Making notches in balsa parts...

[Diggs392]

Hello there. I just recently gotten into building these planes and picked up few o the 900 series kits. Looking at the instructions, the "formers" do not have the notches cut in them where the stringers would go. I know I have to make a copy of the patterns for these pieces from th plans, but was wondering what is the best method to attach the pattern to the balsa piece. I have seen some people using a "contact" cement, double sided tape, etc. but was looking for what seems to work best without fully adhering to the piece of balsa allowing eAsy removal.

[David Lewis]

Glue stick works well. Also if you extend the notch lines outside the pattern with a pencil, you can place the part on top of the pattern.

[tom arnold]

Walmart carries a "repositionable glue stick" that is made from the same stuff as on sticky notes. Peels off easily from the balsa after cutting.

[backyardbalsapilot]

I use an Elmer's glue stick to attach the paper patterns to balsa, cut the part out/make the notches, then apply isopropyl alcohol over it, let it soak into the wood, then peel off the paper off with the tip of an xacto knife.

[Chris A.]

In the past, I've made reverse image copies of the parts, cut them out and held them one at a time face down against the balsa sheet and rubbed them through with acetone. The part marking comes out with a very crisp image positive side up and the balsa dries quickly and doesn't smudge. DO NOT DO THIS INSIDE NOR NEAR ANYTHING FLAMMABLE !!! ACETONE FUMES ARE BOTH TOXIC AND EXPLOSIVE!!! Having said the foregoing, the resulting image is very sharp with almost no bleeding. Doing one or two parts at a time means you don't have to use as much acetone and it is quicker. Acetone evaporates very quickly, just don't breath the fumes.

Once the part is cut out, I use a notcher made of 1/16" section paint stirrer material with a 1/16" strip of 200 grit sandpapaer glued to the edge. I found it much easier to control depth and make an accurate notch than by cutting out with a #11 blade. This method also gives you a nice square bottom to the notch. If the notches are close to each other, like with bulkheads, you are less likely to break out the bulkhead material in between notches. With very soft balsa, use a finer grit.

[davidchoate]

I first always go to Staples and get a copy or 2 of the plans. I then can cut and slash patterns and not regret it.I assume You know about making a notching tool. I use tissue or tracing paper, and use a glue stick to adhere the pattern to the wood. Careful though it slides around easy. I also have (when building with contest wood) Made templates from Styrene. For wing ribs that are same size for example, and store them with the plans for when I crash and have to rebuild. You also can glue the stringers onto formers without notching. Just remove the stringer thickness from the formers to compensate. I prefer not to see the vertical lines of the B formers showing through the tissue, but thats My preference. Or I scallop between to hide it. Some Guys think it appears like scale panels, but thats just silly. I never saw a canvas covered Bipe with former lines. But they do have longeron and wing rib bulges.

[NcGunny]

Temporary glue sticks work good. Also severals sites sell a Notcher tool. I use a single edge razor blade to cut my notches and a sanding stick to get em all to depth. Although lately I have only been building FF planes where wing ribs are all the same size. I stick the whole batch and sand em as one piece. The Notcher will make em fast though.