Grateful

Discussion in 'New member introductions' started by bill, Jan 21, 2021.

  1. bill

    bill Silver

    Like the title implies I am grateful that a resource like this exists. I retired at the end of 2019 and in the early months of 2020 needed away to stay busy or go insane. I had a vision of creating some silver castings using the lost wax method. I already had some silver. 42 years ago I had the opportunity to store 40 gallons of used darkroom fixer/hypo at my disposal. At that time I used steel wool and steel re-barb to cement the silver out of the acidic fixer solution. After drying the powder it leaves a black silver powdery substance. Without the capital to buy silver I started with the 40 year old silver powder and a oxy/ace torch and brought the silver back to 99 fine. Over seven troy ounces so far.

    Living on a fixed income created some challenges. I had thirty years of junk laying around to start with. Old propane tank? How can i cut this apart I thought. LOL Yes in the beginning it would take hours or days just to find the next best thing to use. Now I work a part time job to support this venture. I have been casting for about a year now. Somewhere between 50 and 100 castings. I cast hand carved pieces that are rather small, less than 1x1x1” to about 1x2x3” horses and jeeps mostly. Also small plaques carvings.

    When I realized I couldn’t figure it all out myself. I bought a book. (Lost-wax Casting: Old, New, and Inexpensive Methods) by Fred R. Sias. This is a great book for any beginner that is financially challenged. I knew at that time I was on the correct path. His book did more to confirm that the processes I was already using were indeed common. I thought if the ancient casters could figure it out than so could I.

    The next reference material I used almost exclusively is the U.S. Navy Foundry Manual 1958. At this point my castings were becoming much better. Christmas presents for the wife’s friends.

    I mostly do lost wax casting using commercial investment. I have made many different investments using plaster as the main ingredient with other cements added. I also use homemade green sand, Commercial bought Delft Clay and Petrobond with whatever I can find, build or modify for a mold box/flask.

    My foundry setup is pretty simple.

    Propane Tank using propane fuel. Ceramic fiber insulation coated with thinned down refractory cement (propane furnace only electric is just ceramic fiber).

    The first setup was a low pressure regulator (the only thing I had) feeding the acetylene side of an old oxy/ace torch handle with compressed air feeding the oxy side. This setup worked well believe it or not and came from old things I had laying around. Free.

    The Second setup was more common. I use a 20lb regulator a 3/4” x 8” black steel with 1” flares both sides the outside flare has three bolts to hold the nozzle. T-valve for on/off control. The nozzle was a square plug with a 1/16” hole hand drilled in the center (sort of) then soldered closed. Using a red hot .030” sewing needle to make the final orifice.

    I also made an electric furnace with a PID controller for temperature control. I limit this one to 2150˚f. But use it mostly for mold prep/burnout @ 1350°f

    I use ceramic crucibles for silver and clay graphite #3 and #4 for copper, bronze or brass.

    I always wanted to use pure copper but find that is one nagging problem. Now I mix my own bronze and use different percentages of tin, lead, pewter with and without lead, aluminum and zinc. Mostly copper and tin. 90%-10%

    So yes I am grateful because I know the answers to the next phase of this journey will be here somewhere.

    Thanks
    Bill

    Maybe I should have titled this “Holy crap I can’t believe I typed all of this”
     
  2. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Heck of a first post Bill but welcome.....you're among kindred spirits.

    Best,
    Kelly
     
  3. bill

    bill Silver

    Thanks. I doubt I will ever type that much again. LOL
     
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    Hello and welcome Bill...
     
  5. crazybillybob

    crazybillybob Silver Banner Member

    Welcome Bill.
    Hopefully you will add some pictures to your future posts (to save all that typing....and to keep some of use that don't read so good engaged);)
     
  6. HotRodTractor

    HotRodTractor Copper

    Welcome. There is much to read and nuggets of info to learn around here.
     
  7. Welcome Bill! I've already learned two things from you. Thank you!

    Punching a needle through a soldered closed hole is a good idea. Maybe not for several thousand hours of service but great for firing a furnace.

    The other idea is using an oxy/acetylene mixer to make a small burner. Great idea and I've got several laying around. I should melt them for the brass but they were too expensive.

    We all learn from each other.

    The downside is this is not a very good place for know-it-alls. They soon demonstrate they don't.
     
    Petee716 likes this.
  8. Tobho Mott

    Tobho Mott Gold Banner Member

    Welcome to the home foundry. It would be great too see some pictures of your gear and castings!

    Jeff
     
  9. bill

    bill Silver

    Thanks everyone. Here was todays project. I will also upload some other picts in the appropriate areas.

    I wanted away to measure the temperature of the melt. So I drilled 30mm into the center of a graphite stirring rod with a 9/64 bit and sanded and tapered the end. Then inserted a K-Type thermometer through a carbon fiber shaft (crossbow bolt I found in the woods) and then inserted into the carbon rod. Glued together and coating the carbon fiber shaft with refractory cement. Hopefully it will hold up for at least one or two 2 minute duty cycles. I have a K-Type in the furnace at the edge of the insulation and want to compare the two temperatures.

    IMG_2984.JPEG IMG_2986.JPEG
     
  10. Petee716

    Petee716 Gold Banner Member

    Welcome Bill
    Boy, your already a lot deeper into this than most new members. Just goes to show we're not the only game in town, but we've got a helluva good game just the same!
    This discussion just reminded me of something. I was recently at Praxair swapping gas bottles and the guy there mentioned a trade-in deal from Victor. If I recall correctly it was $50 off a new torch with a trade-in of any old cutting torch in any condition. I dont need a new one right now but I thought I'd pass the info along.

    Pete
     
  11. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Hey Bill, from your first post it sounds like you have both a propane fuel fired furnace and a resistive electric furnace. I'd be interested in hearing a little more about those, and a few pictures would be great.

    Best,
    Kelly
     
  12. bill

    bill Silver

    WARNING | DANGER
    LEGAL DISCLAIMER AND ANY OTHER LEGAL JARGON WE CAN COLLECTIVELY THINK OF SO YOU DON’T DIE AND I DON’T GET SUED.
    Do not build this unless you are insane or don’t mind death by electrocution if you are careless.

    Seriously this has zero safety features on the furnace or the controller other than a simple unprotected on/off switch and thats only used when I need to take the lid off so the element isn’t shorted from metal flasks. Most connections are non shielded open buss blocks.

    So. Here are a few picts of the electric furnace and my hand drawn schematic. To be honest this would be great for melting anything that benefits from a neutral atmosphere but I use it almost exclusively as a burnout oven for burnout cycles with the lost wax projects. It is more valuable for that use. But it will hit 2000° in five minutes when running in 240v mode.

    The furnace is separated for the controller by one romex wire and male plug. The controller is wired for 110 or 220v. There is one outlet that uses one dedicated 220 volt receptacle and the other uses 110 volts depending on what temperature range is needed.

    I started with a single temp controller but quickly realized I needed one with ramp and soak functionality.
    Now I use an Auber SYL 2352 Ramp and Soak with 30 programmable steps. I cant remember where I bought the heating element but it was relatively cheap. I think under $20 for two 30” coils. The coils need to be stretched. Mine are about 3-5mm apart and totaled around 13 feet. I am sure I am missing something but its late. I started this earlier but had to pause to melt and cast a new piece. Pictures below.

    These picts are named but I am not sure if you can see the titles.
    The first five are the rough build. No pictures of the lid but its insulated and held in place with bolted pieces of flat steel. The other pictures are the controllers and schematic.

    extra fiber.JPEG empty can.JPEG first layer.JPEG refractory cement for rigidity.JPEG another inch of insulation and coil.JPEG 1350°F.JPEG first controller.JPEG second controller front.JPEG second controller back.JPEG schematic.JPEG button.jpeg still wet from the bucket.jpeg
     
    Tobho Mott and Mark's castings like this.
  13. Jason

    Jason Gold

    Bill I stuck a graphite rod in my electric kiln too. It didn't last that long at all. Here is a cheap thermocouple that you can stick in and leave. After all, it's never fun to pull out. :(

    https://www.amazon.com/Uxcell-a15063000ux0338-Stainless-Temperature-Thermocouple/dp/B017LB3BQA/ref=sr_1_15?crid=3UOYE17GRNET7&dchild=1&keywords=type+k+thermocouple+probe&qid=1611379987&sprefix=type+k+ther,aps,201&sr=8-15

    Welcome by the way. Nice death trap ya built there. lmao. I never stick anything in my electric kiln with the power on to it.
     
    Last edited: Jan 22, 2021
  14. OMM

    OMM Silver

    Did I miss something or did you miss something? Where is the full unedited video? Pictures are fun, and we do love them. But we love unedited videos even more!
     
  15. bill

    bill Silver

    Sorry OMM no video. Haven't graduated to that step as of yet. I will work on it. Thanks Jason someday I will post pictures and a description of the real death machine I created last fall. Centrifical casting machine designed for 4x8" plater flasks. Used once almost burnt the house down. LOL
     
    Tobho Mott likes this.
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    How many amps at 240vac?

    I have a 10" bore furnace that I use primarily for resistive electric melting and a 14" furnace that I use primarily for heat treating, but they both could be fuel fired. The 14" just has a removable electric section. I have two coils for a bout 8kw total. They have a few more bells and whistles than yours.

    http://forums.thehomefoundry.org/index.php?threads/the-furnace-thread.276/

    I use the Auber controllers too. They are basically the same thing as the other imports but higher priced, but their manuals are clear and understandable and Auber supports them, so they get my business. Looks like you are set but don't splash any metal on your coil. It will alloy and fail in short order. Ask me how I know! I wind my own coils......much cheaper. You can just buy the resistive wire from pottery supply houses by the pound in any size/material/power level.

    Hopefully you wont need another but if you ever do, short video of the coil winder here:
    http://forums.thehomefoundry.org/index.php?threads/furnace-fail-reconstruction.209/page-3#post-3670
    Here they are in the latest incarnation of my furnace.
    http://forums.thehomefoundry.org/in...w-mass-electric-furnace.607/page-4#post-16069

    Thanks for the post.......keep'em coming.

    Best,
    Kelly
     
  17. bill

    bill Silver


    Thanks I had one of those. It lasted once in the melt. But that is an awesome price and I may just buy one for the future. The one I built is going into the molten copper to get actual temps. Then I can compare that to the internal thermometer in the furnace. It's really just for reference. I believe some of the defects I have can be attributed to over heating. Especially when there is a lot of dross. This will get used in the propane furnace since I do the bulk of my melting in there. I plan to build another electric 240vac using my first controller and I will need a better design than what I currently use.
     
  18. bill

    bill Silver


    Kelly. That is one flippen furnace. WOW. The coils look awesome. Are the coils fastened into the grove in any way or does the tension hold them in place. I thought I would have to fasten mine but they stay in the grove from the tension in the coil. To answer your question about current I would have to say 12.5 amps. And I don't melt very often with the electric. Currently it is too valuable as a burnout over for the molds. I plan to build a dedicated electric furnace for melting but that's in the future. I think it would help a lot with my continued quest to use pure copper for some of my castings. Certainly help eliminate some atmospheric challenges with additional oxygen and hydrogen being absorbed into the copper. I am certain there are well known ways to eliminate those issues. Just not known to me at the moment. LOL I will read this forum like a good book. Like I said before the answers are in this forum.

    I would also like to thank everyone who reached out to welcome me and I look forward to a great education.

    thanks again
    Bill

    Here is the description for the coil I am using.
    uxcell Heating Element Coil Wire AC220V 3000W / AC110V 750W Kiln Furnace Heater Wire 7.2mm800mm 2PCS
     
  19. Jason

    Jason Gold

    Oh NO Bill... It's not for dipping in the melt buddy. But it's perfect for measuring inside kilns. If you want one for dipping in the melts, get the mifco. I just bought one and it's better than jacking around with graphite rods. Worth every penny. Wish I bought it sooner. Stick it on a 4buck chinese type K meter and you are good to go.
    Check out this thread. http://forums.thehomefoundry.org/index.php?threads/do-you-measure-metal-temperature-and-how.1344/
    https://mifco.com/shop/pyrometers/replacement-8-thermocouple-tip/
     
  20. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    In my original electric furnace the walls were insulating fire brick and I did anchor the coils every 90 degrees with a hook shoved into the IFB. In the latest molded fiber version the shelves have a slight downward angle and they just sit in the shelves. I overstretched the coil slightly on original install so they compressed, but over many cycles they tend to shrink.......they actually expand when heated and I've seen some grow out of there grooves, but mine seem to stay well captured upon heat, but when they cool they shrink, but the grooves are deep enough and with the slant, they don't shrink enough to pull out of the groove. Those coils are Kanthal (FeCrAl) which doesn't have much hot strength compared to NiCr but has higher operating temp and life.
    I use my 10" bore almost exclusively for aluminum melting though it's also seen various other low melt point metals. I think it would do brass and bronzes but the moldable ceramic fiber has max service temp of 2300F which is about the same as the Kanthal A1 coils, but is it is really well suited for Aluminum. It is very air tight and I think the interior actually becomes oxygen depleted to a degree. I say so because when melting dirty metals, it's very common to get a flash when I open the lid. At worst it is air and either way that is a happy furnace atmosphere for aluminum. For copper alloys, I would think you'd want as little O2 as possible, so that would put that theory to the test....or just use cover fluxes as needed depending upon the alloy.
    I've built this same furnace in IFB, Dense Castable, and Modable Ceramic Fiber, and the latter is my favorite, then IFB, then Dense Castable.

    If I was to do it again, or what I'd recommend to someone who wants to build a resistive electric furnace, would be to use 2600F ceramic fiber board. A little pricey depending upon furnace size, but if you used 1.5"-2" thick planks, cut a hole with a recip saw the size of the desired bore, then use a round nose/core box router bit to make the shelf into the board. You could use a rabbiting bit for just a square shelf but with the core box bit, the coils could be retained when you stack (but don't glue) the layers. The outside of each layer could be cut round or left square.....just depends on how you'd like to package it. For the base and lid, just use a piece of solid board. It's very light. You should mask up and machine the stuff outside.

    You might put a very thin layer of mortar like Satanite on the surfaces for extra durability but I might hold off on that. That fiber board is completely unwetted by aluminum.

    Here's a source I've used.

    Ceramic Fiber Insulation Board (2600F) (2" X 19.7" X 39.4") Thermal Insulation 816183020137 | eBay

    For the coils, you could wind one that just had a straight section to jump grooves, but I think you'd be better off winding separate coils, run a straight lead outside the insulation, then you could connect them in any number or combination of series or parallel you desire, and if you damaged one, it's easy to replace by disassembling the stacked fiber board layers.

    That's fairly decent power. Each of my two coils are ~16amps @ 240vac or 4kw each. They are 14ga Kanthal A1. When I designed it, I used the recommendations in the Kanthal handbook at the link below. I get finer control when operating one coil. Since it's a lift off furnace, I can get an A20 in that 10"bore, and it gets a very up close and personal look at the radiant heat from those coils.

    https://www.kanthal.com/globalasset...-elements/resistance-alloys_s-ka041-b-eng.pdf

    On the subject of contact pyrometer, $53 is a pretty good deal for the MIFCO K-Type probes. I think they are coated with SiC. I use graphite rods over an Inconel sheahted k-type. If you only use them to dip, you'll get several hundred dips.....I do. If you leave them exposed to air they will be reduced by the O2 in several hours. I'm on my 4th since the beginning of time and I accidently broke two of the four by walking into them since they hang on my furnace cart. The 5/8" gouging rods are a little over a buck a piece and if you have K-type wire can be a very in expensive contact pyrometer. Many Digital Multimeters have a k-type port and will read temp in C of F directly.

    Best,
    Kelly
     

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