balsa lenths
 

ok guys question in my hopes to scratch build a p51 i see that its a boxed fuse with a 48' sides but the lhs and craft store carry only 36' pieces is there some place online to get longer pieces or os ot ok to make them in more then one piece?

RE: balsa lenths
 

Order directly from Sig or Lone Star.

RE: balsa lenths
 

Go to balsa usa .com click on wood they will have everything you will need.

RE: balsa lenths
 

36" is the norm that's for sure. It's more than OK to make it out of two or more pieces.

Good luck,

Frank

RE: balsa lenths
 

Just remember to not but join them, but cut each end on a 45 and fit them together. It helps if you can arange to have a former mid way through this seam.

Also remember to true up the edge so you have a straight edge to work with. It is real easy to get a step, or a bend at the joint line. One trick to remember, If you lay the two pieces one on top of the other, and make sure the edges line up, then make the 45 cut through both pieces at the same time, it doesn't mater if you are cutting exactly 45, or 42, or 49 degrees, When you flip the top piece over and but the two angles together it gives you a straight sheet

Ive built several planes using sheeting joined like this for both fuselage sides and wing sheeting. I've yet to have one of these splices flail even in a crash that destroyed the plane.

Don

RE: balsa lenths
 

Just make your splice on a diagonal, or an "L" joint and you'll be fine.

If possible, make the splice in an area that will have a doubler behind it

RE: balsa lenths
 

very good tips guys as soon as the sea hawk is repaird i am going to start either a me 109 .40 or a p51 got plans for both mostly building it for the fact that my father inlaw dont with i will LOL but as soon as income tax comes back i am ordering a four star 40 for my next flyer i am looking forward to the builds thanks guys i will try some joints on some scraps frist

RE: balsa lenths
 

Don, is that cut and splice called a scarf splice??? I have shown it to people but I'm not sure what it is called.
Gene

RE: balsa lenths
 

Here ya go. Their prices are pretty good.
http://www.nationalbalsa.com/

Paul

RE: balsa lenths
 

The diagonal is a "Scarf" and the "L" shape is a "Lap"

RE: balsa lenths
 

Is it ok to use 5 minute epoxy for scratch building or major repairs or is it really better to use 30 minute epoxy?

RE: balsa lenths
 

Much better to use 30 min

RE: balsa lenths
 

Typical lengths are both 36 and 48 inches.

If you are doing a sheet side, the 45 degree angle will work fine, but it would be better as a lap joint. A lap joint means that you glue another thin sheet of balsa right behide the joint. 3/4" to 1" will give plenty of glue surface, with the grain crossing the joint line.

If you are doing a lap joint on a stringer or spar (especially the spar), then you want the length of the joined surface to be 10 to 12 times the thickness of the spar. Be sure to line up the grain of the wood with the cut.

RE: balsa lenths
 

Gene, it may be. I'm not sure though. Back when I used to replace the flat leather belts on lathes and such, we used a similar approach, We layed one side of the belt down and then folded the other back onto it, with the top end about three inches back from the bottom one. We then sanded a taper on the belts untill there was fresh material along the length of the sanding. Some hide glue on the joint and clamp it between a couple boards with some wax paper between the boards and the leather and let it set for a couple days. WaLa a new belt. Not much call for that today. The basics are the same though. The more surface area you can glue, the stronger the joint. If you look at some of the wood trim in the lumber yards today, they are made up of finger joint stock, several long V's cut to incrase the glue surface. It is very strong because of the extra surface, and the fact that there isn't a single plane that can be stressed to cause the joint to fail. A 45 degree cut like I suggested will fail if the bend is 45 degrees to the length of the sheet. It is quite strong if the bend is across the sheet

MinFlyer, a lap is not the L shape, but the description above of the belt lap joints. IE one sheet laps over the other. Getting the lap angle right is very difficult on something like a 1/8" sheet of 3" wide balsa. If the angles are not dead on, you end up with a very weak joint. To get this joint to work, you would need to lay out the sheets like I described for the leather belt. one over the other Then the sanding would need to be done by sanding in only one direction so there isn't a bow in the surface, it has to be dead flat. Then the second issue come up, the sanding line also has to be at exactly 90 degrees to the length of the sheet, otherwise you will have an angle in the joing if you have full contact, or only have a narrow contact along one edge. It is a very difficult joint to make in thin stock without some accurat jiging for the surface preperation. The 45 cut is the best as you have less room for error. You still need to keep the cut 90 degrees to the surface though.

Don

RE: balsa lenths
 

I stand corrected.

RE: balsa lenths
 

Mike it is a rare time when you need to be correct. This is the first that I know of. Don

RE: balsa lenths
 

Hey, if I were perfect, I'd run for "God" :D