| Author |
Message |
Tim Zimmerman
Guest
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 Posted:
Tue Feb 22, 2005 6:48 pm Post subject:
Converting stick welder to tack welder. |
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I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
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Clandestine
Guest
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| Posted:
Tue Feb 22, 2005 7:16 pm Post subject:
Re: Converting stick welder to tack welder. |
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Those "tack welds" are created by resistance heating between the
parts. There is no arc involved. It takes considerably more power
(watts) to weld by resistance than by arc. They are also done faster
than most arc welds. To put this in perspective those electrical
components required about 1,000 Amps in ½ second. Usually the current
is turned on/off by an SCR (or similar switch). I have never heard of
converting an arc welding power supply into a resistance welding power
supply. Keep in mind these critical factors during this type of
welding
FORCE - you must "pinch" pieces together (approximately 500 lbs)
POWER - you need a high, controlled amount of electricity
TIME - You need to regulate the power flow within 1 cycle (1/60
second).
Unitek-Miyachi makes small resistance welders. www.unitekmiyachi.com |
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Clandestine
Guest
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| Posted:
Tue Feb 22, 2005 7:25 pm Post subject:
Re: Converting stick welder to tack welder. |
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Build your own resistance welder at home:
http://users.frii.com/katana/spotweld.html
Good Luck, please post results or casualties.
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Josh Sponenberg
Guest
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| Posted:
Wed Feb 23, 2005 1:18 am Post subject:
Re: Converting stick welder to tack welder. |
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Clandestine wrote:
| Quote: | Those "tack welds" are created by resistance heating between the
parts. There is no arc involved. It takes considerably more power
(watts) to weld by resistance than by arc. They are also done faster
than most arc welds. To put this in perspective those electrical
components required about 1,000 Amps in ½ second. Usually the current
is turned on/off by an SCR (or similar switch). I have never heard of
converting an arc welding power supply into a resistance welding power
supply. Keep in mind these critical factors during this type of
welding
FORCE - you must "pinch" pieces together (approximately 500 lbs)
POWER - you need a high, controlled amount of electricity
TIME - You need to regulate the power flow within 1 cycle (1/60
second).
Unitek-Miyachi makes small resistance welders. www.unitekmiyachi.com
I can vouch for the Unitek-Miyachi system, they work well and the price |
is usually decent. They're step-pulsed, capacitive-discharge systems,
and are as far removed from arc welding as swimming is from bob-sledding...
I worked for 4 years at a battery "wholesaler" my main job was to crack
dead packs open and "re-cell" them, and then glue them back together.
generally cheaper for the customer than buying a new pack, and 9 times
out of 10 they had more capacity. If you're looking into this kind of
stuff, let me know and I'll give you my former boss's contact info and
he'll be able to point you to our connection on the west coast where we
got our welder from. |
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Jamie
Guest
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| Posted:
Wed Feb 23, 2005 3:49 am Post subject:
Re: Converting stick welder to tack welder. |
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Tim Zimmerman wrote:
| Quote: | I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
find your self dead microwave oven ( high power line), use the |
heater tap on the transformer. |
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Barry Lennox
Guest
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| Posted:
Wed Feb 23, 2005 6:10 am Post subject:
Re: Converting stick welder to tack welder. |
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On Tue, 22 Feb 2005 12:48:03 GMT, "Tim Zimmerman" <Z@UCBerkeley.edu>
wrote:
| Quote: | I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
|
I believe you are following the wrong path here. You need little
voltage, but a LOT of current.
I made a very good spot welder for batteries and similar tasks from an
ex microwave oven transformer, the biggest I could find. Hack off the
HV secondary, thousands of turns of very fine wire, then I rewound it
with just 3 turns of wire, but I packed in as much 8g and 12g wire as
would fit, and paralleled all the turns.
The secondary is controlled by a SSR (Croydom CSD2410) pulsed by a
simple 555 timer circuit. It can vary from about 75-300 mSec I can
also switch in one of 3 wirewound resistors in the secondary to give
me fine control.
The electrodes must be made to suit your exact application, and some
trial and error can be expected. I first used copper and brass, but
now get much better results from a proper spot welding electrode
machined to suit my application. It was not cheap, about $11 for a
3/8" rod about 3 inches long, but it gives very good results. It had a
trade name like "Elkalloy" IIRC.
For optimum results, it is also important to control the electrode
pressure, but I find I can achieve satisfactory results by hand.
Barry Lennox |
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Martin H. Eastburn
Guest
|
| Posted:
Wed Feb 23, 2005 6:10 am Post subject:
Re: Converting stick welder to tack welder. |
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Clandestine wrote:
| Quote: | Those "tack welds" are created by resistance heating between the
parts. There is no arc involved. It takes considerably more power
(watts) to weld by resistance than by arc. They are also done faster
than most arc welds. To put this in perspective those electrical
components required about 1,000 Amps in ½ second. Usually the current
is turned on/off by an SCR (or similar switch). I have never heard of
converting an arc welding power supply into a resistance welding power
supply. Keep in mind these critical factors during this type of
welding
FORCE - you must "pinch" pieces together (approximately 500 lbs)
POWER - you need a high, controlled amount of electricity
TIME - You need to regulate the power flow within 1 cycle (1/60
second).
Unitek-Miyachi makes small resistance welders. www.unitekmiyachi.com
Likely a capacitive discharge to deliver the high current. |
Or like said a RC that drives an SCR as a switch of a storage Cap.
Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer oldtree@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder |
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Si Ballenger
Guest
|
| Posted:
Wed Feb 23, 2005 6:10 am Post subject:
Re: Converting stick welder to tack welder. |
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|
On Tue, 22 Feb 2005 12:48:03 GMT, "Tim Zimmerman"
<Z@UCBerkeley.edu> wrote:
| Quote: | I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
|
Check the rec.crafts.metalworking news group. Lot of info there
on things like this (and a lot of other DIY stuff). |
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Eric R Snow
Guest
|
| Posted:
Wed Feb 23, 2005 10:08 pm Post subject:
Re: Converting stick welder to tack welder. |
|
|
On Tue, 22 Feb 2005 12:48:03 GMT, "Tim Zimmerman" <Z@UCBerkeley.edu>
wrote:
| Quote: | I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
Tim, |
The reason your stick welder is not good for spot (what you call tack)
welding is because the voltage is too high and the current too low. I
experimented with a microwave oven transformer and was able to get 400
amps at 3 volts. This is done by removing the high voltage secondary
windings and replacing them with a few windings of heavy wire or even
copper bars. See other replies for links etc. for building your own.
ERS |
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mike
Guest
|
| Posted:
Thu Feb 24, 2005 12:28 am Post subject:
Re: Converting stick welder to tack welder. |
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Jamie wrote:
| Quote: | Tim Zimmerman wrote:
I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
find your self dead microwave oven ( high power line), use the
heater tap on the transformer.
|
How well did this work when YOU tried it? How did YOU keep from killing
yourself on the high voltage winding?
mike
http://nm7u.tripod.com/homepage/welder.html
--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/ |
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Steve Taylor
Guest
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| Posted:
Thu Feb 24, 2005 1:59 am Post subject:
Re: Converting stick welder to tack welder. |
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mike wrote:
| Quote: | How well did this work when YOU tried it? How did YOU keep from killing
yourself on the high voltage winding?
|
When I did it, I drilled the HT winding out. Brutal, but fast. To be
honest, the idea didn't work for me at all, and I built a miniature
capacitor discharge welder that DID do the job - a modest bank of old PC
power supplies yielded enough capacitors to hold "useful" amounts of
energy.
Steve |
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mike
Guest
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| Posted:
Thu Feb 24, 2005 3:51 am Post subject:
Re: Converting stick welder to tack welder. |
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Steve Taylor wrote:
| Quote: | mike wrote:
How well did this work when YOU tried it? How did YOU keep from
killing yourself on the high voltage winding?
When I did it, I drilled the HT winding out. Brutal, but fast. To be
honest, the idea didn't work for me at all, and I built a miniature
capacitor discharge welder that DID do the job - a modest bank of old PC
power supplies yielded enough capacitors to hold "useful" amounts of
energy.
Steve
|
Post some details on voltage, capacitance, how'd you switch it?
electrode construction?
mike
--
Return address is VALID but some sites block emails
with links. Delete this sig when replying.
..
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
MAKE THE OBVIOUS CHANGES TO THE LINK
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/ |
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Guest
|
| Posted:
Thu Feb 24, 2005 6:10 am Post subject:
Re: Converting stick welder to tack welder. |
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Hi. Oddly enough, you can do spot welding with an arc welder. I tried
it, and all I got was the typical mess that you would guess. Burned up
spots with no strength.
But, just because I cannot do it does not mean that it can't be done.
There are plans on Ebay:
385664469
This auction is for a set of completely illustrated plans to build a
spot weldi
ng/cutting gun that works with your arc welder for less than $50.00.
I have not tried this out, so please buy the plans and report back to
the group.
Or, you could try Eastwood's version, which is very similar, but uses
carbon electrodes. Also, please report back to the group after trying.
http://www.eastwoodco.com/jump.jsp?itemID=795&itemType=CATEGORY&iMainCat=688&iSubCat=795
Recently, I tried to do a blind spot weld with 1/8" steel. It worked
just great. So, the problem may be power, control, and excessive heat,
which the above solutions allude to. Note that this is arc welding,
not resistance welding with a low voltage rewound microwave oven
transformer. |
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Martin H. Eastburn
Guest
|
| Posted:
Thu Feb 24, 2005 6:10 am Post subject:
Re: Converting stick welder to tack welder. |
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|
Eric R Snow wrote:
| Quote: | On Tue, 22 Feb 2005 12:48:03 GMT, "Tim Zimmerman" <Z@UCBerkeley.edu
wrote:
I need a tack welder for joining thin plates and electronic
components. Like the tack weld you see in your NiCad battery packs.
I have no practical use for my 120v, 80-Amp stick welder so now I'll
convert it into a tack welder.
I like to get some ideas on how to make a setup that will be safe and
precise enough to do small electronic welds like the welds found on
some relays. Does this sound possible, if not can you point me to a
place to get a spot welding setup?
Thanks
Tim,
The reason your stick welder is not good for spot (what you call tack)
welding is because the voltage is too high and the current too low. I
experimented with a microwave oven transformer and was able to get 400
amps at 3 volts. This is done by removing the high voltage secondary
windings and replacing them with a few windings of heavy wire or even
copper bars. See other replies for links etc. for building your own.
ERS
With only 3 volts, the resistance of the metal and any 'dirt' best be doing zero ohms... |
Not much punch through voltage.
Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer oldtree@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder |
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Nick Huckaby
Guest
|
| Posted:
Thu Feb 24, 2005 10:07 pm Post subject:
Re: Converting stick welder to tack welder. |
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|
"Martin H. Eastburn" <oldtree@pacbell.net> wrote
| Quote: | I experimented with a microwave oven transformer and
was able to get 400amps at 3 volts.
With only 3 volts, the resistance of the metal and any 'dirt' best be
doing zero ohms...Not much punch through voltage.
Martin
|
How about 12V? Would two car batteries work? |
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