Need to measure usage of gas, wire and electricity....?

[hotponyshoes]

I wonder if wire cost is in similar proportion to gas (pennies)...?

Probably.
It sounds like you are teaching students or something though?
If that's the case then I would expect each fillet to be slightly different plus they will be getting false/missed starts etc so they are not going to use the same amount of wire on each weld anyway.
And I don't expect you will get a set of scales that can weigh a 15kg spool accurately enough for that without spending several years worth of wire on them.

If you count the length of wire used remember to account for the 3m (or whatever length the torches are) that will be unusable at the end of the roll.


For what you are doing, trying to work out the actual cost-per-weld seems pointless.
It might be better to monitor the overall use over a week/month and then divide by something useable like the number of students trained or number of sessions run or something.
I would think you would want to allocate the costs against something you can charge for as I'm guessing you will charge them a fee per session or course or something.
Not give them an invoice at the end for
4hrs of training @ £85/hr
122xfillets @ £0.02
Total £ 342.44

If you do need this data for some other reason then have a look at some of the industrial machines. You are unlikely to find much info in consumer brochures so you might need to try and get a rep to visit or get through to one of the installation guys.
Some of these welders have terminals that output data telling you exactly how much wire was deposited on each individual weld. They also constantly monitor the power input of the weld so from that you could probably work out the actual electrical consumption pretty well.

Even then, a welder might use slightly less power on the first few runs and then start using a bit more when it warms up and the cooling fan kicks in.
Again, to be precise in electrical usage you would need to plot it against the weather as the fan might run less in the winter than the middle of summer!
If you have the luxury of a temperature controlled air-conditioned workshop then you will need to take into account the extra costs of the a/c running harder when a welder is chucking out heat!!!

 

[hotponyshoes]

Incidentally, steel is by far the biggest cost:
2000x1000x3mm sheet steel , £78.
2000x1000x6mm sheet steel , £156

Test pieces are 150mm x 75m
so 150 x 75: 11,250
2,000,000 divide by 11,250: 177
£78 divide by 177: 44p for 3mm or 88p for 6mm
so a T Fillet is 88p for 3mm and £1.76 for 6mm
Food for thought!!!

The material probably outweighs the process by such a margin that you could work out a fixed rate and run with that.
I.e. material cost + 5% = total cost.

Again, look at the costs of everything over a period of time or number of items produced and you could probably work out that % fairly well.

There are a lot of other factors to account for as well.
For example, I welded a broken stainless steel chair up for somebody the other night.
Gas/wire/electricity + prep & finish consumables - probably less than £1 for the 4 small tacks it needed.
The mig welder is a £3500 machine and I have probably only used it 10 times.
It's probably out of warranty now as well so really I should be adding £350 to that job to account for depricatiation on that if it blows up tomorrow.

 

[buel]

Probably.
It sounds like you are teaching students or something though?
If that's the case then I would expect each fillet to be slightly different plus they will be getting false/missed starts etc so they are not going to use the same amount of wire on each weld anyway.
And I don't expect you will get a set of scales that can weigh a 15kg spool accurately enough for that without spending several years worth of wire on them.

If you count the length of wire used remember to account for the 3m (or whatever length the torches are) that will be unusable at the end of the roll.

This is brilliant.

For what you are doing, trying to work out the actual cost-per-weld seems pointless.
It might be better to monitor the overall use over a week/month and then divide by something useable like the number of students trained or number of sessions run or something.
I would think you would want to allocate the costs against something you can charge for as I'm guessing you will charge them a fee per session or course or something.
Not give them an invoice at the end for
4hrs of training @ £85/hr
122xfillets @ £0.02
Total £ 342.44

If you do need this data for some other reason then have a look at some of the industrial machines. You are unlikely to find much info in consumer brochures so you might need to try and get a rep to visit or get through to one of the installation guys.
Some of these welders have terminals that output data telling you exactly how much wire was deposited on each individual weld. They also constantly monitor the power input of the weld so from that you could probably work out the actual electrical consumption pretty well.

You know what, I will explore this. Great thinking!!

Even then, a welder might use slightly less power on the first few runs and then start using a bit more when it warms up and the cooling fan kicks in.
Again, to be precise in electrical usage you would need to plot it against the weather as the fan might run less in the winter than the middle of summer!
If you have the luxury of a temperature controlled air-conditioned workshop then you will need to take into account the extra costs of the a/c running harder when a welder is chucking out heat!!!

This is excellent advice and I certainly see your concern. To be honest, as long as I can get an accurate estimate, I will be happy. At the start of the thread, I mentioned that '
I’ve been happily tasked with incorporating our wonderful Lincoln Virtual Reality Mobiles in to our workshop and curriculum for the start of the new academic year in September. I’m very excited about this as I truly believe in the virtues of VR in welding (and in general).
This is where I need help; in order to perform an accurate cost-benefit analysis, I obviously need to measure the usage of the consumables in a traditional lesson, as in gas, wire and electricity (steel will be easy).'
So you see, as long as I have the steel costs, it's a no brainer (at least the difficult first few weeks of teaching students how to lay a bead), this just led me on to the costs of the other consumables as it got me curious. That said, my ultimate aim is to get the costs of an average two hour lesson. Drilling down to the cost per joint was just a luxury that I found interesting....
Does this help explain why I am doing this?

 

[buel]

The material probably outweighs the process by such a margin that you could work out a fixed rate and run with that.
I.e. material cost + 5% = total cost.

Again, fantastic and a real help for me.

Again, look at the costs of everything over a period of time or number of items produced and you could probably work out that % fairly well.

There are a lot of other factors to account for as well.
For example, I welded a broken stainless steel chair up for somebody the other night.
Gas/wire/electricity + prep & finish consumables - probably less than £1 for the 4 small tacks it needed.
The mig welder is a £3500 machine and I have probably only used it 10 times.
It's probably out of warranty now as well so really I should be adding £350 to that job to account for depricatiation on that if it blows up tomorrow.

Just brilliant.

 

[buel]

Hi all.
Update: Today we used the inline Energy monitor. I wonder if someone with more experience than me can tell me if this is what I should be looking at and, if so, if the usage is appropriate (roughly, as I am aware that a whole hour of welding will give a far better approximation):
Reading started at 3.55kwh and finished at 3.57kwh, 13 seconds welding:

 

[buel]

Can anyone help with this?