Which argon regulator for mig?

[Jack_K]

I decided just to buy a Harris 825, it isn't cheap but it should work well. At least according to the marketing stuff it has a large diaphragm and "reduces the amount of surging"

The cheap regulator I am currently using started squeaking randomly within a year of buying it but it still kept working at least. Since I smashed the low pressure gauge (replaced bottle and forgot to replace the chain) I replaced it with a gauge from an old regulator. Currently I can turn off the bottle and after a short time most of the pressure will be gone between the regulator and solenoid, before it would take weeks.
If I didn't just order something now I would probably end up wasting quite a bit of money in gas when I work on my projects on the weekend.

 

[Jack Ryan]

I was thinking a better (dual stage) regulator would reduce the difference between the trigger on and off pressure, reducing gas consumption.

That difference in pressure is a function of the regulator (and flow meter) calibration pressure. When you release the trigger, the pressure behind the gas solenoid increases to the calibration pressure. When you pull the trigger again, that built up pressure escapes. The resultant gas surge can waste gas, for example, when stitching, has the potential to cause turbulence and contaminate the beginning of the weld, and for some people, it is just annoying.

Now that I think about it the higher initial pressure might actually help a bit anyway to fill the length of hose between the solenoid and nozzle when the trigger is pulled.

I think that would be the case if your MIG had a preflow function.

I will do some more research into options and find a regulator which is good value (quality but not heaps of extra cost for no benefit)

I think if you can find a reasonably priced regulator-flowmeter (bobbin / pea shooter type) with a calibration pressure of 20 or 25 PSI you would be well served. If you don't mind a bit of gas surge, a more common and cheaper regulator-flowmeter calibrated at 50 PSI would do. Personally, I would start with the latter and if gas surge proves to be an issue, upgrade.

It is (usually) possible, of course, to adjust the calibration pressure from 50 PSI to 25 PSI to reduce the gas surge. The flow meter calibration will no longer be correct but that course might suit you better.

Don't get too bogged down in analysis though - it cuts into welding time.

Regards
Jack

 

[Jack Ryan]

I decided just to buy a Harris 825, it isn't cheap but it should work well. At least according to the marketing stuff it has a large diaphragm and "reduces the amount of surging"

Personally, I prefer the bobbin type flow meter but if you prefer the flow gauge, go for it.

Jack

 

[tom2207]

I didn't suggest that you did. I gave an example of two stages saving gas.



They will pass as much if not more as a multi stage regulator. Both types have a maximum flow - if you don't get enough gas, you have the wrong regulator.



That is gas surge and has nothing to do with the regulator and much to do with the calibrated delivery pressure and volume of gas hose.



They are not magic, if something happens, it is for a reason.

I would guess that your two stage regulator gas a lower delivery pressure. Most cheap single stage regulators are calibrated at 50 or more PSI - that is what causes gas surge. If you get a decent (say) Harris single stage regulator that is calibrated at 20 or so PSI, you won't get the hiss.

All this is easily verifiable - you just need to look.

In the end, if you are happy with what you have, that's fine. If information is going to be passed on though, it needs to be based on fact. It is one thing to say, "I use this and it works", it is entirely different to say "I use this and it works because it is a two stage regulator". That needs to be more than an assumption.

Anyway, enough of this, time to move on.

Best regards
Jack

I use it because it works ,,, I dont know how a bumble bee flys ,, but they do and while technically they shouldnt be able to ,,, all that does is show that we have a lack of understanding .
I dont meter delivery pressures , so I dont know , I actually dont even meter flow rates , but I do meter my bank account and that is all the proof I need .

 

[Jack Ryan]

You should hear the difference when you pull the trigger, I always find a two stage regulator
reduces the surge a lot.

Unbelievable. Do you know what causes gas surge?

As I stated earlier, the two stage regulator probably has a low calibration pressure compared to the single stage you used.

When I wake up in the morning, the sun rises. Therefore, me waking up in the morning causes the sun to rise.

Jack

 

[tom2207]

Unbelievable. Do you know what causes gas surge?

As I stated earlier, the two stage regulator probably has a low calibration pressure compared to the single stage you used.

When I wake up in the morning, the sun rises. Therefore, me waking up in the morning causes the sun to rise.

Jack

does it matter why gas lasts longer ,,,, or are you just happy that gas lasts longer .

if single stage regs were the mutts nuts , no one would buy multi stage ,,, they cut gas consumption when stitching , its really that simple , because you cant understand why does not make it any less true ,,,,

when a wise man points at the stars ,,, only a fool looks at his finger.

 

[Hood]

Re the single and multi stage. I now use an Esab Edge multi stage and it has cut my gas usage massively, something like for every 3 cylinders (10m³) previously I now only use 2.
Cost of gas saved made no difference to me as the customer gets charged for what I use but hassle and time having to go and collect a refill makes the change well worth it.

 

[Hood]

Here is where I quantified the savings.

Is there a worthwhile difference in single vs two stage regulator

Just thought I would update this with regards the Esab Edge two stage I bought. I have been using it for a while but only now that I have been doing a big job of the type I have done before can I sort of quantify how much gas I have saved. Previously I would go through roughly 1.5 cylinders of...

www.mig-welding.co.uk

 

[Jack Ryan]

I'm sure you are saving gas, you just don't know why.

That's it for me.

Jack

 

[Hood]

I'm sure you are saving gas, you just don't know why.

That's it for me.

Jack

And I don't care why as long as I am My Saturday mornings are valuable biking time and sadly I need the van to collect the cylinders

 

[tom2207]

been thinking about this ,,, is it just as simple as the second stage is working less so any errors are against a lower upstream pressure and thus have a lower effect percentage wise against the first stage pressure ...

or , they cost more so theres more room for them to be better made to tighter tolerances and this has the knock on effect ,,,, like ive said before , I dont care how it works ,,, it just does.

 

[hotponyshoes]

been thinking about this ,,, is it just as simple as the second stage is working less so any errors are against a lower upstream pressure and thus have a lower effect percentage wise against the first stage pressure ...

Regarding welding start-up surge, yes, basically this /\

Say the bottle pressure is 200bar and you set the regulator outlet pressure to 10 bar,
The spring inside the regulator is holding back 190bar of pressure and allowing 10bar to flow.
This 10bar is flowing out into free air
When you let off the trigger and the solonide closes the pressure on the outlet side of the regulator starts to build up until it reaches the set pressure at which point it pushes the valve closed.
You have some tolerance in the spring plus some friction in the valve so you need slightly more than 10bar to shut it off.
Say those tolerances are 10% then that's 11bar of pressure sat in the line between the regulator and the welders solonide.
When you pull the trigger the gas comes whooshing out and, again, you have spring tolerance and friction to overcome so you might also be getting 10% error on the 200bar in the bottle for the fraction of a second it takes for the regulator to stabilise chucking a small blast of 20bar into the line.

A 2 stage (welding) regulator is basically 2 regulators built into the same body. The first one might drop the pressure to 200bar and feed an internal chamber, the second one takes it from 25bar to the 10bar outlet pressure.
So, when you're pulling the trigger the 10% of error is only over the 15bar difference on the 2nd stage rather than the 190bar difference of the bottle.

I've put "welding" in brackets as a lot of things use 2 stage regulators but they are not combined into one unit.
Important things like breathing air for divers and really important things like beer dispense will use a bottle regulator to send 10bar out to a line and then secondary regulators are attached to the line.
The same method is also quite common in welding when you are using a gas purge when you would have one bottle regulator and 2 or more secondary regulators for the welder and the purge(s).

I am under no doubts that 2-stage regulators save welding gas if you are making multiple starts.
I have noticed that the bottles with the built-in regulators have less start-up surge than a traditional arrangement though.
I'm not sure if they are 2-stage or just better balanced to the bottle?

Another advantage of the 2-stage is you don't need to adjust it so much as the bottle pressure drops. Not noticed how the inbuilt regulators compare on that front as I don't weld for long enough or repetitive enough to find out.

 

[tom2207]

that tesla valve is actually a one way valve with no moving parts ,,, he was a smart cookie ....
I service all my own dive gear , [and have the certs to say I can] ,,,

 

[Jack Ryan]

Competing companies probably don't know why each-others attempts
result in varying success, what hope do we have.

Competing companies, aside from back yarders, know exactly how their and other manufacturer's equipment works.

It is not rocket science or magic, it is physics. Reputable manufacturers don't say that their two stage regulators fix gas surge because they don't.

Jack

 

[Jack_K]

I didn't think asking what regulator I should buy was going to start a big argument.

A two stage regulator at least would make the output pressure more consistent due to quicker response. When I was searching to reduce air pressure drop I discovered this information.

It would be interesting to see actual data on the argument between dual and single stage (and various models). It would be good to see it charted with flow, pressure and amount of gas used with different weld durations.

 

[Jack Ryan]

I didn't think asking what regulator I should buy was going to start a big argument.

An argument is not what was intended. Scientifically, the properties of pressure gauges and flow meters are well understood. It is frustrating when that is ignored in preference to "what someone reckons".

A two stage regulator at least would make the output pressure more consistent due to quicker response. When I was searching to reduce air pressure drop I discovered this information.

That is not actually the case. There are two significant differences between single and dual stage regulators - droop and supply pressure effect.

• Droop is the difference in delivery pressure between zero flow conditions and the regulator’s maximum flow capacity.
• Supply pressure effect (SPE) is the variation in delivery pressure with changes to the supply pressure.

Single stage regulators have little droop and a largish SPE. Multistage regulators have a large droop but very little SPE.

That means that if you are using a large amount of gas continuously, or if a bottle in a bank might be changed while you are working, a multistage regulator is required. Otherwise a single stage regulator (of similar quality) is more than enough.

Assuming similar quality regulators of the same basic type (diaphragm), a single stage regulator will respond faster than a multistage. That is because the cascaded control loops of the multistage regulator take longer to stabilise after a pressure change event (it has a longer time constant).

It would be interesting to see actual data on the argument between dual and single stage (and various models). It would be good to see it charted with flow, pressure and amount of gas used with different weld durations.

You will not get a properly controlled experiment unless you obtain samples in the same class that were designed for the same purpose.

As I have mentioned, gas surge is caused by two things:

• The calibrated pressure of regulator and
• The volume of the gas hose from the regulator to the solenoid.

These factors have nothing to do with the design or operation of the regulator. Therefore, gas surge has nothing to do with the regulator.

There are quite a few manufacturers (including Harris and Lincoln) of "gas saving" equipment. None of them makes a simple two stage regulator for the purpose,

There are three main strategies for the mitigation of gas surge - reduced calibration pressure, relocating the regulator to the welding machine (reduced gas hose volume) and the use of small orifice restrictions (flow limiters). Some use a combination of these.

A particular two stage regulator may reduce gas surge significantly but it is not because it is a two stage regulator. It is likely because it uses a low delivery pressure or is pressure limited.

In the end, people can do what they want.

Regards
Jack

 

[tom2207]

Jack R ...
Not wanting to cause an argument , as I dont see this as an argument at all ,,, just a swap of points of view ,,, so
Do you think that using a two stage regulator for multiple [ ie 100s or even 1000s] spot/ tack welds will reduce overall gas usage .

 

[Jack Ryan]

Jack R ...
Not wanting to cause an argument , as I dont see this as an argument at all ,,, just a swap of points of view ,,, so
Do you think that using a two stage regulator for multiple [ ie 100s or even 1000s] spot/ tack welds will reduce overall gas usage .

I'm fine discussing the issues - no argument here.

If you can stop the surge for hundreds or more spot welds then a lot of gas would be saved - no question about it.

If your two stage regulator does not create surge, that is great. The only thing that concerns me is how did it stop the surge. I am not aware of any feature of a two stage regulator that would do that. I would be interested to know the answer to that.

You probably said already but can you refresh my memory? Which two stage regulator are you using?

I am mostly concerned with regulator flow-meters (fixed pressure variable orifice, uncompensated) and those have a calibration pressure which directly affects gas surge - turn it down and the gas surge goes down too.

There are several other configurations as well so it would be good to determine exactly what you have.

Thanks
Jack

 

[tom2207]

I run a mix of regs ,, I buy out of date medical ones , they have to change them at the due date , and that suits me
I have for example 2 murex saffires and 3 gas arc multi stage , and at least 2 harris regs
just what ever turns up , if they are about 30 quid , I buy them . forty if they look nice but I wouldnt pay more well unless it was really pretty .

 

[tom2207]

Jack, why don't you give us two examples on how two competing regulators work, put this subject to bed for us, after all it's not rocket science, when your at it explain how two stage regulators have been observed saving us gas too.

Jack is totally correct in saying a two stage reg wont stop gas surge ,,, but will it reduce its magnitude by the % of the second stages pressure drop over the first ,,, so the surge is reduced by so much as to be really not noticeable ,,,
anyway , many will agree that a good two stage reg will cut down gas use in some setups ,,, granted some wont lol
but its a forum after all , If I wrote good morning , someone would dispute that its actually good , and many would debate if its even morning at all
and then there would be a health and safety aspect involved somehow too.