Sand Pot, could it be a salt replacement.

[Natlek]

JTknives , what we find and read on net for this sand pot is for very big sand pot .Think about this , if you make 900mm. Dia and 1500mm depth sand pot you really have a problem to solve with mixing- fluidizing sand .But we need very small chamber and it is much easy to fluidized sand . I don t think that we need special kind of diffuser ?

 

[JDWARE]

some info here:

Handbook of Fluidization and Fluid-Particle Systems

 

[JTknives]

some info here:

Handbook of Fluidization and Fluid-Particle Systems

This is the first book we started researching back in the beginning.

 

[JTknives]

JTknives , what we find and read on net for this sand pot is for very big sand pot .Think about this , if you make 900mm. Dia and 1500mm depth sand pot you really have a problem to solve with mixing- fluidizing sand .But we need very small chamber and it is much easy to fluidized sand . I don t think that we need special kind of diffuser ?

A lot of the fluidize beds for heat treating and high temps out there are actually rather small. Yes there is industrial size setups but also lots that are shop size. We don't want to go to small becaus it will effect its usefulness.

 

[Natlek]

A lot of the fluidize beds for heat treating and high temps out there are actually rather small. Yes there is industrial size setups but also lots that are shop size. We don't want to go to small becaus it will effect its usefulness.

What I try to say is this .They make big size because they most HT irregular form of steel ,say same tool for injection plastic .In that case that object inside / say it is cube shape / disrupts flow of air and sand and that is problem .I even think that because that they using diffuser plate , to spread the air over the entire surface on bed . We HT knife which have a very slim profile which will not disrupt the flow of air and sand and I think that we don t need very large Dia. tube .Today I tried it with 3-inch stainless tube / this is the largest diameter which I can found here , for now / hole in the middle and 2.5bar pressure .I can t see what happens inside but sand raised the level of about 3-4cm and I can easy slide blade inside . I still looking for a transparent plexiglass tube of 4 inch , I think it is best to observe what is going on inside pipe.....

 

[Beanman13]

Natlek I like your idea of a transparent chamber For testing. It will be great for testing different diffuser designs.

 

[JDWARE]

There is a small thread from 2008 on bladesmithsforum on fluidized beds. The thread is titled "High and Low Temp Salt Pots" but it's about sand.

http://www.bladesmithsforum.com/index.php?showtopic=9465

Aldo suggests using "regular Schedule 40 pipe instead of Stainless because the Alum.Ox. is not corrosive" (I assume he means black iron)

Any thoughts on whether or not black iron schedule 40 or 80 will hold up in the heat - 1600 to 2000 F?

 

[JTknives]

Ok I picked up most of the stuff today. Got the tube and plates to seal the end of the forge chamber and the tube. Also got the stainless tube to feed air into the pot. I also scored a box of kaowool that's 2" thick. So we are just about there. Should have a good start on it in the next few days.

 

[Salem Straub]

Funny, I just remembered having seen a video years ago somewhere on the internet... it was a hearth forge idea, like a general blacksmith would have, but the "firepot" contained white sand stuff that looked like lava when hot, and metal was heated in it for forging.
I believe it was a fluidized bed forge, although at the time it simply looked like magic.
I can't find it again, though. Anyone else see that? Maybe I dreamed it?

 

[JTknives]

There is a coal style forge out there that uses ceremic pellets and propane. The pellets are large, think large like crushed gravel. The propane burns inside this ceremic mix and gets hot. You treat it like coal, burry the steel. This is what kinda sent me on this mission, then I saw what peters was using and bam. I have an idea for the bubbler that should be easy to make and zero maintenance. Basically a fludize bubbler cap but a defuser plate on top. Our pots are so small in comparison to some of the large industry size units that we might be able to get away with one bubbler. The trick is to keep the bubbles separate and not to let them coalmanate as thy rise to the top. This is actually a problem that is heavily studied. There are lots of research papers out there on bubblers and columation but thy are like $35 for a download. I will draw up a solid model of the "bubbler" and post it to see what you think. I might need to drag this contraption over to salems house for a proper test. Give me a reasion to play with his power hammer again

 

[Salem Straub]

Any time, buddy! Bring some billets to chomp, too!

 

[JTknives]

Would be fun, I have been wanting to try one of your rose pattern jelly roles.

Ok guys construction has started. First I need a top and bottom disk to seal off the heating chamber. The top is 304 and the bottom is A36. Being that I'm on a budget and that I own a plasma cutter I figure I would save the $100 and cut them my self. Because I used 2 different materials the metal shop wanted to charge 2 set up fees of $45 plus cut time. I said no thanks I will cut if at home with my plasma. So I was scratching my head on how to cut a nice circle. I thought I could use a string and sharpy and make a line and then hand cut that. But what if I connected the plasma to that line. And what if the line was steel.

So this was born, I have 3 holes. Small hole is .25 that takes a 1/4" carbide locater pin and the other 2 fit the tip of the plasma and are spaced to make my 17" and 4.5" circles. I started with the a36 as it was much cheaper to mess up.

It works rather slick if I do say so, so I kept cutting.

First disk cut. As I cut I got a better feal for it and was able to speed up and create a much smoother/clean cut.

Finish is not to bad all things considered.

If I'm being nit picky which I am, I need a 16-7/8" disk and I cut a 17" disk.

Next up was to tackle the stainless 1/4" 304 plate. Because need to use the corners of the sheet I used the cut disk to lay out the optimum center so I had little waste.

Cut without a problem. Stainless cuts different and the dross from the cut is not hard like on carbon steels which makes just popping it off problematic.

Next I wanted to clean up the plasma cut edges and bring them to perfect size of 16.875. So I set up my tool rest so the edge of the rest was exactly 16.875" away from the rest minus half the Diamater of the carbide center pivot.

Next I set the disks on the rest and ground the edge till the center carbide pivot pin touched the edge of the rest. Then I just turn the disk around the center and presto a perfectly round ground surface.

And presto a perfect 16-7/8" disk

Then because I am who I am I set the rest at a 45° angle at a measured distance away from the belt so I could do the same thing to the disks but this time chamfer the edges evenly.

And there we have it. Might be crazy but I take pride in my craziness.

Using the jig I cut the 4.5" hole for the sand pot.

Oh not bad if I do say so my self. I actually measured it with callipers later and it's dang close at around 4.520-4.535.

Here is the pot in the 4.5" hole. Fits perfectly with just enough resistance to keep it from falling out. It will be welded into place to create a sand proof seal.

I also cut out the clearance hole in the bottom disk for the air supply pipe.

I will resume the build in the morning

 

[Natlek]

So far so good . I like your CNC work

 

[kuraki]

Looking good JT.

 

[Van Zanten]

your project is progressing very nice! Good luck!

 

[Kevin McGovern]

I was just listening to a peice on the radio regarding Molten Salt Reactors. Of course I immediately thought, "JT is totally going to build one of those". https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiHktzl8ILRAhULxYMKHWD4C4IQFgglMAA&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FMolten_salt_reactor&usg=AFQjCNGocSsa_tBzPeh86MnBsKe_PEo76w&sig2=kJsZzkiXmPH4lH711oqgrQ

 

[Van Zanten]

what about this: the aluminium oxide grit still is abrasive, doesn't it scratch or slightly deform the objects to be heat treated?

 

[JTknives]

No the grit does not damage the steel. It moves so slow and with such low velocity it does nothing but clean the steel. Thy actually use these to clean steel parts that get contaminated with plastic and other residue.

Ok another update. I had a little time today to work on it. I figured it was to to actually assemble the pot so that's what I worked on. First I marked and drilled the holes for the bolts in the stainless top plate.

Then set the plate and tube on my anvil and tacked it making sure to square the tube up while tacking.

Next was time to run a weld around the entire tube/plate joine. Man I love how stainless welds, very smooth.

Then I flipped it over and welded the other side. I did not need to do this but I'm going to grind and radius the actual pot so I want a nice seamless blend from plate to tube.

Then test fit it into the body and everything look like it lines up perfect.

Next I will weld the gas supply tube onto the base cap and then weld that into the bottom of the pot.

 

[Van Zanten]

Looking good JT!

 

[cdrew]

Any mot progress on this. Very interested.

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