Hello from Ontario

Discussion in 'New member introductions' started by Bldr J, Jan 1, 2021.

  1. Bldr J

    Bldr J Copper

    Hello from Canada.

    I have zero casting experience, but watched one of my clients cast a bronze sword and was instantly hooked, I never thought it was within the realm of the hobbyist.

    I am in the beginning stages of building a propane tank furnace, but am having second thoughts on the design/process, thinking it may be too small for some of the items I may want to cast. I'm a contractor/designer/tinkerer and like to suggest things to my customers that don't exist or aren't readily available, leaving myself to figure out how to make it...I'm now on the hook for making a shower valve trim plate and accessories for a copper shower I'm putting in. I had a machinist set to make it for me, but am thinking casting might be more appropriate.

    I have a crucible (A5) some 2" ceramic wool, some petrobond like material and a few bags of Unicast 70 which was recommended, but I now feel has too much thermal mass. I was able to pick up some Charles Hones "Buzzer" burners out of a salt-bath furnace which I'm hoping to use with propane as the fuel (for now). I also have a Charles Hones 55 forge/furnace (natural gas) that I'd someday like to hook up.

    I have some rudimentary metalworking skills, can weld, and am currently learning how to use my baby CNC lathe, but nowhere near skilled.

    On to making the furnace now...or researching...
     
  2. Tobho Mott

    Tobho Mott Gold Banner Member

    Hello and welcome to the home foundry from just outside Ottawa ON, Bldr.

    I have a furnace I made using Unicast 70. Did you get yours from from Smelko Foundry Products in Milton too?

    It does have a lot of thermal mass to heat up, so it can seem a bit slow if you will normally be doing just one pour starting with a cold furnace. However once heated up it holds that heat well. I use mine with a powerful waste oil/diesel burner

    If you cast a thin hot face (1" or less if you think you can manage it) to wrap in a couple inches of ceramic fiber blanket insulation it will help it get up to temp faster than a monolith of solid refractory, while remaining very durable.

    That said, my lighweight furnace with a much thinner painted on hotface of Satanite is even faster even if I just run propane, and definitely my go-to when I am just doing one pour that day, and that is the cast most often. But I expect it will need to be repeatedly patched up and have its lining repaired now and then, whereas I expect the unicast lining to outlast me. It's got 5 years on it and still in like new condition aside from a hairline crack or two that occurred on its initial firing and hasn't gotten any worse since.

    I have build threads for both furnaces linked in my sig if you want to see how I did it, both with and without using Unicast 70.

    I'm not familiar with the Charles Hones equipment you mentioned. Pictures please!

    Jeff
     
  3. Bldr J

    Bldr J Copper

    Thanks for the info Tobho Mott!

    Yes, I got the Unicast 70 from Smelko, I had enough of debilitating analysis, so I thought I'd just ask at Smelko, thinking the unicast might be an insulating castable, or that I could put a thin face of it. I can't seem to find any tech info on it, and don't really need/want a furnace that will last for ever if I outgrow it, I have enough "first projects" that don't seem to die, and are too good to throw out. The Unicast is probably a better long-term bet for a furnace for durability, but casting is not my main hobby/business. How much longer does the furnace take to heat up when made of Unicast vs. Satanite? I'll check out your previous posts thanks for the tip - were you able to get a 1" face with the Unicast? Did you trowel or cast it?

    The Charles Hones burners look(ed) like this on the salt bath furnace (I only got the burners and nat.gas regulators - couldn't lift the rest):

    IMG_0096 (Medium).jpg

    and the furnace that I have is this:
    IMG_0097 (Medium).jpg
    All running on low pressure natural gas...

    Thanks!

    Josh,
     
  4. Tobho Mott

    Tobho Mott Gold Banner Member

    There's really no comparison when starting from cold, by the time the unicast furnace is preheated enough to switch over from burning propane to oil, the satanite furnace nearly has the metal up to pouring temperature. However that is using the same burner and settings, and the satanite furnace has a much smaller bore to heat up. It can fit my #12 crucible at most (but I usually use a #6). whereas the unicast furnace makes the #12 look kinda small. So that is another big factor that plays into it which can not be ignored. I was happy to use it until I found out how much quicker my more portable newer furnace gets the job done when starting from cold. But I think for a crucible that is not so undersized for it (or a furnace that is not so ovrersized), the unicast would keep up a little better.

    I cast the 1" hot face, but that isn't to say I could actually "pour" the stuff. I scooped in a couple inches at a time of the very thick and dry mix and used a long steel wand chucked into a reciprocating saw to vibrate it into place. Vibration makes the stuff flow like it's a lot wetter, it's really surprising. This is all covered in the oil furnace build thread.

    Jeff
     
  5. Bldr J

    Bldr J Copper

    Thanks Jeff for all the info. I have to say I was a bit disappointed and frustrated when I specifically asked for insulating castable refractory and was told this was better...also found out that the blanket I got is not rated as high as I thought - it is Durablanket, 2150F recommended, 3200deg melting point. Is that what you used under the Satanite in your newer lightweight furnace? Great videos and I found your previous comments on AA...seems like you went through a bit of what I did, 5 years ago.
    The lightweight seems to be the way to go, for me at least. I'm going to source the Satanite out. Thanks so much for your help, videos, etc.

    Josh.
     
  6. Tobho Mott

    Tobho Mott Gold Banner Member

    I used a 2600F rated ceramic fiber blanket for both my builds, at least the innermost layer. The Red Dwarf (satanite furnace) has 2300F blanket for the outer layer because I ran out of the 2600 blanket. I bet you would be fine with the blanket you have, behind an inch of that castable. If you don't line your furnace with Unicast, you can at least use some of it to make some crucible plinths.

    FWIW I have no regrets about building my heavier furnace with the 1" dense hot face. It's a little clunky to preheat with my small burner and it's large size, but I would like to get more use out of it in the future when I can hopefully spend more time in my foundry.

    And if you think the Black Dread has a lot of thermal mass, you should see my even bigger furnace! The lining is about 8" thick and from what I can tell it's just solid dense castable.

    Jeff
     
  7. Jason

    Jason Gold

    Josh... what do you consider low pressure NG??
     
  8. Bldr J

    Bldr J Copper

    Hi Jason, low pressure natural gas < 1 psi for me, probably closer .25 psi in a residential line? I looked up the burners I have, and for the one furnace which I will be (or at least I'll try) using the burners from is actually a high pressure burner, due to the arrangement of the outlet of the burner and the valve assembly, so it looks like I'll be using propane. Thanks for prompting me to check..

    A closer look at the burner
    IMG_4290 (Medium).jpg
    and the assembly it came with:
    IMG_4293 (Medium).jpg
    tells me its a high pressure burner...
    image_123927839 (Medium).JPG
    so I'll use the propane regulator I have from my large torch (up to 15 psi). I did see in the Charles Hones catalogue that some can run naturally aspirated on low pressure, but not the one I have, it might be older technology compared to blower-based designs.

    Thanks,
    Josh.
     
  9. Jason

    Jason Gold

    7" WC here is typical here. I have yet to see a commercially built furnace setup to run on low pressure. I run a ng forge on low pressure with a ribbon burner, but would love to run my furnace on NG. Next to induction, it's probably the last frontier for us metal casters.

    You can try propane, but it might require dicking with the orifice on your burner. Give it a whirl. ;)
     
  10. Zapins

    Zapins Gold

    A foundry out in sacramecalifornia ran their furnaces off natural gas. Seemed to work well.
     
  11. Jason

    Jason Gold

    SO does Barry in Baton Rouge. But he has a 7psi 2" gas line in his place! I've seen it, it's bad ass! When you have to measure pressure in inches of water column you know it's small. I fart with more pressure than what comes out my gas lines. (note I said GAS lines and not ass lines!)
     
  12. Zapins

    Zapins Gold

    Ya its not always available in every town. I wonder if it's available here at my place. Hmm...
     
  13. Peedee

    Peedee Silver

    You may find the company meter will physically restrict the volume of natural gas available, they are typically bellows type with sliding valves.

    The supplier can install larger meters but it is usual over here for that to be only for commercial premisis (Resteraunts etc.)
     
  14. OMM

    OMM Silver

    I doubt it. If you're on a residential property you are restricted to 7 inches of water column, which is aboat 1/4 psi.. Most residential properties are restricted to less than 1 1/4 to 2" interior branch line.

    Each branch line has static restrictions depending on the length of the line, and other appliances taking draw.

    Yes it is a good chart, but you need to account for other branch draws.
    A6C730ED-E340-4334-8242-0718D314A26F.jpeg
     
  15. Jason

    Jason Gold

    My gas guys told me it's all up to the meter. But getting them to up your pressure by changing out your regulator on it is not going to happen. You havent had to go through the ass pain of adding a gas line, getting a sign off from a plumber, doing the leak test and then had to beg the city guy to get off his lazy ass to come look at a gauge so you can get your heat turned back on. Trust me, its painful! If you want high pressure gas, rent a place in an industrial area cuz you ain't getting it at home with out bleeding some cash!
     
  16. Zapins

    Zapins Gold

    Sounds like I'll be sticking with simpler options and saving for my milling machine instead :)
     
    Jason likes this.
  17. OMM

    OMM Silver

    In Ontario there is no chance in hell a residential property will get anymore then 8 inches of water column pressure after the meter. I personally have a 1 inch main trunk that enters into my residence with 3 90° elbow's and a 10 foot trunk. Every 90° elbow has about 5 foot of static restriction. So, at the end of my 10 foot pipe trunk, with static restriction is aboat 25 feet at the end of the 10 foot trunk. Using the chart above, I am really choke down to 224,000 BTU distributed through my whole building home.


    if you are considering adding more load, a very mathematical calculation needs to be done. This was my simple chart for my load calculation. you can’t really skimp on this. but, you can work with seasonal or off demand devices.

    0DC2C17F-FCF6-4DB7-8F6C-D4553F67FFFF.jpeg

    If you have been playing along and understand, I cannot use all my devices running simultaneously. it's almost impossible for me have all my appliances running at full bore unless I had all my windows open in both shop and house, cooking for a party of 20 and 2 to 3 people taking a shower.
     
    Last edited: Jan 7, 2021
  18. Peedee

    Peedee Silver

    There is a really simple way to get better flow through a meter but I'm not telling. One of the guys I worked with dealt with meter fraud and I was amazed by how ingenious yet simple people can be.
     
  19. OMM

    OMM Silver

    With natural gas metres it is almost impossible, unless you break the seal, which in my area is checked every month. Our metres are big nonferrous poppet valves.
     
  20. Jason

    Jason Gold

    Yeah I knew a guy that had a 400k pool heater HOT TAPPED into the line before his meter!:eek::rolleyes: I do not recommend this! Pretty crazy to see a large pool go from 45 to 95 is less than 24hrs!
     

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