gas mixes

Date 07-24-2003 02:48

I use 95-5 gas(Argon-oxygen mix) It is by far the best for spray-arc, but I use it for any job that comes by. It will cost a few bucks more for a tankfull, but unless you are using several bottles per day, the extra cost will never show up on your bottom line.

By welder_guy2001 (***)

Date 07-24-2003 03:51

for short arc welding 75% argon and 25% carbon dioxide mix is nice. smooth bead, not too much spatter. if you don't care about spatter or looks, 100% carbon dioxide is the cheapest.

By dee

Date 07-24-2003 22:47

Jim,
You've undoubtedly seen reference to Ed Craig and http://weldreality.com before. Ed's general recommendation is Ar with something less than 20% CO2... I'm using what my supply company calls 18% without certification papers for it's accuracy, and I'm quite pleased with it's versitile and efficient performance (the 2% margin allows for acceptably modest variation and inaccuracy with a very slightly lower cost per fill). Ed has proficient command of the laws of physics as they relate to welding; take advantage of his free advice. Spend a few hours and study it in depth. Although it's a large site it's worthy of the effort.

regards,
d

By HappyWelder (*)

Date 07-27-2003 22:02

About 20% CO2 will make sure the penetration is adequate. I think that a low amount of CO2, around 8%, is only advisable if you are welding with solid wire and spray arc.

I assume You are welding non-stainless steels. Otherwise please disregard this post.

/Happy

By jimwelds (**)

Date 07-29-2003 00:17

I thank everyone for there answer. I was try to get 85/15 argon ,co2 I only wind 75/25 but I'll keep looking Thanks Jim

By dee

Date 07-31-2003 03:29

Jim,
Around here you'd need to have it mixed special. I've been able to rent tanks with 75/25 mix and others including 100%Ar, but this stuff with <20% CO2 is apparently some species of unusual around these parts, and it was necesary for me to buy the tank and have it filled to my specs. I think you'll find the bigger suppliers will be able to fill your own tank with any mix you request... my biggest problem was trying to avoid explaining WHY that was the gas I wanted to use. You might think I was from Mars by the looks I was getting, but after I explained that this was the gas the engineer specified and substitution was not up to my discretion, they became very helpfull.

Regards & good luck
d

By billvanderhoof (****)

Date 07-31-2003 04:01

Good job- always blame an unavailable authority. I used to ride on a first aid squad- lots of patients didn't want to ride on the stretcher "insurance company requirement" always ended the argument.
Bill

By mudbone (*)

Date 05-02-2004 16:33

My maintenance department uses 75/25 argon/co2
my production welders, at one time used 90/10. my supplier told me he had an "Automotive Mix", 92/8. I now use a 85/15 mix. All of these are common mixes. no speacial ordr required.

By brande

Date 08-01-2003 06:03

A good gas for carbon steel, with spray and short arc is, any argon/C02 in excess of 80% argon. True axial spray arc will rarely occur with less than 80% argon/balance C02.

As a good all around gas for the two processes, I find that 85% argon/ 15% C02 works very well fo me. Give it a try.

Let me know how you make out.

Good Luck
brande

By supermechanic (**)

Date 08-01-2003 12:14

I've been mixing gasses at the wire feeder with a "y" valve and a turbulator for a long time, I find the ability to custom mix very helpful. Often times a bit more or less co2 in the mix makes the biggest difference.
It is far more economical as well, for only two bottles are needed.(I have not tried a tri-mix yet.)
If anyone else has thoughts about point-of-use mixing, I like to hear them.

By jwright650 (*****)

Date 08-01-2003 15:16

I had looked briefly into the mixing rig you are talking about and I like the idea of being able to adjust for the mix that you are after. I haven't actually used one so I too am curious what others think of this.
John Wright

By ssbn727 (*****)

Date 08-01-2003 16:34

Hello john!

Now I do'nt know of the specifics of this product but, the concept sounds like a rather interesting one to say the least...

Does this set-up have some sort of gas analyzer hooked up tp it so you could accurately tell what are the percentages for each gas being mixed? I only ask this because, the gas analyzer could also be used to show that one could achieve some repeatabilty when one is mixing in order to use again, and again for a specific weld process/procedure, and then adjusted to another mix for another... All the way down to the PPM's!!! Wow!!! now thats accurate!!!

looking foward to any responses!

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By jwright650 (*****)

Date 08-01-2003 17:37

SS,
http://www.smithequipment.com/products/gasmixer/gasmixer.htm

http://www.thermco.com/mixers.asp

Here are a couple I found surfing.
Let me know what you think of this concept. I talked to a welding supply house here in town and he had some other models to show me.
John Wright

By ssbn727 (*****)

Date 08-01-2003 18:08

Hello John!

I like the concept very much John because, of the fact that you have more control in not only customzing your mixes but, also being able to eliminate or minimize the potential for the gases to separate or stratify!!!

These systems are cost efficient for companies that use alot of mixed gases when welding in the long run, and not recommended for smaller shops that generally use a variety of different processes but, in proportion, do'nt use as much mixed gases when they're welding as you already know... Besides, the initial investment probably would set them back a bit, and there ROI (return on investment) would be long in coming back to the small shops, if any!!!

Both of the brands sound good to me especially the built in gas analyzer with alarm... The only thing I'm worried about is what do I do when the mix is'nt correct, and the alarm goes off!!! Do I stop welding or does the system have a separate proportional mixing tank whereby the gas that's been already mixed has enough in there until the rest of the system compensates for this condition. Correct me if I'm mistaken!

The fixed ratio on some of the models by Thermco would become troublesome on some of the models used for welding with shielding gases that require tri-mixes but, I think the model 6105 could work for those type of gases. I'll let you know more when I get some better understanding of how these systems are configured, so that I can make a better assesment when comparing the two brands and their models...

Respectfully,

SSBN727 Run Silent... Run Deep!!!

By jwright650 (*****)

Date 08-01-2003 18:36

There is a shop here in town that mfg's mechanical equipment. They use an ORCA tri-mixer system that is piped through out the shop and each welding station has thier own mixer to supply the ratio and type of gas required for the type of material to be welded(ss,alum,cs etc...).
I was told about it and invited to go see it,but haven't been over to look for myself.
John Wright

By ssbn727 (*****)

Date 08-01-2003 18:53

Hey John!

Now that sounds like a system that would work well without the need for a gas analyzer and alarm at every station... I guess the gas analyzers are more expensive than having a separate mixer at each station. Besides, the welding that most large mechanical shops do would'nt be so exotic to the degree whereby the accuracy of the mixes would become of concern...

Are the mixers at each station also three gas mixers also?
I ask this because Smith makes one tri-mixer (I do'nt think it's got an analyzer or alarm) that's probably less expensive than Thermco's model

Anywho, I'll check out the ORCA system online to see what they offer...

Respectfully,

SSBN 727 Run Silent... Run Deep!!!

By swnorris (****)

Date 05-03-2004 13:17

Hi Jim,

You didn't indicate your steel application, but to get into spray arc in the GMAW process, the minimum transition arc currents from globular transfer to spray varies with the gas mixture, type of steel, and wire diameter, as you probably know. When welding mild carbon steel, the minimum current for .030 diameter wire is 150 amps, .035 is 165 amps, .045 is 220 amps, and .062 is 275 amps. These are based on a shielding gas mixture of 98% argon with 2% oxygen, which is what we use in our shop with .035 wire on mild steel. I've also heard that a 95% argon with 5% oxygen is good for spray transfer, as swellwelder has mentioned. For short circuit modification, I agree with welder_guy2001 that an excellent gas mixture would be 75% argon with 25% carbon dioxide, because of the high welding speeds without burn through, minimum distortion and spatter, and clean weld appearance. I don't know about any other codes, but if you're welding to D1.1, short circuit transfer is not prequalified.