Last weeks video demonstrated several different welds done by the Miller Diversion 180 and also an Everlast powertig 185 micro.
Both machines performed well for steel and aluminum up to .125" but both stumbled when I tried to weld a 1/4" plate to a 1 1/2" solid piece of aluminum round stock.
No real surprise. Neither machine is rated for anything that thick but I tried anyway just to push the limits.
It seemed to take forever to get a puddle with both machines using straight argon with the pedal floor boarded.
So what is it that turned both of these machines into aluminum welder beasts?
How is it I was able to weld a piece of 1 1/2" thick round stock to a 1/2" thick plate?
You probably guessed already. Adding helium is the kicker.
I hooked up a cylinder of helium with a western Y fitting with valves and set the flowmeters to what appeared to be around a 50/50 mix. I set each flowmeter to about 10cfh.
If you are curious about where to get a Y fitting like this,( Its called a western # 411 Y) you can find it here at weldfabulous.com
I have not dealt with them, but they seem to have a pretty decent online store for welding supplies.
Accuracy of percentage of helium is not very important for most applications. In fact, anywhere from 50-80 percent seems to work just fine. The more helium , the hotter the arc. 80 percent seems to be the limit before arc starting and stability was a problem.
OK, so where would this be needed?
Both these machines are limited . One is 180 amps , the other is 185 amps. If you have a 185 amp tig welder, you will encounter certain aluminum jobs that seem too thick. I have a Miller Dynasty 200dx 200 amp tig welder it I occasionally run into aluminum jobs where I need more amperage.
But I am usually able to get over the hump by using the helium.
When it takes more than 3 seconds to puddle aluminum, you probably really have enough amperage. Thats a rule of thumb.
With the helium hooked up, I puddled 1 1/2" thick aluminum in about 3 seconds with 185 amps.
without helium, it took like 30 seconds at max amperage to get a puddle going.
7/24/11...This just in...Thanks Phil
Just got an email from Phil that lists part numbers and sources for Y fitting without valves and check valves.
here it is...
" I have the Dynasty 200DX and have added helium to weld ¼” and thicker aluminum. I ordered my parts through my local welding store and they matched prices on the web for me. Below is a picture of the brass Y fitting and check valves that were used.
What I did was unscrew the B size 5/8-18unf fitting from the Y fitting and place the check valves between those two fittings. See the picture below. Your welcome to add this information to your site.
Part numbers are listed below for the Western fittings that were used.
4043 is probably the best choice for filler.that's a big hole. but i have seen it done before.
if you have a piece of copper to use for backing , that will help hold the argon and will help with less grinding afterwards.
a low preheat of only about 150f will help things go better.you could even set it on the grill for a few minutes before welding.
whether its safe or not probably depends on the location of the hole more than anything..
i am not really able to make that call so you might have to go with your gut on that one.
best of luck ,
Thank you for your input and speedy reply, my repair turned out fantastic. I did have some 4043 kicking around the shop and the copper backing works amazing. I have been watching your videos for quite some time now and could never have achieved such results have you not gone out of your way to put up your site...
Oh and the tig finger is an indispensable tool, use it every day on the job. Thanks again.
copper backing held in place to support weld drop thru, and to trap argon to help make a cleaner weld.
Aluminum parts like this heat up quickly and its hard to find a place to rest your hand. With a Tig Finger , problem solved.
even without a preheat, the first bead all the way round the edges of the hole should preheat the part enough for the rest of the beads to flow easily.
stopping to let cool for a minute or two between beads will help to limit the heat affected area
good looking weld repair
touching up the back side is easy because the copper backing helps mold the weld.