New roaster (600k of photos)

[Dimal]

Re: New roaster (600k of photos)

That must have been very exciting nunu :P, but very expensive .

I bet the tech involved didnt perform that little trick for anyone again... not the best way to impress someone ,

Mal.

[nunu]

Re: New roaster (600k of photos)

Most of the damage was centralised around the caps. The lid and most everything else was still functional. This biggest loss was time cleaning up the mess. Being a simple thing like a power supply, replacing parts isnt too expensive compared to other pieces of equipment in the van. The power amplifier (klystron) was undamaged, and that part was like $5000usd on its own.

[Mark]

Re: New roaster (600k of photos)

Could you tell me if youve had any firther luck with a PC power supply? Thats what Im going to try using next week, before I build it, just to see how it powers the motor? What are your thoughts? Where did you get that battery youre using to power the motor?? And does it just use a standard 12volt charger?

I havent really looked more into a PC power supply, but Ive used them for other things before and there are a few gotchas. For one, most ATX supplies dont have a power switch so you need a way of turning it on. Also they tend to not like being turned on without a load, so it can be a good idea to put in a load resistor so it always draws some current even if nothing else is connected. If this sounds like too much work maybe stick to batteries?

The battery I have was just one I had already, but its just a standard 7Ah gel cell lead acid. You can pick them up at Dick Smith, or any other electrical store for about $30-$40. Your mechanic friend might even be able to give you an old car battery or something? The charger is just a standard lead acid 12V charger, again, Im sure you could pick one up at Dick Smith or Jaycar.

Also - howd you go with heatproof piping, or exaust extension pipe? Did you try any of those??

My wooden holder thingy is working fine, I doubt Ill be changing it any time soon.

Cheers,
Mark

[doxhead]

Re: New roaster (600k of photos)

Nice one Mark, Im well impressed.

Im getting grumpy doing 100g batches every 2-3 days so I might have to have a crack at your design myself.

Luke

p.s. I recognise that fan, that beautiful lovely fan.

[Mark]

Re: New roaster (600k of photos)

Cooling beans is far more important than cooling visiting relatives though ;D

[doxhead]

Re: New roaster (600k of photos)

a solid point well presented.

[nunu]

Re: New roaster (600k of photos)

Hmm...does an evaporative cooler work well for beans?

My relatives tell me to put on a jacket when the temp drops below 20 degrees. I miss home, and havent been back since January 2001.

[AndyCJ]

Re: New roaster (600k of photos)

Thanks for that Mark - Ive managed to wezel a freebee 12v battery from a guy at work, so Ill test out the motor, and then attach it to the pot next weekend (with a bit of luck).

Will experiment with a heatgun and extension tubeing when I get the rig setup.

Did you use an alloy strip for the stirring arm? Whats the melting temprature on alloy anyhow? Im assuming its not showing any signs of melting.

Picks up as I build it I think - so perhaps some next week.

[Mark]

Re: New roaster (600k of photos)

Yup, just a piece of aluminium. Melting point of Al is 660 degC, so it shouldnt be a problem.

Looking forward to the pics. Good luck.

[AndyCJ]

Re: New roaster (600k of photos)

Mark,

Another question. My motor has 4 wires coming out of it... and Ive really got no idea which ones to hook up to the battery? If I just try a bunch of different connections can I blow up the motor? Are the cables color coded the same, and if so, which ones do you connect with which??

A guy at work reacons I could short the motor... which would suck. What colors did yours have and how did you wire it to the battery??

Sorry about all the newbe questions... but itll get there in the end.
Cheers,
Andy

[Mark]

Re: New roaster (600k of photos)

Mine had four wires, I just kept connecting them in pairs until it turned. Actually I took a guess that it would be the top left and top right connections on the plug and got it right first go. Bear in mind that the motor will be quite capable of turning backwards if you hook it up reversed, but it might not spin as freely. So if you get it turning, try it with those connections reversed and see if it works better.

I cant think of anything in a DC motor you could short? But maybe Im missing something. You can certainly short the battery you are attaching to it, just attach one wire and then touch the other wire to the other plug terminals for a second and see if the motor turns. If the wires start glowing red and the insulation melts off them then youve shorted your battery ;D (A semi decent lead acid battery will actually survive this sort of ham-fistedness for a second or two anyway, but I wouldnt recommend trying it)

[AndyCJ]

Re: New roaster (600k of photos)

Mark - again, thanks.

I have got the motor working now, and Ive got to say its a treat to watch... My daughter kept asking me to turn it back on. Theres something very very satisfying about this whole project!

I actually talked to a guy in Dick Smith (David), a new store upstairs in the new galleria on Elizabeth St, right by Burke. This guy knew his stuff, and headed me in the right direction straight away. Red to red first, then try black on each of the other wires till the motor turns - simple. Told me a bit about electricity at the same time! Good to find someone with a brain for a change.

Ill be attempting to fit it this weekend, and then writing a review up with the pictures for next week! Cant wait - quite excited about it all now!!

[AndyCJ]

Re: New roaster (600k of photos)

ok - for you lot who are watching this thread... well, I hit a few snags, and I think Ill write a full "guide" type article once Im done.

But for now, heres where Im at.

I go the engine fitted to the pot, and Ive used a bit of steal for the stirring arm. Its all working (turning) and thats great. I found that if I used standard bolts thou it wasnt so good because the beans jammed between the stirring arm and the bolts. So I replaced them and got the "rounded" type bolts which work a lot better... and look kinda nice too hey!
This is the stirring arm close up, you can see the rounded bolts attaching the engine.


Marks wiper engine has steel mounts, and mine had rubber mounts... not sure how this will go once they come under serious heat, but Ill have to wait and see. They are super tight so the rounded bolt heads are flush with the bottom of the pot.


Another problem was the stirring arm height... its currently a bit high, and once the beans have stirred round a few times, then all end up flat on the bottom of the pot, and the arm rotates ABOVE them!! So Ill be lowering the arm this coming weekend to just above the height of the bolts, or Ill put a skirt on the arm to make sure its moving all the beans about.

Another problem is the battery charger. It does a great job of powering the motor round, but its the type with no on/off switch, and it seems to have an automatic cutout of some sort, so once the arm has turned around about 30 times the charger stops supplying power to the motor! No power, no stir... no good. Im going to introduce a battery in the middle there and that should put paid to that happening.

Anyone got a spare car battery they dont want (pick up from Melbourne CBD)!! Anyone?!!

So, I just did a normal heatgun roast this weekend... but Im hoping itll be my last.

[nunu]

Re: New roaster (600k of photos)

Good old angle iron, nice and solid. So you have a gap between the stirring arm and bottom of the pot, so you can clear the bolts? You could probably twist the angle iron just a bit, so it nearly scrapes the bottom outside the bolt radius. Two problems arise: 1. Inside the bolt radius, beans will still collect under the stirring arm. 2. Steel is obviously not as flexible as aluminium, so tweaking the steel to get it right will take quite a bit of time.

You could leave it as is, and attach a sweep to the flat side, or underside even. A coat hanger could even do the trick.

[Mark]

Re: New roaster (600k of photos)

Thats looking great Andy. How many beans did you try it out with? I found that once I had a reasonable amount of beans in mine, it worked best with the stirring arm a little high, that way it kind of moved the top level of beans around, and their movement stirred the rest. If I put the arm low enough to get the bottom layer of beans, it just pushed the entire bean mass around in a circle in one big pile, rather than mixing them.

Also you might find that once you hook it up the a battery you the motor will spin faster as the battery is more capable of supplying the current for the motor. (In DC motors speed is proportional to voltage, not current, but youll find your charger wont be putting out the full 12V if you are running it hard). That extra speed might make the difference.

Just suggesting you dont go to too much trouble working on your stirring arm until you have the motor running in your final configuration. You might still need to change it, but those changes will be different at different speeds.

The flat head bolts look very nice, Id love to do that to mine, however the bolts on mine screw into threads in the motor itself, not into nuts, so Id have no way of tightening them. Something to keep an eye out for next time I buy a motor.