Turning

Subject:
Re: I did glue the scraps to make the blanks... *PIC*

Mike Stafford
Back a number of years ago I did an extensive study of CA glue in conjunction with a project that seven kids were working on (one of those kids was my son).

They were using CA glue to assemble structures from balsa wood. It was by far the strongest glue particularly when you considered how much weight the glue added to the structures. We started out using Titebond and it added so much weight that we had to switch to CA.

During our testing, which amounted to piling barbell plates on top of these balsa wood structures to see how much they can hold we noticed some interesting phenomena with regard to the brittleness of the CA.

With most glue joints we are told that the glue is stronger than the wood. This is true for CA as well but when a structure built with CA breaks it does not tear apart wood at the joints. The glue joint is ripped apart with a shower of tiny crystals. We could see this very well during our testing on the videos we made to see how the structure failed. You could actually see a cloud of dust as the joint exploded.

This brittleness got worse as the structure aged and structures that were a year old practically broke without breaking the wood.

By the way the kids ended up in 6th place in the World Finals with an 18 gram structure made from balsa no larger in cross section than 1/8"X1/8". Their structure held 1190 pounds. The winning team held more than 1460 pounds.

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