Spray transfer?

[Spark plug]

I have seen spray transfer mentioned a number of times wile reading through the forum, but I don't fully grasp the term. Had a search but couldn't find a proper explanation, could someone please clarify?

Sorry if this is a stupid question.

 

[mike 109444]

If you follow this link then download the "user guide" you will find a very good explanation of the various types of transfer. A good manual in general!
http://www.boc.com.au/shop/en/au-boc-industrial-store/magmate-180p-15amp-mig-welder
Others may be able to give a more down to earth explanation.

 

[normspanners]

Spray usually starts at about 200 amps when you have the wire speed correct all you hear is a buzz from the weld not a crackle that you get with dip transfer, as the wire melts immediately it leaves the tip and is burst into microscopic particles and travels to the job in a similar fashion as a paint spray gun, hence 'spray transfer' it is like pouring molten metal into the joint, the only problem is you can only really weld, down hand runs, as the weld pool tends to 'run away' with gravity, so positional welds are a no go.
When in spray you get a very clean weld, with very little splatter also you dont get the little explosions you get from dip,after all the spatter is usually caused by the wire dipping into the molten pool and the wire explodes, out away from the weld pool.

 

[Tino]

There are three basic modes of M.I.G welding. 1. Dip transfer. 2. Globular transfer, and 3. Spray transfer.

Dip is low power, the wire feeds out touches the the work piece at rapid regular intervals. This causes a short circuit and rise in current, this melts the wire and the arc is re-established. The wire feed out dips into the weld pool short circuits etc, etc. Happens about 100 times a second. Very good for thin material and positional welding.

Globular transfer is higher power. Its a transitional stage between Dip and Spray, not quite one thing or the other. Large drops are sent across the arc into the weld pool. The arc is continuous but everything is a bit splashy and unstable,not very good.

Spray is at higher power. The arc is continuous, and fine droplets spray across the arc into the weld pool. The weld pool is very fluid so not usually used for positional welding, but very good for thicker material.
Use Dip
Avoid Globular
Use Spray

 

[Spark plug]

Ok that makes more sense now, I've just upgraded from a 180a mig to a 380a and I unknowingly discovered spray wile playing with the higher settings.

 

[rich r]

Someone once said to me that another way to think about spray transfer as being more like arc welding. The electrode (ie wire) never touches the surface (once the arc is established), but there's an arc present between the two which melts the end of the electrode (ie wire) and surface, and deposits metal from the electrode into that molten surface. He was trying to explain Mig techniques to a bunch of people (like me) who'd only done arc welding. I guess it sort of explains what's going on.

 

[Robotstar5]

The sound is different too, instead of the "frying bacon" for dip transfer, spray transfer is more of a "hiss".

 

[normspanners]

I have used a MIG in spray at over 500 amps with the wire feed flat out and feeding 6mm bright steel in like TIG welding, on some massive fillets, but the heat was tremendous.

 

[migmag]

I used to work for a firm that made the table sub structures for Mcdonalds, The base plate was 12mm mild keyed into 3mm 2"od tube.

After an hour messing with settings I found what worked ( I am not pro trained welder ) turns out I was accidentally spray arching these tables.
Sorry not pics but as said above the sound was more like a pulse arch and the finish was perfect.
Passed the acid test and the destructive tests 130% over spec...........

 

[migmag]