Most Commonly asked Questions & Building Tips

An easy way to keep this Tips page handy is to print it out!  Just set your printer properties to 'Landscape', and then print a set of full-width Building Tips to use at your building table!  
As you might guess, we field hundreds of questions about our building techniques, and receive calls about small problems modelers come across when they are building.  Typically, we hear them over and over again.  These are usually very easy to solve, because we've had the same problem ourselves and have found the best solution to it.  Once again, this page is here for help save you time and trouble while building your models.  Write us with your questions!
Q:    I'm getting ready to sheet my fuselage, but I can't see how in the world this sheeting is going to roll on and stay around these rings with the glue-joints that make up the fuselage.  Am I doing something wrong?
A:    No, you're okay. ( In fact, this may be the Number One question asked by our modelers. ) First of all, you never want to sheet just the 'rings'.  You will sheet the designated areas in one solid piece on the left or right sides of the fuselage.  It's a round fuselage, and all of our fuselages are tear-shaped from front to back, and many have a break and a bevel in the front like our GeeBee Z or R-2 models.  The glue (joined) area of the 'rings' on certain models may be slightly higher than the other parts of the fuselage.  You want to take a LONG sanding board and work those joints of the 'rings' down until the whole fuselage is one long smooth line, and as we said, teardrop shaped, uninterrupted until you reach the break for the bevel in the front.  DON'T sand the bevel or the break, leave them squared off just as they are.  You're just sanding foam here, so take care not to sand too much, you can bring it down to a teardrop shape with a minimum of effort.  Once this is done, you'll easily see how you've made it so that the sheeting will roll on in one long sheet with no problem whatsoever!  Again, do NOT sheet the rings individually, this can and will affect the strength of the model.
Q:    I'm having a lot of trouble finding the 3M 2060 Lacquer Masking Tape you mention in the building Techniques Page.  Can you help me find some?
A:    You bet!  In fact, it has been a BIG problem, because the 2060 really is THE tape for the job, but fewer Home Depots carry it than we originally thought.  We've been searching for a dependable national outlet where you can find it, or at least order a few rolls if they don't have it on hand.  Well, we found it!  Sherwin-Williams, the house-paint stores you can find from coast to coast, stock the 3M 2060 Lacquer Masking Tape as standard stuff in most of their stores.  More importantly, they have a company-wide stock number for it, #155-3874.  This means you can call them, and if they don't have it, they can order it in for you, and you don't have to buy a whole case of 36 rolls, which would be a tad inconvenient for most modelers.  
Q:    I have finished sheeting some of my flying surfaces, But I've noticed that some areas of balsa lifted near the edge of the flying surface.  Is there something special I should do with the Foam Bond to make sure that little flap stays down?
A:    Once you've used the Foam Bond, you won't need to use it again.  Foam Bond is a water-based glue, and that's the secret here.  You can use any other water-based glue to hold that edge down.  We use Aliphatic Resin, like Sig-Bond, Tite-Bond, or Elmer's Wood Glue.  Simply work some of that under the flap, and use some Lacquer Tape to hold the flap down to the edges.  Near the edges, it's better to use Aliphatic Resin than Foam-Bond, as Foam-Bond remains rubbery and does not sand easily.  Aliphatic Resin sands very well in those spots, making it ideal.   
Q:    On top of my GeeBee fuselage, behind the cockpit, where the two balsa sheets join, there is a tight turn where the balsa doesn't want to stay down.  I also had the same thing on some of my warbirds.  What's the best method for fixing this problem?
A:    That's an easy one.  Use some Aliphatic Resin under the flap, spray the outside of the flap with a 50/50 mix of ammonia and water.  Then strap the flap(s) down with some Lacquer Tape, just as in the last Q& A.  Those spots are a little tougher, and sometimes the balsa is a bit harder than you'd like it to be, and won't bend as well as it should.  That's why it's so important to use the spray mixture to penetrate and help the bending.  If you use the mixture, it also helps the wood to dry and stay in the shape you've bent it into.
Q:    I built my rudder, but when I started to fit it, I noticed that the rudder is taller than the vertical stab area of the plane!  Help!
A:    Relax!  The rudder is cut the same height as the fuselage, but once you've added the capping to the full round edge of the rudder you've made it a different height by adding thickness to the top and the bottom.  Once you add your capping to the top of the vertical fin, you'll fill in most of the difference.  The bottom of the fuselage, however, doesn't call for any capping, and that often leaves about 3/8" of difference.  You can add some scrap to the bottom until they equalize in height, or you can add a little to the top of the fin.  I'd be surprised if anybody noticed 3/8" of height added to a fin & fuse that stands 16 or 18 inches in height!  If added to the bottom, you could also use hardwood to help mount your tailwheel gear.  If you're striving for absolute scale outline, then trim off the rudder bottom a little and re-cap that area so it matches.  That's the beauty of foam!
Q:    I have capped everything once and then sheeted over it and trimmed the edges square, why do I have to go back and cap everything again?  Isn't once enough?
A:    No, once is not enough.  Once you get ready to cover your plane, you're going to have to round your leading and trailing edges, etc.  If you tried to round the edges now with just the first round of capping in place, you'd sand through the sheeting to foam all over the place.  That's a BAD thing!  By adding the second layers of capping, you'll add enough material there so that you can round the edges nicely without fear of sanding through to foam.
Q:    My friend already has a Jack Devine GeeBee model like the one I'm building, but she keeps telling me NOT to sand my balsa too much.  I want my plane to look great like hers does, how can I do that if I can't sand it until it's smooth?  
A:    Now THAT is an excellent question!  What if I told you that your plane can look AWESOME and you won't have to sand the balsa much at all?  Sandable sealers are available, like Sig's Lightweight Sandable Sealer.  Once you are ready to do some smoothing, apply the sandable sealer, and let it dry.  It's lightweight, and fills and smooths the balsa in ways sanding NEVER could!  After a light sanding, you'll have removed almost NO balsa, but your model will be as smooth a baby's bottom!  Remember, foam sheeted models are exoskeletal, that means their strength comes from the combination of the foam, the exterior balsa shell & the capping, and the proper adhesive.  Take away any of those things, and you'll cause a severe strength problem.  So, tell your friend she's right!  Her plane is probably the toughest plane at your flying field because she built it right!  You should listen to her! (Yep, the woman is usual!)  By the way, uh, where is your field?    (c;
Q:    I sheeted one side of my wing last night but not the flip side, and when I came back today, my wing was warped!  Did I ruin it?  If not, how can I fix it?
A:    It's not ruined.  Did you ever watch the westerns where the rawhide ropes shrink as they dry and tighten around our hero's hands?  Well, once you wet down the balsa with the ammonia & water mix, it loosens it up and makes it more pliable, but like the rawhide in the westerns, when it dries it shrinks like crazy, pulling your wing into a warp.  You can save it, though.  First, take your 50/50 ammonia & water mix, and spray it on the entire outside of the balsa that dried, and make sure you wet it thoroughly.  Let it sit for a good 20 minutes so the balsa can loosen up again.  Next, roll the Foam-Bond onto the flip side and get it ready for sheeting, and sheet it the same way once the Foam-Bond goes clear on the foam and the balsa sheet.  Make sure you keep the side you first sheeted moist until your wing is fully sheeted, then let both sides dry together.  On smaller surfaces where you might have applied too much tension during sheeting and ended up with a slight warp, wet it down the same way, and with the warped side up and the ends up on something, place a weight on the middle of the warp, enough to bend it back slightly past center.  Let it dry there, and when you remove the weight, your warp should be history.
Q:    I've built foam wings before, but I usually use the method where I tape the sheets together, put some kind of glue on them and the wing core, place them in the shucks ( Note: The shucks are the remaining pieces when a foam wing is cut from a block.  The wing fits like a glove inside of it.  Ours are shipped inside their 'shucks' as well.), and lay a sheet of plywood over it and weight it down with concrete blocks, and walk away until it's dry.  Why can't I build mine this way?  It sure looks like it would work.
A:    Yes, it can be done that way, but we a have a few reasons why we don't use that method.  We use Foam-Bond because it lends a second kind of strength to our models, and that is flexibility.  Now, one of the properties of Foam Bond is that it dries rubbery, and doesn't sand well.  That's why we join our sheets prior to sheeting, we don't want Foam Bond to ooze out from between the sheets and create a sanding problem.  But...We DEFINITELY want to use the Foam Bond!  The simple fact is that our wings just don't fail.  There is really only one difference between our wings and other foam wings sheeted with balsa, and that is the adhesives we use!  Foam-Bond makes all the difference.  Next reason;  if there is a warp in a wing-core, then it's also in the wing shuck, they're the same piece of foam!  If you lay a warped wing into a warped shuck and glue it and weight it, it's going to come out WARPED, same as it went in!  No amount of arguing can change that, it's pure physics!  Now, when a wing and the sheeting are rolled with Foam-Bond and allowed to dry, once the Foam-Bond goes clear it is time for sheeting.  So, you spray the OUTSIDE of the sheeting with a 50/50 mixture of ammonia and water to make it pliable.  Here's the beauty of this method:  Say the wing core is warped, for whatever reason.  No problem!  You press the leading edge of the wing down onto the sheeting on a straight, flat, smooth surface, and then keep downward pressure as you roll the wing core backwards onto that flat, straight surface.  When you've finished the rolling-on, the wing core is absolutely straight.  You then do the other side the same way (in the same session, very important), and let both sides dry together, straight as an arrow.  That's right!  Your warped core would actually come out as straight as the table top!  And then it dries that way, period.  So, our method used with our Foam-Bond adhesive guarantees consistently straight wings, more strength, and also acts as a concrete block repellent, keeping concrete blocks OUTSIDE of your shop! 
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