Help me make another attempt at shell casting

Discussion in 'Investment casting Ceramic shell method' started by 01binary, Jul 2, 2018.

  1. Jason

    Jason Gold

    2.80 a pound? That's getting close to what sil bronze can be bought for if you look hard enough.

    No denying Andy the binary01 has done an exceptional amount of work. We still dont know what he's using as an alloy. In the beginning, I made tons of ingots of anything aluminium. One day, I'm either going to anilate some big texas ants or put them all in the trash.
  2. Zapins

    Zapins Gold

    Yeah that's what I thought too. Crazy prices.

    Bronze is 4 something now per lb. I think 4.30ish if I remember what I paid the other day.

    I've always wanted to pour an ant hill. Especially those fire ants. I'll show you some real "fire."
    Jason likes this.
  3. 01binary

    01binary Copper

    I got the new shells prepared in half the time thanks to the advice I got here about putting several coats per day, but then my forge stopped working. Did anyone experience an issue with propane tank no longer working with the 1-60 PSI high pressure regulator all of a sudden? I've been reading and watching YouTube videos on propane check valves this entire week, but nothing is helping so far.

    The last thing I did is using a steel cutter and welder in the same room as where the forge was stored so it's possible debris got in the propane lines - but I just replaced my propane tank, the QC coupling from the regular to the tank, and then the regular itself. The last two things I have left to replace is the forge burner and the hose. When I disconnect those two and just blow through the hose, it comes out strong on the other end at the burner, so it doesn't seem clogged - and everything else is already replaced.

    Even if I open the connection to the tank slowly, something keeps shutting off the pressure when I get around 50% of the full power (I guess that would be around 30 PSI). This has never happened before with this same forge and any tank.
  4. Zapins

    Zapins Gold

    My money is on a clogged nozzle hole.

    Clean it out with a welding tip wire cleaner. Propane has some sort of oil in it that builds up inside the drilled hole of the nozzle as it is used. Also debris in the pipe is forced into the nozzle even if it looks clean it doesn't mean it is clean. I have had the same issue many times. It's always a clogged nozzle hole.

    If this happens during use where the pressure slowly drops off and the outside of the bbq tank has ice on it you need to warm the tank in a bath of warm water (larger bucket of water). Propane needs heat from the environment to help the liquid propane inside the tank enter the gaseous phase. If it doesn't have access to that heat because of ice build up then it can't put out as much propane gas and you get lower pressure and lower temperatures.
  5. 01binary

    01binary Copper

    I tried the nozzle again and I guess my impression was wrong last time, it does seem clogged. I bet the gas just builds up inside of the hose because it doesn't have enough outlet, and that causes the valve to check. I will look for the welding tip wire cleaner.


    Back from Airgas, they said I would have to cut the forge burner apart to gain access to the outlet hole, and even then the problem could be in the valve just before it. Looks like I have to order a new burner and wait for it to come in.
    Last edited: Sep 19, 2018
  6. Al2O3

    Al2O3 Administrator Staff Member

    01, Happen to have a picture of the burner? A naturally aspirated propane burner is a pretty simple device. Sure you could get some repair help here.

  7. Jason

    Jason Gold

    I don't trust a damn thing any clown from airgas tells me. They sell the stuff and seldom use it themselves.
  8. 01binary

    01binary Copper

    I have this burner:

    Today I cut the nozzle out of the burner tube and cleaned the 1mm hole with welding tip wire cleaner, but no difference. My next guess is that the problem is with the last cut-off valve fitting right before the nozzle. Two years ago when I got this forge, the same guy in the Airgas store crimped that fitting onto the hose that originally came with some weird German fitting. I also sort of destroyed the nozzle when I cut it out of the burner with a steel cutter. I guess I could re-weld it and patch with high-temp putty, then get a new fitting and re-crimp... I will try that next while I'm waiting 2.5 weeks for the replacement burner to arrive. I will get some pics tomorrow.
  9. Zapins

    Zapins Gold

    Just get some pipe from home depot and drill a #57 hole in the tip of a pipe cap. Done.

    You'll have to order that bit size. It isn't commonly available.
  10. Jason

    Jason Gold

    I agree. Screw buying a burner. It all comes down to the regulator anyways.
  11. Tobho Mott

    Tobho Mott Gold Banner Member

    You might be able to find a variety of those tiny sized drill bits at a decent hobby shop, if you don't like to wait for stuff to ship. People use them for building models etc..

  12. Zapins

    Zapins Gold

    I'm pretty sure I saw the small bit sizes (#57) for sale at horrible freight near the grinding wheels and consumable products. Might check there first.
  13. DavidF

    DavidF Administrator Staff Member Banner Member

    Yep, their metric drills. I've used them for cleaning the nozzle on my 3d printers.
  14. Zapins

    Zapins Gold

    There's a good idea. I. Going to have to file that away for my next nozzle clog. Super frustrating until I figured out it was the nozzle.
  15. 01binary

    01binary Copper

    I replaced every part of the system, and finally traced the problem to the regulator. I don't actually understand the construction of high pressure (1-60 PSI) regulators, but there is a nut opposite the "T" handle that adjusts spring tension. There is a valve that can be closed by that spring, and it's sandwiched between the handle and the nut on the opposite site, so the spring can be compressed or extended either by turning the handle (which screws in) or by turning that nut. Anyway, even on my brand new regulator the handle does absolutely nothing, but unscrewing that nut results in full 60 PSIs instantly when you get past a certain point. The drawback is propane leaks when that nut is unscrewed (and of course I loose all control over the pressure), but since I have no other ideas I will keep using it that way.

    I should be able to pour both of those shells this Thursday.
  16. Zapins

    Zapins Gold

    You could get an inline needle valve from ebay to control the pressure better if you like.

    Surprising the issue was the regulator.

    I use a Mr. Heater regulator which I think is 0 to 30 psi. Seems to work alright. Was cheap to buy too.
  17. Jason

    Jason Gold

    I'm not. It's the only part with moving pieces. The low pressure one I bought at lowes is a chinese piece of shit. I'm sure the slightly larger ones are no different. If you want a decent regulator these days you have to shell out a grand. I'm no stranger to grabbing my ankles when it comes to regulators. I've got this one and it's passable at best. Seems to always be out of calibration when we get it checked. I should have spent another 400bucks, live and learn.:(
  18. Zapins

    Zapins Gold

    Dear god that's money.

    What about the 2 stage regulator they sell at air gas for 80 bucks? You can buy 10 of those for the price of 1 in that link. Food for thought for us poor peasants!
  19. 01binary

    01binary Copper

  20. Jason

    Jason Gold

    Most regulators can be stuck on a 3000 psi bottle, but most cannot service 2500 psi. This is just an example. Any new regulator that costs less than 100bucks should be #1 suspect when an issue arises. Good stuff costs good money. I tried bumping up a low strut once and didn't pay attention to the regulator I had on the bottle. As soon as I opened the valve, pop went the regulator and down came the airplane. It was on a saturday morning and the pax were there waiting to depart. Live and learn!

    01, Powder coating removes off aluminium the easiest with "Aircraft Remover" Then send through the bead blast cabinet.
    If you need to remove anodizing off aluminium, it's liquid plumber. Use the non enviromentally friendly stuff.

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