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P1 Group Build?


BenKeith wrote:
Wow, you had to machine a new piece. That was expensive.

Benkeith, there were 2 adapters, I didn't have to start over on a 2nd. Since the roundstock that I started on was longer than I needed, I decided to just cut it in half and make 2 of the adapter plates at the same time for only a little more labor time involved since each machine had already been set up for the prior operation on the first plate.

There is a show coming up this weekend, so people need a lot of stuff done this week. I'll get back to this probably over the weekend... the oversized hoseclamps need to be cut and a small section taken out, then re-welded back at the correct length. And I have to find some sort of cushioning material between the plate and the glass...
Edited by JackH on 09/26/2016 3:27 PM
Well, my next suggestion would be to visit a local hydraulic shop and find a lip seal that fits what you have and cut groves for one or two of those. Problem there is the get dam proud of those things sometimes.

Another option, if you have an automatic transmission shop around, they use a lot of different types of rubber lip seals in their clutch packs and you can just cut one to length to fit, those are fairly cheap but not as stiff as hydraulic if you have a huge gap.
I have a few extra parts now... the top black bezel on the stock unit, and also the black bakelite chimney will be useless in a little while. If anyone needs these parts, please contact me off list, they are free if you pay shipping to where ever you are (US only please). If you are on Oahu we can meet somewhere, no shipping.

The only update I have is, the top of the plate has been drilled and tapped 1/4-20 for three screw holes at 120 degree intervals to hold down either 3 long studs to hold the cap and pyrex tube in place, or else 3 hold down studs (short) for a clamp type arrangement on the pyrex tube. I opted for 3 because we have 3 degrees of freedom; x, y, and z wherein the pyrex tube can shift. (4 actually, if you count a torsional rotation)

Yesterday, I just held the pyrex tube in place and did a bean airlift test (with cold air and green beans), to see how much bean movement I could get, and what my max roast size would be....

Arrrrghhh, the results were less than stellar, very disappointing. it seems my sample size would be limited to 175g ish... looks doable, but 200g BARELY moves. This is with green beans, of course; so after a little drying 200g or even slightly more might be a possibility. But this is still very disappointing... I was hoping for 220g-250g. I'm being limited by the basic design and airflow of the original P1, and if I want more I am pretty sure I'll have to start sourcing parts and going with my own design, like the other people here who have done similar work. :(

I did take some video, but I don't think I need to post it here... everyone knows what slowly moving beans looks like.

Building from scratch does not sound that difficult to do, but what's holding me back is the roast size has diminishing returns and that point appears to be JUST about near the 200g mark.... bigger than that, I won't need (very often), and smaller than that, I can still make up (and have been doing so) by doing multiple roasts of the same bean if necessary. Hmmmph. Let me stew on this awhile. Its hard to jump ship when you've already collected 3 P1's in the garage... the pyrex tubes can be used in the new design, but machining new tops and bottoms would be a lot more work.

Have you put about a 15 degree tilt to it?
Yes, I've experimented with about 5 to around 20 degrees, a little over 10 degrees seems pretty good... but there isn't enough air, especially with coffee that has larger, heavier beans like ka'u, which has the largest beans I've seen. Ethiopians seem to work best, they have tiny beans; but even then I can still do only 200g max, I think. This will work, but I think I'll look for an old vacuum cleaner that someone doesn't want to do some tests....
Are you boosting the voltage? It took me about 140 volts to get to 28o grams
Haven't measured my voltage with a dmm, but yes, I'm using a variac which goes to 140v. I hear the P1s vary in their airflow quite a bit, though; I think I will try one of my other ones and see if it is able to lift more beans than the current one I'm using.
The other thing I note ( working with my new one) is that it's takes more voltage to get the bed moving, than keeping moving. Try stiring / moving the beans a bit to get motion going. PS, didn't do this with my old p1.
UGHHHH! I opened up one of the other P1s and although the owner says it has almost no use on it, there are problems with stuff that people just don't use very often... in this case, there are layers of cockroach egg casings bunched up in the nooks and crannies of the black bakelite lower portion. I was so disgusted I ran the unit under the faucet while scrubbing with a stiff brush (sparingly near the motor)! and its drying out in the sun right now, I want to leave it a few days in the sun before running any current through it...
*SIGH* I've sort of resigned myself to just building another roaster at this point. The only thing that will be salvageable from this project are the pyrex bake a round tubes... to be used just above the new roast chamber so I can easily see what the beans are doing. I guess I can also use the aluminum adapter plate upside down as a top 'hat' on top of the pyrex tube... have to make a new bottom, though, so the pyrex can be joined to the yet-to-be-designed-and-made roast chamber (probably stainless?).

P1 will still be around as my backup roaster, though, in case something happens to the primary, but the sample size will be limited to 150g-175g ish. I'll just use them with the menard's hurricane lantern glass and see if the 'belly' in the glass helps to toss around more beans.
my 3" turbo intercooler coupling hose has arrived, I nearly lost a couple fingers trying to use a large knife to cut it into 3x 1" sections as the 3" section was way too long. Silicon can be cut with a knife, but it ain't fun and my knife is SHARP.

test roast of a couple batches of around 175g-200g turned out so-so with the lantern glass. I had to use more tilt than before, nearly 20 degrees? to get the beans circulating and they aren't going around and around so much as over-under near the top of the tilted portion. P1 does a credible job... but a bit small on the batch size. Will have to make another roaster.


walt_in_hawaii wrote:

P1 now has the adapter plate mounted securely. Now I put the pyrex tube into the adapter; I have to find some insulating material to soften the contact between the plate and the glass so it doesn't crack. Also, the hose clamps I ordered are the WRONG size:

I wouldn't worry about the pyrex cracking, in my poppery 1 I have a tube held in place with nothing but a pipe clamp. borosilicate glass undergoes such little thermal expansion that so long as your clamp isn't way too tight, you shouldn't have any problems.

For your reference: http://forum.home...post_54374
"Grind it like it did you some great injustice!"D.L.Clark
Sorry, have to post a pic when I get home, but I've been using the silicone intercooler sleeve with the Menard's hurricane glass and getting reasonable results with my old P1. I'm roasting 150g consistently, and I think I can go to 175g, given the amount of agitation I'm getting, but I'm still experimenting. I have been using the normal 'router speed control' in the black plastic case which is sold by several different vendors on amazon, I got mine for around $18. It worked fine with the P2, but with the P1 (which uses around 250 more watts) it started to 'time out'.... it would click off in the middle of a roast. I'm running into a thermal barrier of some sort, I think it is rated at 15A. It would take 3-4 minutes to cool down and reset, and gets very hot to the touch. I ordered the 'heavy duty' router speed control for around $35 or a tad more, and have been experimenting; its takes getting used to, this one doesn't go from 0-100%, it only goes from 0-60% roughly so its hard to get it into 1C, I have to flip it to 'full' and do away with the knob... so early part of roast its incremental knob adjustment, then from about 3 minutes I just flip it to 'full' and have to use the fan control to stall the heater a little and come up gradually.

My stainless rods have come in, so I'll start to put together the chamber assembly for the new roaster which will have a little more capacity than the P1.
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