Tig welding aluminum

Discussion in 'Castings, finishing/ repair/ and patina's' started by Zapins, Sep 5, 2018.

  1. Zapins

    Zapins Silver

    If I need to weld cast aluminum and layer it up so it is about a third or half an inch thick. Fill in some gaps etc is that going to work in the same way you can layer and fill in bronze or steel?

    I've never tried aluminum before and want to double check before I go this route.

    My tig can draw 40 amps at the moment (without upgrading to water cooled and a bigger cable).
     
  2. oldironfarmer

    oldironfarmer Silver Banner Member

    Same way. Of course there are differences in setup you need to look up, like blunt tungsten.
     
  3. Zapins

    Zapins Silver

    Yep. Already familiar with that . The tip melts into a ball which is weird but expected.

    I'm thinking of casting a 3d printed extrusion screw for the wax extruder and casting it in aluminum. But it would have to be done in at least 2 or 3 pieces and welded together. Way beyond the capacity of one #16 crucible.

    I am also thinking of taking it to an amish iron caster in lancaster pa and paying him to pour it for me in iron. Still figuring it out.
     
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    Zap, Im assuming you mean only pull 40 amps from the wall?? It takes alot of amps to tig aluminum. It sucks the heat away very fast.
    Cat tail foundry?? How big is the part your trying to cast up??
     
  5. Zapins

    Zapins Silver

    Yes pulls 40 amps. If I could ever get an electrician to help me install an arc fault breaker so I could meet the God damn code in CT and guarantee that it would work on an arc fault I could use the full 100 amps with a water cooled torch.

    The part is fairly large. Probably about 2.5 feet long by about 3 inches in diameter although it is hollow inside (maybe 1 inch of hollow space?). It would be better if I could scale it down a little more and keep half inch thick walls but I'll need to fiddle with mesh mixer a bit more and see if I can figure out how to thin it down more.

    I think it will be just over the capacity of a #16 crucible.

    Yes cat tail foundry.

    I could also maybe cast it at the local iron place but I'd need to somehow coat it in shell and bring it down here burnt out and ready.

    I wonder if iron pours better into a cold shell just like aluminum and bronze?
     
  6. DavidF

    DavidF Administrator Staff Member Banner Member

    Pouring iron into a cold shell may cause it to solidify too fast producing alot of white iron.

    I though we were past that whole arc fault breaker thing??

    What's this part your looking to cast in iron?
    Sounds like it is a piece of pipe?? Could you fabricate something from dom tube instead??

    Edit. Ok you making a screw
     
  7. Zapins

    Zapins Silver

    This is the item I'm casting, except I modified it to have a different attachment for a pulley, and made it hollow and added holes on the ends to ensure proper drying during shelling. https://www.thingiverse.com/thing:48589

    I think the way I planned to make the wax extruder will probably not work very well with just a car jack for pressure, so I'll be removing the piston from the cylinder and installing this extruder screw inside it. That way I can constantly extrude wax using the hydraulic cylinder.

    Unfortunately not past the arc fault issue. The last I heard from the electrician/inspector it was required. Maybe over december I can go sort something out but I doubt I'll find an alternative. They seem full of crap in CT. Rules for the sake of rules.
     
  8. DavidF

    DavidF Administrator Staff Member Banner Member

    I think they are full of crap. Have you seen in writing the law stating you have to have an arc fault breaker or is some retard telling you this strictly verbally??
     
    Jason likes this.
  9. Zapins

    Zapins Silver

    The town inspector verbally told me on the phone. He was in a hurry to get rid of me, so perhaps I'll go pay him a visit in person and figure out what the hell since he is the one who seems to be standing in my way. The electrician is just a bystander in this issue. I remember someone posted a link to the relevant code from 2017 and basically the gist of it is arc fault are only required on 115v not 220, so I don't know what the issue is in putting in a new sub panel and then wiring in arc fault breakers in for the 115v lines and normal 220v breakers for my welder. Will have to get more details to figure out what the issue is.
     
  10. Jason

    Jason Silver Banner Member

    40 amps from the wall should allow you to go pretty damn high with your machine. I have used 1amp per thou on AC, (tungesten to a sharp point, inverter machine) Work your balance. Light up on the stuff and DO NOT MOVE or dip in the puddle. Watch the little black shit start to swim around and it will disappear, now dip your filler and start moving. I thought you started TIG on aluminum like I did?? Or maybe that was OCD with his invertig? Chinese isn't hard for chinese babies mentallity. You have an old school transformer machine so yeah you need to ball your tungsten and might actually have a wall issue. Sorry, I can't say. I dont get to tig much aluminum, but I like it and never found it really that hard. The biggest thing is CLEAN CLEAN CLEAN. Use a brand new stainless steel brush and brush your metal. Don't let it get contaminated with any steel. Wipe your stuff down with straight acetone.

    Remind me again what miller you have??
     
  11. Zapins

    Zapins Silver

    Syncrowave 250. Lovely machine.

    I'll grab some aluminum rod and go for it. Do you think aluminum will be strong enough for an extruder screw? I could make it in bronze but that would be expensive. Might have to buy a new crucible though to pour the Al so maybe it would work out to the same price in the end? Hmm.
     
  12. Jason

    Jason Silver Banner Member

    I'm not sure about the entire screw idea. It should work... but my gut is not only will it have to compress the wax at the end, won't it also have to keep the entire wax turd spinning the length of the screw? It's a measurable distance thing it will have to move that wax. Just measure the total length of the thread... I just see this thing locking up until you heat it pretty good. Everyone wants soft, not liquid. I'd be willing to bet around 120degrees should keep wax pliable enough to poop out the die without pissing on the floor. :D How's that for an analogy? :oops: OMG! I wonder if Dave will edit this one???:D :p

    Ya didn't want to do a piston and keep the threads clean and outta the wax?
     
  13. DavidF

    DavidF Administrator Staff Member Banner Member

    If I could figure out a way to be just as descriptive I would.... :rolleyes::rolleyes:
     
    Jason likes this.
  14. Jason

    Jason Silver Banner Member

    lmao.. I did get my point across right??:p
     
    DavidF likes this.
  15. crazybillybob

    crazybillybob Silver Banner Member

    The issue with an aluminum Screw is that they like to strip threads off. To counter act that you have to make the nut much longer to spread the load across more threads or make larger threads. You might be further ahead casting an aluminum Tube and Using your lathe to cut the threads. It would give you more control over the profile of the threads . Casting an agar might be doable but an thread for the load that you you're talking ... I know I couldn't pull it off. But then again you have proof that you are a much better caster than I am. You might be able to pull it off.
    CBB
     
  16. DavidF

    DavidF Administrator Staff Member Banner Member

    Yea but you left out the part where if the screw is loose in the bore the wax might shart out the end as its rammed. :eek::rolleyes:

    Another reason for using a know alloy goes back to the beginning with the making of the pattern. Different aluminum alloys have different rates of shrink. If you dont know how much it will shrink, then how do you know how much to scale up your pattern??

    If the wax is only to be heated to 120' then it may be possible to just 3d print the screw and use it. Petg would probably hold up if printed solid. I think it would be worth a try.......
     
  17. DavidF

    DavidF Administrator Staff Member Banner Member

    HMM ???? Gear pump!! ;)
    Pump the liquid wax into a cooling cylinder dropping the temp back to a mush state then through a nozzle to extrude.....
     
  18. Zapins

    Zapins Silver

    They use screw extruders to make plastic and all sorts of things. I think it should work for wax too. The screw isn't a simple augers. It has a taper to it and some screws have a decreasing distance between the threads which helps heat and compress the extrudate.

    I would make the screw on a lathe if I could but the geometry of it is difficult to machine and I definitely don't have the skills to do it. Maybe a multi axis 3d mill could make it.

    I could make it out of bronze, it might come out roughly the same price as in Al. Since I'd have to buy a new crucible anyway to cast the Al.

    I was going to cast the screw maybe 4 or 5% larger then lathe down the outer edge so it is flat.

    I read on the extruder forums that a gap of 2 to 3 mm between the screw and the wall works well so it seems the tolerances aren't super tight like I was thinking. The tighter the gap the better it extruders but also the more stress is put on the screw.

    I think a full plastic part would break since the printer has a max print height. So it has to be printed in multiple sections and glued together.
     
  19. DavidF

    DavidF Administrator Staff Member Banner Member

    Pretty sure petg could handle it. If in doubt you could print the parts solid, but with a center bore that a bit of steel rod or tube could be epoxied into.

    For plastic im sure its ok, but wax may be a different story. 2 to 3 mm sounds awfully high maybe 2-3 thou or 0.2mm???
     
  20. Zapins

    Zapins Silver

    That's more in line with what I was thinking and aiming for.

    Think I should just make it out of bronze? It wouldn't be hard to weld together and I think bronze and steel play nice.
     

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