Anyone seen a similar chart to this but in millimeters?

[earthman]

http://www.weldingtipsandtricks.com/mig-welding-basics-3.html

OK, I could manually convert all those figures into metric ones by using a calculator but does this formula still stand true for metric materials in the first place?

So for example, would 1 ampere for every 0.025mm thickness of metal be right?

The factors (times by) of 1, 1.6, 2 & 3.5, how did he work that out for inches in the first place I'm wondering? Would they be the same for wire measured in millimeters??

 

[Shedendman]

Forget about what someone elses chart says do one for the welder you have,which is different to mine,his and the guys down the road.
You could spend an age working out what wire speed for what amps for what metal thickness and still end up with not a getting it right.
Jodys chart doesn't cover things like different thicknesses ie 0.8mm to 2mm or what position your in etc,whole different ball game that will throw what you have on the chart

 

[chunkolini]

Dont worry about charts. When I started I had a notebook with settings for every job I did.
it never made any sense to me whatsoever.
Eventually you learn what settings re power and wire speed work, it just takes time.

 

[chunkolini]

What I have noticed is that over the the power goes up and I compensate by moving faster and get a better result

 

[earthman]

Damn, I thought that a chart like this would have been ideal.

 

[Shedendman]

Damn, I thought that a chart like this would have been ideal.

It might,but you'd spend half the day looking at it and get sod all done

 

[earthman]

It might,but you'd spend half the day looking at it and get sod all done

Well I don't actually weld a lot or frequently enough so it wouldn't, in fact I think that it would save me time and having to look for similar scrap metal to practice on a LOT.

 

[penfold]

Scrap steel costs buttons and practising until you've got it right means not making a mess of whatever it is you're making.

 

[earthman]

It might save you time.

Tell me, how would set your welder for, let's say, 100A?

I have no idea to be honest.

100A? That would be for a really thick piece of steel right??

I just hate having to guess at things/do a balancing act with the wire feed and power settings every time. Apart from listening for the bacon sound I don't have much of a clue, can't really see what's happening through the helmet, let alone controlling the torch movement.

That video seemed like a really good idea to me, using a formula/measurement to take the guess work out of the wire speed, that would have been a great help and a big step for any beginner I'd say.

I'm tinkering by myself at home, may not have to weld anything for months, the only metal I have is what I've found on the street basically so it's pretty rare to come by for me.

 

[Hood]

Have a look at the MillerWeld Setting Calculator if you have a smart phone. It will give you a rough starting point from where you can then tweak to get a better setting for your machine.

 

[Jim Davey]

You'll need to forget about amps, and start learning to think in terms of wire feed speed and volts. Amps are just a by-product of the two.

 

[BrokenBiker]

100A? That would be for a really thick piece of steel right??

No...100A would be suitable for 2mm...maybe 2.5 depending on technique

 

[earthman]

No...100A would be suitable for 2mm...maybe 2.5 depending on technique

Just been looking at the specs of mig welders in Machine Mart, 150A machine, maximum welding thickness is 5-6mm.

 

[earthman]

Go to a scrapyard, buy some bits of steel, make your own chart.

There are multiple problems with charts though, and especially with hobby machines.

Most of the generic charts use 'amps' and 'wire feed' - you can't set amps on a mig for a start...

Second, wire speed - the chart says "x inches/mm per minute" - yeah, that's fine, but the dial goes 1-10 (unless you have a calibrated display). So, you get the tape out and measure off all the increments and it still doesn't work.

Most hobby machines (and some midrange) use the weld output to drive the feed motor. While it's a constant voltage supply, the voltage still droops when the arc is struck (the cheaper the machine, the more this happens, but it just does anyway) and the wire slows down. So, your measured 50 ipm into thin air becomes 35 ipm while welding...

Honestly, practice never hurts and if you're really fishing around that much with voltage and speed then it sounds like you could do with some.

I'm far from 'experienced' but I can look at a bit I need to weld and set dials on my machine then usually only have to tweak feed speed a bit - I've never had or used a chart (primarily because I think they're usually pointless unless specific to a certain machine/wire/gas combo) and never felt the need for one...

Fair do's, some good points you make there, measuring the wire going into thin air etc,...I don't know how he came up with 6 seconds in the first place either?

So far I've just muddled along really, thankfully nothing that I've welded has broken/fell apart so that's a good start, sure could do with being neater though but that takes a lot of practice I know.

Trouble is, even if I spent a few days doing it now and got acceptable results, if I pick that torch up in 6 months time I've forgotten/back to square one practically. Lol

 

[ukracer]

Trouble is, even if I spent a few days doing it now and got acceptable results, if I pick that torch up in 6 months time I've forgotten/back to square one practically. Lol

I struggle with this at first. not least as my memory is shot to pieces.

I got round this by taking a photo of what I was welding and the best settings I could get. Combine the two and save them measuring your material and write it on there.

Next time you have something to weld similar size you have a Base setting.

It's not perfect and I am not a welder but it helps me.

I

 

[PhillipM]

Also, please tell me how you 'set' a mig welder to 125A...

I turn the dial until my screen says 125A

 

[BrokenBiker]

I turn the dial until my screen says 125A

So do I but only a few cheap units have that feature lol.

 

[BrokenBiker]

Just been looking at the specs of mig welders in Machine Mart, 150A machine, maximum welding thickness is 5-6mm.

That is working on 2 assumptions...first you v grind the joint so you can get the weld to penetrate and then build it up afterwards, or assuming you don't want a full penetration weld and just want to weld something so it stays together...general rule of thumb is for every millimetre of steel thickness you want to weld, you will need 40ish amps...this alters if you were welding large sections of steel though as the thermal mass of the steel will suck the heat out of the puddle so you will need more amps.

For instance, i can set my welder up to run a bead on 3mm thick flat bar and it will do it fine all day long with full penetration...but if inthen try to weld 2 bits of 3mm box section together side by side, I will need more power as the box section has more thermal mass...

It's not as simple as saying 'the box said I can weld 5mm so I'm going to put the metal together and run a slug down it'.

 

[BrokenBiker]

So, how does it do that?

Does it vary the wire speed to keep both the voltage and current stable or does it vary the voltage in a very unmiglike fashion?

My cws alters the read out when voltage dial is altered to give memory based amps shown on screen...it's not perfect but it's bloody close. I set the dial to give the right amps, set the wfs by memory now and then tweak until right and it gives good results

 

[earthman]

That is working on 2 assumptions...first you v grind the joint so you can get the weld to penetrate and then build it up afterwards, or assuming you don't want a full penetration weld and just want to weld something so it stays together...general rule of thumb is for every millimetre of steel thickness you want to weld, you will need 40ish amps...this alters if you were welding large sections of steel though as the thermal mass of the steel will suck the heat out of the puddle so you will need more amps.

For instance, i can set my welder up to run a bead on 3mm thick flat bar and it will do it fine all day long with full penetration...but if inthen try to weld 2 bits of 3mm box section together side by side, I will need more power as the box section has more thermal mass...

It's not as simple as saying 'the box said I can weld 5mm so I'm going to put the metal together and run a slug down it'.

Interesting point you make about the box section/thermal mass, what if you could heat up the work piece first, say in an oven, do you think that would help?