350P porosity issues

[Danno]

I would like to know if anyone else has had porosity problems with their 350P. Mine has given me porosity issues since the day it was new(2012). Miller replaced the feed assy. and the memory card or board in it but no luck. I got rid of the regulator that came with it and put a brand new flow meter out and still no luck. I have my best luck my flow meter turned up to 35-40 cfm. where do you guys have yours set for pulse mig?

[H80N]

I would like to know if anyone else has had porosity problems with their 350P. Mine has given me porosity issues since the day it was new(2012). Miller replaced the feed assy. and the memory card or board in it but no luck. I got rid of the regulator that came with it and put a brand new flow meter out and still no luck. I have my best luck my flow meter turned up to 35-40 cfm. where do you guys have yours set for pulse mig?

What are you welding?? Steel..?? Aluminum..??? filler metal...?? type of gas?? Joint prep..?? Cleaning??

Porosity is usually caused by a gas coverage or contamination problems...

[Danno]

It does the same thing whether I'm welding steel or aluminum. if its steel I use either .035 or .045 E70 S6 w90/10, if aluminum its 3/64 5356 w/Argon.

Joint prep doesn't seem to matter nor does cleaning.

In the 40 years I have been a fabricator I have never had bump my gas flow this high, nor could I not track down a leak or oxy ingestion problem.

Welding aluminum is very sooty, not the dime/puddle look I use to get with my old 30A spool gun, and if I hit the bead with a grinder its just full of porosity but not on the outside surface.

One day I welds like a million dollars, the next day I want to crush it.

[Danno]

I forgot to mention when welding aluminum I use a XR Pro push pull and a Tweeco #4 for mig.

[H80N]

Still thinking a gas problem... maybe a blockage...

have you tried one of the NOZZLE flowmeters...???

they measure what actually comes out

http://weldingdirect.com/gasflowchecker.html

there was recent thread that sounded a lot like yours... it was a bit of teflon tape in the gas line...

once that was removed everything was fine...

Here are some threads you might find useful

http://www.millerwelds.com/resources/communities/mboard/forum/welding-discussions/31935-millermatic-350p-gas-issue

http://www.millerwelds.com/resources...imension-nt450

[Danno]

Thanks H80N, I check it in the morning!

[Danno]

Well I took the machine apart this morning and started testing from the flow meter hose to the bulkhead fitting/solenoid connection with compressed air, tested fine, hose from bulkhead fitting/solenoid to feed assy. flow was perfect. Now then when I hooked up my tweeco #4 I felt air coming from the trigger area, dismantled the gun to test again and there was more leaking around the goose neck to cable connection than was coming from the defuser. this was the first time I had taken the gun apart and was surprised it leaked that bad from the factory. however that doesn't explain why my XR Pro does the same thing. I'll keep looking.

What do you owners of the same machine use for a gas setting?

[H80N]

Well I took the machine apart this morning and started testing from the flow meter hose to the bulkhead fitting/solenoid connection with compressed air, tested fine, hose from bulkhead fitting/solenoid to feed assy. flow was perfect. Now then when I hooked up my tweeco #4 I felt air coming from the trigger area, dismantled the gun to test again and there was more leaking around the goose neck to cable connection than was coming from the defuser. this was the first time I had taken the gun apart and was surprised it leaked that bad from the factory. however that doesn't explain why my XR Pro does the same thing. I'll keep looking.

What do you owners of the same machine use for a gas setting?

Am concerned about using compressed air for this... what kind of pressure..?? you might be overpowering your gun seals... (shield gas pressure typically runs from 3 to 10 psi while flowing from what I have read)

and you are NOT measuring the CFH at the nozzle...

I m not understanding what this accomplishes

Here is MIG Gas CFH Flow rate chart that you might find useful

http://www.netwelding.com/MIG_Flow_Rate_Chart.pdf

.
(sorry but the chart comes with a couple of pages of sales pitch)

[Danno]

No I am just checking for blockage, so no not with a flow meter at the tip but, it does leak like heck where the goose neck connects to the hose assy. possibly drawing in oxygen.

What this test has done is, proves to me there is no blockage anywhere in the system and that gas or air will freely flow from one end to the other.

The mig gun leaks in the handle area, but the Aluma Pro XR does not.

I looked over the flow rate chart, and for a far back as I can remember I have ran about 20-25cfh on a non pulse machine on any thickness, we just never adjusted the reg./flow meter from there.

Air gas says on this machine 35-40 cfh, man that sounds high! I would think that would draw oxygen right in, maybe even a small child or pet...

But now where to look?

[H80N]

I would still measure gas flow at the nozzle and see how it tally's with the settings at the regulator

Your air pressure test still strikes me as having little utility....

I might blow the lines out backwards though and see if anything pops out

[mikesystem]

this is the same problem i had with my hobart i had it pissed me off to the point i bought a new 350p anyways yesterday i started looking to figure out why mine was doing the same as yours if i wanted a clean weld i needed to run it at 50 cfm to get a clean weld if not it looked like popcorn found two things with mine the liner had oil in it down inside i let out about 5 feet or wire and used a white rag wiped the wire down and was oil on the rag it was coming from my wire feed rollers so i cleaned it up changed the liner and now it welds like new again back at 20 cfm but its been doing it for a few years and never really took the time to take it apart and see what the problem was but its mint now

[H80N]

this is the same problem i had with my hobart i had it pissed me off to the point i bought a new 350p anyways yesterday i started looking to figure out why mine was doing the same as yours if i wanted a clean weld i needed to run it at 50 cfm to get a clean weld if not it looked like popcorn found two things with mine the liner had oil in it down inside i let out about 5 feet or wire and used a white rag wiped the wire down and was oil on the rag it was coming from my wire feed rollers so i cleaned it up changed the liner and now it welds like new again back at 20 cfm but its been doing it for a few years and never really took the time to take it apart and see what the problem was but its mint now

CONTAMINATION...!!!!

Oil would sure muck things up and cause porosity....

.....

Porosity is usually caused by a gas coverage or contamination problems...

[mikesystem]

CONTAMINATION...!!!!

Oil would sure muck things up and cause porosity....

ya but it would clean up with gas cranked to the max and weld looked great but 50 cfm flow is crazy high also the oil was not noticable by eye

[H80N]

ya but it would clean up with gas cranked to the max and weld looked great but 50 cfm flow is crazy high also the oil was not noticable by eye

Am agreeing with ya...

Contamination is one the fist things to look for... along with gas coverage

[Checkered Flag]

I had a 350p, Between being too big for the job and not getting the desired results, I sold it. Turned up high it was great, but down low it was well, just not low enough for what I do.