Home made roaster

[Javaphile]

Re: Home made roaster

Those burners look really cool in the night shot Framey! 8-) 8-) 8-)

Java "Go Go Gadgetbot Roaster!" phile

[AndyCJ]

Re: Home made roaster

So is the PTFE like a dounut shape? and the end of the roaster goes through it, and its bolted to the front?

In theory, could the back mounting support the entire drum, making the PTFE redundant? Would 1/2 inch hold the weight of the drum and beans, or would it be too much?

Man - the burners look unreal at night alright.

[Framey]

Re: Home made roaster

Better view of the back end.
Lots of drilling...
The drive shaft is basically a big bolt with a couple of coaster sized washers for support.
The bigger holes in the coaster   will hopefully allow chaff to exit more freely. In theory the beans wont be that high up the drum and therefore wont fall out... I can see the holes clogging up with chaff though hmm
The guy at the bolt shop assured me that I would be able to machine the thread from the rod and still have a shaft that is half inch in diameter > he was wrong. You can see that between the bearing and the coupling the drive shaft at half inch still has a fair depth of thread on it. I dont think it matters, but Im not a fan of false assurances.

[Framey]

Re: Home made roaster

The new, more simple drive system.
Threaded stainless which was supposed to be 14mm... has been machined down at one end to fit the coupling. Half inch was the smallest bearing size the guy at the bearing place wanted to sell me, so the drive shaft had to be half inch. The shaft from the motor is 8mm so I need a coupler that was half inch on one side and 8mm on the other.
You can see the stack motor there too.
The white thing on the nose is a machined piece of PTFE (teflon) It will be bolted onto the outside of the housing and the nose of the drum will spin on it.

[Framey]

Re: Home made roaster

More photos.
I just like the way the burners look at night

[AndyCJ]

Re: Home made roaster

Damn! Good luck on that one dude, its gotta be great knowing someone who can machine stuff. I know a welder, who built me some stuff relativly cheap in the past, but I think Ill try the local shop first, they did a couple of mods for me already. Last one was drilling a 0.1ml hole through a hex screw so I could try microfoaming.... but thats another story!

Good luck, and thanks for the measurements - Ill be adding them to the plan.

[Framey]

Re: Home made roaster

Andy, Im not the messiah Im just a very naughty roaster  


2 burners fit under the category of better to have and not need. As you may be starting to guess Im just making this up as I go along. Ive read BTU/Mj figures for successful BBQ roasting etc but really just hoping it will be at least enough. If it turns out to be too much heat I can turn them down or increase available air or just disconnect one. Im going to check out thermocouple probes today.

Size of enclosure just relates to the drum you want to use I suppose. My enclosure is approx 320mm deep and 280mm wide.  About 500mm high at the front and 460mm at the back due to the slope.

Capacity Im guessing will probably max out at 700g, but tough to work out. I usually roast 3 or 4 batches in the old colander so maybe between 600g and 1kg a week. But I always mess up the timing and end up supplementing my supply with some beans from a local roaster. I use a fair bit of coffee but I probably only drink about half of it. Im always mucking around with micro blends and dose levels, so lots of experiments I dont end up drinking  :-[

Im heading to Tamworth for the weekend and taking the bits of the roaster on a road trip Ive had a change of heart on the drive shaft to drum configuration (thanks Steve), so Ill be getting my father in-law to machine a couple of things and help hook up the motor and a switch. With any luck Ill come back from Tamworth with the drum rotating in the housing.

[AndyCJ]

Re: Home made roaster

Wicked - thanks for that Framey. Ill check out those places, but probably wait till you get it fired up like you suggested. Avoiding the same hickups will be the key (also saving cash 2 I guess).

Is there a reason youre using 2? Wouldnt one be heaps in the enclosed space of the SS box? They sure look like they would do the job.

Ive got my plans done - but wanted to know if youde be happy telling me some of the basic measurements of the box - I saw the drum measurements at the top of the post, but wanted to go to the steel fab guy armed with measurements so he can cost it.

Any idea about capacity Framey? Im guessing itll easily do 500g at a time, but are you aiming higher than that? How much are you using a week at the moment? Im doing 500 in the 77Roast, and using it in just over a week (9-10days). the only thing I want changed really is the bean consistency - getting an even roast - then working on repeatability too.

So many questions... and plenty of time.

[Andy]

Re: Home made roaster

...you can wait till next christmas if you like Boris... I want one well before that

Nice work Framey. Thanks for sharing with us... you DO have a following

[Boris]

Re: Home made roaster

Dear Framey,
I imaging there are about 1/2 the members watching this masterpeice come together all thinking the same thing. I want one! I hope you have alot of spare time, would you be interested in knocking up about 500 or so? No pressure, before Christmas 06 would be fine, I could wait till then. ;D

Very impresive. Puts my Mc Guiver setup to shame :-[

Boris

[Framey]

Re: Home made roaster

The burners are made by an Italian company called Polidoro.

They were $54ish each. The ones I got are 50mm in diameter and 300mm long and are all stainless. The place I bought them was called Combustion Instrumentation, but Im sure any gas related company would be able to source them. Let your fingers do the walking  
There is a Gameco in Vic and maybe try combust.com.au Just guessing?

NB: They are unproven as a heat source for roasting coffee. I think the Mj/h rating was 19? Until I actually get them under a drum full of beans I wont be sure. The one burner managed to heat a wok up over 200*C fairly easily, but they are still an unknown quantity roasting wise. They were recommended to me when I described the application to the seller.

[AndyCJ]

Re: Home made roaster

Framey - did you just buy that from a shop? If so, can you send me the details of what you brought to save the hastles of having to learn all about it? What shop did you get it from again? Wonder if theres one down here in Vic??

Man-o-Man, that looks COOL.

Im doing plans tonite on the train - and gonna talk to the steel guys next week.

[Framey]

Re: Home made roaster

The first shot shows the flame probably a bit more orange than it really is. Im still working on air mix.
Second burner photos.

[Framey]

Re: Home made roaster

Just some photos of one of the burners fired up.
The original cast iron burner stove thingy I bought about six months ago is now makes for a nice support for the new burner whilst testing

[Framey]

Re: Home made roaster

Sorted the injector today. Ive got the original ones back in now, so in theory all should be well.

From what Ive read PTFE can operate at 260*C not sure what actual melting point is. The block of PTFE will be bolted on the outside of the box, so it wont be exposed to super high heats. I might use some insulation board as a gasket/heat shield.

The main airflow will be from the front of the roaster ie the open end where the green beans go in and pour out. That air is cooler outside air so it acts more to dampen the heat and drag smoke and chaff through the perforated rear of the drum. Once the smoke and chaff exit the rear of the drum hopefully it will be drawn upward and out the chimney. I might end up running some ducting from the chimney to divert the smoke.

I originally bought a dual ring burner cast iron burner on legs. I intended to build the roaster around the burners but in the end I think you are better off deciding what drum size/capacity you want and then buy a burner that fits the job. I wouldnt say the gas injectors on the camp type stoves are too cheap. They actually had really good adjustability.

I found that wherever I went that I needed plans. If you rock up to most fabricators or engineers with a vague descriptions and just verbal explanation of what you need, they dont want to know you, which I fully understand. I got quite a few
" If you bring me a drawing with the appropriate dimensions Ill make it, but Im not going to design it for you", comments :-[   I also found building scale models helped heaps when it came to showing them what you mean.

Money wise it will depend on lots of variables. Stainless got pretty expensive if you went thicker than 1.2mm. The fabricator I used was really good with design suggestions and seemed genuinely interested in the final product.

-Enclosure fabrication was $380 That included drum work, insulation board ($30 ish a sheet?), lots of stainless rivets and angle.
-Piece of stainless pipe was $50

When I add up what Ive spent so far it is a bit scary, but if and when I roast that first batch Ill forget all about it... for at least 10 minutes anyway