Homemade mixer for $100

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Wasn't sure exactly where to put this thread, but here it goes.Mixers being kinda expensive I figured I'd try this. Works well so far. Total cost was 100 bucks on top of the extra regulator I already had.I picked on of these up for about 32 bucks. It's actually supposed to go into a regulator and provide two hoses out. But it does flow backwards.The valves were only 5 bucks more so why not ? I wasn't sure about one bottle having lower pressure than the other, and back feeding. Seemed entirely possible since that's how you fill nitrous bottles. I got oxy acyl check valves. I had to have some hook up and ends added since inert gas and those have different style fittings. So that's what made it add up to 100 bucks.This is my poor little machine FULLY maxed out on 220. Htz were all the way up for this machine at 250. At 200 amps and 75 balance iirc. So I was trying to stretch the heat as far as I could go. The far right really looks like **** (my intake not customers). I am trying to find my settings and see if it will go. Nope. The next bead to it is a few seconds once the heat caught up to the area I was trying to weld. I just wanted to play so I ran with it. Ehhh still yet. Now this is with some heat. I tried on the other side first with 5 cfm helium, 10 cfm argon. So about 33% helium. A bit higher than you get it pre-mixed. But easy to know exactly where my ball was in the regulator without guessing if it was 4.5, 3.75, etc. So for now I wanted something easily duplicated. I turned the amps down to 170, and htz to 150 just to see the difference knowing it may not weld. Welp, it works pretty damn well. At that setting I got a puddle right away. I did end up going up to 200 amps so i could actually weld right away. But the puddle was wet enough to start. Would have probably had to wait 4-5 sec is all. i ended up also with the htz at 175 so i could change my torch angle a little less straight up and down. It was pretty extreme since this is .500 AL to .125.  Balance was still at 75, which is odd because the etch lines are very different. Will have to look into that one. But first test was with 3/32 rod barely wanting to melt, and with the helium it was melting the 1/8 at will, and digging into the .500 plate. I had to back the heat with the pedal as I welded which was awesome. You can see the last pic the beads are nice and wide, and the edges are laying down like they shouldSo far, liking 33%, which I could not have got with the pre-mix.Never seen anything on here like this, or anyone mix like this. Sure it's not the first time, but thought I'd share in case it could help someone.For any of the more experienced guys, that's a pretty good etch line right ? not too wide ? (on the second weld)
Reply:Looks like it works great.  I've always wondered if something as simple as this could work."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:This whole subject goes clean over my head/experience level. I am just passing along a link to another thread...http://weldingweb.com/vbb/showthread.php...ghlight=mixing Originally Posted by SundownIIIActually, in discussing gas blending with Smith, the process is considerably more involved than it appears on the surface. Their mixers take a gases' specific gravity into account when sizing the orifices for the different mixers. Than and how the gases are directed during the "mixing" process.It would be interesting to put a gas analyzer on your output stream to determine the accuracy of the system. People, in the know, that I have talked to claim it's impossible to accurately blend welding gasses with a Y setup.
Reply:I talked about this idea way back.  A few people on the forum said they do this, the rest seemed to want to scold me for even implying the idea.  http://weldingweb.com/vbb/showthread.php?t=35064  I think the idea seems fine, I can't imagine why the gasses wouldn't mix correctly.  If you aim to have 15 cfm in gas and you set 10 cfm on argon and 5 cfm on helium, it seems likely that you will end up with 10 cfm of argon and 5 cfm of helium coming out of the end of your torch.I've never tried this but that is because I mostly weld thin materials, 1/8th is the thickest I've really welded.  It often seems suggested or even stated to me that there is more benefits to adding a bit of helium to the mix does more than just increase the amount of heat going to the metal.  It often seems like they say the arc becomes more stable and things just go better.  Do you feel this is true?I definitely think the weld looks good.  It really doesn't look like the first weld was done with 75% balance on (I am not calling you a liar), it looks more like 50/50, I am really interested as to how helium effects etching.  Do you still need to do some pre-weld cleaning?Miller 330 a/bp water cooledI believe in gun control, I hold my gun with two hands.  If you want to know why, click here.Buy American or bye America.
Reply:Can it be done... yes. The problem is you've really got no control over the mix. If you want mystery mix to play with, thats fine. For anything code it's not. Theres no way you could get say 85-15 with this to do Mig. 75/25 ish maybe. 98/2 argon-O2, nope. Also helium ain't cheap. Do you really need to run 25-40% HE ( figuring rough numbers plus or minus on your 33% blend since you really can't get a good set point, especially as the cyl pressure drops.)? Or could you get the same results at say 10%He and get 3x the moneys worth from your He? Also He doesn't behave like most gasses because it's so light. That tends to throw basic calcs out of whack compared to what you'd think they should be.There is a reason commercial mixers cost what they do. It's not just so you can spend money on something other than gas. If you set the machine to give you 98-2, thats what you get, every time, and it's usable for code work. Mixers pay when someone uses large quantities of gas, or frequently needs to change mixes to meet customer WPS's often on multiple machines. Today you need to run 75/25 for job "A" in the morning, and 85/15 after lunch for job "B". Tomorrow it's 92/8 argon /Co2 and the next day 98/2 Argon/O2. I'm not knocking your general idea, just the practicality of it. Helium can be used to effectively boost the performance on tig. It's been shown in several posts. I know Zap did a test on this in the past. It's not the "wonder" gas many think however, and is the cost worth the performance upgrade, or would you have been better served just buying the right machine in the 1st place? If you do 1/8" alum all day with a 200 amp class tig, and  very occasionally need to run 1/4"-5/16" then a Helium mix might be the ticket. Most of the time I see people looking at other gases as a crutch because their skills aren't up to snuff. They want that "magic gas" to fix their inadequacies in their skill or their poor choice in a machine. Whats the point of dumping nitromethane in a stock Honda Accord? Do you really think you'd hang with the top fuel dragsters by doing that?Oh FYI: Helium will leak thru "tight" fittings and Orings. Don't ever forget and leave you cylinder on or you won't have any He left later on. There's a few here who do helium tight welds, ask them how tight those welds have to be compared to "normal" leak proof welds.Last edited by DSW; 10-10-2010 at 06:49 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I'd +1 to DSW on the precise mixing thing, there are some folks mixing Co2 and Ar to get something like a 50/50 for low cost and still pretty good looking welds by using a "Y" setup.I have no idea how helium is going to play with Ar in a "Y" setup though, if the results stay constant over time it's a good deal for your purpose.I you are going to put manifolds together, I'd probably try guessing at 5% helium and if it goes badly just move up the helium till it does, economy is well, economy.Matt
Reply:Good ideas presented, but the whole premise is flawed.Mixers, such as those made by Smith, factor in the "specific gravity" of the gases involved to arrive at a percentage mix.Simply feeding a Y with 10 CFH of Argon and 5 CFH of Helium DOES NOT give you a 66%/33% mix of Argon/Helium.  You would have to consider the specific gravity of the two gases and the flow rates.  Helium being much lighter than Argon, would require a much higher flow rate to achieve a 33% mix.Interesting little experiment to "play around" with different gas mixes, but it wouldn't cut it at all for code work or even shop consistency.As has been mentioned, with a properly designed mixer, when you dial in a 75/25 mix of Argon/Helium, that's what you get, and that's why mixers cost what they do.This has been discussed in detail in previous threads.  I'm not going to rehash or go thru a more detailed explanation of the falacies of mixing gas with Y valves.PS.  If you put a gas analyzer on your output stream, I suspect you'd find that your "homebrew mix" contains less than 10% helium.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Originally Posted by pinjasDo you feel this is true?I definitely think the weld looks good.  It really doesn't look like the first weld was done with 75% balance on (I am not calling you a liar), it looks more like 50/50, I am really interested as to how helium effects etching.  Do you still need to do some pre-weld cleaning?
Reply:I have a question related to this topic.  I know people make their own gas mixes for scuba diving, do people ever do this for welding?If you only need to use a certain % mix, then why not just make the mix yourself? Take an empty tank fill to a certain pressure with Ar, then top off with He to another pressure point.  If you follow the calc for correct pressures you will have a tank of whatever gas mix you want.Im not recommending anyone do this at home because of the obvious dangers, but wouldnt this be easier to get the gas mix you want? (Keeping in mind that the ideal gas law used to calculate how much of each gas to use holds true to pressures of around 3600psi)
Reply:Originally Posted by ggarnerI have a question related to this topic.  I know people make their own gas mixes for scuba diving, do people ever do this for welding?If you only need to use a certain % mix, then why not just make the mix yourself? Take an empty tank fill to a certain pressure with Ar, then top off with He to another pressure point.  If you follow the calc for correct pressures you will have a tank of whatever gas mix you want.Im not recommending anyone do this at home because of the obvious dangers, but wouldnt this be easier to get the gas mix you want? (Keeping in mind that the ideal gas law used to calculate how much of each gas to use holds true to pressures of around 3600psi)
Reply:So I had to come back and leave a note for myself and hint for others. Once you take out the helium, put the argon BACK. Chased my tail for a good hr. Balance down to 70, lower than I ever need it. More scrubbing, test pieces, rods, tungsten, take "Y" off. Finally move cfm back to 12-13 to solve problem DOH lol  Early day fellas. So far so good. More testing show good results for my needs. Dunno what it is % wise by how mixxers measure. It's OK it's not right. i'll be the first to point out what works is not always what is right. But fills my needs until I decide to buy big Bertha
Reply:Originally Posted by 10secgoalWasn't sure exactly where to put this thread, but here it goes.Mixers being kinda expensive I figured I'd try this. Works well so far. Total cost was 100 bucks on top of the extra regulator I already had.I picked on of these up for about 32 bucks. It's actually supposed to go into a regulator and provide two hoses out. But it does flow backwards.The valves were only 5 bucks more so why not ? I wasn't sure about one bottle having lower pressure than the other, and back feeding. Seemed entirely possible since that's how you fill nitrous bottles. I got oxy acyl check valves. I had to have some hook up and ends added since inert gas and those have different style fittings. So that's what made it add up to 100 bucks.This is my poor little machine FULLY maxed out on 220. Htz were all the way up for this machine at 250. At 200 amps and 75 balance iirc. So I was trying to stretch the heat as far as I could go. The far right really looks like **** (my intake not customers). I am trying to find my settings and see if it will go. Nope. The next bead to it is a few seconds once the heat caught up to the area I was trying to weld. I just wanted to play so I ran with it. Ehhh still yet. Now this is with some heat. I tried on the other side first with 5 cfm helium, 10 cfm argon. So about 33% helium. A bit higher than you get it pre-mixed. But easy to know exactly where my ball was in the regulator without guessing if it was 4.5, 3.75, etc. So for now I wanted something easily duplicated. I turned the amps down to 170, and htz to 150 just to see the difference knowing it may not weld. Welp, it works pretty damn well. At that setting I got a puddle right away. I did end up going up to 200 amps so i could actually weld right away. But the puddle was wet enough to start. Would have probably had to wait 4-5 sec is all. i ended up also with the htz at 175 so i could change my torch angle a little less straight up and down. It was pretty extreme since this is .500 AL to .125.  Balance was still at 75, which is odd because the etch lines are very different. Will have to look into that one. But first test was with 3/32 rod barely wanting to melt, and with the helium it was melting the 1/8 at will, and digging into the .500 plate. I had to back the heat with the pedal as I welded which was awesome. You can see the last pic the beads are nice and wide, and the edges are laying down like they shouldSo far, liking 33%, which I could not have got with the pre-mix.Never seen anything on here like this, or anyone mix like this. Sure it's not the first time, but thought I'd share in case it could help someone.For any of the more experienced guys, that's a pretty good etch line right ? not too wide ? (on the second weld)
Reply:Originally Posted by 10secgoalSo far so good. More testing show good results for my needs. Dunno what it is % wise by how mixxers measure. It's OK it's not right. i'll be the first to point out what works is not always what is right. But fills my needs until I decide to buy big Bertha
Reply:This is what I want to do for my MIG setup. Run mostly CO2 and argon most of the time mixed from 2 bottles and have helium on tap when I need it.Glad to see good results with aluminum with a smaller amount of helium.Trimix and pure helium is just getting too expensive and hard to find these days.If 25% helium works almost as good a pure helium why not?old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder
Reply:Yes, do it!Just confirm the torch flow with a portable gas flowmeter. Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.