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SawDustSniffer
28th Sep 2012, 09:38 PM
Disclaimer > do not try this at home , or atleast say " WATCH THIS " to a mate before hand , so he can upload your error in judgment too Utube , so the HOLE WORLD can laugh at you , ( just remember i said DONT do it , so dont sue me )

looked in the metal working section ,????? no real section for Furnaces ???? so since you have to make an object before you can cast it , CNC is a good place , and every one with a CNC wants to turn there MDF object into metal?


for the last few weeks ive been collecting parts/ materials for the next corner of my shed , the foundry
ive been stalking some Furnace Forums for ideas ,
and decided im gonna make one

for the furnace i went with a size #10 crucible , 200mm high 160mm wide , holding 2.4lt of the glowing stuff
so based on the size of the crucible i drew this up , with a 20mm gap between the crucible and the wall of the furnace
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the " hot face " i selected is called "Shiracast 160AR" about $66 a bag from "the fire brick company " , its good for 12months at 1600c temp (cast iron poring temps)
i also purchased KIOwool , a ceramic insulation rated at 1250c to insulate the hot face ,. and all that will go in a cut down 40 gallon drum

so last night i turned the cad drawings inside out , so i can machine up some " molds " , they will be 50mm slices , milled from polyurethane foam , then glued back together , and finished with polyurethane glue

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then using a" speckle gun " i plan on building up the surface until its 30mm thick , the last 10mm will have chopped up carbon fiber added to help reinforce it together



for the HEAT i opted for diesel , LPG wont get up to a high enough temp , and waste oil ( better temp ) is too hard to get too burn stable
i went for a 140psi fuel injection pump rated at 200lt per hour , a high pressure fuel regulator , and a " water misting " head ( 0.3 square mm hole ) , it should burn about 4.5lt of diesel per hour , inside a 50mm diameter tube , with a blower for the air

i just got the misting head up to pressure , with rubber hose , for a test of "atomization " and fuel flow , and will have to replace the fuel tube with metal and set up the burner properly , but it spat fire , first go

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so this is what im up too

Master Splinter
28th Sep 2012, 09:52 PM
Hummmm.... 20 plus kilos of molten iron....can I suggest a small crane for safety....

SawDustSniffer
28th Sep 2012, 10:08 PM
Hummmm.... 20 plus kilos of molten iron....can I suggest a small crane for safety....

nar employ a suicidal bloke to do it for you ? i don't want to get within 3 foot of 2.5lt of molten iron , it will give you at tan at 10feet

im building this to withstand iron temps , but brass will be the hottest ??1100c( i keep telling my self ) , to the brim with brass is 18kg , (#10 crucible ), a 2 person lift and pore "crucible plucker"

will only go to 900c with aluminium most of the time

with the left over materials i will make a small Number4 sized one as well ( 0.75lt ) , and in time a #40 crucible would be nice at 6.7lt or 50kg of brass , would need a crane for that one , or design it as a tilting furnace

Scott
28th Sep 2012, 11:04 PM
I think you've been sniffing too much saw dust. :D Nonetheless, don't let me stop you, enjoying this so far.

Finn562
29th Sep 2012, 02:07 AM
Back in the old days I used to smelt gold in a diesel furnace, all you need to add is a fire brick tub and a blower vac. You'll have the noise of a 747 on take off and more heat than you'd ever need. Fantastic bit of gear the diesel furnace :U makes me feel all happy inside.

Ian

twistedfuse
29th Sep 2012, 03:45 PM
Awesome project. Look forward to seeing it and some projects when done. You'll probably get some jobs off here too, be nice to get rough casts done and then machine them clean on certain parts.

SawDustSniffer
30th Sep 2012, 02:55 PM
did a bit more on it today , i went back to the oil instead of the mist sprayer for cooling the bit ?/ quicker to set up on a 10min cut , and my compressors in my van , and it was raining , and i cant think of any other excuses

i cut out some " spinners " from 3mm aluminium , these spin the air inside of the "blowers tube "
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also cut out an aluminium plate , that the 2 blowers , fuel regulator & switches will bolt too

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and tapped out the 6mm copper tube , and tapped it out so the "jet " screws onto the the end of it
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a number 10 crucible they say only needs 4.5lt per hour of diesel , at a 14:1 oxygen / fuel, with 20% oxygen in air , its only 315lt of air per hour , a lot less than i thought , my big blower might get turned into a sawdust extractor


( this new upgrade is giving me the ##### , connection keeps dropping out on down loads , have to wait 5min after clicking "reply to thread " before i can type , ??? i just dont like it, the up grade is slower than the original ?? , yes my connection is crap at 2kbs , but thats a mobile telstra broadband in my area ( over sold band width ) and the new cable roll out wont come to Darwin at all )

it takes so long , ive managed to draw up the next part in CAD while i waited

twistedfuse
30th Sep 2012, 08:45 PM
Great work!

Second ya on the new website. Not having the same issues but just seem clunky and slow.

RayG
30th Sep 2012, 10:03 PM
Hi SawDustSniffer,

Great project, I think oil fired is a good way to go, cheap to run and plenty of heat. Mine is LPG fired with forced air.

I got a chance to see Nick Muller's oil fired furnace in action a few weeks back, when tuned and running it was nice and clean, (no smoke)

There are some threads in the Metalwork forum including some with video's of NIck's setup.

Good luck with the project, I'll be watching with interest.

Regards
Ray

Ueee
1st Oct 2012, 12:24 AM
Um....where the blazes did this forum spring from...did i miss something?
After all my research i would go with Ray and say waste oil is the go, lots of good info on the net, cheap, hot and easy. Also no so dangerous if you spring a leak.....for simple UMO plans try here: melting metal in a home foundry, backyard metalcasting, metal casting (http://www.backyardmetalcasting.com/index.html)
Are you going to use a steel crucible? My old flower pot furnace ran on coke, but i got better results with a bit of 250mm steam pipe on its end in the forge. I could also never get the steel crucibles to stay liquid tight, they would always spring a leak....bad welding i'm sure.
Watching with great interest

Finn562
1st Oct 2012, 01:29 AM
( this new upgrade is giving me the ##### , connection keeps dropping out on down loads , have to wait 5min after clicking "reply to thread " before i can type , ??? i just dont like it, the up grade is slower than the original ?? , yes my connection is crap at 2kbs , but thats a mobile telstra broadband in my area ( over sold band width ) and the new cable roll out wont come to Darwin at all )

it takes so long , ive managed to draw up the next part in CAD while i waited



What operating system are you using. If I use my desktop (windows Vista) it locks up etc etc, but if I use my laptop (windows XP) all seem ok.

Just remembered I have a miniture furnace I inherited from a reli, I'll have to fire it up to see if it works and take some pics. It uses a reversed vacuum cleaner for air.

Ian

SawDustSniffer
1st Oct 2012, 02:30 AM
managed to get a few good hours out in the shed tonight

i knocked up a HDPE , round to square converter , yer HDPE aint the best but i had some , looks like ive found something to cast in aluminium already
machining HDPE with a strong wind is not good , shed is now full of fake snow , very festive

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so then i put it together

at the moment its got o.15mm jet in it , this week some 0.3mm jets will arrive , with the 0.15 jet it runs 1.125 lt per hour , im hoping 0.3mm will give me just over 4lt per hour ( some ones got to try it
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yer looked at waist oil , and saw there burners , with heaters that get too hot and clog , the filtering , have to start them on LPG , who knows what the mechanic pores in that drum , a couple of liters of synthetic oil and it will be smoking like an Indonesian child , yes it will get hotter , but my furnace im making will only last 12months at 1600c , iron melting is not a priority , i just think diesel is just easier , and at 4.5lt per hour , affordable with the lest amount of stuffing around

the only thing not in these photos is the 140psi fuel pump , its in a fuel drum , fan speed controller + pump switch and shut off tap
i looked at the web sites at burners , and scratched my head , just spray the fuel down the pipe , so thats what ive done , my own plans

i splurged and got a clay graphite number 10 crucible

SawDustSniffer
1st Oct 2012, 02:42 AM
was about to spit the dummy about being moved , so before i did i looked where i was moved too ,
:2tsup: cool :2tsup: a new forum page just for me , i wont be complaining
i guess now im not in the "CNC section " i dont have to post photo's of cutting and cad files i used , ( i still will )

cheers ken

SawDustSniffer
4th Oct 2012, 09:56 PM
so you guys seam to think waste oil is hotter than diesel ? , i pulled this off a different site


Natural Gas.....1,030 BTU/cu ft
Propane.........2,500 BTU/cu ft
vegetable oil 120,000 BTU/gal
gasoline......125,000 BTU/gal
waste oil.....125,000 BTU/gal
Kerosene.....135,000 BTU/gal
diesel.........138,500 BTU/gal

hard coal 13,000 BTU/lb
soft coal 12,000 BTU/lb

SawDustSniffer
5th Oct 2012, 01:03 AM
ive started on the foam mold for the furnaces body

i put the glue a bit too close to the edge on the first 2 layers i glued together , there is still a round peace to go on the " top " (bottom ) but i will glue that on last so its easier to compress the sheets together with sheets of MDF while the glue dries
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Ueee
5th Oct 2012, 01:05 AM
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?

SawDustSniffer
5th Oct 2012, 06:43 PM
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

Finn562
8th Oct 2012, 02:57 AM
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?

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MuellerNick
12th Oct 2012, 09:29 PM
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. :o Makes roughly 200 kW.

Nick

epineh
13th Oct 2012, 09:39 AM
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.

SawDustSniffer
13th Oct 2012, 10:35 AM
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


N
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
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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
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SawDustSniffer
13th Oct 2012, 08:46 PM
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
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hopefully i can remove the partical board " form work" from the top after it cools

epineh
14th Oct 2012, 11:18 PM
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.

SawDustSniffer
15th Oct 2012, 06:48 PM
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)

epineh
15th Oct 2012, 07:18 PM
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.

SawDustSniffer
15th Oct 2012, 11:00 PM
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

epineh
16th Oct 2012, 12:04 AM
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.

Ueee
16th Oct 2012, 11:52 AM
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.

eskimo
24th Oct 2012, 02:36 PM
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:doh: