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  1. #16
    Ueee's Avatar
    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Well there you go. I have always just read on all the casting sites on the net that UMO burns hotter.....but i guess the comparison is always against LPG. I still like the idea of using up all that free motor oil, and oil burners seem to need to be less precisely made and more robust than injectors etc, especially when so close to such a source of heat.
    Out of interest was there coke on the list too?
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  2. #17
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    no coke just the coal , what sort of coke ? cokeacola =0 the 3rd ones way too expensive to use unless your smelting at a rave

    ive heard a lot of bad things about "waste oil " , the sludge in cooking oil , you might as well re distill it before use or the solids will encrust on the inside of your hot jet , with waste motor oil , you dont know what the mechanic pored into it , heard of one bloke that got 20lt of bad oil and didnt find out until he had pored it into his 40gallon drum , could do nothing about the smoke , he blames " synthetic oil " , the funny thing is he had to pay some one to take his oil away after ( free oil must be a good deal ) , at 4.5lt per hour ??? 6 bucks ???? diesel is affordable , clean ,heaps easier

    then the jets are a work of engineering , you need LPG to start it off , an air compressor ,blower and a "PHD in patience" to work it out

    the jet on mine cost $12 , the regulator $30 , and a fuel injection ,fuel pump $80 , it even lights of a spark ( long BBQ lighter ) , the only problem i had was shutting the flame off ( a good problem ) keeps running for 2min after the pump is turned off because of pressure in the fuel line , a bypass tap returning pressure back to the tank fixed that problem

    i hope to work out too get it too burn well with no manual adjustment , a fuel pressure sensor after the regulator should beable to get a programmable chip ( aurdrino ) to set the fan speed to the corresponding pressure , and just having a sooty =down to zero fan speed , and a neutral flame at the 3/4 mark ,and a 1/4 turn into lean , if you turn the fuel pressure up , the fans will follow automatically keeping the fuel / air mix set by the dial , ive got an O2 sensor to set it up with , but dont think it will need one once the fan speed to pressure is set in code for that burner / furnace setup , it will change a little with humidity / air pressure but once you have a good burn , you can turn it up or down without adjusting the fans, and should beable to put approximate temp settings on the fuel pressure dial
    how come a 10mm peg dont fit in a 10mm hole

  3. #18
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    I'm starting to wonder how I managed to smelt gold at Lancefield through the 80's, I sure wish I had some pic's of the furnaces I used. We had a 5,000lt diesel tank on a stand, it gravity fed down to the sheds through 5/16 copper tube into a simple gateway tap. The tube then ran in through the side of the forced air tube approx 2-21/2inch with the end pinched with a pair of sidecutters.
    I'd put some diesel on a rag and light it up and leave it burning under the end of the diesel tube to heat it up a bit, then crack the diesel and slowly open up the air and voila!! away she'd go, fine adjustments by looking at the flame and roar it made, then eight hours later I'd have 18 - 20 pound of gold and silver to pour.

    Here's a sad little rig I inherited about 6months ago, I wonder how hot heat beads get?

    ?Furnace 2.jpgFurnace 3.jpgFurnace 4.jpg
    Attached Images Attached Images

  4. #19
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    Me stupid!

    I didn't even know that there's a casting sub-forum. Only realized it, when a thread of mine was moved over there (thanks for the clue by 4).

    I'm messing around with my waste oil burner since this spring. It does get better over time, and I more and more understand how it works and what NOT to do.

    I have also tried it with diesel (heating oil to be precise), and that works better. At least, easier to fire up and get a clean flame. I even let it run with "women's gas". That is a mixture of gasoline and diesel. But that's a bit scary (don't try that at home).

    But I only succeeded in melting CI, but not getting it to a casting temperature.

    Aluminium is no problem at all. I even have to pay attention to not run it too hot, so my iron crucible gets burned.

    My setup is more or less crap. At least, made out of crap. I tried quite some things that headed towards engineering. But I removed them as they made no difference.

    My blower is a compartment blower from a VW Passat. It has 400 Watts, and that is already a bit more than necessary. Power supply is a regulated laboratory supply, so I can adjust the air flow. I had a turbolator (SP? to make turbulences) in the intake, but made no difference).

    Oil supply is through a pressurized tank (2 bar). The oil goes through a rubber tube to the "jet". That's just a copper tube (ID 4 mm). What did make a difference in atomizing the oil and helps at burning it was this setup:
    At the end, I had a plug with a 1.5 mm bore. At the other end of the tube (the cold end), I blow in a small amount of air. This air is taken off of the pressurized tank (so the pressure is regulated). That air goes through a small adjustable throttle. You really don't need much air! Short after the air-inlet, the oil goes in.

    So I have no fancy flame holders, or something that resembles and even acts like a burner. All happens just inside of the furnace's chamber.

    Initially, I had a lid on top of the furnace. But I had to drop it once (because when I lifted it off, I burned myself). The opening was 7 times that of the inside's area (that was the engineering part). The new lid I cast now has only 4 times the area. And that looks like it works better. I tried to find a reason for that, but at least back pressure makes no difference. Maybe more something like increasing turbulences inside the furnace. And having more heat radiating surface that increases the speed the oil burns at.

    At full throttle, I burn 20 liters of oil per hour. Makes roughly 200 kW.

    Nick

  5. #20
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    Quote Originally Posted by Finn562 View Post
    Here's a sad little rig I inherited about 6months ago, I wonder how hot heat beads get?
    Surprisingly hot, you can melt aluminium quite easily once you get enough air into them, we have been doing so with an old 20l drum lined with blue river clay for some time now, we used a steel ladle rather than a crucible as we were only doing small batches (knife handles) but with a large surface area the steel gets glowing red hot within minutes.

    You might be surprised how well that sad little rig can melt stuff

    Nice work on the burner Ken, watching with interest !

    Cheers.

    Russell.

  6. #21
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    Quote Originally Posted by MuellerNick View Post
    Me stupid!

    I didn't even know that there's a casting sub-forum. Only realized it, when a thread of mine was moved over there (thanks for the clue by 4).
    Nick

    the Foundry was only set up 2 weeks ago , i started this thread in the CNC section and got moved

    Quote Originally Posted by epineh View Post
    N
    Quote Originally Posted by epineh View Post
    ice work on the burner Ken, watching with interest !
    Cheers.Russell.
    ,
    will be working on the burner today , i have a larger "jet " fitted now ,. and am working on the motor speed control for the fans , hope to have it blowing flames by tonight

    last week end i cast my furnace and lid , they turned out well , ( no cracking ) , i used 1 3/4 bags of "shirecast 160ar "

    the lid is hollow and full of "kiowool " , all the shirecast refractory is about 20mm thick

    with my furnace , the input tube is 50mm , opening up to a 75mm donut ( 1 1/2 xtube) , there is 35mm (1/2 the donut) gap between the the crucible and the wall , the exhaust port is 75mm , and the gap over the top of the crucible has the same area , as the area of the exhaust port at 22mm ,

    the lid is showing where the joins were in the foam mold , and need sanding before firing the refractory , i found this " sirecast 160AR " good stuff , a clay with grit and hairs , i didnt notice any shrinkage , and built up the thickness over 12hours , keeping the working surface wet at all times
    top of lid.jpgbottom of lid.jpg

    i had to burn out the foam in the furnace , i removed as much as i could before torching it , once the burners ready today ill torch it again , there is still a fare bit of foam on the inside , and i cant remove the partial board layer stuck to the top
    outdise furnace.jpginside furnace.jpg
    how come a 10mm peg dont fit in a 10mm hole

  7. #22
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    got the burner running tonight with the fans speed controller , it works well

    so i propped up the furnace , and fired it up to complete the burn out ,i lit it upside down first and shut it off once the out side got to 100c and let cool down again ,this time i went too 200c ( 7min ) and once its cold , ill fire it up too 400c ,
    im just a bit worried there still might be some moisture in the refractory
    1st burn out.jpg

    hopefully i can remove the partical board " form work" from the top after it cools
    how come a 10mm peg dont fit in a 10mm hole

  8. #23
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    I have a question about the polyurethane foam, do you use the chemicals to make a block for milling or do you buy a premade block ?

    Cheers.

    Russell.

  9. #24
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    i found a block ,a housing trust tenant left it behind when they moved out , i grabbed it quick smart ( was changing the locks )
    yer factory made , it was 1200mmx900x200 , probably would have made it out of MDF sheet if didnt have the block on hand ( MDF packing sheets are free from work)
    how come a 10mm peg dont fit in a 10mm hole

  10. #25
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    OK so is that just the white packaging foam, what I would call coolite ?

    I can get heaps of that stuff of various shapes and sizes but I thought it wouldn't mill all that great, I know it can be cut with hot wire but I just figured it would leave a weird finish if the little bubble bits let go.

    Cheers.

    Russell.

  11. #26
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    no it was polyurethane foam , not Styrofoam
    i haven't tried to mill Styrofoam yet , but will try , for lost foam casting the styrofoam is suppose to burn out quite clean when you pour the molten metal in
    how come a 10mm peg dont fit in a 10mm hole

  12. #27
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    Ah ok I am with it now.

    I was going to try lost foam for a spindle mount for my next machine but decided to go with the good old fashioned timber pattern instead, though lost foam is on the to do list.

    Cheers.

    Russell.

  13. #28
    Ueee's Avatar
    Ueee is offline Blacksmith, Cabinetmaker, Machinist, Messmaker
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    Lost foam is supposedly easy to do as you don't need oil bonded sand. You just plaster the foam with plaster base coat and bury in sand. Having said that the only casting i have done is the traditional pattern and casting sand method. For one off's i think lost foam would be great, but if casting multiples making many foam patterns would be painful.
    1915 17"x50" LeBlond heavy duty Lathe, 24" Queen city shaper, 1970's G Vernier FV.3.TO Universal Mill, 1958 Blohm HFS 6 surface grinder, 1942 Rivett 715 Lathe, 14"x40" Antrac Lathe, Startrite H225 Bandsaw, 1949 Hercus Camelback Drill press, 1947 Holbrook C10 Lathe.

  14. #29
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    Quote Originally Posted by MuellerNick View Post
    Me stupid!

    I didn't even know that there's a casting sub-forum.

    dont feel stupid Nick..leave that to me..I found out later than you you...I must be blind

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