Dasher Posted April 27, 2019 Share Posted April 27, 2019 Hi all from Australia, I'm new to smithing generally, but have years of steel fabrication experience, I have just completed my 1st mini forge, made from a 20lb propane cylinder, it seems to be ok so far, but depending on the advice I get for my main query, it might need some changes. My problem is I can't get a flame of sufficient strength, I can get a good neutral flame only by lowering gas pressure to very, very low, or near closing the gas cock, which suggests to me I am short of air. My burner is a combination of a few different designs I've seen, trying to make use of what I had laying around, I stated with a 3/4"pipe mixer with a 3/4"" to 1"" coupler as a flare, mixer tube is around 8"long, with a slotted socket acting as a choke/ venturi inlet, then a 3/4"" cap with a 1/4" nipple brazed into it projecting the burner tip [mig tip] down the mixer past the venturi. This system was not all that great, I got heat ok, but not fierce heat, and minimal air intake noise, so I changed the venturi system to a 1" Tee, going for more air volume, it improved, but only just, on anything over 5 or 10 psi the flame is full yellow and fluffing or puffing as I call it, the choke is not being used at all, the full 1"" opening of the tee is needed just to get a decent flame at low gas pressure My thoughts now are that I may need to make the 1"tee a 1 1/2" tee, the other thing that I realised too late is I made no allowance for simple tip position adjustments, it is doable but not incremental, and requires different length mig tips or nipple extensions. At the moment the mig tip orifice is almost 1" below the tee, which might be hindering venturi suction, the noise of intake is minimal, and does not effect conversation at all. Thanks for taking the time to read all this, and I appreciate any advise. One other thing that may be relevent is the forge is lined with 3" of ceramic fibre every where except the porch which is 2", and NO rear door, which possibly is pushing pressure back against the venturi and hindering it from drawing. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 27, 2019 Share Posted April 27, 2019 The forge could benefit from a baffle wall, which is merely an addition. Your burners are your problem; neither one of your attempts are an acceptable design. You need to at least skim over the Burners 101 thread, and get a clue what you are doing. Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 27, 2019 Author Share Posted April 27, 2019 I have looked through that thread, but I struggled to find detailed info, I will look again, hopefully I'll be able to recognise more detail now I have a bit of hit and miss practise, I have no issue re doing the whole burner, the only problem is screwed pipe and fittings are far and wide here . I would kill for my old bsp tap and die set that my step dad threw out 30 or 40 years ago without asking me Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 27, 2019 Author Share Posted April 27, 2019 Thanks Mike, I looked through the burner 101 thread, and I think with what I have already, a slightly modified Frosty Tee burner is the simplest modification, if I use a cross piece instead of a Tee, my existing gas plumbing should be ok, saving me the issue of finding 1/4", or 1/8"" pipe and tapping and threading to suit, by the way, would the lack of a rear door possibly induce excess back pressure? The burner modifications might take care of the fluffing of the flame, so I will wait and see, I do intend to open the rear anyway for longer stuff eventually. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 27, 2019 Share Posted April 27, 2019 2 hours ago, Dasher said: possibly induce excess back pressure? Possibly, but not likely. What you need is a stronger flame. Your forge is good enough; concentrate on the burner. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted April 27, 2019 Share Posted April 27, 2019 11 hours ago, Dasher said: Hi all from Australia, Welcome to IFI... We won't remember that once leaving this post, hence the suggestion to edit your profile to show location. READ THIS FIRST That thread will help you get the best out of the forum. You might want to look into the OZ Roll Call Thread in Everything Else. Great bunch folks from down under. Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 28, 2019 Author Share Posted April 28, 2019 OK, Thanks, I'll get a couple of fittings tomorrow and see how I go Thanks Iron dragon, I'll work on my profile now Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 30, 2019 Author Share Posted April 30, 2019 Update on burner, thanks to advice from Mikey 98118, I've modified my burner closer to a Frosty T burner spec, some difference in fittings mainly due to what is easily obtainable near me, as it is atm, I have nearly 2" movement for the jet up and down adjustment, once I get some 1/8"" pipe, I can make the gas inlet side less clunky, and still keep 1/2" - 3/4" tuning adjustment, I've added a couple of pics showing the new set up, and also the lit burner, the lit picture doesn't really show the flame colour well, but it has a small 1-1 1/2" blue cone , and is throwing a lick of yellow from the door, I hope someone might be able to tell if the flame looks ok or not, but I think I'm in the ball park now and will play around with it a bit, at least the thing roars loudly now. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 30, 2019 Share Posted April 30, 2019 You have more to go, but I think you are well on your way toward getting there. You, Yes, a smaller gas tube will bring up your flame heat Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 30, 2019 Author Share Posted April 30, 2019 There is a 1/4 tube holding the gas burner inside that 1/2" nipple Mikey, but I intend to make it with 1/8", straight into the 1"" cross, not least to make it less clunky, less likely to be damaged, plus it will lower the COG Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 30, 2019 Share Posted April 30, 2019 Where I'm going with this is that the 1/8" pipe will give better gas flow into the MIG tip. If you use schedule #80 1/8" pipe, then you can run 1/4" MIG tip thread directly into it, and make a very smooth transition for the gas between pipe and MIG tip. This will increase the power of your burner, and ease construction. If such pipe isn't redillty accessable, 8 to 6mm, or 1/4" brass or steel tube can do an acceptable job too. edillty ??? Let's try "readily" instead Quote Link to comment Share on other sites More sharing options...
Dasher Posted April 30, 2019 Author Share Posted April 30, 2019 Yep, got that,, that is in my plans, but, 1/8"" pipe seems hard to get near me, I will have to go to the far side of town, a couple of hrs drive, so I''ll try to fit it in with another trip. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted April 30, 2019 Share Posted April 30, 2019 You could just attach the MIG to the copper tube, and slide the tube into something to stiffen it up (a double tube, etc.); that is harde to improve on for strong gas flow; just a thought. Quote Link to comment Share on other sites More sharing options...
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