I am currently using a tiny *** miller 150 stl welder no pulsing capability.

Material 304L sch10 pipe
.040 tungeston
100% argon
65-68 Amps
1/16" 304L Filler Rod
(I am not taking the filler rod out of the shield gas)

Weld Type (flat surface weld, traveling slightly uphill all the way to a flat weld)
&
Weld Type (using a grinded v groove (same problems)

The Problem --->

I am able to get a good bead going nice and flat puddle and close grouping how-ever I am having a problem with burn-through on the inside of the pipe. As soon as I get the puddle nice and hot and get a bead going it's burning through the sch10 pipe and leaving a nasty droopy black burnthrough. But if I lower the amperage I cant get the puddle hot enough and have a shitty bead appearance. AKA material not hot enough.

What can I do to help get the metal puddling without burning through? Do I have to purge the inside of the pipe with argon as well?

Also, what kind of equipment can I use to purge with (my budget is low but I don't have time to make something myself).

 

Having a foot pedal will help. I usually travel faster as the metal get hotter.

 

jump your tungsten size up to at least 1/16". without pulse, you should be at about 60~70 amps. my guess your problem is your speed.

also try using .030 or .045 rod. smaller rod gives you a lot more control. it sucks when you have gaps though.

packpurging is really easy. you need:

bottle with argon
regulator or flowmeter
hose coming off regulator (which in some cases i've taken 5/16 or 3/8 vaccume line and zip tied it to the fitting)
some sort of valve (i've used an airblower with a zip tie, which worked out well because i used the long end of the gun, which is metal, to stick in pipe)
aluminum foil.

ball up aluminum foil and stuff it in end of pipe that your purge isn't going in. ball up more aluminum and stick your air blower gun through the middle and then put that in the other end of the pipe. when your ready to start welding, zip tie the trigger down and wait for a minute while the piece fills up with argon.

i've heard flow should be 6cfh all the way up to 20cfh. depends on size of the piece and how much of a hurry your in.

its ghetto, but it works. your quality on the outside will get better as well.

 

What do you mean by burning through? Are you speaking drop through or the sugaring on the inside of your welds with your current setup? .040" tungsten is great for welding thin-walled tubing but for something that is sch10 which I believe is right around .060''? I would use 1/16 tungsten like the above person mentioned setting your amps right around 60-80 amps while using your foot pedal to keep a nice steady bead. Make sure you backpurge that's probably why you're having sugaring on the inside of your welds, depending on the OD of the tubing you are welding it will vary. I would set my flow meter right around 20-30cfm and let it run for a good 30 seconds with argon making sure there's no oxygen in there to contaminate the welds. If you're still having problems with drop through I would suggest turning your amperage up or weld slower. Also another way to get good penetration is to create a flat on your tungsten. Just enough to keep a stable arc which is about .020"-.030". It would probably help you out a little.