Author Topic: first furnace build  (Read 6349 times)

Offline tom osselton

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first furnace build
« on: August 20, 2013, 02:46:16 AM »
I've been wanting to build a furnace for years now and the combination of wanting to finish my Dad's engine this is it so far: hey I've been buying tools  :ddb:

 

 and seeing what all you guy's are doing I've made the plunge. I did a bit of casting back in school, grade 8 metal class (of 68) and am just getting to it now ..... better late than never.  I can't take credit for the design I followed Ironman's design It is a beer keg with 2 inch thick fiber insulation type using a blower..  http://madmodder.net/index.php/topic,7802.0.html

 I mixed up some fireclay which cracked as it dried out so I leveled it off with sand and put a single layer of fiber down for the base I figured with the fireclay one layer will be fine and in the pic you can see a shelf for a kiln I am using this because I don't have a crucible yet so I don't know how big to make the recess, if needed I can put another doughnut layer of fiber.  The sides are coated with sodium silicate to glue the 1" fibrefax as it's called here and a second layer  goes on top of that staggering the joints.

 


The lid was a bit of a disappointment I had two lines marked out, one where the top meets the side and the to cut line 2 " lower my son wanted to cut it and by the time I looked the top line was cut, plasma cuts quick! not his fault though.  :bang:  there is also a 4" vent hole in the top. I decided to just lay the fiber flat, it is a rounded surface so I could still get 2 layers in the center area so it was silicone'd and I drilled a few small holes to tie it off with some high heat wire for a kiln from the ceramic store. Worse case scenario I can weld a band to extend it back to the desired dimensions.



The next thing to do is apply a zircon refractory coating I used itc 100,  I mixed it 2 parts water to 1 part itc strange stuff leaves some grit like sand at the bottom of the cup seems to have mixed ok though so i brushed it into the bottom joint.


The blower I had for a long time, actually I don't remember where I got it so there ya go, anyways I found a motor and made a adapter plate for it and it seems to push enough air. I could only find some pipe with a 1" inside dia so that means the flow is being reduced from the get go the blower opening is 2 3/8" it should take the next size pipe so for the time being I reversed the flange turning it down in the lathe to fit the blower the threads still catch for a couple of turns. My thinking is I could unscrew one pipe and screw in the other although the larger probably will not need the reducer. For the fuel line I milled a slot and bent the tubing so it will spray down the center, I also because of the reduced pipe size made a brass jet with a 19 drill hole I figured without using a regulator it would slow the gas down a bit maybe making it last a bit longer it looks ok on the chart and I can run it flat out so maybe a bit bigger I'll see how it melts metal! :D





I didn't know if I would keep the two separate or put on one base so a temporary stand was screwed together out of wood.




This was all purcased at the local ceramic supply store
cost: fiberfax 1" $12.60 per foot
         sodium silicate $8.95 per liter
         itc 100 $100.00 per pint
         fireclay $7.00  2.5 kg
         bentonite vollclay iron free $32.00  50 lbs

I figure it probably cost me about $250.00 the end result is a inside measurement of 13.5" high by 11 " wide, so that's it thanks for looking and here are some pics of it running!















thanks for looking!  :beer:
« Last Edit: August 20, 2013, 08:03:22 PM by tom osselton »

Offline Nigel

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Re: first furnace build
« Reply #1 on: August 20, 2013, 02:40:48 PM »
Hi Tom, thanks for posting the details and pics of your project.  It's a project that I hope to get round to doing some day.  Ever since I read an old 1950/60's book 'Foundrywork for the Amateur' by B. Terry Aspin , I have been fascinated by the idea of making my own castings.  Look forward to your progress updates.  Good Luck!  Nigel
You don't know what you can't do until you have tried!

Offline tom osselton

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Re: first furnace build
« Reply #2 on: August 20, 2013, 03:21:57 PM »
Well I have to say I'm quite happy with it there is a couple of hot spots around the lid but that should be easy to patch once the lifter for the lid is made so the lid can rest in the same spot each time.

Offline ironman

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Re: first furnace build
« Reply #3 on: August 22, 2013, 12:33:10 AM »
Thanks Tom

I did not know that you had started a separate thread.

It looks like it will melt very fast. When you melt aluminuim be careful because kaowool heats up so fast you will over heat aluminuim so easy.

I can see the furnace shell getting hot between the lid and body, you will need to have a kaowool gasket to sit in between them.  Don't let hot gases get behind the kaowool and the metal shell otherwise the kaowool will fail very quickly.

Wow your prices are way more expensive than in Australia.

Zircon paint is sold in 25kg pails which is about 20 pints. It cost $96

Kaowool is sold in a box and the blanket is 25mm thick (1"), 7.6 m long (25ft) 600 mm wide (2ft)  $100 a box.

I photo'd the label of the zircon paint.

Hmmm class of 68 eh , I was in grade 8 in 1968.


Offline tom osselton

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Re: first furnace build
« Reply #4 on: August 22, 2013, 03:11:32 AM »
Well I belive it was grade 8 for me as well Mr Dixon's class. Your price for the paint is way better, I should have tryed shopping around but I just wanted to get it done I will definetly see if I can source it out better. Mine came from a ceramic store about 3 miles from me as well as the bentonite and fireclay. I will fix the hotspot's  for sure there are two the worse one shown the other is just a couple if inches that is with the furnace running flat out with no regulator just a size 19 brass orfice in the tube.  I belive that the hotspot was from cutting the wool  pulling it out to silicone it but not putting it back in the same spot I should have used a reference point or mark. I also have a dimmer switch hooked up to the blower so I can control the heat better.

Offline Mayhem

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Re: first furnace build
« Reply #5 on: August 22, 2013, 09:30:44 AM »
Looking good - thanks for posting

RobWilson

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Re: first furnace build
« Reply #6 on: September 27, 2016, 02:59:28 PM »
Hi Tom


Did you get an further with your dads engine ? 



Rob

Offline tom osselton

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Re: first furnace build
« Reply #7 on: September 28, 2016, 04:04:34 PM »
Hi Tom


Did you get an further with your dads engine ? 



Rob
I haven't touched it in a while, I bought the piston rings but was not sure what size gland material or what type temperature wise, I bought some off one site and recieved what looks like yarn covered with graphite and found a place with 1/4" square high heat packing but I'd have to buy the whole roll  :doh: but I'm going to have to get back on track and carry on. I did buy a couple tools for rolling in boiler tubes off ebay just because they could be useful and had to check them out.
Mainly I have to stop playing Juan Valdez and get off my ass!  :)

RobWilson

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Re: first furnace build
« Reply #8 on: September 28, 2016, 04:12:49 PM »
All in good time Tom   :proj:

I must have at least 10 unfinished projects at this moment in time  :Doh: 


Looking at the cylinder castings it looks an interesting engine .


Rob