Hands Free Bellows Testing

[Don Taylor]

Re. Smoke Pens. I was watching the smoke curl up from a mosquito coil today and wondered about using that as a smoke source for leak testing. I might try it tomorrow.

 

For those of you in countries that do not suffer from mosquitoes, a coil seems to made out compressed sawdust and some sort of additive that mosquitoes do not like. You light the outer end of the coil and it smoulders away emitting smoke and a not unpleasant smell.

 

This page has a picture of one burning along with a good reason not to use them:

 

http://globalexcellenceonline.com/beware-smoke-from-mosquito-coil-equals-100-cigarette-sticks/

I tried this today and I would say that it is not a useful test.

 

If I moisten my lips and hold them close to a known leak in the fold of one of my bellows then I can feel the air from the bellows. When I tested the same spot with the rising smoke from the mosquito coil then the smoke really did not change its behaviour.

[Chris Ghent]

 

I also tried using shoe glue instead of PVA and got much better results, which raises the question why do we use a wood glue rather than a contact cement?

The answer is we don't necessarily. Old bellows were probably made with a cooked collagen (animal) glue. Some modern makers use Titebond premixed animal glue. Contact glue is messy and doesn't evaporate to such a thin and consistent layer.

[Terry McGee]

Hmmm. If you want to glue an animal back together, then animal glue makes sense.

 

Terry