Hi Brian and welcome to Stunthangar!

As Ty said, brass tubing is about as good a anything.  If larger holes like 1", then aluminum tubing can be used.  Use a soft metal and an X-Acto blade will sharpen the tube.  All the metal removal comes from "slicing" the edge on the inside of the tube.

BIG Bear
RNMM/AMM

Thanks guys.  3/4 aluminum tube sharpened with x-acto doing the trick.
BC

     
      Try and find glass shop tools they have brass hole saws in all different sizes. Summer mecca catalog I think. Might be others though. Thanks John Jordan

For what weight I saved (surprisingly little), the hassle of hole cutting was hardly worth the trouble. Better by far to get good lightweight balsa in the first place would be my 2 cents worth.

Andrew

Andrew,

I can honesty tell you that the removal of "material" does remove weight.  Especially if you start out with balsa wood that should be tossed.

When I came back to CL, for my first CL builds, I used my "old stash" of wood that I had for building R/C models.
 
Wood that was just purchased from the large balsa supply houses. Probably extra heavy to say the least.

You say, " Better by far to get good lightweight balsa in the first place."

I believe you are absolutely correct on this issue and your opinion is valued at much more than two cents.

Here I am wasting time trying to do my best to lighten a model, when a more realistic "choice of wood" is the better approach.

Now I have a few models, even with my efforts to trim weight, that are still a bit heavy.

Live and learn. And in my case, generally the hard way.

I look back in hindsight and now it's understandable why I took critism from many of the experienced modelers.

Laying out a game plan to design and build a CL model, you cannot rule out the "importance" of using contest grade wood and as you said, lightweight balsa wood in the first place.

Proof of the pudding can be seen in Robert's videos.

I bit the bullet and reciently purchased contest grade balsa. $161.00 worth.

It's a start.

Lightening holes are all well and good, but there's a couple of things you should consider before tearing into your stock of lumber:

1. original stock weight, this has already been said before, if you're buying heavy wood, stop doing it!

2. reduction in structural integrity. If you put holes everywhere you may end up with a part that has the same overall shape, but has all the structural integrity of cheese, and swiss cheese at that. A little bit of extra trime spent utilising built up balsa structures will produce a better, lighter and stiffer product than a sheet part with holes in it. (Incidentally, if you have 8-9lb stock, stripping it down into sticks to do a built up tail is not a bad way to go.

3. finish. If you're doing something vintage or OTS having it full of holes is going to look wrong, or if you're going for a nice finish the holes can be a royal PITA. better to do a thinner built up structure and sheet it, and go about finishing it in your nomal fashion.

I used to put lightening holes in everything until I started to evaulate what I was doing, nowawadays if I need to lighten something I'll try to make more of a geodesic cutout rather than a pile of holes as loads are transferred better, and I can save more wieght removing material where it can be removed and leaving where it needs to be left.

I like Forstner bits, but they don't work really great on balsa.  They tend to load up with shavings, and the back side of the hole gets blown out.  Even when I try to bore a hole through a paper template stuck to the wood, the bits like to cut off a nice sharp disc of paper which blocks the cutter and keeps it from shaving away the wood.  It sort of works if you back the bit up and brush it off, and blow out hte hole before drilling a bit further and repeating.

Recently I needed to punch a hole in a rib in a built wing so I could visually inspect the bellcrank.  There wasn't room to get at it with a brass or copper tube like I'd usually use since i had maybe 2" before the next rib.  I looked around the bench for a second and found a tray of spent shell casings I picked up on my last trip to the shooting range.  Since steel cases generally aren't reloadable and have little scrap value, they are frequently left to rust away by the shooter.  I happened to pick up a few for hobby purposes.  I found that a .45acp case of Russian origin (soft steel) sharpened as nicely as brass tubing with a sharp X-acto blade.  I was able to bore a .45" hole in the 4# 3/32" balsa rib in about 3 turns.  Just with the trash cases in that tray, I can make short hole cutters for balsa from under 1/4" up to 3/4", assuming I can remove the plastic hull from spent shotgun shell cases without trashing the brass.  I might even glue some fine grit sandpaper around the base of the cases so they're easier to turn with fingertips.