You can buy a venturi vacuum generators for about £15 IIRC from farnell
www.farnell.co.uk but I expect lots of others can supply the same or
similar items in the UK and elsewhere. They are used for material
handling for paper etc. I found the performance to be quite good at
about 90% vacuum and was using it for de-aerating silicon mould making
compound. Much cheaper than a vacuum pump but they use a lot of air but
I didn't need to run it for more than a few minutes at a time. I have
since got a 2nd hand vacuum pump which generates higher vacuum and uses
a lot less power. Unless you want to make one I would just find a cheap
supplier to buy one from.

Norm Dresner wrote:

I'd like to build a desoldering station. Conventionally this is done with a
soldering iron and a vacuum source. In the best units the tip of the iron
is hollow and the vacuum draws through it. But I don't want to purchase a
vacuum pump for the same reason that I don't want to purchase a commercial
soldering station: cost. I have a compressor. Since there are COTS
desoldering stations that work from a compressed air supply it's possible,
using the Venturi effect, I believe. Are there any on-line tutorials for
creating a vacuum from an air source?

TIA
Norm