Dec 06, 2004, 12:18 AM
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Repeat the above step on any corners or angles. On tapered elevators I like to do something similar on the flat end too (I don't bother if the end's sanded into a curve)...I use a separate piece there for the end, and leave some excess to wrap around the TE as shown in these pics. If there's a dowel joiner at its LE you can turn up your iron and finagle that joint smoothly as well. Of course then I'd use yet another piece to cover the grain of the dowel too...lol

Next, lay your covering down (the method you mentioned earlier would work nicely) and iron it to your 'elevator.' Use a pulling motion out and down with the iron as you come over the edge to ensure the covering's sticking to the sharp edge itself.
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Old Dec 06, 2004, 12:22 AM
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Now make slits perpendicular to each edge you've covered, this way there's no overlap when you wrap the covering around the far side of each edge.

This forms a wedgelike piece that's removed. I actually like to center the point the slits radiate out from slightly INSIDE the corner. If you just use a single piece of covering for each side, this can leave a tiny squarish bit of wood uncovered at the corner...but no worries here, the corner itself is already covered!
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