Spray arc...

[Dadnatron]

Just took my 1st official welding 'class'. Actually, its basically just proctored booth time.

I was introduced, on my 1st day, to Spray arc. Now, this was a very interesting technique, of which I've heard but have no experience. He set up the machine in such a way, because I had told him my goal in this class is to become more proficient at farm repair with some fab work thrown in.

I was only there for about 2hrs and during that time, I was simply running beads on scrap plate.

My questions for you are:

1. What is the most 'portable' size machine which would be likely capable of spray arc technique? I understand the 'basics' however, I don't know what sort of 'size/amperage/voltage' machine would be required. I was using a Miller 350P, I believe. Actually, I guess what I am asking, is what 'voltage' is typically required to get spray arc with a given wire size. And, while I was using .045 wire yesterday, is there a benefit to doing so, on a farm. The wire was larger than any I've seen used before, but I've also not used that 'heavy' of a machine before. What wire size would you 'max out' at for a typical farm repair for a novice?

2. I understand that spray arc requires good metal cleaning. And I understand that most things that can be done with spray arc can also be done with short circuit. Is there a benefit to one or the other? I really liked that there was essentially no spatter, and even I could make a decent looking weld, after a few tries. (my travel speed inconsistency certainly would show up easily).

3. I've read the 'spray arc' threads (or at least what has been linked) on Welding web. I really liked the technique, and felt relatively confident in it after a bit. However, if the 'machine required' is simply more and or more $$$ without really giving me, as a farm repair with some fab work, a real benefit, I don't want to head down that path right now. In a perfect world I'd have a portable machine for field repair and a big machine in my shop. However, my current shop is a storage shed and all welding is done outside.

4. I also recognize the heat developed, and that it cannot be used on thin material. But how 'thin' is typically 'too thin' for spray arc? I recognized that the gloves they had available weren't really designed for a lot of spray arc welding. I just noticed a very small blister on my left wrist, which must have been too close to the heat for too long.

Basically, is spray arc worth my time, given my situation?

 

[BukitCase]

There may be a few exceptions, but typically a 200-250 amp machine with 10% or less CO2, rest being Argon and maybe a small % of a third gas -

Upsides of spray - much faster deposition so used in production welding a lot. Hotter so a bit easier to get good penetration.

Down sides - more expensive gas than short circuit, mainly flat or slight incline, NOT good in out of position, pretty easy to burn thru anything less than about 1/4", needs a more expensive machine AND a heavier torch if used for long welds or it can burn up the torch - That 350 you were using is about a $5k machine, my mm252 starts at around $2500 and I've done spray with it, don't think I'd want any less -

Most smaller welders don't usually (if ever) have a high enough voltage output for spray -

Try changing the parameters in this calculator, it'll tell you when you get too thin for spray -

MIG Solid-Core Welding Calculator - MillerWelds

you'll see that recommended voltages are higher with spray, even WITH a small % of O2, which seems like a bad idea anyway - I was always taught to keep O2 OUT of my welds...

Anyway, I looked into this a fair amount and decided to just stick to C25 gas/short circuit, even with my mm252 - for one thing, I couldn't find an AFFORDABLE welding positioner that would rotate my 12,000 pound backhoe so I could weld FLAT :laughing: ...Steve

 

[Shield Arc]

Basically, is spray arc worth my time, given my situation?

No! Spray arc is only good for high production work. Basically, it is a pain:thumbdown:. Metal has to be really clean. I played with it some, I was impressed with the speed. But it is not worth it to me!:thumbdown:

 

[dragoneggs]

No! Spray arc is only good for high production work. Basically, it is a pain:thumbdown:. Metal has to be really clean. I played with it some, I was impressed with the speed. But it is not worth it to me!:thumbdown:

When SA speaks, welder hacks should listen. I was sort of curious about the whole spray arc thing as well. Case closed for me.

 

[yomax4]

You were using a 350P for Spray Arc? Hopefully they showed you the Pulse process that the machine was made for. Much better. You really don't need a 2-300 amp machine to do spray or something very similar. You can also drop down in wire size and up the volts with the right gas and achieve similar results you just wont be welding anything very thick. Spray is one of the many things you should be aware of but with the newer technology of the newer machines you can get beautiful welds with short arc and or pulse. Spray Arc is a dated process in my opinion. Good Luck learning though. You have a lot of reading and practice ahead.

 

[Shield Arc]

If you want some speed, check out metal core. A guy on Welding Web sent me a spool of metal core. This is very fast, and the metal doesn't need to be near as clean.:thumbsup:

 

[Big Barn]

If you want some speed, check out metal core. A guy on Welding Web sent me a spool of metal core. This is very fast, and the metal doesn't need to be near as clean.:thumbsup:

Carl. Why would a retiree/hobbyist like yourself be concerned with "speed"?

 

[Shield Arc]

Old habits are hard to break. I've always been into speed!

 

[Oldpath05]

I think it is rare that spry arc with .045 wire is needed for farm use, when you start getting into that size or bigger, it's mostly for high production and multi pas welding, .045-.052 is the main wire size at the shipyard, use on pulse mode and spray/mig on Miller 350s. I mostly use .030-.035 70s at home.

 

[Tractor Seabee]

Interesting, showing my age now. Never seen the process for structural work. Back in my day Spray Arc was used for building up worn parts for re-machining to restore it back to original specification. We sent out compressor parts to specialty shop. We had problems with the new layer peeling off do to poor bond. That was caused by sloppy cleaning. They found parts had to be cleaned and pickled for best results. On shafts they cut the bearing surfaces down several thousands to get a heavier layer; still had to clean before welding. Overall it was a good process when done right.

Carl do you have the equipment to do spray arc? I would like to come over and watch it done. May Mark would also.

Ron