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Grenadier's big thread of RÃ¶ntgen related shenanigans

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Proud Mary

Sat Nov 13 2010, 09:04PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

On reflection, I must say I am inclined to share Klugesmith's scepticism about an entirely glued structure, and will go back to my first suggestion, which was to use angle irons on the corners, inside and out, which is what I would surely do were the problem mine.

Adam Munich

Mon Nov 15 2010, 03:38AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Well it all depends. If I can find some 60/40 plumbing stuff then I'll solder it. If not, I'll use glue.

I'm not going to use angle irons because that would require me to drill a whole bunch of small holes, and that would create even more problems to solve.

Steve Conner

Mon Nov 15 2010, 10:13AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

In the olden days, large banks of lead-acid batteries used to get their cells joined together by "lead burning". The battery's own voltage was used to weld the terminals to lead busbars, using a lead stick as the welding rod. Maybe you can weld your lead box together in the same way.

Probably not such a good idea in this era of health and safety, but then neither was casting the lead in the first place.

Wolfram

Mon Nov 15 2010, 01:24PM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Steve McConner wrote ...

In the olden days, large banks of lead-acid batteries used to get their cells joined together by "lead burning". The battery's own voltage was used to weld the terminals to lead busbars, using a lead stick as the welding rod. Maybe you can weld your lead box together in the same way.

Probably not such a good idea in this era of health and safety, but then neither was casting the lead in the first place.

I tried this by accident once and was greeted by a large choking cloud of lead vapor. Not recommended.

Anders M.

Adam Munich

Mon Nov 15 2010, 08:41PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I never intended to try that anyway. Sounds like a good way to destroy my plates.

Adam Munich

Thu Nov 25 2010, 05:18PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Well I couldn't find any leaded solder no matter where I looked so I ended up getting a roll of thick rosin cored lead free stuff, only because it melts at 430*F. That gives me about a 120* lee-way before the 5% antimonial lead melts, so if I work slowly and have a wet sponge on hand I should be able to solder it w/o too much damage. I plan on soldering the thing together sometime before monday.

Since it's cold now I'll do the soldering inside.

klugesmith

Thu Nov 25 2010, 07:04PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Happy Thanksgiving, Adam.
It's cold here too -- buckets of water were frozen over the last couple mornings.

A lesson from welding class:
Consider tack-soldering all 8 corners of your box before doing any of the long joints.
(or put it together with a few temporary screws, or many angle brackets & clamps).
1) keeps the whole thing square from the outset.
2) otherwise if you start at one end of a long joint, thermal expansion/contraction may cause it to develop an unwanted gap or skew before you get to the other end.

By coincidence, speaking of shielding boxes, I'm about to find out if 5/8" drywall (gypsum board) can practically block x-rays at NST voltage (15 kV RMS). If so, then I'll make a box out of that, this weekend, and play at the limited voltage before getting out the lead and the oil.

Adam Munich

Thu Nov 25 2010, 07:24PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Yeah I was planning on soldering the corners before anything else. I still haven't decided If I want to solder things from the inside or outside though.

As for staying square, all the sides line up perfectly so I don' think it'll be too hard to do. It's kind of like putting those little birdhouse kits together; everything just fits.

As for your drywall discovery, that's pretty interesting. Y'know what you can do for short experiments is mix lead shot with plaster of paris. That would make castable, yet brittle and clunky shielding. It'd be good for short experiments though. The best part about it is that you can get your lead shit back by simply dissolving the plaster in HCl. Lead reacts very slowly with acid but the gypsum would dissolve away in only a few minutes.

Proud Mary

Thu Nov 25 2010, 08:01PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Klugesmith wrote ...

By coincidence, speaking of shielding boxes, I'm about to find out if 5/8" drywall (gypsum board) can practically block x-rays at NST voltage (15 kV RMS). If so, then I'll make a box out of that, this weekend, and play at the limited voltage before getting out the lead and the oil.

That sounds exciting! I'll be interested to hear how you get on with that.

klugesmith

Thu Nov 25 2010, 08:08PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Grenadier wrote ...
Y'know what you can do for short experiments is mix lead shot with plaster of paris. That would make castable, yet brittle and clunky shielding. It'd be good for short experiments though. The best part about it is that you can get your lead shit back by simply dissolving the plaster in HCl.

Did you change the vowel in shot on purpose?
At one summer job we used sacks of shot as weights to hold things down.

One had been creatively modified, sort of like this picture was modified today.
Except in the 70's, the word LEAD was implicit & did not appear on the sack label.

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