Search found 1043 matches

by Rich Feldman
Fri Jul 31, 2020 10:50 pm
Forum: Images du Jour
Topic: Caden Burkhardt-Fusor Progress
Replies: 14
Views: 952

Re: Caden Burkhardt-Fusor Progress

Looking good there. I bet your "NST" is a high frequency power supply, which is warned against in FAQs here. * When it's off, what's the DC resistance between the two high voltage output wires? Can you measure a DC resistance between those wires and a metal part of the case (if any) or the ground pi...
by Rich Feldman
Wed Jul 29, 2020 7:47 pm
Forum: Vacuum Technology (& FAQs)
Topic: Rotary gear pump for vacuum
Replies: 5
Views: 329

Re: Rotary gear pump for vacuum

Lest there be any doubt, behold the head of my enemy. gem4.jpg . These parts are being saved for a while, which is probably more than they deserve. gem5.jpg . The motor (visible in OP), with handle and cord and switch, will go to August 8 flea market if that happens. Otherwise goes into the transfor...
by Rich Feldman
Wed Jul 29, 2020 2:52 pm
Forum: Images du Jour
Topic: Demo Fusor Progress
Replies: 19
Views: 651

Re: Demo Fusor Progress

Another thumbs-up here. Following on Dennis's suggestion, about plasma color. The color difference between deuterium and hydrogen is detectable only with high spectral resolution instruments. So you don't need to buy heavy water or PEM cells. Preparation of hydrogen gas has been in school chemistry ...
by Rich Feldman
Mon Jul 27, 2020 5:16 pm
Forum: Vacuum Technology (& FAQs)
Topic: Rotary gear pump for vacuum
Replies: 5
Views: 329

Re: Rotary gear pump for vacuum

I suffer from an affliction called duty to stuff. Spent more than an hour unsticking and cleaning up the pump core; now it can be turned freely with fingertips on oily shaft. With clear plastic sheet ends, it would make a nice artifact for show-and-tell. This pic also shows the pitting of aluminum p...
by Rich Feldman
Mon Jul 27, 2020 1:39 am
Forum: Vacuum Technology (& FAQs)
Topic: Rotary gear pump for vacuum
Replies: 5
Views: 329

Rotary gear pump for vacuum

Couple years ago I reported a flea market item dragged home on a rainy day: a Welch 8890 "GEM 1.0" vacuum pump. Unfortunately the product did not suck, although the motor ran fine. Internet taught me that it's a two-stage rotary gear pump instead of vane pump. Like oil pumps in many engines (picture...
by Rich Feldman
Thu Jul 23, 2020 6:59 am
Forum: Images du Jour
Topic: Comet NEOWISE
Replies: 13
Views: 657

Re: Comet NEOWISE

After clouds Monday and Tuesday, it was nice to see the comet again Wednesday. Followed it later than ever before, until 10:55 pm. First pictures by me, after more than an hour of tinkering, while the comet sank into the mucky layer. These were 8 second exposures, f/2.6, ISO 112, with slightly diffe...
by Rich Feldman
Tue Jul 21, 2020 8:12 pm
Forum: Images du Jour
Topic: Comet NEOWISE
Replies: 13
Views: 657

Re: Comet NEOWISE

Very nice pics there. Monday was the first day in 10 that I didn't see the comet at all. Spent an hour under a moving layer of clouds, attending with binoculars to the known location of comet in case a thin spot in the clouds went that way. Couple of times I thought a local glow was showing through,...
by Rich Feldman
Mon Jul 20, 2020 5:22 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: DallasMakerSpace Fusion Project
Replies: 6
Views: 315

Re: DallasMakerSpace Fusion Project

Sounds very promising; thanks for sharing.
When someone has a moment to spare, look up the difference between electrolysis (of water) and hydrolysis.
by Rich Feldman
Sun Jul 19, 2020 5:47 am
Forum: Images du Jour
Topic: Comet NEOWISE
Replies: 13
Views: 657

Re: Comet NEOWISE

Evening sky on Saturday was much clearer than previous 3 evenings (which had smoke from distant wildfires). Successful viewing session, from home street and back yard, was the longest yet of 11 for me. Found it with binoculars at 9:16. It was visible to naked eye (practiced, adapted, and bespectacle...