Help with welding

[duke peterson]

Hello

I am trying to build a smoker out of a old compressor tank. My cook chamber will be about 900mm long and 450mm diameter which I think makes it about 37 gallons?

I have done a bit of welding before mainly on thin metal with adequate results but never with thick metal.

I am trying to weld sealing strips around the door of my smoker. This involves welding the 3mm strips to the 6mm smoker door. I am using a BOC 190C which obviously is a 190amp welder which I think should be capable of this? I am really struggling to get adequate penetration. I have tried cleaning the metal very well, making sure i have a good earth, pre heating the metal, i am using the welder on its highest voltage and amp/wire speed setting but no luck. Sometimes my welds look OK but just don't hold up under force, other times for no reason that is clear to me the wire burns very quick and i get crappy splattery welds. I am using a extension cord, could this be a problem? Have also tried drilling holes and doing plug welds but still don't seem to hold?

Getting really frustrated and would appreciate your help.

Cheers
Elliam

 

[motocrash]

Is your welder plugged into an extension cord? At 190 amps it should be penetrating very good/back cutting the 3 mm stock. You're not getting enough heat/amps.

 

[daveomak]

Clean the metal so you are getting a good ground.... The ground is as important as anything on the hot end...
Try some 6013 in 3/32 diameter stick...

 

[JckDanls 07]

You say your wire feed is wide open (fast) ?? try slowing wire feed WAY DOWN so the metal has a chance to heat/melt (penetrate) before it fills up with wire/bead ... But also... extension cords aren't good ether ...

 

[daveomak]

6013 rod won't work on a wire feed... No S*IT....

 

[duke peterson]

Will try thanks, I thought that the ampage was also controlled by the wire speed control so I had to have it up?

 

[motocrash]

6013 rod won't work on a wire feed... No S*IT....

Funny,I was thinking that too :D

 

[duke peterson]

Also yes I'm using a extension cord, should I not be?

 

[ghostguy6]

Try using these settings or something close to it. You get better penetration with straight polarity, DCEN or direct current with the electrode negative. Also try moving the electrode in small circles or semi circles. It looks like you are just holding the gun steady while holding the trigger. When doing your plug welds, start at the middle then move to one side, work your way around the whole with the wire aimed at a 45* angle. Once you complete the full circle fill the middle of the weld if required but hold the electrode straight down for maximum penetration. Using an extension cord does lower the available power to the welder unless you use an oversized gauge cord.



Short Circuit Transfer


(generally used for thinner metals
and out of position welding)



Wire Size & Wire Feed Speed:
.035" (0.9 mm) at 360-380 ipm

.045" (1.1 mm) at 185-195 ipm

Shielding Gas & Voltage Range:
CO2 23-24 Volts 75% Argon/25% CO2: 21-22 Volts

CO2 gas is economical and has deeper penetration on steel, but may be too hot for thin metal. 75% Argon / 25% CO2 is better on thin steels, has less spatter and better bead appearance.

Amperage Range:
180-190


Spray Arc Transfer

(generally used for thicker metals in the flat or slightly horizontal position)
Wire Size & Wire Feed Speed:
.035" (0.9 mm) at 400-420 ipm
.045" (1.1 mm) at 210-220 ipm

Shielding Gas & Voltage Range:
98% Argon/2% O2: 24-25 Volts

Amperage Range:
200-210

Steel Welding Wire:

For steel, there are two common wire types. Use an AWS classification ER70S-3 for all purpose, economical welding. Use ER70S-6 wire when more deoxidizers are needed for welding on dirty or rusty steel.

• Must be used with CO2 or 75% Argon/25% (C-25) shielding gas
• Indoor use with no wind

 

[cjohnson3006]

I'm assuming with it being 190a welder it's a 240v input and not 120v? If it's 240v, make sure extension cord is at least 6ga or 12ga for a 120v. Not sure what you have but my experience on the small portable welders is .030 wire seems to work best as the ground cables on them are small and lose a lot of current

 

[LanceR]

Good morning, Elliam

From the pictures you posted it is clear that your welds are not penetrating and they appear cold. You don't mention whether you are using self shielded flux core wire, gas shielded flux core or solid wire. As each has it's own set up requirements and preferred welding techniques it would be helpful to know which you are running, what shielding gasyou are using (if any) and what classification the wire is.

I am a hobby welder and not a professional so I'll keep my comments basic. The first two things I'd check would be that you have the correct polarity set for the wire you are using and that you have a really good ground/earth. Most wire feeders come with cheap sheet metal ground/earth clamps and I've always replaced them with solid copper clamps and I use a short strip of tinned copper ground strap under the clamp to ensure a really good ground/earth.

You are correct that amperage is controlled by wire feed speed. But there are some technique differences between self shielded flux core, gas shielded and solid wire that affect penetration, too. And a properly sized gun liner, contact tip etc along with properly adjusted and sized feed rolls are all necessary, too. Have you checked them?

The melting of the base metal, and the amount of penetration that results, happens at the front edge of the weld puddle so you need to stay at or near the front edge. Staying in the rear of the puddle or in one spot just piles more weld metal on top of the old weld metal and does nothing for penetration or strength.

If you cruise over to weldingtipsandtricks dot com you'll find dozens (hundreds, really) of very good welding videos. You might want to subscribe to the weekly video while you're there.

Good luck and keep us in the loop, please.

 

[duke peterson]

Hello

Thanks for all the useful advice. I am using sheilding gas and the wire pictured. I currently have the earth on the negative, so I should swap this yeah? Will also eliminate the extension cord and see how I go.

Thanks again

 

[cjohnson3006]

Yes put earth/ground on the positive

 

[LanceR]

POLARITY CHECK!! A couple of posts have called for a DCEN (direct current electrode negative) and I don't think that's correct although as I wrote in a post above I'm not a professional welder. Elliam is using an ER70S-6 SOLID WIRE. I'm looking at three different references (Miller, Lincoln and ESAB) all of whom call for DCEP (direct current electrode positive) with his solid wire. Quoted from Miller's website: "MIG welding requires DC electrode positive, or reverse polarity."

Please let me know if you are seeing something different.



From what I see the gas Elliam is using is an Australian mix of Argon, CO2 and Oxygen at 93%/5%/2% which would be somewhat unusual in the US where straight CO2 or Argon/CO2 in a 75-80% argon/20-25% CO2 would be more normal for mild steel.



Elliam, looking at the tech sheet for your .9mm/.035" wire shows a range of 90-220 amps and 16-30 volts but with no wire feed speed listed which seems strange given that it's for a wire electrode....... And I think that the high end of that would surely put you in spray transfer country with more potential heat warping of the steel and more spatter than you want.

As I understand things, lower voltages result in narrower droplet cones (yielding a narrower bead if no electrode manipulation), and higher voltages result in wider cones while higher wire feed speeds mean higher amperage and deeper penetration etc.

For short circuit transfer I suspect that a good starting point is something like DCEP (ground/earth the work not the electrode), a contact tip to work distance of 9-13mm (3/8-1/2"), 19 volts and 3.8m/150" per minute wire feed speed. If my (alleged) brain cell is correct that should bring you in at about 120 amps.

The tech sheet calls for 15-20 l/min gas flow (30-40 CFH?) which seems high to me but who knows? At any rate, the high argon content of your gas should help with minimal spatter and a nice smooth bead once you have everything dialed in. And after you have the other things dialed in you can run some practice beads on scrap while turning down the gas flow until you see signs of porosity. Then bump it back up some and you should be using the most economical amount of gas that gives a smooth sound weld.

If you aren't sure of the actual wire feed speed at any particular knob setting, cut the wire at the nozzle, pull the trigger for six seconds and multiply the wire fed out by ten for the actual wire feed speed per minute. Feed rolls, gun liners and contact tips wear and feed roll tension can change causing changes in wire feed speeds at a particular knob setting as can a tightly bent gun cable. If you have an unexplained issue that you can't troubleshoot, check the actual wire feed speed and straighten out the gun. And yes, that's from experience....

And if the welding gas cylinder was filled a while ago sometimes the gasses settle out from each other. One thing that works for some folks is to disconnect any regulators from the tank, put on the transport cap and roll the cylinder around on its side for ten seconds or so to re-mix the gases. It certainly can't hurt to try it.

And now that I've written all this maybe someone who really knows what they're doing with welding will come along.......

 

[daveomak]

Yep....

http://www.weldreality.com/ehauststraighpole.htm

 

[duke peterson]

So have just spent all morning fiddling with settings included the ones suggested and still my welds lack penetration, tried switching polarity and initially thought they were a bit better with the earth positive but still not penetrarinp the 6mm steel.

Have also eliminated the extension cord but welds still rubbish.

Starting to dispear

Thanks again for your help.

 

[LanceR]

Check out weldingweb dot com

There are a number of Aussie welders there. I`m sure that an introductory post describing your problem will draw attention.

And do you want to o by Duke or Elliam?

Good luck

 

[LanceR]

Hmm... I should have asked this at the start. How many amps is the receptacle and branch circuit you are plugged into?

 

[daveomak]

I'm beginning to wonder if that tank is some weird metallurgy...

 

[cjohnson3006]

Are you pushing your weld or pulling it? You will get better penetration pushing your weld in a semi circle slightly ahead of your weld puddle. Keep your tip 1/2"-3/4" away from your work surface. Not sure of your technique but if tip touches the metal, your wire will lose some current