|
Heat Gun...Max Capability?
|
| freshbeans |
Posted on 08/07/2010 09:05
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
What's the most coffee I could hope to roast with a heating gun element?
(under 12 minutes) -Scott |
| |
|
|
| seedlings |
Posted on 08/07/2010 09:11
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
With my breadmaker I can easily get 1.5# of coffee to the end of first crack in 12 minutes. 1.25# in 10 minutes or less.
I roast with the lid closed, so it should be fairly efficient (read: max).
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/07/2010 09:52
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
I'm thinking high density cylindrical fluid-bed. Similar to the Sivetz heat gun on steroids.
I cranked out 4oz thru the heat gun in about 4 minutes.
It was suprisingly tasty (Yirga). The blueberry was very pronounced.
Anyway, ...got me thinking the element could do more.
Is 1 lb crazy? (with a differant blower) -Scott |
| |
|
|
| seedlings |
Posted on 08/07/2010 11:39
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
freshbeans wrote:
I'm thinking high density cylindrical fluid-bed. Similar to the Sivetz heat gun on steroids.
I cranked out 4oz thru the heat gun in about 4 minutes.
It was suprisingly tasty (Yirga). The blueberry was very pronounced.
Anyway, ...got me thinking the element could do more.
Is 1 lb crazy? (with a differant blower) -Scott
Did you see my original air roaster (http://homeroaste...ead_id=552)? I used an auxiliary leaf blower and two heat guns to roast about 1.25# in a design pretty much identical in concept to what you want.
You will run into trouble when the airflow to loft the beans drops the heat from the heatgun down too low. With one heatgun I couldn't get the beans above 300F. VERY inefficient roaster compared to the breadmaker + 1 heatgun.
CHAD
Edited by seedlings on 08/07/2010 11:44
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/08/2010 06:18
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
Hi Chad, I'll go back and have another look. Sounds like good news. It will likely be a matter of getting the RC right.
At least the heat source sounds like it's in the right neighborhood.
I think the leaf blowers have alot of CFM, but pressure may be more important for this one. -Scott
|
| |
|
|
| seedlings |
Posted on 08/08/2010 15:09
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
If the center mesh hole is about 25%-30% of the area of the hopper, and funnels down, it will work for sure, especially at a 1# range. When you get up to Sivetz's 12 pounder, there may be some math to think about. Oh, and leaf blowers have plenty of pressure... they're essentially plastic vacuum cleaner motors in reverse.
CHAD
Edited by seedlings on 08/08/2010 15:10
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/09/2010 05:49
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
I've already had some materiels picked out for a 1lb project....small and fun.. I've put aside the propane for this one, it seems electric will be a bit more accessible.
Anything over 2.5 I'd probably go back to gas.
Any favorites on heat-gun choices out there??
-Scott |
| |
|
|
| seedlings |
Posted on 08/09/2010 07:34
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
I choose cheap heatguns - mine was $9.99 from harborfreight. It's lasted almost a year now, but I did have to repair it once. The screw terminal between the power cord and the guts of the gun got hot and started to melt, so I just bypassed that terminal and soldered the wires together.
A more expensive heatgun isn't hotter, but might last longer? If you have cool air blowing on the gun, then it shouldn't overheat, but I'd still stay cheap for testing purposes.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/10/2010 09:36
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
Is it feasible to dissect the coil and reshape it inside a different heat tube? (as long as it gets sufficient cooling)
-Scott |
| |
|
|
| seedlings |
Posted on 08/10/2010 10:14
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
freshbeans wrote:
Is it feasible to dissect the coil and reshape it inside a different heat tube? (as long as it gets sufficient cooling)
-Scott
Yep. The roaster I'm working on is based on two replacement elements. On some heatguns there are two coils, one to drop voltage to the fan (like most poppers), so the one with the lowest resistance is the one you want for heat.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/25/2010 06:31
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
...As predicted by Chad. The Milwaukee-gun brought 3/4lb
up to 400 in good time. No mechanical agitation, no breadmaker. However, ...That was it.
I re-outfitted the gun with a small single stage blower(like a baby ametek) It will push 1lb nicely, but it's too much cfm for that coil. A little more heat is all I need.
The question; Does any one make a gun that will offer another 25% heat?
The other option is the candy store that Dan posted.
Ideas? -Scott
|
| |
|
|
| seedlings |
Posted on 08/25/2010 08:03
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
Scott, you could perform open-heart surgery and remove some of the heatgun's nichrome, which would lower the resistance and draw more current, increasing the power. If you want 25% more heat you'll have to remove about 25% of the nichrome... If you have an 1800W gun, 120V, 8ohm element, then you'll need to reduce that element to 6.4 ohms to get a 25% increase in power.
P = (V*V / R)
1800W = 120V*120V / 8ohm
25% more power
1800W * 1.25 = 2250W
Now:
2250W = 120V*120V / 6.4ohm
CHAD
Edited by seedlings on 08/25/2010 08:07
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/25/2010 09:00
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
Will this shorten the life of the coil? ...Not that it matters.
This is just a fun little experiment. Thanks,Scott
|
| |
|
|
| seedlings |
Posted on 08/25/2010 09:42
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
My unscientific opinion is that since you have increased air flow, that counteracts the higher-temperature nichrome to equal a similar lifespan.
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
|
| freshbeans |
Posted on 08/25/2010 10:13
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
Well, this is a pretty unscientific experiment. I'm going for the surgery. It may fry the switch, but that's a few more BTU's I can use.
If it works, I'll post it. If it ignites, I'll post video.
Thanks,Scott |
| |
|
|
| Dan |
Posted on 08/25/2010 12:21
|
Founder - Member
Posts: 1798
Joined: 10/24/2005 17:09
|
I would look at the Master Appliance Heat Guns and Heat Blowers. You can buy replacement heating elements from Grainger. For instance, here is a Heat Blower Element I used on an industrial parts washer. It is 750° (with lots of air blowing over it), 120V, 16A, $38.
http://www.graing...Pid=search
|
| |
|
|
| John Despres |
Posted on 08/25/2010 13:17
|
Super Admin
Posts: 2082
Joined: 01/09/2008 07:55
|
seedlings wrote:
Scott, you could perform open-heart surgery and remove some of the heatgun's nichrome, which would lower the resistance and draw more current, increasing the power. If you want 25% more heat you'll have to remove about 25% of the nichrome... If you have an 1800W gun, 120V, 8ohm element, then you'll need to reduce that element to 6.4 ohms to get a 25% increase in power.
P = (V*V / R)
1800W = 120V*120V / 8ohm
25% more power
1800W * 1.25 = 2250W
Now:
2250W = 120V*120V / 6.4ohm
CHAD
If you increase your power that much, be sure to run non a 20 amp breaker or it'll only work for a few seconds. My guess is that won't be enough time.
John
Respect the bean.
John Despres
Fresh Roast 8, Gene Cafe, JYTT 1k, Quest M3, Mazzer Mini, Technivorm, various size presses and many more brewers.
|
| |
|
|
| freshbeans |
Posted on 08/25/2010 13:53
|
Super Admin
Reasonable
Posts: 1400
Joined: 03/06/2010 11:10
|
Hi John, too much juice for this set-up. 30 second roast is too quick...even for me.
Dan, thank you. That element is designed to handle about 40cfm @ 750 degrees. I'll be ordering asap.
I never completed a roast, but the experiment proved it's worth pursuing.
The blower will move 1lb. A better element will provide enough heat.
Moving on without the heat gun. Bigger cord, heftier switch
and hopefully a machine that doesn't look Frankenstein.
Thanks All -Scott
|
| |
|
|
| SteveN |
Posted on 08/25/2010 14:07
|
1/4 Pounder
Posts: 128
Joined: 03/16/2010 19:36
|
Dan wrote:
I would look at the Master Appliance Heat Guns and Heat Blowers. You can buy replacement heating elements from Grainger. For instance, here is a Heat Blower Element I used on an industrial parts washer. It is 750° (with lots of air blowing over it), 120V, 16A, $38.
http://www.graing...Pid=search
Omega also has replacement elements for $24: http://www.omega...._GUNS.html
Edited by seedlings on 08/25/2010 14:16
|
| |
|
|
| seedlings |
Posted on 08/25/2010 14:19
|
Administrator EMERITUS
Posts: 4295
Joined: 06/27/2007 11:39
|
Scott, shortening the element didn't work? I'm interested in how exactly it failed..!
CHAD
Don't put the cart before the horse. Put the horse in the cart and listen to him say "weeeee" all the way down the hill.
|
| |
|
for you