Home made roaster

[nunu]

Re: Home made roaster

Youre not talking about the big, IR temp guns are you?

If you want a pocket sized one, theyre cheaply gotten at a Radio Shack or even Best Buy might carry them. If there are any locally, Frys might be a good place to look as well.

[Javaphile]

Re: Home made roaster

Hhhh.....The small one is all Im looking for. I tried both Best Buy and Radio Shack here a year ago looking for one with no luck at either and the closest Frys is halfway accross the country unfortunately. I may end up having to resort to ordering it on-line and paying the shipping.

Java "Always looking for a new toy" phile

[Javaphile]

Re: Home made roaster

A quick update. I stopped by the local Radio Shack today to check on their IR thermometers and the only one they had was $50US and had a max temp of 400F.

Java "Still looking" phile

[Framey]

Re: Home made roaster

Ive got an IR temp gun. I bought it for Heat gun roasting. It isnt too bad, but seems to register about 10*C above what my thermocouple shows at the same stage. I think the one I got reads up to 615*C  It seems to help if you get fairly close to the beans. They are handy but not super accurate. They dont like reflective surfaces.
As long as you use the same temp gun you will be able to log roasts.
The most important thing is that it is another roasting related accessory  

[Javaphile]

Re: Home made roaster

The most important thing is that it is another roasting related accessory

But of course!! ;D : 8-)

Java "Points to his sig" phile

[AndyCJ]

Re: Home made roaster

Hey Framey.... hows progress??

[Framey]

Re: Home made roaster

Steady as she goes Andy.

I test fired the burner set up a couple of nights ago, a couple of moments of uncertainty with gas flow, but once flowing properly it seems like the new tap adjustable gas injectors are about 8mm too short     I will have to muck around a bit because I had to drill the the burner brackets out a tiny bit to accomodate the new (too short it seems) injectors. If I can get the burners working properly with some adjustability Ill be very happy.

I took the various parts of the roaster to a friend that is currently a coffee technician, and used to be a gas fitter, I wanted to get his opinion and advice on the setup so far. He told me Id need more air flow than the smallish vents would be providing. As a result Im putting legs on the roaster and drilling quite a few holes in the bottom to increase the available air in the chamber.

I spoke to a bearing/transmission guy and after many concerned looks from him the solution for allowing the front protruding part of the drum to spin, is to bolt on a block of Polytetrafluoroethylene or PTFE or Teflon and allow the drum opening (50mm cylinder) to spin on it. The back end isnt as big an issue. I need a flange, a piece of stainless rod, a 12mm bearing and coupling device to join the 12mm shaft with the motors 8mm shaft.

I need to get a small chimney with a butterfly valve made up and the vanes welded in.

I drilled lots of holes in the end cap of the drum last night. Drilling stainless steel isnt much fun.

Oh, and I want pick up a small bench of some sort to bolt the roaster to.

So all in all a fair bit left to do, but a good couple of days mucking around and I could get most of it done.

Happy Australia Day one and all  

[AndyCJ]

Re: Home made roaster

Not so good about the injector length, but unreal about the other stuff - especially good advice from a mate in the trade!
Couple of questions.
Doesnt PTFE have a melting point of 335degrees? Would your roaster ever run hotter than that?
With airflow, youve just got 2 gas jets lit? and the flame pulls air through the vent/holes - then the end of the drum is pierced with holds, and the air comes out the front of the drum (and out the chimney?) - am I getting it right? Theres no other "air flow" other than holes yeah?

Instead of the gas injectors do you think you could use one of those cheap cast iron "Camp stoves" that hook onto a LPG bottle, and have that inside the box (with the bit with the tap on the outside of the box of course?) - Or are the gas injectors cheap too?

Did you make up plans? Im keen to get down the local steel fabricator and ask what sort of cash hed charge... how much was your fabrication (do you mind me asking?!)

Its a real inspiration to get into a bit more tinkering! Thanks Framey!

[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  

[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

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

[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 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.

[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

[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