Chapman HT oven WIP

D dmcmd : You've sure got me bit by the bug to learn more. If you have a chance would you check these two items to confirm they're what I need? Amazon item # B0C8LV6VNZ for the RasTech Raspberry Pi 4 4GB Starter Kit (or would the CanaKit Raspberry Pi 4 4GB). Both these kits contain the 3 amp power supply, but since the 7" display is powered from the Pi, I was planning to order a 27 watt power supply. Perhaps make a comment about which, The RasTech or CanaKit you'd prefer? The CanaKit folks sure have been around a while, and I don't know anything about RasTech, but that doesn't really mean anything since I've been away from uC for a while

Also this B07VNX4ZWY (ROADOM 7’’ Raspberry Pi Screen} for $60.

Edit Sat morning: Shucks, I just placed the order for the above using the CanaKit. After all, didn't cost me anything, just spending my daughter's inheritance {g}

While I did like the idea of copper heatsinks of the RasTech kit, CanaKit has been around longer so decided to go with that one. I suspect either would be just fine.
 
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K Ken H>

I bought my raspberry pi 4 4gb for $75 on amazon 7 weeks ago, and I thought that was way too high. No way I would pay the current amazon prices for it right now. They should really be about $50.

To run the oven controller, I would be able to do it on a raspberry pi 4 1gb model since the controller app on the pi is very lightweight. They sell those at microcenter in houston for $35 right now.

The Roadom 7" screen IPS 1024x600 is the one I have.

I doubt there's any difference between rastech and canakit.

The power supply I'm using is a meanwell MDR-60-5. Probably way overkill for this project, but it mounts on a din rail next to the other stuff I'm using as well.
 
Well, I saw you used a 4gb Pi 4, decided to stay with that size. I didn't know how much computing load was required with the PID code. I saw the bare Pi was less expensive, but with my starting knowledge I thought I'd start with the kit figuring it would have everything I needed, and help me get started with some basic programming. Ideally I'd just wait and see if perhaps you might release your code really to load up and run (please, please) {g}. BUT, I still like to have a basic understanding of what's going on. I'm a pretty good program designer, but have always struggled with the coding.... just don't do enough of it.
 
Here is where I am on the door. I'm again making a frame within a frame design. The inner frame will hold the firebricks, and they'll be rabbetted so they protrude up and out of the frame to lay against the face of the oven. The second outer frame will then hold ceramic wool over the top of the fire bricks, and clamp it down between the two frames, so really, the ceramic wool will be up against the front of the oven and it won't be brick on brick. I think this will provide a superior seal on the front. Both of these frames will screw down onto a panel built exactly like the back panel of the oven. So it is all removable and adjustable.

The weather has now made a turn for the worse in Houston, so I'm probably done for this weekend. And next weekend I'm busy, so it may be a few weeks before I get anything else done here unless I can spend some time on it after work during the week.

Note in these pictures the fire bricks are not in the inner frame so it looks like the ceramic wool is flat. It won't be. It'll stick up and over the firebricks that will be sticking out.

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Ken H> said:
Well, I saw you used a 4gb Pi 4, decided to stay with that size. I didn't know how much computing load was required with the PID code. I saw the bare Pi was less expensive, but with my starting knowledge I thought I'd start with the kit figuring it would have everything I needed, and help me get started with some basic programming. Ideally I'd just wait and see if perhaps you might release your code really to load up and run (please, please) {g}. BUT, I still like to have a basic understanding of what's going on. I'm a pretty good program designer, but have always struggled with the coding.... just don't do enough of it.
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K Ken H>
As of right now, the program has never been run to control anything. It just looks good. I'm pretty sure it'll work, but it is going to have to go through months of debugging to make sure everything is perfect before I let anyone else use it. Also, I took a trip to microcenter and bought one of those pi 4 1gb models to make sure what I said before was correct. I'm sure it'll work, but I want to prove it. I was there anyway buying a pi5 I'm putting into a drone, so I figured I'd pick one up. Probably not a bad idea to have a backup anyway.
 
Scrolling thru Amazon's listing there's only $2 or $3 difference between the 1gb Pi 4 and 2 Gb Pi 4. On Amazon the only Pi 4gb I saw was $130 vs the $150 I paid for total kit. There are better prices on ebay.

Those are some NICE screen displays you've built for the
 
Ken H> said:
Scrolling thru Amazon's listing there's only $2 or $3 difference between the 1gb Pi 4 and 2 Gb Pi 4. On Amazon the only Pi 4gb I saw was $130 vs the $150 I paid for total kit. There are better prices on ebay.

Those are some NICE screen displays you've built for the
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K Ken H>
Yeah these prices are really ticking me off. I bought a pi5 8gb today for $175. It had three (!) price tag stickers on it, one on top of the other. The middle one said $125, and the bottom one said $95. So microcenter had it out on the floor for $95 at one time and just kept raising the price to go along with what other people are selling them for, even though they paid whatever they got it for initially that allowed them to sell it for $95 in the first place. All us little guys are just getting messed around by the big guys. Maybe I should just go fishing instead…
 
dmcmd said:
Maybe I should just go fishing instead…
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Don't go fishing just yet - they are several of us that are really interested in the controller/software for this project. After it's finished, THEN you can go fishing {grinning broadly}

I've lead this thread a bit off topic, would you mind emailing me sailingtoo at gmail.com - not sure that really does any good for email harvesting, but it does seem better than actually writing out the complete email address {g}
 
When you do get this all figured out, I'd love to know how to do it myself! :)
 
RAM prices are skyrocketing because of the stupid AI craze so prices of all computers are going up as well. Retailers often raise prices to cover the cost of re-stocking the product. It’s terrible, but the tech bros don’t care.

Back on topic, this is a very cool thread and project. Thanks for sharing.
 
Finished the door today (minus the hinges and closing mechanism). My least favorite part of metal working is tapping holes. I've messed up enough projects with broken taps that I'm always apprehensive about it. Today I only had to tap 12 and they went just fine. Then I put sheet metal skins on one of the frames and the front of the door. I think this door design will work. It's really heavy, though.

Next, I'm going to lay out the electronics and start working on the control box. It might be a week or two until I post again, as I'm busy this coming weekend and can't work on it.

Here's some photos of the door.

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That is surely is going to be a well build solid oven. That door is really solid. Comparing to my EvenHeat door it's amasing. The EvenHeat door only has a sheet metal (SS) band the width of the firebrick that hold the brick together. So far it's holding up good, but it's not near so solid as your door. Any idea what your oven is going to weight when complete? My EvenHeat is only 18" long while I "think" I remember your oven is going to be 24" long?

You're surely doing a good job of documenting to make it an outstanding WIP. Keep up the great work - especially the software part {g}.
 
Ok. I'm ready to start collecting parts for mine. I think I want a ~18x4x4 inch chamber.

Where's a good place to buy bricks and ceramic wool. I haven't found anywhere in my area that stocks them.
 
I bought mine online from Axner. K-23 is what I got and they were the real deal.
They came pretty well packaged for shipping them and I think they were decently fast.
 
Ceramic wool is easy to get from Amazon. I made the mistake of getting the cheap K23 Fire bricks from Amazon and they insulate horribly! Oven took longer to get to temp each time I used it!

I found 3" thick real K23 about a 100 minute drive each way from me at a pottery supply place; the 3" bricks were the same price as what I paid for 2.5" garbage bricks on amazon.

Maybe take a day trip and try to pick some up? The Potters Center in Garden City Idaho lists K23 in stock. Spokane Washington has a lot of pottery stuff; some of those places may be able to tell you where to look locally if you call around. They will often have to order a pallet of them, but if they do kiln repair, they may have some extra left over. Shipping the bricks often costs as much as the bricks themselves!

Another option is to look at FB marketplace for a used kiln and reuse the fire bricks? The tops and bottom of a kiln often have uncut bricks in there.
 
Good to know about the Amazon bricks. I have a couple of emails out to a couple of places in Spokane but I haven't heard anything back yet.

I'll revisit them with phone calls in a day or two.
 
Stick with a name brand/manufacturer in the US. BNZ is the brand of the bricks I got; I believe they are in PA. There are other manufacturers around the US like Morgan Thermal and one in Boston, Massachusetts, as well as others in the US. Imported bricks will be hit or miss and make sure you get the soft IFB, not hard fireplace bricks!
 
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