plugging holes in thin 304 with CD welder

I'm trying to develop a process to plug 1/16" holes in 0.015" 304 stainless with minimal heat input. I need a strong, reliable, hermetic
seal. I will have thousands of these to do, and the holes are a bit hard to get at.
I'm thinking I could put a 3/32" sphere of 304 in the hole, hold it in place with a copper electrode, and capacitive discharge weld it. A CD welder vendor I spoke with thinks I won't get a hermetic seal, though, because all the current will go to the first spot to melt around the contact area between the ball and the hole.
Any thoughts on this? any other suggestions?
TIA, slim
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On Thu, 13 Jun 2013 17:17:38 -0400, Slim Gaillard

Greetings Slim, Though I have no experience with capacitive discharge welders and can't comment on them I do have experience with transformer type spot welders and think one of them would work. Do you have access to both sides of the work? I have spot welded 304 sheet with a hand held spot welder and it worked fine but I wasn't aiming for a hermetic seal. The copper electrodes kept air from getting to the area that got hot enough to melt so oxidation wasn't a problem. But if you can only get an electrode on one side of the weld there may be problems with oxidation. So you may need to use shielding gas to insure a hermetic seal. If the current pulse is large enough and long enough and the ball is kept under pressure as it deforms from the heat I think you should be fine. If the ball is held against the sheet with enough pressure then I think it will be making contact all around the edge of the hole so I'm wondering why the cap discharge vendor thinks it won't work. Maybe you can find a jeweler with a cap discharge welder and have them weld a few test pieces. Eric
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On 6/13/2013 8:12 PM, snipped-for-privacy@whidbey.com wrote:

Thanks Eric, I should have said: the parts are only accessible from one side. I'll try a CD welder as soon as I can get my hands on one...
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wrote:

Have you considered sllver brazing?
Dan
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We have a similar problem blocking holes in sheet steel to make them IP65+ rated. We use a special 'pop-rivet'.
Supplied by Rivco here in the UK. I'm sure similar will be available in your area.
http://www.rivco.co.uk/Rivco/Products_files/Rivco%20catalogue%2809-12%29%28LR%29.pdf
Much, *much* quicker than welding or brazing.
JB
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