Question for all you carpenters out there

  • Thread starter Thread starter Slick Rick
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Slick Rick

Slick Rick

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For a project at uni I have to make a platform out of balsa wood to hold a large weight. My question is will drying the structure out i.e. Putting it in an oven for a day, weaken the structure or make it stronger. The platofrm is on a tight weight limit and im hoping drying it will save a few grams. I am using superglue for the joints if that helps.
 
My guess it would make it weaker. Less moisture means more dry and brittle wood. Though, my woodworking skills and knowledge is very poor.

I base my opinion of wood furniture my brother has made in the past. It lasted two years in the hot SoCal sun before it would fall apart due to dry, brittle wood caused by drying out in the hot air and contact from direct sunlight.
 
You are on the right track with the superglue.
If you make it a lattice or laminate with the grain of the wood running in opposite direction in the layers you will have good to great strength, with light weight.
 
Heres where Ive got so far if your interested. I wanted to do cross trusses but I think that would increase the weight too much and make it unecessarily rigid. You also get marked down if your structure is 'over engineered'


Ive highlighted the weak joints in green and red, im thinking of reinforcing them with some wood glue and sawdust...
 
It's funny, a few years ago we had to build structures like this out of balsa to hold weights, and it were to be put on an earthquake simulator machine. The one that held the weights the longest won. Everyone else made real elaborate designs, but me and my partner made something super simple, like yours, except it was a square tower. We doubled up the balsa for the verticle pieces, and we were just using simple Elmers glue. We had cross beams all the way around to hold the weights, and just had the angled beams all facing the same direction all the way up. Funny thing is our design won, yet it was the easiest one to build! Just goes to show how simple things can be good designs.
 
You can use sawdust (very fine) and superglue to make your fillets. Also look at the hobby shop for something called 'microballoons', which are a powder made for fillet work.

One thing I see - with your diagonal struts all pointing in the same direction like that, you may get some torsion in the clockwise direction. I'd consider reversing one set so they meet at at point with the other set. You may be able to eliminate the third set, even, to save weight.
 
Here it is now, almost finished i think.

Duke
One thing I see - with your diagonal struts all pointing in the same direction like that, you may get some torsion in the clockwise direction. I'd consider reversing one set so they meet at at point with the other set. You may be able to eliminate the third set, even, to save weight.
Click to expand...

For that Im going to get some cotton string and wrap it round the separate sections like this
 
Ah, wait, I see - in the unfinished pic, it looked like all bays had the diagonal oriented in the same direction. Now I see you've alternated the diagonals on alternating bays. That should work to prevent the torsion I was predicting.
 

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