outline cutting... glue question for a woodie

I have a quick question that I couldn’t find in archives… whats a good glue to use to glue together wood planks so I can cut out an outine, then be able to break them apart for chambering… so far I was thinking of using gorilla glue… but that might be too strong. I need something strong enough to hold the planks together while using a jigsaw but then be able to break apart without damaging the wood.

any suggestions?

If I stick w/ gorilla glue, how much should be applied between each plank?

FYI… Im using a hardwood (cedar), not balsa…


secondary question… the specs for gorilla glue is 100% waterproof… is it possible to do the final glue up using gorilla glue then just apply a waterproofing shillack/varnish to the wood and not have to glass it? It’s prolly a dumb question, but why not ask… saves me material and time… assuming it works well… i dont wanna cut corners that will end up biting me in the ass.

Hey Scott,

I have used a heavy paper between the joints, then after gluing them up and rough planing, I was able to break the joints. Just remember that if you don’t fill the chambers with anything, keep the board away from heat, as it will expand and pop the glass, if you go the glassing route.



Just remember that if you don’t fill the chambers with anything, keep the board away from heat, as it will expand and pop the glass, if you go the glassing route.

thats in part why I wanted to try the waterproofing route… heres the product im looking at using…

heres the description of it:

Clear For protection of all exterior wood decks, fences, siding and more WaterGuard protection SunBlock UV protection Exclusive scuff guard formula Creates mildew resistant coating

I remember Jim Phillips, Benny, Velzy and others said you don’t need vents for chambered balsa . . .

This thread says so . . .


in the 50’s they used chambered balsa, but they didn’t use vents . . .

I’m confused now . . . any experienced balsa shaper care to answer?

I have never used vents in the balsa boards that I have done that are chambered. One thing I have learnt is that if you are doing a hollow balsa board you want to make sure that there are some stringers breaking up the hollow area into smaller chambers otherwise expansion can cause problems. I learnt this from the guy who makes the hollow balsa blanks I used. I just shaped a hollow balsa and it has multiple stringers for this reason.

NOTE: a hollow balsa board is not the same thing as a chambered board. It is actually made from deck and bottom skins and strip planking on the rails. So there tends to be a lot more air in them than a chambered board, although I’m sure if you had a lot of time and patience you could get a chambered board close to what can be achieved with a hollow one.

I think it has also been mentioned before that if you had a vent you would need to make sure that all of the chambers were connected otherwise the vent would be of little practical use.


Scott, I won’t call myself an experienced balsa (or red cedar) boards shaper, but I did

build a few. Never vented any chambered balsa.

I do not glue the timbers for rough shaping. I cut the desired rocker in them using a bandsaw, then assemble them with fluted wood pegs that are driven into slightly under-dimensionned holes. This ensures a firm assembly for rough shaping but you may disassemble the whole thing pretty easily when you’re done.

Red cedar is strong enough so that you don’t need to glass it. Some kind of marine varnish will do the trick.

We had a thread about that, look for “chambering” or something like that.

When this came up a week ago or so, I went through the archives…sorry I didn’t post or bookmark what I found, but it’s in there. Jim P talked about repairing a chambered balsa which had self-vented on an airplane…

He found that it had been chambered to within 1/8" or so of the outside. Said it was way too thin. Recommended 1/2" thickness left everywhere.

He also described gluing up the planks for shaping, then popping them apart for chambering. For the planks, he uses a single drop of yellow wood glue (like Titebond) every 6-8". That’s all it takes to hold it together for shaping. You want to do all the shaping prior to any chambering, so when you do chamber, you know just how big to make the holes. After shaping, he bumps them down on the carpeted floor until they pop apart. Piece of cake.

He uses bicycle inner tubes to clamp the balsa together when gluing - both with the drops before shaping and with all the glue & stringers after shaping. The inner tubes pull strongly on the wood but conform to the shape without digging in. Hope that helps. If I missed anything, its a problem with my memory, not Jim’s techniques…