Ask your WELDING questions here.

[ADV8]

Originally Posted by David R

The electrode turns black. Ya can't miss it. No big loss, just clean it up, re sharpen and resume welding. I use a belt sander and cordless drill. I then put a fine finish on the point with a tungsten sharpener.

Don't forget a mask being that $hit isn't exactly loaded with vitamins.

[Twin-shocker]

Originally Posted by MODNROD

OK welding guru's, here's my dumb-arse question for the week.

I currently have a 200A MIG (I use it gasless mostly, outside for 90% of the time), I can weld OK with the thing, but I'm not a welder (if that makes sense!). Used mostly for making exhaust systems, and light 3mm or 4mm chassis stuff.

I'm gettting close to having a shed (woo!hoo!), so can soon do all this stuff indoors, but I also would like something that will weld up aluminium (for bike brackets) and thin plate (for my VW Bug project), so I thought I'd get a TIG and practise, same as before with the MIG, and my 10 yr old MIG is getting long in the tooth.

Also, the actual TIG welding itself. I can use a MIG fairly well (without having a ticket and 20 yrs on the job of course), I can use stick too, and I'm not sure if it's relevant, but but my trade is in electronics, and I have held the highest soldering standard available for nearly 30 years (are the processes involved as similar as they look?). Will adapting be all that difficult?

I've seen 200A Inverter TIG/MMA (whatever that is......)/cutters for about $500 Oz and they look attractive. Will this size machine do the job I ask of it?

And yes, I realise a $2000 machine would do it better, but it's hard to justify the expense for what is really a hobby. A basic machine that will do the job is all I'm after, no frills. Is 200A the size I would need? 250A? 180A?

Thanks for any answers.

A used quality TIG set would be a better idea than new Chinese, unless you are only going to be using it very rarely. If you can gas weld, then TIG will come pretty easily, but any form of welding experience should help you. 200A set will be fine for most things, and if you can something with water cooled torch is a good choice.

[David R]

For aluminum you need AC TIG

[elmo_4_vt]

A Question about a Stupid mistake...

So I recently just went through my first 10lb roll of .035 wire - Took about 3 years to give you the idea of the amount of welding I do. All using shielding gas on a Lincoln 175. No problem, went to Lowes, and they had a 2lb roll of .030 wire. Bought it, came back, and decided to take out the instructions (gasp) to make sure that the liner was the same for .030 and .035 (which it is). While I was hooking things back up, I realized that my polarity was still hooked up for the gass-less, flux-core type of welding. Apparently, I've been using this since I've gotten it with the wrong polarity on the tip vs. ground. Once I set everything back up, I continued to weld and it felt and sounded better. I only had another 5 minutes worth before that day's project was finished though. Some of the difference could have been the smaller wire size, but not all of it. The "fizzing" sound was definitely more steady and constant.

My question is, what does using the polarity backwards do? I, like most hobby-ist welders, wouldn't ever call my self a welder, but my welds look alright, I get good penetration, and nothings ever come apart. I haven't had much of a chance to use the new settings, but don't quite understand why the difference between flux core and gas shielded. Can anyone explain it to me?

Thanks,
Don

-

[djborden]

Originally Posted by David R

The electrode turns black. Ya can't miss it. No big loss, just clean it up, re sharpen and resume welding. I use a belt sander and cordless drill. I then put a fine finish on the point with a tungsten sharpener.

Thanks.. Can you tell what will happen welding with an oxidized tungsten? (puddle or arc if anything)

David

[kirkster70]

Originally Posted by djborden

Thanks.. Can you tell what will happen welding with an oxidized tungsten? (puddle or arc if anything)

David

You will contaminate your weld and introduce porosity, making the weld weak and ugly. The arc will even turn a different color.

[kirkster70]

Originally Posted by Twin-shocker

Those settings mean you are wasting a fair amount of gas...........if you have a watercooled torch, then cut time by half. Also a very good idea to use gas saver front end torch parts, as this will help to save even more gas.

Yeah, I blew through a 125cf tank pretty quickly. I think I may even be able to drop down to 8 sec. I have an air-cooled torch for now, so I know I need to use more gas than a water-cooled setup.

I'll have to look into gas saver parts. Thanks for the info.

EDIT - just found the gas saver pyrex cups. Do I want standard or large diameter? I'm running a WP-17 torch. I'm not really sure of how they save gas? Thanks again in advance...

[David R]

CFH Count more than post flow. You need enough flow to keep porosity out of your welds on carbon steel. Depending on gas cone size, amps, and other conditions. 8 to 20 CFH.

[djborden]

Originally Posted by kirkster70

You will contaminate your weld and introduce porosity, making the weld weak and ugly. The arc will even turn a different color.

Thanks, appreciate the info.

David

[KTM640Dakar]

Originally Posted by elmo_4_vt

A Question about a Stupid mistake...

So I recently just went through my first 10lb roll of .035 wire - Took about 3 years to give you the idea of the amount of welding I do. All using shielding gas on a Lincoln 175. No problem, went to Lowes, and they had a 2lb roll of .030 wire. Bought it, came back, and decided to take out the instructions (gasp) to make sure that the liner was the same for .030 and .035 (which it is). While I was hooking things back up, I realized that my polarity was still hooked up for the gass-less, flux-core type of welding. Apparently, I've been using this since I've gotten it with the wrong polarity on the tip vs. ground. Once I set everything back up, I continued to weld and it felt and sounded better. I only had another 5 minutes worth before that day's project was finished though. Some of the difference could have been the smaller wire size, but not all of it. The "fizzing" sound was definitely more steady and constant.

My question is, what does using the polarity backwards do? I, like most hobby-ist welders, wouldn't ever call my self a welder, but my welds look alright, I get good penetration, and nothings ever come apart. I haven't had much of a chance to use the new settings, but don't quite understand why the difference between flux core and gas shielded. Can anyone explain it to me?

Thanks,
Don

-

Solid wire w/ gas use DC+
cored wire w/o gas use DC-

Polarity always refers to the electrodes polarity ( the cable attached to the wire feeder)

Using the wrong polarity will make your arc erratic. Most of the heat is on the positive side of the DC arc. So hollow cored wire does not need to be melted as much as solid wire so you run DC- to it and you get good penetration into your plate.

Always read the sticker on the inside door of your Lincoln welder. It has all the setup information that you need.

[clintnz]

What grit & type of grinding stone do I need for sharpening tungstens? Got a TIG machine on it's way to the workshop, I suspect a few electrodes are going to be seriously harmed in the process of us learning to use it so I want to get a dedicated wheel for the 6" bench grinder.

Cheers
Clint

[NitroAcres]

Originally Posted by clintnz

What grit & type of grinding stone do I need for sharpening tungstens? Got a TIG machine on it's way to the workshop, I suspect a few electrodes are going to be seriously harmed in the process of us learning to use it so I want to get a dedicated wheel for the 6" bench grinder.

Cheers
Clint

I got a double sided Ryobi in my small shop..and the "Fine" side is Tungsten sharpening only...in my big shop I have a single dedicated grinder uses a 6" "Fine" wheel..from McMaster Carr.

[David R]

Been using a fine 4" belt sander with the electrode chucked in a battery powered drill turning slow.
This cleans up the tungsten even above the point.

I then dress them on a Sharpie which is a dremel with a diamond wheel.

I could live with out the sharpie if I had to.

For the guy with a new tig welder on its way. Enjoy it. I replace my tungsten frequently. I keep a dish of sharpened ones. Smaller tungsten sharpens easier and quicker than larger diameter ones. 1/16 works great up to almost 200 amps then it blows like a fuse.

It does not matter what color band is on it when I dunk it in the puddle.

Smaller costs less so its not much of a big deal if I have to break the big ball of filler off the end before sharpening.



David

[johns]

Anyone familiar with the Krupp KW welders? I'm going to check out a KW 250 next weekeind and it seems like a good deal ($325 including dials and a small 5l gas bottle). Looks a bit old on the outside, but the inside (where the wire spool sits) seems ok.

I can't find any info online except two ads, a KW180 for about 200 without bottle and a KW400 for 750.

[Twin-shocker]

Originally Posted by kirkster70

Yeah, I blew through a 125cf tank pretty quickly. I think I may even be able to drop down to 8 sec. I have an air-cooled torch for now, so I know I need to use more gas than a water-cooled setup.

I'll have to look into gas saver parts. Thanks for the info.

EDIT - just found the gas saver pyrex cups. Do I want standard or large diameter? I'm running a WP-17 torch. I'm not really sure of how they save gas? Thanks again in advance...

There is really no need for Pyrex cups unless you are doing a job where being able to see through the cup makes things much easier. Gas saver kit front end parts for various size tungstens are produced by CK, and really do seem to make a difference in that you can run much lower pressure and still get good gas coverage.