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  • Back-gasing on Stainless Steel TIG

    Where do you buy this stuff from, or do you just make it. Do I need another Argon tank and regulator? Or just make a vacuum chamber and fill it with argon. I'm being serious. I have to have manifolds that won't break or crack under extreme heat 1600+deg F ie: Turbo cars. I've been doing alot of reading but I've had no success. A little help please.

    James
    Miller Dynasty 200DX SOLD
    WeldTec Water Cooler SOLD
    Miller Millermatic 180 w/ Spoolmate 100
    20Ton press
    And lots of Cut-off and grinding wheels
    www.IAGPERFORMANCE.com

  • #2
    I typed "Back Purging Stainless Steel Welds"......

    http://huntingdonfusion.com/HFT/modu...tegories&cid=9

    First site on the list.

    Shows a variety of different products.

    Many different ways to backpurge. Paper & Tape, Inflatable Plugs, etc etc.....

    The research for your application, I'll leave up to you.

    Have a Good Night.
    Later,
    Jason

    Professional Spark Generator by Trade.

    Comment


    • #3
      Originally posted by StillBoostin View Post
      Do I need another Argon tank and regulator? James
      I read on the Internet that this is the easiest way, if it's in the budget. Again, see my sig for qualifications.
      RETIRED desk jockey.

      Hobby weldor with a little training.

      Craftsman O/A---Flat, Vert, Ovhd, Horz.

      Miller Syncrowave 250.
      sigpic

      Comment


      • #4
        Good link Jason, lots of cool tools to get the job done!
        at home:
        2012 325 Trailblazer EFI with Excel power
        2007 302 Trailblazer with the Robin SOLD
        2008 Suitcase 12RC
        Spoolmatic 30A
        WC-24
        2009 Dynasty 200DX
        2000 XMT 304
        2008 Thermal Dynamics Cutmaster 52
        Sold:MM130XP
        Sold:MM 251
        Sold:CST 280

        at work:
        Invision 350MP
        Dynasty 350
        Millermatic 350P
        Retired:Shopmaster 300 with a HF-251

        Comment


        • #5
          back purging can be as simple as card board and tape, tin foil. just need to seal off the inside and poke a hole to feed gas in and another one to let air/gas out. if its a one time job, i would just make some thing to handle it. if its to be an on going thing may well be worth adding in the $ for a fast reusable system.
          as for getting the gas to purge with.
          you can get a T for the tank and add a 2nd gage, get a 2 gage setup, some have just added a T to the line feeding the welder, keep in mind you torch will lose flow this way so upping the flow will be needed. a T for the tank and a cheap gage off e-bay would be one of the better less expensive options.
          thanks for the help
          ......or..........
          hope i helped
          sigpic
          feel free to shoot me an e-mail direct i have time to chat. [email protected]
          summer is here, plant a tree. if you don't have space or time to plant one sponsor some one else to plant one for you. a tree is an investment in our planet, help it out.
          JAMES

          Comment


          • #6
            Like ManofSteel posted about this earlier, best is to get a seperate tank of argon with gauges and use that to use for your purge. You can tape the back end shut with just the hose going in, when you have enough gas coming out the other end to put out a lighter, that's enough (think it's about 10cfh, might be wrong)...Just putting a t-connector is no where near accurate enough...James/fun4now: If you put a t-connector and then put another set of gauges, I would think the hose going from the 1st set of gauges to the tig torch would be too inaccurate (because you don't accurately know how much is going to the tig torch even if you know how much the 2nd set of gauges get from THAT 2nd gauge reading, then you would have to subtract the reading from the 2nd gauge set from the 1st one, guessing the rest is going into the tig torch....accurate enough????
            hmmm..... If you wanted to be accurate, I wouldn't do it that way,
            unless I'm missing something?
            I'm not late...
            I'm just on Hawaiian Time

            Comment


            • #7
              Yep, you're missing something

              I use a simple valved y splitter... http://www.weldmet.co.uk/product_inf...874c48fdceb5f2, fitted after the reg
              Fit a flow meter to each of the splitters outlets and the flow can accurately set for both the machine and the purge line. The purge doesn't really need a flow meter (headers are small diameter in the grand scheme, very little flow is required to prevent coking/sugaring of the root) but they make life easier

              The purge is running all the time you're welding so set the machines flow rate with the purge ON. The purge reading will fluctuate slightly when the welders gas solenoid opens but it's no big deal. Super accurate flow readings are pretty meaningless anyway- the important bit is the O2 content in the pipe!

              High purge flow rates can actually cause problems- turbulent flow encourages mixing of the purge/atmosphere. What you want is a steady, low pressure flow to allow the argon to replace the air. Remember argon is denser than air- purge inlet at a low point, outlet at a high point!

              Purge rates depend on fit, size of tube (read purge volume) with fit playing a big role. Pipe welding often means open roots which obviously means lots of escape routes for the purge- this is where expensive 'purge dams' come into their own (along with taping up areas that yet to be welded)

              Headers are typically done with a closed root and being small diameter don't warrent dams. Simply cap both ends of the runner being welded (with a small hole in both caps), argon in at a low point, out at a high point. Give the purge a couple of mins to displace the air before commencing welding. A lighter can be used to establish that most of the O2 is gone when the purge exhaust puts it out. For critical work this won't cut it (a proper O2 meter is required) but it's fine for an exhaust.

              I usually start at around 5l/min and turn the purge down to 2l/min once established. That's enough to prevent coking, shouldn't be any worse than straw to maybe a little blueing

              Comment


              • #8
                Cracked headers is (potentially) another issue that purging alone may not cure. The temperatures achieved by a tuned, turbocharged engine are pushing things with regards to 304.

                321 is a better choice but (in the UK at least) is not only a lot more expensive but very hard to find, especially as pre-formed mandrel bends

                A lot of the turbo headers i've seen use sch10 304. Purged or not, i've seen a lot of cracked ones- some centre line cracks but not always. Some had let go at the outside of bends, nowhere near a weld. I suspect poor welding/fabrication (partial pen welds, cooked welds and/or welding under high restraint) played a big role in those failures but it's only speculation on my part

                I've not had any problems using 316L dairy bends (1.6mm/ 0.065" wall) but i don't do many turbo headers and most of those i have done are on bikes (lower temps due to improved airflow over them). While the moly content might, maybe improve things a little over 304 both alloys have the same temperature limitations on paper

                Comment


                • #9
                  Can't speak about headers but backgassing is simple, cheap and easy. I use a T fitting on a single bottle with 2 flowmeters. If you find HTP weld on e-bay, he sells flowmeters for 45 bucks. about 20 for the fitting, so 65 bucks total. I get from a friend what is reffered to as speed tape, nothing more than adhesive backed alluminum. its fairly heavy gauge (heavier than tin foil) and stands up to the heat very well. You might need to clean off the adhesive if you really cook it. I take a length of oxygen hose from my second flowmeter and stick a piece of copper tubing in it so i can bend it to shape and it wont melt. Thats about it. Turn up your flow, tack your pipes, cap them with tape, put the backgass in the low end (argon is heavier than air) and wait until a lighter wont stay lit, maybe a minute more if your not comfortable with that.
                  Dynasty 200 DX
                  Millermatic 175
                  Spectrum 375
                  All kinds of Smith OA gear

                  Comment


                  • #10
                    Bert
                    hmmm..... If you wanted to be accurate, I wouldn't do it that way,
                    unless I'm missing something?

                    awwww man, your breaking my heart. you miss-trust my infinite wisdom,and i thought you loved me. i'm going to have to go cry now.

                    i attached a pic of where the T goes for best results.
                    some have just upped there flow rate and added a T only to the feed line to the torch. this is much less accurate but can be done. as said the flow rates are not that exact any way. as long as you have enough to cover but not so much as to pull in air, you are good to go.but adding an extra $60 to the project for a T and 2nd gage that you will use many more times would be an acceptable cut in profit / increase in price. later if you get a 2nd tank you can still use the gage on it as a perg so its $ put toward a better way later. the tank is the big $ part of a perg setup.
                    Attached Files
                    thanks for the help
                    ......or..........
                    hope i helped
                    sigpic
                    feel free to shoot me an e-mail direct i have time to chat. [email protected]
                    summer is here, plant a tree. if you don't have space or time to plant one sponsor some one else to plant one for you. a tree is an investment in our planet, help it out.
                    JAMES

                    Comment


                    • #11
                      James, Ok, that's cool!!! I could see doing that!! Love your crayon drawing, but unfortunately, still better than I can draw
                      thanks
                      I'm not late...
                      I'm just on Hawaiian Time

                      Comment


                      • #12
                        Wow thanks for the ideas. That web site is great. I emailed the company in the USA(Florida) that sells that product. I like the blater idea. Hope it doesn't cost a fortune. If money is right I'll just get the second tank. I just receive the catalogue from HTP and it is on sale for $39.95. That is half of what I just payed for my victor!

                        Peter you sound like you do what I do. Thanks for the advice.

                        This is one heck of a forum. Glad I decided to go BLUE!

                        James
                        Miller Dynasty 200DX SOLD
                        WeldTec Water Cooler SOLD
                        Miller Millermatic 180 w/ Spoolmate 100
                        20Ton press
                        And lots of Cut-off and grinding wheels
                        www.IAGPERFORMANCE.com

                        Comment


                        • #13
                          response to the dialoge

                          hey guys i noticed some of the advice going on in here, and not to be a smart a$$ but i am a proffesional welding contractor and am a very consistent stainless and exotic metals spe******t (at least thats what they tell me when they want me to weld at the nuclear facilities and aero space industries that i service, pointer #1 peter argon is heavier than oxygen so i dont understand why you put it in at a low point and exhaust out a high point, can be done but will cause alot of turbulence till o2 is cleared, and i dont recommend using the same bottle to purge and supply your torch , ok i guess if you dont mind looking like a bush league player but youd never be allowed on one of my jobsites, but again if its not critical you can always grind your welds out and deal with the inconsistent pressures and issues youll experience, just get rid of any possible variable and let your welds show your skills off. in my opiunion if you cant do something right , dont do it unless you run mickey mouse welding inc, proffesional gear gets you proffesional results good luck guys

                          Comment


                          • #14
                            Originally posted by man of steel View Post
                            hey guys i noticed some of the advice going on in here, and not to be a smart a$$ but i am a proffesional welding contractor and am a very consistent stainless and exotic metals spe******t (at least thats what they tell me when they want me to weld at the nuclear facilities and aero space industries that i service, pointer #1 peter argon is heavier than oxygen so i dont understand why you put it in at a low point and exhaust out a high point, can be done but will cause alot of turbulence till o2 is cleared, and i dont recommend using the same bottle to purge and supply your torch , ok i guess if you dont mind looking like a bush league player but youd never be allowed on one of my jobsites, but again if its not critical you can always grind your welds out and deal with the inconsistent pressures and issues youll experience, just get rid of any possible variable and let your welds show your skills off. in my opiunion if you cant do something right , dont do it unless you run mickey mouse welding inc, proffesional gear gets you proffesional results good luck guys
                            ??????????????HUH?

                            You wouldn't be allowed on site if you used one tank for both? Why not? With 2 flowmeters there is no reason i know of that indicates a shortcoming. Please explain this statement.

                            Putting the argon in on the bottom, although not necessary should allow the lighter air to rise to the top, making less turbulence than puting the argon in the top and having it drop and mix with the air. Its like pouring oil into water, they will tend to mix until gravity has a chance to separate them.
                            Dynasty 200 DX
                            Millermatic 175
                            Spectrum 375
                            All kinds of Smith OA gear

                            Comment


                            • #15
                              You wouldn't be allowed on site if you used one tank for both? Why not? With 2 flowmeters there is no reason i know of that indicates a shortcoming. Please explain this statement.

                              i was thinking the same thing, just figured the question would come off wrong. i know apearences can be a big part of company's reputation, looking pro. VS rag-tag. but as long as 2 regulators are on the tank stable flow is acheavable and looks pro.
                              slide in with a dyn200DX under one arm and a 60quft tank with 2 reg.'s , what more could you ask for. i would call that guy a pro.
                              now sticking a plastic T in the feed line and sharing one feed not so good looking if you know welding.
                              thanks for the help
                              ......or..........
                              hope i helped
                              sigpic
                              feel free to shoot me an e-mail direct i have time to chat. [email protected]
                              summer is here, plant a tree. if you don't have space or time to plant one sponsor some one else to plant one for you. a tree is an investment in our planet, help it out.
                              JAMES

                              Comment

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