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  1. #1
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    Nov 2010
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    Default basic gas torch vocabulary for newbs

    When I read the different metalwork books from the library, various home made tools are portrayed as relatively easy exercises.

    You just go to the shed, shape up a bit of silver steel then heat to "straw" or "cherry red" then either quench in oil/water, cool in air then maybe reheat or chuck it in a tin full of sand in the oven when nobody is looking and hey presto you have a new home made gizmo. Precise instructions are usually given in the books.

    As a starting exercise, I tried to heat up some metal with a little gas torch and there wasn't even the slightest hint of a colour change.

    Suspect I have to get a much bigger flame.

    My little gas torch screws directly into a tiny gas cylinder - easily held in one hand - what do I need to buy to get little bits of metal red hot ?

    any good web sites or previous threads to get me started learning what I need to buy ? Am not sure of the right words to search for in google / ebay / gumtree etc

    Bill

  2. #2
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    near Warragul, Victoria
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    Default Torch

    Bill, If you can afford it, get a Bullfinch brazing torch ..... search through the posts on this forum for Bullfinch . Mike

  3. #3
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    Default

    Bill, there are several ways of doing what you want and I'm sure all of those methods plus a few will be posted here shortly.

    For small items, say heating the tip of a 10mm round, a Bernzomatic or similar from Bunnings works well. You can also buy a torch similar to the Bernzomatic torch that attaches to a standard bbq LPG gas bottle.

    For larger items I use the oxy/lpg set, others will use oxy/aetylene.

    For big stuff I use a homemade (made from waterpipe fittings) LPG torch.

  4. #4
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    Athelstone, SA 5076
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    Default

    Quote Originally Posted by bob ward View Post

    For big stuff I use a homemade (made from waterpipe fittings) LPG torch.
    drawing?..or it didnt happen...lol

  5. #5
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    Default

    Quote Originally Posted by eskimo View Post
    drawing?..or it didnt happen...lol
    No drawings but I can do a photo and a few words of description. None of the dimensions are super critical, the whole thing is just an oversize bunsen burner.

    300mm long 1/2" water pipe
    At the RH end is a socket tapered on the inside
    At the LH end is a 1/2" x 1 1/2" socket
    LPG nozzle is a .6mm MIG tip (use a .8mm tip for 3/4" pipe and a .9mm tip for 1" pipe)
    You need air intake holes with a total area twice that of the piece of pipe and a choke so you can fine tune the airflow.
    The nose of the MIG nozzle needs to be 1/2" back from the start of the 1/2" pipe.


  6. #6
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    Default

    I think the nomenclature is pretty easy...

    We have smelly stuff tap.

    Hot bit

    Sparky thing for lighting it...
    Gold, the colour of choice for the discerning person.

  7. #7
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    Default

    Quote Originally Posted by bob ward View Post
    No drawings but I can do a photo and a few words of description. None of the dimensions are super critical, the whole thing is just an oversize bunsen burner.

    300mm long 1/2" water pipe
    At the RH end is a socket tapered on the inside
    At the LH end is a 1/2" x 1 1/2" socket
    LPG nozzle is a .6mm MIG tip (use a .8mm tip for 3/4" pipe and a .9mm tip for 1" pipe)
    You need air intake holes with a total area twice that of the piece of pipe and a choke so you can fine tune the airflow.
    The nose of the MIG nozzle needs to be 1/2" back from the start of the 1/2" pipe.


    Ta Bob

    Quote Originally Posted by .RC. View Post
    I think the nomenclature is pretty easy...

    We have smelly stuff tap.

    Hot bit

    Sparky thing for lighting it...
    hahaha

  8. #8
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    Default

    Quote Originally Posted by bob ward View Post
    No drawings but I can do a photo and a few words of description. None of the dimensions are super critical, the whole thing is just an oversize bunsen burner.

    300mm long 1/2" water pipe
    At the RH end is a socket tapered on the inside
    At the LH end is a 1/2" x 1 1/2" socket
    LPG nozzle is a .6mm MIG tip (use a .8mm tip for 3/4" pipe and a .9mm tip for 1" pipe)
    You need air intake holes with a total area twice that of the piece of pipe and a choke so you can fine tune the airflow.
    The nose of the MIG nozzle needs to be 1/2" back from the start of the 1/2" pipe.

    Bob, I wonder if you could just clarify, does the gas valve and jet assy screw into the reducing socket, through a bulkhead style fitting - like some 10mm plate of appropriate diameter, and threaded 1 1/2" bsp?
    Secondly where are the air inlet holes, are they in the bulkhead plate or more likely perhaps, through the side of the reducing socket, under what I presume to be two annular rings, the inner being fastened by the SHCSs to the reducer, and the outer ring being a close sliding fit over the inner, and slotted to allow the air to be throttled as it passes through to the holes underneath in the reducing socket?
    Finally what is the purpose of the socket on the hot end? Thanks,
    Rob.

  9. #9
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    Default

    Quote Originally Posted by steamingbill View Post
    ...........My little gas torch screws directly into a tiny gas cylinder - easily held in one hand - what do I need to buy to get little bits of metal red hot ?......
    any good web sites or previous threads to get me started learning what I need to buy ?...........
    Bill
    Bill, it is soon getting cold outside. We run two slow combustion heaters to keep our home cosy. If by any chance you happen to have a wood fired heater too.... just wait for some logs to turn to glowing charcoal, and you can heat treat or anneal some fairly large objects for free.

  10. #10
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    Default

    Ropetangler, the reducing socket is a transition piece between the air intakes and the 1/2" pipe. LPG in, MIG nozzle and air intake is one piece of steel. The photos are blurry (backgrounds are sharp) but you should be able to see how I made it.






  11. #11
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    Default

    [QUOTE=bob ward;1762661]Ropetangler, the reducing socket is a transition piece between the air intakes and the 1/2" pipe. LPG in, MIG nozzle and air intake is one piece of steel. The photos are blurry (backgrounds are sharp) but you should be able to see how I made it.

    /QUOTE]

    Thanks Bob, I think that I have it now, the air control is in 2 pieces (not counting the gas valve and jet assy.) The reducing socket has been machined for a close sliding fit in that inner section, and likewise the outer air control ring I assume.
    You didn't comment on the socket on the hot end of the burner, is it just a replaceable end, as in a consumable part and replaced when it gets slowly consumed if used in a furnace, or does it serve another purpose?
    Rob
    Last edited by Ropetangler; 3rd Apr 2014 at 09:12 AM. Reason: fix spelling error

  12. #12
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    The socket on the flame end as I mentioned is tapered internally and is referred to as a flare. All the reading I've done on these LPG torches suggests that you need a flare to stabilise the flame. I know nothing of the dark arts of flame mechanics so I just go along with conventional wisdom and include a flare.

    Flame stability is something to do with the decrease in pressure of the gas flow as it exits from the pipe into the flare into the atmosphere as I understand it.

    The flare runs surprisingly cool, I've never seen it become red hot even when running a furnace for an hour at a time, but yes its a readily replaceable consumable if need be.

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