I tried posting this earlier, but I got an error message when I went to
post it. So, I am not sure the first message went anywhere. If this is
a double post, I apologize.

I am attempting to build a resistance soldering unit from a small car
battery charger. I am following these directions:

http://www.trainweb.org/girr/tips/tips1/solderer.pdf

I am using a 12v 6a charger that, I think, is too small. I can just get
two pieces of .005 brass sheet soldered together before the charger
circuit breaker shuts off the charger. The charger will run for about
6-7 seconds. This should heat it up within 3 seconds. I would like to
solder up to around .025 brass sheets together too. I found a 12/30/75
amp charger at Menards that is probably my next step. But I would like
to be able to vary the current coming out. Do I need a variac for this?
Does this go on the input (110v) or the output (12v) side of the
charger? What specs (volts/amps/watts) should I look for on this? I
also know that I could use a filament transformer of around 6.3v 6-20
amps on the secondary in place of the battery charger. Any suggestions
on which is better? I KNOW that using a light dimmer switch for the
adjustment setting is a bad idea.

I already know that American Beauty and PBL sells these. But for around
$500 for a 250 watt model, I think I will screw around with this some
more. I am bidding on a 300 watt model on ebay right now.

I also searched around the Internet for more instructions. But
everything I found was pretty vague. I am electronics illiterate, but I
can usually figure stuff out with some clear directions.

ANY help on this would be greatly appreciated.

THANKS!

Mike

On 1 Jan 2006 13:06:45 -0800, "mj" wrote:

I tried posting this earlier, but I got an error message when I went to
post it. So, I am not sure the first message went anywhere. If this is
a double post, I apologize.

I am attempting to build a resistance soldering unit from a small car
battery charger. I am following these directions:

http://www.trainweb.org/girr/tips/tips1/solderer.pdf

I am using a 12v 6a charger that, I think, is too small. I can just get
two pieces of .005 brass sheet soldered together before the charger
circuit breaker shuts off the charger. The charger will run for about
6-7 seconds. This should heat it up within 3 seconds. I would like to
solder up to around .025 brass sheets together too. I found a 12/30/75
amp charger at Menards that is probably my next step. But I would like
to be able to vary the current coming out. Do I need a variac for this?
Does this go on the input (110v) or the output (12v) side of the
charger? What specs (volts/amps/watts) should I look for on this? I
also know that I could use a filament transformer of around 6.3v 6-20
amps on the secondary in place of the battery charger. Any suggestions
on which is better? I KNOW that using a light dimmer switch for the
adjustment setting is a bad idea.

I already know that American Beauty and PBL sells these. But for around
$500 for a 250 watt model, I think I will screw around with this some
more. I am bidding on a 300 watt model on ebay right now.

I also searched around the Internet for more instructions. But
everything I found was pretty vague. I am electronics illiterate, but I
can usually figure stuff out with some clear directions.

ANY help on this would be greatly appreciated.

THANKS!

You're not getting nearly enough current from a small battery charger.
One 500-watt resistance soldering box (Wassco Glo-Melt model 105-B2)
has voltage taps from 1.0 to 5.8 volts -- which, at 500 watts would be
500 to 86 amps.

You might try a soldering gun --without the tip. My (old) Weller
D-550 delivers 240 or 325 watts at 1.5 volts. That's 160 and 216 amps
-- if the load resistance is low enough to accept it. There's one
;ike it on EBay right now:

http://cgi.ebay.com/ws/eBayISAPI.dll...y=46 413&rd=1

Looks like current production D550's are rated at 260/200 watts.
The D650 is rated at 300/200 watts. You might also try a 150 from
HF( item 42685) for $9.99. You could use two or more in series or
parallel to get more heat.

The tubes on the Weller are threaded 7/16-14 so you could connect to
it with a couple of bolts. Use very heavy wire like #4 welding
cable, automotive ground braid or copper strip for (short)
connections from soldering gun to work and stinger. The issue isn't
overheating the wire, but minimizing voltage drop everywhere but in
the load itself.

Yes, a variac would be the best control. With a variac, I'd tape the
trigger down on the gun and use the variac to control it. A foot
switch might be handy too.

Hi Don,
Yeah...I had thought about using a soldering gun for the power pack.
But I sort of like the portability of the soldering iron that I already
have built. I have a foot control, but it is a simple momentary ON
(while the pedal is to the metal) or Off (foot off the pedal). The
thing is, this setup works. I am just not getting the current I need at
the end of the carbon. I am hoping to get some more replies before I
throw more money at this. I "think" a larger charger with a variac will
work. If you don't mind taking a look at this auction, I am looking at
this variac:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

This would go on a 12/30/75 amp charger something like this one from
Amazon:

http://www.amazon.com/gp/product/B00...nce&n=15684181

One of the things that I don't understand (I don't understand a lot of
what I am doing, this is only one of them) is which side does this go
on? The 110v or the 12v side? My guess is the 110v side.

Thanks for the reply.

Mike

Definitely on the primary (110v) side. Just remember that the Variac does
NOT isolate the output from the 110v input. I'm sure your aware but thought
I'd mention it. The output of the soldering gun would be AC but the
charger, of course, is DC. I had considering building one but also using a
DC cap in the circuit to give it just a bit more "punch". I've not looked
inside one of the commercial units to verify if those are done that way or
not.
Respectfully,
Ron Moore

"mj" wrote in message
ups.com...
Hi Don,
Yeah...I had thought about using a soldering gun for the power pack.
But I sort of like the portability of the soldering iron that I already
have built. I have a foot control, but it is a simple momentary ON
(while the pedal is to the metal) or Off (foot off the pedal). The
thing is, this setup works. I am just not getting the current I need at
the end of the carbon. I am hoping to get some more replies before I
throw more money at this. I "think" a larger charger with a variac will
work. If you don't mind taking a look at this auction, I am looking at
this variac:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

This would go on a 12/30/75 amp charger something like this one from
Amazon:

http://www.amazon.com/gp/product/B00...nce&n=15684181

One of the things that I don't understand (I don't understand a lot of
what I am doing, this is only one of them) is which side does this go
on? The 110v or the 12v side? My guess is the 110v side.

Thanks for the reply.

Mike

On Sun, 1 Jan 2006 19:51:46 -0600, "Ron Moore"
wrote:

Definitely on the primary (110v) side. Just remember that the Variac does
NOT isolate the output from the 110v input. I'm sure your aware but thought
I'd mention it. The output of the soldering gun would be AC but the
charger, of course, is DC. I had considering building one but also using a
DC cap in the circuit to give it just a bit more "punch". I've not looked
inside one of the commercial units to verify if those are done that way or
not.
Respectfully,
Ron Moore

They're not. They're AC. AC heats just as well as DC, why rectify
it?

You're right that DC with a cap would have more punch -- if you want
divots in your sheetmetal.

I was thinking of the welder mech that is used to link batteries into packs.
Don't know why I was thinking that. I'm sorry, I not sure what you were
referring to that is not DC output, unless it is the resistance welder and
not the charger. Once again, my mind was on the wrong box. Great article
on the shopbuilt resistance soldering device. I may have to build one, just
to have one in case..... The Variac would be great to control current,
especially with the soldering gun, which may be too much anyway. Sorry
about my confusion.
Respectfully,
Ron Moore



"Don Foreman" wrote in message
...
On Sun, 1 Jan 2006 19:51:46 -0600, "Ron Moore"
wrote:

Definitely on the primary (110v) side. Just remember that the Variac does
NOT isolate the output from the 110v input. I'm sure your aware but
thought
I'd mention it. The output of the soldering gun would be AC but the
charger, of course, is DC. I had considering building one but also using
a
DC cap in the circuit to give it just a bit more "punch". I've not looked
inside one of the commercial units to verify if those are done that way or
not.
Respectfully,
Ron Moore

They're not. They're AC. AC heats just as well as DC, why rectify
it?

You're right that DC with a cap would have more punch -- if you want
divots in your sheetmetal.

On 1 Jan 2006 16:41:37 -0800, "mj" wrote:

Hi Don,
Yeah...I had thought about using a soldering gun for the power pack.
But I sort of like the portability of the soldering iron that I already
have built. I have a foot control, but it is a simple momentary ON
(while the pedal is to the metal) or Off (foot off the pedal). The
thing is, this setup works. I am just not getting the current I need at
the end of the carbon. I am hoping to get some more replies before I
throw more money at this. I "think" a larger charger with a variac will
work. If you don't mind taking a look at this auction, I am looking at
this variac:

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1

That'll work.

This would go on a 12/30/75 amp charger something like this one from
Amazon:

http://www.amazon.com/gp/product/B00...nce&n=15684181

Uh....I think you're right to wait for more replies.

One of the things that I don't understand (I don't understand a lot of
what I am doing, this is only one of them) is which side does this go
on? The 110v or the 12v side? My guess is the 110v side.

Right.

Interesting idea, I never thought of that approach. Have you done this and
did it work?? How well compared to a commercial unit like the American
Beauty??

You might try a soldering gun --without the tip. My (old) Weller
D-550 delivers 240 or 325 watts at 1.5 volts. That's 160 and 216 amps
-- if the load resistance is low enough to accept it. There's one
;ike it on EBay right now:

On Mon, 02 Jan 2006 05:25:52 GMT, Bradford Chaucer
wrote:

Interesting idea, I never thought of that approach. Have you done this and
did it work?? How well compared to a commercial unit like the American
Beauty??

You might try a soldering gun --without the tip. My (old) Weller
D-550 delivers 240 or 325 watts at 1.5 volts. That's 160 and 216 amps
-- if the load resistance is low enough to accept it. There's one
;ike it on EBay right now:

I haven't, and I don't have an American Beauty to compare it to -- but
I do have an old 500-watt Wassco. I use a little O/A torch for
silverbrazing small stuff, but I certainly do a resistance soldering
experiment if you'd care to define the experiment.

Gunner has soldered wires together by pressing a soldering gun (sans
tip) against a splice to be soldered.

My priority job right now is to fix the Reznor unit heater in my
shop that doesn't wanna light off until I smack it with a pipe.
I think it needs a new gas valve or gas valve controller after a mere
20 years of service. I thought it just needed a new thermocouple --
until I discovered that it doesn't even use a thermocouple. Uses
flame rectification for flame proving and that seems to be working
because the ignitor quits sparking once the pilot is lit.

Unnnnggghhh. Wanna fixit before it gets cold in MN. A cold shop
is not a happy shop.

Bradford,
My unit works...sort of. It ran long enough to get two pieces of .005
brass sheet strips soldered together before the internal breaker kicked
in. It takes a little bit for it to cool before I could try it again.
Even soldering the .005 strips took about 5-6 seconds. The commercial
units will do it in about 3. I just need more power coming out of the
carbon rod, which I "think" is more amps and maybe lower volts.
Mike

That's right, lower voltage, higher current. When the voltage is too high,
you will just get arcing and pitting of the parts and electrodes.

As to transformers, keep poking about on Ebay. I picked up some a while
back.

On 2 Jan 2006 03:25:24 -0800, "mj" wrote:

Bradford,
My unit works...sort of. It ran long enough to get two pieces of .005
brass sheet strips soldered together before the internal breaker kicked
in. It takes a little bit for it to cool before I could try it again.
Even soldering the .005 strips took about 5-6 seconds. The commercial
units will do it in about 3. I just need more power coming out of the
carbon rod, which I "think" is more amps and maybe lower volts.
Mike

I do that all the time. I have to solder the center pins on coax connectors
and have 2 notches filed in the part of the gun the tip attaches to. Just
stuff the pin in and pull the trigger about 2 sec and it is melting solder.
Slip it over the end of the wire and pull the trigger again and it is a done
deal. The pins stick in the gun tight enough that when you pull the gun off
it tests the connection too. I have also used it to solder car battery
cables etc. but you have to remove the tip for that.
My PACE Kit has resistance soldering tweezers that are wonderful for DB
connectors. The wire leads in those is about 14GA. I have never measured
the voltage and current in it though.

Glenn

"Bradford Chaucer" wrote in message
...
Interesting idea, I never thought of that approach. Have you done this
and
did it work?? How well compared to a commercial unit like the American
Beauty??

You might try a soldering gun --without the tip. My (old) Weller
D-550 delivers 240 or 325 watts at 1.5 volts. That's 160 and 216 amps
-- if the load resistance is low enough to accept it. There's one
;ike it on EBay right now:

You would use the variac on the 120 v side of the stepdown transformer so
it is feeding thtransformer a variable input voltage. Never on the output.

That said, you are still taking the wrong approach, the transformer in that
battery charger is still to high a voltage output and to low a current. You
want like a big asses old4-5 v filament transformer with a 100 amp output!!

On 1 Jan 2006 13:06:45 -0800, "mj" wrote:

I would like to
solder up to around .025 brass sheets together too. I found a 12/30/75
amp charger at Menards that is probably my next step. But I would like
to be able to vary the current coming out. Do I need a variac for this?
Does this go on the input (110v) or the output (12v) side of the
charger? What specs (volts/amps/watts) should I look for on this? I
also know that I could use a filament transformer of around 6.3v 6-20
amps on the secondary in place of the battery charger. Any suggestions
on which is better? I KNOW that using a light dimmer switch for the
adjustment setting is a bad idea.

Hi Bradford,
Actually from what I've read on using a filament transformer is that a
6.3 v with anywhere from 6-20 amps is "supposed" to work. I don't know
how well this concoction is going to work compared to a commercial
unit, but I am willing to throw around $100 at it to find out.

I am looking around for a filament transformer on ebay. Unless you have
an old tube type TV set that you could pull one out for me. LOL.

Earlier you had asked how this setup compares to an American Beauty. I
don't know. I've never gotten my hands on an AB or any other commercial
units for that matter. The one that I am looking at from PBL is a 300
watt unit. From my rudimentary electronics knowledge, a 6v (or there
abouts) transformer with even 20 amps on the output is 120 watts,
correct? (6 x 20). Your idea of using a 4-5 volt / 100 amp output would
get me up to 400-500 watts. Where I would find something that big, I
have no idea.

Mike

Do a search on Microwave Oven Transformers in RCM. A typical MWO
transformer is good for about 1000 watts. The secondary is fairly easy
to remove and a new secondary can be wound on. You get about one volt
per turn so you don't have to have many turns.

I can find Mircowave Ovens for two or three dollars at the St. Vincent
de Paul that are guaranteed to be defective. I have only purchased
two, but both of those had good transformers.


Dan

I've heard of doing this too. And I might have access to an old
microwave. The one in our kitchen needs to be replaced one of these
days. This might be a good excuse to replace it.

Then all I need to do is figure out how to rewire the secondary....

But I am sure you guys will be able to explain that to me LOL.

Thanks
Mike

Hey Dan,
Wow...there is a lot of information on MWO transformers. The one that
gave me the fuzziest feeling was this one:

Quote text:
I have a microwave transformer from a 600 W oven. This is very confusing to
me because the power in side has the standard two lead connection. The part
that puzzles me is, the out side has three connections. Which connections
are the ones I should use?

DANGER! WARNING! Microwave oven transformers make lethal voltages.
If you don't know what you are doing (and from the above, you don't),
please don't screw around with them.

[Normally I'd say Google is your friend, but in this case it'll give
you just enough information to kill yourself or some innocent
bystander.]
Unquote text

Good golly this looks like fun! There was another posting on how I only
need to be within inches of it for the volts to just jump out and
attack me.

Are these things really that lethal?

Mike

According to mj :

[ ... dangers of microwave transformers ... ]

Good golly this looks like fun! There was another posting on how I only
need to be within inches of it for the volts to just jump out and
attack me.

Are these things really that lethal?

As is -- pretty close. Though I don't think that they actually
get *that* high in output voltage.

But -- once you strip off the secondary (finer wire), you should
be fine. It is that secondary which creates the high voltages. You'll
be replacing the secondary with only one or two turns, I think. And you
want *heavy* wire for those turns.

That original web page which you posted really was worrying me
about some of his techniques. And -- by the time I read to the end, I
discovered that he was having just the problems that I expected --
failures of the footswitch and the connectors which he used. He would
have been better off putting the switch which he made in series with the
*primary* of the transformer, not the secondary. I would have built the
footswitch box pretty much as he did -- but I would have run a power
cord directly into it, and put an AC outlet controlled by the switch in
the box. Then, it could be used to switch pretty much anything which
needed a footswitch, and the switch would not need to be a particularly
high-current one, either. *Certainly* -- don't use the phone plugs to
switch power line voltages.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

According to mj :
Hi Bradford,
Actually from what I've read on using a filament transformer is that a
6.3 v with anywhere from 6-20 amps is "supposed" to work. I don't know
how well this concoction is going to work compared to a commercial
unit, but I am willing to throw around $100 at it to find out.

I am looking around for a filament transformer on ebay. Unless you have
an old tube type TV set that you could pull one out for me. LOL.

Most tube type TV sets had series-connected filaments which
added up to 115 VAC. There would be a filament supply for the CRT, but
IIRC, that was derived off of the flyback transformer for high-voltage
isolation.

What you really want is a transformer for a serious transmitter,
broadcast style. The final output tubes tended to have their own
filament transformers, separate from the HV transformers, and those tube
filaments ran at quite high current and quite low voltage -- just what
you need.

Earlier you had asked how this setup compares to an American Beauty. I
don't know. I've never gotten my hands on an AB or any other commercial
units for that matter. The one that I am looking at from PBL is a 300
watt unit. From my rudimentary electronics knowledge, a 6v (or there
abouts) transformer with even 20 amps on the output is 120 watts,
correct? (6 x 20). Your idea of using a 4-5 volt / 100 amp output would
get me up to 400-500 watts. Where I would find something that big, I
have no idea.

Old filament transformers for broadcast transmitter tubes.

I suspect that those are still made.

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---