I don't have much experience spot welding. I am looking at an assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.
Thanks,
Eric

wrote in message
...
I don't have much experience spot welding. I am looking at an
assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.
Thanks,
Eric

I think the floor-mounted spotwelder I used when learning to design
and build machines could be turned up to handle steel as thick as 12
gauge, nearly 1/8". You could simulate spot welds by filling punched
holes in the top sheet with MIG.

The process is imprecise and may be restricted by the bulk of the
electrodes.
-jsw

On 12/2/2017 3:07 PM, Jim Wilkins wrote:

...You could simulate spot welds by filling punched
holes in the top sheet with MIG....

"Plug welding". Would be faster than either screws or rivets, but not
as fast as spot welding.

I spot welded 2 1/8" pieces as a test of my home made spot welder and it
was nearly perfect. I have not had the occasion to use it on 1/8 for
real. But I'm sure that a commercial welder could easily do it.

http://www.mwdropbox.com/dropbox/MOT...rPrintable.pdf

wrote:
I don't have much experience spot welding. I am looking at an assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.
Thanks,
Eric

The first welds will be easy. Once you start to change thicknesses it
might get more interesting. Do you have a spot welder now?

Had fun with a bunch of big spot welders at Fab Tech in Chicago a month
ago. The best part when a sales person welded over a weld with some sort
of resistance sensing welder. It turned the current WAY up to overcome
what it though was shunt of a nearby weld. Got a nice shower of sparks.
Surprised the soft carpeting didn't go up in flames. Then we both got
shooed away and a Sr. guy gave a lecture and demo.

On Sat, 02 Dec 2017 11:26:01 -0800, etpm wrote:

I don't have much experience spot welding. I am looking at an assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.

The Harbor Freight #45690 spot welder doesn't handle that much, in my
experience. I've spot welded a lot of .1" + .1" assemblies with good
results but .1" + .125" just tacked instead of welding, and .125" + .125"
didn't stick at all. The .1" was cold-rolled and plated steel; the
..125" was hot rolled and I probably didn't get enough of the mill scale
off to get good enough conduction.

The https://www.harborfreight.com/240-vo...der-61206.html
item is similar to the #45690. #61206 is rated at 2.5 kVA. With
twice that power you probably could weld .125" + .125" reliably and
quickly, but if you need a good strong three-layer weld I imagine
8 to 10 kVA would be needed. Do you have any factories or shops near
you with a good sized spot welder so you could try out your assembly?

--
jiw

On Sat, 02 Dec 2017 11:26:01 -0800, wrote:

I don't have much experience spot welding. I am looking at an assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.
Thanks,
Eric

Yes, its a very viable method.


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On Sun, 3 Dec 2017 18:29:16 -0000 (UTC), James Waldby
wrote:

On Sat, 02 Dec 2017 11:26:01 -0800, etpm wrote:

I don't have much experience spot welding. I am looking at an assembly
that is made from 3 laminated pieces of 1/8" mild steel. Since I
designed the assembly I can choose the fastening method and was
wondering if the parts could be reasonably spot welded together. The
assembly process would be to first weld two parts together and then
weld the last part to the now 1/4" thick assembly. I am also
considering blind rivets and screws. But spot welding would obviate
any drilling or tapping. And I was thinking someone here would have
the practical experience to let me know if this scheme of mine is
practical.

The Harbor Freight #45690 spot welder doesn't handle that much, in my
experience. I've spot welded a lot of .1" + .1" assemblies with good
results but .1" + .125" just tacked instead of welding, and .125" + .125"
didn't stick at all. The .1" was cold-rolled and plated steel; the
.125" was hot rolled and I probably didn't get enough of the mill scale
off to get good enough conduction.

The https://www.harborfreight.com/240-vo...der-61206.html
item is similar to the #45690. #61206 is rated at 2.5 kVA. With
twice that power you probably could weld .125" + .125" reliably and
quickly, but if you need a good strong three-layer weld I imagine
8 to 10 kVA would be needed. Do you have any factories or shops near
you with a good sized spot welder so you could try out your assembly?


Id not attempt it for anything other than experimental work with
anything less than a 15 KVA spot welder. The little Miller portable
spots are not going to do it.

If you hunt around a bit...you can find them for $500 or less. Ive
given at least 3 that size or bigger away. Come to think of it..I
may have a 30kva machine available for about that price. Its either a
Western or American. I can check if anyone is interested. Ill be
closing down a big machine shop over the next few months in Chino,
California and will have some gear available at good prices.

Gunner

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