spray welding gas info needed

[dvcarrara@shoreham.net]

I am somewhat new to spray welding and have been using 92%argon, 2% oxygen mixture with great results. I am trying Airgasses steel mix extra (argon-helium-carbon dioxide) which I was told performs great on mill scale and oily material. I can’t get the arc stabilization initially as I start the weld, it takes 3/4 of and inch to stabilize and it asks globular as this happens sending spatter all over. I have tried numerous settings, sickouts, and flow rates. I have a brand new MM350 (which I love) am running .045 e70 wire, 300 Bannard. Please help


Dana

[tacmig]

What materials are you using and what type of weld are you trying to make. Lap, Butt, corner??

[dvcarrara@shoreham.net]

At this point i am just trying to control the splatter. I am welding scrap A36, A572, A656, A514. I can get some nice welds at 30 V and 380 ipm at 35 cfh but the splatter is very bad. I tried cleaning the material and it’s still there. I switched back to 98argon 2oxygen and there is no spatter at all not even one. I must be doing something?

i am doing butt lap and just welding on top of scrap at this point to try and adjust

[welder_one]

airgas stell mix extra does not allow a true spray transfer. i know this from experience. the helium in the mix creates too much heat and causes spatter. give them the bottle back and stick with 90/10 or 92/8. if you are going to short transfer then the mix extra will be better. the 90/10 bead doesnt lay down very flat, you'll have to crank up the inductance past the recomended settings if you want to stay with 90/10. i also use the mm 350p and i love that machine as well. i can spray at 28.5 volts and 500 ipm with 0.35 wire and the 90/10 mix. so, the "steel mix extra" isnt all that it is cracked out to be.

last year i ran into a problem with spray transfer. we had just switched gas suppliers and the management got talked into this "extra" mix. after several headaches and questions later we went back to the original supplier and back to 90/10 and everything was back to normal.

[welder_one]

oh, and by the way, welcome to the board.

[tacmig]

I agree with welder_one, gas mix is critical in ST and keep an eye on your material all your "A" material you are using for practice is struc-1 carbon and can be tricky to ST with higher inductance levels. I have good results with 95/5 and .35 wire and perhaps you might want to back off the .45 just for grins to see how .35 and even .30 works for you. For all it's worth perhaps the best advice I can give you on this one is to be sure to log your results for future use!

TacMig

[dvcarrara@shoreham.net]

Thank you for your help.

What do you recommend is the best gas for spray? You mentioned 90% argon and 10%co2, how does this differ from 98ar-2ox? I was told that co2 cools the gun tip better allowing longer welding times. I had a MM251 previously, and at sometimes I thought I was going to melt the gun. What other differences do you see? I spoke to a few people and everyone has their own favorite. I weld a lot of high strength steel and the 98-2 works great, or at least it has, or I thought it did. I read in my books that you can’t spray with anything under 90 % argon, so how does steel mix extra say that you can spray when they only have 68% argon?
So going to the .035 is better, this must lower the spray transition current? I will call my gas supplier and change tanks; I agree the extra is impossible.
Thank you both
Dana

[welder_one]

no prob, dana. i am not sure about the other mixes 98/2, or 95/5. i have never used them. only one i have used for spray transfer is the 90/10 (with any luck). i agree that you need atleast 90% argon to achieve spray. glad that i could help.

[tacmig]

I hope I added a little insight. REMEMBER keep that log! it's your best guide you will have in the future!

[tnjind]

When is it benificial to use the sprayweld process? and what exactly is it?
I have heard of it but not tried it. My esab should be capable I might try it.
Tim