Almar;
The link you posted http://pyrotechnic.narod.ru/Black_Powder.pdf I read in the last couple of years. The good thing is, the guy has a lot of good information, but the bad thing is, the guy has a lot of good information. haha
He can confuse a person about as much as he can help you not be confused. I guess one of the reasons, he is based in Pyrotechnics and maybe not so much in shooting. All in all it's a good read, but there is a LOT of information to digest in that article.
Es
Testing the kiln with PID prototype....more to follow.
It looks pretty ugly right now, but if this works I'm going to make it all nice.
Oh yes, it works, the PID learned the system quick, it keeping it right at 560deg with a couple of degrees. I chose 560 deg for a test because 550 is where cellulose degrades and I didn't go higher in case it overshot before the PID could react. Now all I have to do is figure out how long I need to let it run and its a set it and forget it, ultra accurate system. Very happy. It will get some more insulation with kaowool and get a permanent location tomorrow. Will increase the input wire gauge too.
Oh man! Yeah it's ugly! Jeez... what's wrong with you Almar??Originally Posted by almar
Es
Testing the kiln with PID prototype....more to follow.
It looks pretty ugly right now, but if this works I'm going to make it all nice.
;~)
Just kidding!! Nice work, and I'm glad it worked! Congrats!
Details on the build??
So, the critical speed on ball mills is very real, and depends on ball mill jar diameter as we know. I just got an interesting lesson on that.
I have a batch of powder in the little Harbor Freight tumbler jar, and it didn't quite finish tumbling before the tumbler motor went *****. I needed to finish it, so just now I threw it on my "Treadmill-Tumbler".
I set the speed at TLAR, (that looks about right), and away it went. Then I thought "No, that seems too fast", so I slowed it down some. When I hit the right speed, I knew it immediately because all of a sudden I could hear the media properly crashing in on itself inside. It is much louder when it's properly milling!
Edit to add: I can't tell from the pic how you built your kiln. I had decided that if/when I build one, I would make it top loading and without a door. Removable top. That way the heating elements would surround the item being heated completely, and possibly heat more evenly...
Vettepilot
Last edited by Vettepilot; 10-02-2021 at 07:44 PM.
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
They used to use metal bands to hold shipping boxes together. (Now it's mostly plastic bands.)
But those metal bands would be a great way to hold a kiln like yours together. They used to sell the tool to ratchet the bands tight and the clamps fairly cheap...
Vettepilot
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
Vette, its a pretty easy build. It took some figuring to find the right coil. I made it from 18 gauge kanthal wire that I made into a coils at .25 in. diameter. and stretched it out to 71 inches to separate the coils. This gives me 1255 watts about 11 ohms and 10 amps. I put the spreadsheet I made to figure it out up here and a picture of how it looks from above while its on.
Last edited by almar; 10-02-2021 at 08:18 PM.
Nice!! Great work!
Designing mine in my head, I'm a bit stuck on how to hold the heating elements in place. You can route out a groove for it, but how to hold it in the groove? It's gonna want to move around a bit, heating and expanding, etc.
Is it my breath? I don't seem to get much response to my posts...
(Except you guys Almar and Double Buck.)
Vettepilot
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
Might be because you guys are so far out in front of us newbies. I keep saying one of these days but have so many things that need to be done first. Really impressed with what everyone has contributed and/or ran with. Nice jobs folks and thanks.
I was a little cheap with that hose clamp but I feel that kiln cement is a better way to go. I ran out of it for the corners, I need 2 lbs for this I got only 1. I just made square grooves with a big files but make them angled to better seat the coil, what I did on this one today was cut 0.75 inch pieces of that 18 gauge wire and forced them in the brick with pliers to peg the coil in along its path.
@MrWolf: Hey, if you can carve out the time, jump in and try it. It's very satisfying when you light off a test sample, and/or go shoot, powder that you created yourself. And you get to save money too!
I too am very busy and it's hard to find time, but it's worth it when I do...
Vettepilot
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
Ah. Didn't realize that was a hose clamp. That's a good idea, but wherever did you find a hose clamp that large??
A lot of people build them with no cement; just clamp the whole thing together.
Vettepilot
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
VettePilot;
Did you ever work that charcoal up? I saw Harbor Freight has a 'clearance sale' on their Dutch Ovens and I've been wanting one, for a long time. I think I'm gonna spring for one, today. I like my paint can retort, and they're cheap, but I'm thinking the thicker cast iron will heat more evenly and hold the heat longer. Let us know how your charcoal comes out!
Almar;
That's a cool rig you built! I bet it works killer. Let us know when you start cooking with it. My hat's definitely off to you guys who can actually design a dang electronic component. I've never understood how you can do that.
I don't know if you had to order your components (kiln cement), but if it will work, a lot of places sell wood stove cement. The last I bought I got from Ace Hardware, actually. I have a buddy that has a home made kiln, and he used a dryer element and used bailing wire to hold his bricks together. It seems to work great for his use. Again, looks have never been an issue for me. Gain of Function is what is important. I heard that somewhere....
Doublebuck. I tried it yesterday for a test and adjusted today for things that I noticed yesterday. I moved it in the shop on a small table with casters, I put some ceramic tile on top of the table and a layer of kaowool. I move it outside when in use. I used it today and charred a full can of willow. I bring it up to 500 degrees without the PID and then shut it off, it coast to 580 and then drops, when it drops I plug in the PID and leave it be for an hour. I charred it at 570 today and it stays right at that give or take a degree or two. The charcoal is great, all cooked evenly and has a 1.9 % ash content and has a dark brown color. Total cook time is 2 hours.
I like this because it give me the option of trying different temperatures accurately, allows me to free up my time instead of constantly watching a thermometer and makes my charcoal very consistent from batch to batch.
The problem I thought of with wood stove cement is that it has large particles in it, maybe I can just sift them out. The dryer element would work, I just needed to design it to optimize it for longevity, power, and keep the amperage low enough to not jump the breaker. Plus doesn't the dryer need 220v? I was limited to 120v.
Last edited by almar; 10-03-2021 at 05:05 PM.
Almar, I love the idea of a PID. My setup is just a gas burner with a tap, sitting in the bottom of a plain old Weber kettle; the retort is an 8-litre soup pot with a thick bottom sitting over the burner. The lid of the pot is gently wired down, and the screw hole for the knob is the vent. I can't burn the off-gas except by taking off the lid and holding a soldering torch to the vent. I just ratted a BBQ thermometer for it from a neighbour's verge rubbish that goes up to 550F.
Your kiln looks great Almar. What do you use as temperature sensor? I have been seeing rigs like this with nichrome heating wires inside made as burnout kilns for lost wax casting using very simple bimetallic strip controller technology, and pottery kilns also have a huge pool of expertise for home builders.
Vettepilot, the metal strapping is a good idea for a kiln strap, but the tools used can apply a very high tension that could easily crush firebrick - they are for retaining a half tonne on a pallet during all the stresses of shipping. My trade uses them for holding stacked drill core on pallets which absolutely positively must not get spilt. Without that high tension they don't do sharp corners al all well, so I think you would be as well using tie wire with twitches, even if its looks are an insult to engineers everywhere.
The 'traditional' 1960s way of holding the firebricks in a form, is sheet metal folded into a box and spot welded.
Last edited by ChrisPer; 10-03-2021 at 08:31 PM.
Chris, i use a K type thermocouple. Its the same PID i use for my lead casting. I use it for all kinds of stuff, its pretty useful. I decided to go with Kanthal 18 gauge because its more durable than nichrome apparently and about as cheap. IT was easy to spool on the lathe with a long 1/4 inch rod. its holding just fine now as it is and i wont be moving it around so i guess i don't need to work at it more. I really like the control i have with the temperature. I may improve a few things eventually with the containers i use to cook the charcoal...time will tell. I don't know how hot this thing can get, i may try to make it peak one day for heat treating O1 or other tool steel.
Almar, I'm not sure about most dryers but on mine the heating element runs off one side of the breaker and all the controls and motor run off the other. The reason I know that is one time my dryer quit heating, but would still run and blow cold air. I took the cover off the heating element and it was good. On further inspection, I had a breaker went bad, and burned half of it up. It's a wonder it didn't cause bad problems, because it smoked half of the breaker. I had to pull it and clean the lugs and put a new breaker in the panel and it worked fine.
Your kiln charcoal sounds excellent! 1.9% ash content is surely excellent as well.
Last edited by DoubleBuck; 10-04-2021 at 02:41 AM.
@Doublebuck:
Oh yeah, you'll love the Dutch Oven. Works great! If you're going to time your cook, you'll have to allow for the time it takes to cool down after removing the heat. It takes quite a while.
I drilled and tapped mine for two 1/4" pipe plugs for vents, and a hole for mounting the thermometer. Dutch Ovens are normally made of cast iron, but I don't know what this one is made of, as it's very hard. Probably powdered metal. Doesn't matter; it acts like nice heavy cast iron as regards cooking, it was just harder than I expected for drilling and tapping. Real cast iron is easier than this was.
The red cedar chip black powder is great! Very fast and very clean. I've got to drag out the chrono for some other testing at some point. I'll let you know when I chrono this powder.
Vettepilot
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
Regards the red cedar wood chips. I bought this large bag at Walmart one day on a whim. I don't recall how much it cost, but it wasn't very much. At first I thought it wasn't going to make very much powder, but I was wrong. The chips are packed into the bag very tightly so there's more there than I thought. Taking out enough to make a half pound of powder took less than 1/4 of the bag. It's "Pet's Pick", 24L size that I bought.
So, if you're having a hard time finding good wood, it's definitely a better than nothing option. (Free wood being better, if you can find it!)
Add: Cedar is popular for fencing, and also for cabinetry/storage. If you know a business doing that, you might get scrap for free...
Vettepilot
Last edited by Vettepilot; 10-04-2021 at 01:31 PM.
"Those who sacrifice freedom for security, have neither."
Benjamin Franklin. (A very wise man!)
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