My little J

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Re: My little J

Postby Bobwieser » Wed Feb 25, 2015 6:47 pm

Towards the end of hot burning I saw some black smoke. I was hoping it was from the galvanized P-channel or parts of the patio heater, it had a sulphur like smell.
I looked in the base of the riser today.
Image
Bummer, A little or a lot over the maximum service limit. What remains is hard so I'll keep using it for fun. It has lost the proper dimensions but I'm OK with that.
Bottom line is the base of the riser gets over 1600F for sure.
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Re: My little J

Postby Bobwieser » Tue Mar 24, 2015 10:15 am

My little J is going to get a little shorter. I'm going to cut the top of the tunnel off the original and fit a new core into the soft insulating material that is left in the metal box.
Here is a mold of a shortened 6" J.
Image
Image

Those are 2 pics of the same side. It will have 2 halves.

The core will be 1 1/4" thick except the top of the tunnel will be 2" thick.

I have an angled trip wire, a cutout in the feed for a P-channel, and a pointed kick tail.

I have dense refractory rated to 3200 F. I want it to be strong so I can move it at times. Or replace it for experiments with castings from granite dust mixes I have been tinkering with.

I'm tempted to add perlite into the refractory mix for insulation and volume to cast both halves with 1 50# bag.
Any suggestions for how much perlite to add and keep the strength? I hope to cast before the end of this weekend.
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Re: My little J

Postby WiscoJames » Tue Mar 24, 2015 12:46 pm

Morning Bobweiser -

I am wondering whether your patio heater threw much heat off to the sides with the reflector and the piece under that. It would be nice if one could throw one of those together without fabricating parts. I have a feeling the propane ones provide a lot more heat. What was your experience?
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Re: My little J

Postby Bobwieser » Tue Mar 24, 2015 1:18 pm

James my patio heater was 40,000 BTU propane. It' been broken for at least 3 years so I can't say side by side comparison. I do think it put out more heat with wood. I did push the little J hard to get the flame up to the top and have the perforated ring glowing hot. It did feel nice without the glow, it beamed the heat further with the glow. When I have my casting done I'm going to try a deflector in the middle above the riser to see if I can get a glowing ring easier. I'll post the results.
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Re: My little J

Postby matt walker » Tue Mar 24, 2015 3:07 pm

Bob, first off, COOL! Love what you are up to, and that patio heater is so neat.

So, I think the biggest factor in these things tearing up refractories is heat cycling, really quick transitions from cold to hot and back. So, if you are really going for durability it's not impact or the like but tensile strength we want to increase, so adding stainless needles is probably where you want to go to try to keep that thing together. I wouldn't add anything else to the mix other than those. Perlite will throw off their careful balance and it won't be the same stuff, and you have plenty of insulation in the surround.

Like so.

Looks like a well designed core casting Bob, can't wait to see it!
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Re: My little J

Postby Bobwieser » Wed Mar 25, 2015 12:32 am

Yea Matt I figured that to. It means about 60# of refractory so I'll have to use more than 1 bag, that's one reason I was thinking of adding perlite. I'm not going to order and wait for needles as I don't have the patience for that. I'm saving my patience for the curing of the refractory. It's for fun and I know that I am violating the basics dimensions but I figure without a drum it might work. If not I'll grind away the kick tail to open up the riser. Wish me luck.
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Re: My little J

Postby Bobwieser » Sat Mar 28, 2015 11:06 pm

I filled my new mold this Thursday afternoon with a Low Cement Castable (LCC) refractory. The same as " My first casting". No stainless needles or perlite so it's dense and non insulating. My mold is 3 7/8" deep so I filled and vibrated it 3 times to remove the air bubbles since there is a tripwire ,P-chanel and kick tail and all have small cavities. I put the molds on an inflated motorcycle tube for vibrating, sorry no pics of that but I hope you get it. The refractory has a shelf life of 1 year, I got it for cheap as over stock and have had it for some time. I know it's well over the 1 years time so I let it sit for 2 days and kept it warm while I waited so impatiently. Today I carefully removed the outer part and broke apart the innards. I think it's going to be OK.
Here is the cast straight on.Image
This is from the riser end showing the angled tripwire.[img][IMG]http://i1320.photobucket.com/albums/u529/bobwieser/2015-03-28_13-24-54_765_zpstxlhlyjs.jpg[/img][/img]
This is a top view of the 2 halves resting together. [img][IMG]http://i1320.photobucket.com/albums/u529/bobwieser/2015-03-28_13-38-58_168_zps4w66v8ls.jpg[/img][/img]
I'm still keeping it warm and will soon heat it to drive out the remaining moisture. I'll post the results of my Redneck Patio heater.
I don't know why but it looks like only 1 pic comes up the others are links to my Photobucket. I hope all can see them if interested.
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Re: My little J

Postby thickstrings » Sun Mar 29, 2015 12:24 am

Looks like a nice casting Bob. What are your plans for the insulation?
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Re: My little J

Postby matt walker » Sun Mar 29, 2015 12:39 am

Looks great Bob, I bet it will rip.
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Re: My little J

Postby Bobwieser » Sun Mar 29, 2015 5:01 pm

Thanks TS and Matt.
Were you able to see the other pics?

For insulation I'm going to cut a cavity into the soft refractory that I made the first little J with.
I might do it this afternoon and set the patio heater top on again.
I'm thinking of burying the core and set it up for cooking. I'll post results as I go.
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