This is a different type of question... Now that I have all the stuff I need to add tig to my buzz box, I decided to build a new enclosure for all the parts and not have a bunch of cable running all over. The last thing I really need is some kind of switch to change polarity. the cheapest thing is to have a bunch of studs sticking out the front of the box with jumpers to select what I want. I have also considered relays, but I would need six 250 amp continuous duty, and what I have seen would cost $200+ total. A replacement switch from a welder is $350. I've thought about making my own switch, but of all the designs I have come up with none are very satisfactory. Does anyone have any ideas?

I'd go with the studs and just move the cables. Heck -- my factory welder uses that method and I paid real money for it.

Two sets of tweco twist locks on your leads will give you a fast and easy way to switch polarity.


JTMcC.

I am just a little confused what it is you are trying or did cobble up. Best of luck what ever it is

If you need to change polarity how did you do it before was there a switch?? or did you just change the leads on the output studs??

You also want to be careful of heat build up unless you also have that figured out .

Watch out for having your output cables coiled and causing a choke which will cut your output to next to nothing.

Two sets of tweco twist locks on your leads will give you a fast and easy way to switch polarity.


JTMcC.

That.

or one of those heavy duty marine battery switches?

444063
230 Amps continuous, 345 Amps momentary made from UL 94-HB, UV stabilized polycarbonate

another model with higher amp rating: Battery selector switch, rated at 360 Amps continuous, 600 Amps momentary

Two sets of tweco twist locks on your leads will give you a fast and easy way to switch polarity.


JTMcC.

X2


Or, just find a used Lincoln AC/DC 225/125 that already has the DC+/- and AC switch built in. Those can be had for around $200-300 if you keep your eyes open

Miller has one that mounts under the hood of some of their Big 40D welders. We had a couple at work but can't remember the exact model. It was a surface mount like on a display, but was mounted on the frame. Might could find one cheap used or fairly priced at the welding store

Please post photo of the particular welder + assortment of parts you're dealing with if you want accurate info.

I'm guessing you have hard wired leads or lugs for stinger and work leads with a "universal" bolt-on type gas-through power block for your Tig torch. With all that bolted to your machine at the same time, that would indeed be a complete mess. A polarity switch will only add to the mess, so I'd scratch that idea. Unless you physically unbolt/unplug your stick electrode holder (stinger) when you are Tig welding (and vice-versa) it's going to remain "hot" at all times which is a concern especially with an older (read high OCV) machine. Not only are you going to be dealing with a tangled mess of leads, you have a major safety hazard on your hands.

This is what you're trying to accomplish right?
Stick/DCEP = Stinger lead to positive on machine, work lead ("ground") to negative on machine.
Scratch start TIG/DCEN = Disconnect stinger and work leads, swap work lead over to positive receptacle, Connect torch power block to negative receptacle on machine.

Unless you can deal with the inconvenience of unbolting leads every time you switch processes, you'll have to buy some connectors. You'll need two female receptacles (+ and - on machine), two male cable lugs (one for work, one for Stinger), and a more specific power connector for your TIG torch (or you can clamp the stinger on your universal block, but that's ghetto and a safety hazard also) . Whether you pick Tweco or Dinse style connectors, It's still about $75-100 worth of parts either way.

Nice thing about having "real" connectors is that you can use your own leads with other people's equipment. Construction sites/ rental industry/ and older machines tend to lean towards Tweco style. Newer machines tend to lean more towards Dinse style. You can buy adapters to go back and forth, or just keep both style connectors in your "spare parts" box if you plan to weld as a pro.

Tweco catalog, see pg 54-56.
http://www.thermadyne.com/IM_Uploads/DocLib_2380_64-2103.pdf

Well said it would be much easier with pictures just to know what you are looking for .

I could no doubt get a Polarity switch for gratis but this sounds like herding cats :grinpimp:

I think he's building his own TIG welder.

Here's what he's working on:
http://www.pirate4x4.com/forum/showpost.php?p=9809964&postcount=4

http://i7.photobucket.com/albums/y257/Fryloc/welder/Picture164.jpg

http://i7.photobucket.com/albums/y257/Fryloc/welder/Picture169.jpg

http://i7.photobucket.com/albums/y257/Fryloc/welder/Picture171.jpg

http://i7.photobucket.com/albums/y257/Fryloc/welder/Picture193.jpg

I really wish him well I give him credit for trying to Tig weld on the cheap.

Just remember you can only have a arc established if you are lucky for 12 minutes out of an hour and that is spaced out allowing the unit to cool down 8 minutes out of every 10.

I think most people would get tired of this real fast.. I know from also trying to also do almost the same thing. I learned a good lesson and I am reminded about this at least 2 or 3 times a month

Just remember you can only have a arc established if you are lucky for 12 minutes out of an hour and that is spaced out allowing the unit to cool down 8 minutes out of every 10.




Only if he's running the machine on Maxine, and I doubt he is.
Those little buzz boxes will make slick scratch start tig welds in reasonable amperage ranges (which give you a reasonable duty cycle) and will probably handle anything a guy will do in his garage on CS/SS. Lower amperage = higher duty cycle.
Scratch start, dry tig rigs have built most of the exotic high pressure power piping, boiler tubing, chemical piping, refinery piping, etc, etc in this country for many decades, a ton of them hooked to old SA-200's but really hooked to all manner of welding machines..
A slick tig hand can use a little buzz box (within it's amperage capabilities) to do 100% Xray code quality work.

And again, your best bet on polarity change is a small set of tweco twist locks, fast, simple, reliable and cheap. Plus it'll let you add lead if needed.

JTMcC.

Only if he's running the machine on Maxine, and I doubt he is.

And again, your best bet on polarity change is a small set of tweco twist locks, fast, simple, reliable and cheap. Plus it'll let you add lead if needed.

JTMcC.

What am I welding with 225 amps?:D Nothing. Most of the time I'll be around 100 amps.


Twist locks... not sure what you are getting at. I'd still need to be able to switch from DCEP stick to DCEN tig. Can't have my work clamp positive and negative at the same time.

Guido, thanks for posting that.

Only if he's running the machine on Maxine, and I doubt he is.

And again, your best bet on polarity change is a small set of tweco twist locks, fast, simple, reliable and cheap. Plus it'll let you add lead if needed.

JTMcC.

What am I welding with 225 amps?:D Nothing. Most of the time I'll be around 100 amps.


Twist locks... not sure what you are getting at. I'd still need to be able to switch from DCEP stick to DCEN tig. Can't have my work clamp positive and negative at the same time. Besides, this is how power gets to the tig torch.
http://www.az-zbum.com/images/power.block.jpg

Guido, thanks for posting that.

What am I welding with 225 amps?:D Nothing. Most of the time I'll be around 100 amps.


Twist locks... not sure what you are getting at. I'd still need to be able to switch from DCEP stick to DCEN tig. Can't have my work clamp positive and negative at the same time. Besides, this is how power gets to the tig torch.
http://www.az-zbum.com/images/power.block.jpg

Guido, thanks for posting that.


Reread my post, and the quoted post I was replying to. It's not hard to follow but you do need to pay a little attention to who is replying to what.
The guy says you'll only have 12 minutes welding time per hour....I pointed out sure, with the machine maxed out but at normal homeowner type amperage you'll have a lot more duty cycle. Hope that's clear to you.

And yes, a small set of twist locks will allow you to change polarity in about 10 seconds, I've done it probably several thousand times over the years.
If you put them out toward the ends of your leads you can put a stinger on a ultra flex whip to make stick welding nicer, and a short whip with a ground on the other.
This is a pretty common setup in the welding workplace.

Google "tweco cable connector". You only need the small or medium ones. Two male/two female or two sets of one each. Ram Welding Supply sells them pretty cheap.



JTMcC.

What am I welding with 225 amps?:D Nothing. Most of the time I'll be around 100 amps.


Twist locks... not sure what you are getting at. I'd still need to be able to switch from DCEP stick to DCEN tig. Can't have my work clamp positive and negative at the same time. Besides, this is how power gets to the tig torch.
http://www.az-zbum.com/images/power.block.jpg

Guido, thanks for posting that.

Yeah that's a "universal" gas-through power block. Throw it in your spare parts box and get a regular power connector that hooks to a Tweco or Dinse connection + convert the machine to twist locks. (read my last post)

Skip down to JasonMT's post here:
http://www.pirate4x4.com/forum/showthread.php?t=709931&highlight=miller+cst

PS how are you converting this thing to DC?

Reread my post, and the quoted post I was replying to. It's not hard to follow but you do need to pay a little attention to who is replying to what.
The guy says you'll only have 12 minutes welding time per hour....I pointed out sure, with the machine maxed out but at normal homeowner type amperage you'll have a lot more duty cycle. Hope that's clear to you.I was agreeing with you

And yes, a small set of twist locks will allow you to change polarity in about 10 seconds, I've done it probably several thousand times over the years.
If you put them out toward the ends of your leads you can put a stinger on a ultra flex whip to make stick welding nicer, and a short whip with a ground on the other.
This is a pretty common setup in the welding workplace.

Google "tweco cable connector". You only need the small or medium ones. Two male/two female or two sets of one each. Ram Welding Supply sells them pretty cheap.



JTMcC.That works for polarity on the stick side, but I may still need to change from dc to ac for tig'ing aluminum.

Yeah that's a "universal" gas-through power block. Throw it in your spare parts box and get a regular power connector that hooks to a Tweco or Dinse connection + convert the machine to twist locks. (read my last post)

Skip down to JasonMT's post here:
http://www.pirate4x4.com/forum/showthread.php?t=709931&highlight=miller+cst

PS how are you converting this thing to DC?
Thanks for the link, I'll check it out.

These things are diode from a big 3ph machine. Each stack is two diodes, so I have full wave rectification here. I still want a "choke" or whatever you call it to smooth out the DC.

http://i7.photobucket.com/albums/y257/Fryloc/welder/Picture169.jpg

Matt:
Read up on power amplifier power supply theory and you'll unerstadn how chokes work. I doubt you'd need one if you have a full wave rectifier. It's too bad Pembleton's closed down, you could find a contactor there that would do the job for you pretty cheap.

Your a better man than I. I have the stuff to convert a buzz box to TIG but haven't even started, too many other things to do to keep busy.

[QUOTE=Urban Wheeler;9865723]works for polarity on the stick side, but I may still need to change from dc to ac for tig'ing aluminum.

QUOTE]


Ok, I might of missed it, but all I saw was the question about switching polarity. This is the first I've seen you mention switching from AC to DC output.

JTMcC.

Yeah, I tried to get over there the other day only to find out they were gone. I need some bits and pieces for another project and Radio Shack seems to be my only local source anymore. :(

[QUOTE=Urban Wheeler;9865723]works for polarity on the stick side, but I may still need to change from dc to ac for tig'ing aluminum.

QUOTE]


Ok, I might of missed it, but all I saw was the question about switching polarity. This is the first I've seen you mention switching from AC to DC output.

JTMcC.

This is on ebay. I'm pretty sure I can use it.
http://i.ebayimg.com/09/!BSw9tlgBWk~$(KGrHgoH-CYEjlLl9odTBKE0WhHN1!~~_1.JPG

Wouldn't it be easier to build one of those truck alt tigs? I see where guys have posted up HF start circuits to go with them. At least then you could pedal it.

I've got a schematic for a foot throttle already.

[QUOTE=JTMcC;9866000]

This is on ebay. I'm pretty sure I can use it.
http://i.ebayimg.com/09/!BSw9tlgBWk~$(KGrHgoH-CYEjlLl9odTBKE0WhHN1!~~_1.JPG

<Dr. Frankenstein voice on> Igor, throw zee switch! <Dr. Frankenstein voice off>

[QUOTE=Urban Wheeler;9866058]

<Dr. Frankenstein voice on> Igor, throw zee switch! <Dr. Frankenstein voice off>

Lol.

http://i7.photobucket.com/albums/y257/Fryloc/Picture296.jpg

http://i7.photobucket.com/albums/y257/Fryloc/Picture297.jpg


With that switch I have it wired for stick ac, dc+, dc-, and tig ac and dc-.

Couple little details, but it's mostly done.