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DIY Kanthal A1 heating coil
Olly82
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Posted on 06/19/2022 2:04 PM
So my 2 different heatguns both state the power to be 2000W. When measuring the actual output, it's actually 1400W. My intension is to replace the original coil with diy kanthal A1 coil. Parameters would be 2000W 10A 220V. Originally wire temperature should be 600C, but not really so sure about it. Obviously raising power will increase the wire temperature. So how much temperature could a heat gun handle?
 
renatoa
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Posted on 06/19/2022 3:10 PM
Not so obviously... there are relationships between wire temperature, airflow and output temperature...
You increase heater power for two reasons: to increase hot air temperature, and/or increase airflow, to lift more beans.
Hot air temperature has a very limited range to evolve during a roast... 200-300C degrees, so plan carefully what you want to do with that power increase.
Roughly, as a rule of thumb, you can plan 1000W for 100 grams of greens.
What is your intended load ?
 
Olly82
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Posted on 06/19/2022 3:31 PM
My HGFS setup running 200gr and more is lacking power. 1kw per 100gr seems right. I can succesfully roast 150gr. Ideally would like to roast about 300gr. I think it's a stretch. 250gr would suffice. I have insulated the sifter already. Using funnel below and up. Glass lid on top. 8 cup sifter itselt can take quite a lot. Putting 2 heatguns to work is not very elegant solution. Maybe 2 heating elements in 1 casing? Over powering as such wouldn't be a problem as pid takes care of the output temp.
There are 2 options as I see. To fit 2 elements into 1, or make my own coil. With the latter choosing the awg seems to be the difficulty. Original awg is 22. Should I go with awg18 to raise the power as 22 awg shorter would melt aluminum already not roasting coffee.
To run 2 heatguns in parallel would not be my preference, as it would pass 10A. My braker is 20A, but I wouldn't dare to run anything over 10. Also my grid is single phase, so in series is not an option as well. Been looking for replacement 2-2.5kw heat gun heating element without success. Therefore DIY seems the only option. From safety standpoint to test the heating element, I should get a laboratory psu to regulate voltage. I am sure there's someone in this sub who has solved the issue and willing to give some advice.
Edited by Olly82 on 06/19/2022 4:16 PM
 
renatoa
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Posted on 06/20/2022 2:38 AM
2000W on 115V is 17 Amps, whatever wire awg, or coils connection you have.
So the 10 Amps is actually the real limitation, not the roaster.

If this issue can't be solved, then the choice is the switch to another machine architecture, with less energy waste, FB owning the crown in this realm...
 
renatoa
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Posted on 06/20/2022 6:45 AM
Regarding your re-wire plans, awg16 has 4x less resistance than awg22.
As a rule, every 3 awg units doubles the wire resistance.
Thus awg19 is 2x than awg16, and half of awg22, as resistance.
This means also double/half the current/power, for every 3 awg units, if same voltage and wire length is used.
To increase power 1.5x times you should use a wire having awg 3 units smaller than the original, and 1.5x longer.

Your initial plans, to use awg16 instead 22 will led to a length about 3x longer than the original, for 1.5x power increase, no idea if this length fit in your heater space.

All the above are valid if we want to preserve the wire temperature as close to the original, and just increase energy transferred to the hot air mass.
If your target is a different temperature for the wire, other computations are required.
 
Olly82
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Posted on 06/20/2022 8:21 AM

Quote

renatoa wrote:

Regarding your re-wire plans, awg16 has 4x less resistance than awg22.
As a rule, every 3 awg units doubles the wire resistance.
Thus awg19 is 2x than awg16, and half of awg22, as resistance.
This means also double/half the current/power, for every 3 awg units, if same voltage and wire length is used.
To increase power 1.5x times you should use a wire having awg 3 units smaller than the original, and 1.5x longer.

Your initial plans, to use awg16 instead 22 will led to a length about 3x longer than the original, for 1.5x power increase, no idea if this length fit in your heater space.

All the above are valid if we want to preserve the wire temperature as close to the original, and just increase energy transferred to the hot air mass.
If your target is a different temperature for the wire, other computations are required.


Thanks. Available wire to me is 18awg. I see heatguns going up to 650C 2300W. Although expensive, I got one with 86€ (was on sale with 2x less the original price). I think Steinel is a brand to believe when they say it's 2300W and 650C.
Edited by Olly82 on 06/20/2022 11:32 PM
 
renatoa
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Posted on 06/21/2022 3:16 AM
For such task I get a 20 Euro generic hotgun labelled 2000W from a major brico local chain, and return if not conform. Leroy Merlin is the first that comes in my mind.
 
Olly82
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Posted on 06/21/2022 11:56 AM
I also have 2 generic stating 2kw. I cannot try all the heat guns in the world. Should receive the steinel 2320e tomorrow. First thing to test the power. 2520 is quite a bit more expensive due to brushless motor (10000 working hours instead of 1000). The price jump from 2kw to 2.3kw is quite remarkable.
 
renatoa
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Posted on 06/21/2022 1:16 PM
I think the BL motor is the reason of price difference, together with the brand label cost.
Extra power could cost zero cents, actually you cut 10% of wire length, nothing is added. The temperature range of such heater is usually 500-800 C, so the original heater can accommodate a broader range of wattages/temperatures by simply adjusting length.
 
Olly82
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Posted on 06/21/2022 1:50 PM
1000kv blc, esc and speed adjuster won't come cheap even as diy. But heating elements after 600C is pushing limits already, as things like to self combust after that heat. I haven't seen any generic heat gun yet to go over 600C and 2000W. The max I have seen was 700C and 4000W, but the price tag is a bit steep for diy project.
 
renatoa
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Posted on 06/21/2022 2:08 PM
Another thing I noticed, the working hour estimation, in both cases... it's waaaay... off

1000 hours is a label attached only to pro multicopter motors in the +$$$ price ballpark. Claiming such life for a brushed motor in a $$ heatgun is funny.
For my hobby multicopters, fitted with budget $20 motors I am changing bearings after maximum 50 hours of flight.
The same apply for 10.000 hours for their BL motor. This equates to 10 years of continuous life for 8 hours daily, 5 days a week... come on...
 
Olly82
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Posted on 06/21/2022 2:22 PM
I am using the motor about 2 hours per month, so 24 hours a year. So 2 years should be covered. Steinel heating element is covered for about 500hrs.
Edit: Steinel hg 2320 e https://imgur.com/a/747MR9Q

Images about what a quality german engineered heat gun looks like when disassembled. Quick power measuring showed 220V 1940W. Motor should take about 100W, therefore heating element about 1840W. Not as advertised total with motor 2300W. Element inside has a marking 2200W. It's a number scam every company is playing with. I should ask 10% refund for missing 10% wattage. But as it is still more powerful than the generic ones I have, I will put it into work. I only bought the gun because it was readily available, half off and shipped with one day. Heating element and motor replacements would have costed the same and would have taken 2 weeks to arrive. I have high hopes for ceramic housing for heating element. It should even out the pid on/off temperature change.
Edited by Olly82 on 06/22/2022 9:15 AM
 
renatoa
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Posted on 06/22/2022 9:36 AM
Could be related to your mains voltage.
Standard in EU is 230 +10-6%, and electric appliances are built for this number.
Every 1% of voltage drop, i.e. 2.3V, means 2% of power drop, which is 46W off claimed 2300.
If you are on the older 220V mains standard, the 10V difference means 91.5% of the reference power, i.e. 2100W
Many parts of EU are still on 220V... but I don't know any major manufacturer, who make stuff for the whole EU space, to fine tune an appliance for 220-230-240V mains.
A notable exception in our hobby, is the Behmor roaster, having a switch on the back panel, to select mains voltage.
 
Olly82
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Posted on 06/22/2022 1:22 PM
My mains is 220V. It would mean instead 2300w I effectively get 2200w. But I measure 1940w. I guess they mean 260w is the fan.
 
Yasu
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Posted on 06/22/2022 1:28 PM
Hi Olly82
In my country
I'm using a heat gun like this, but I'm not sure if this is helpful?
The price listed is the list price, but I got it used for about 1/3 of what I paid for it.

Optional heaters for 220V 230V are also available.
It might be radically interesting to use the one for 200V with 220V!

You can also get replacement heaters for any voltage for 4,000 yen.

Product name PLAJET - Stationary type (High power 200V)
Part Number / Model Name PJ-230
Rated power consumption AC200V-3000W 50/60Hz
Switch Slide type 3-step changeover switch (off, blast, hot air)
Hot air temperature Approx. 600°C *Measurement is taken at 10 mm from the air outlet.
Air volume 0.51 m3/min
Wind speed 450m/min
Main unit weight Approx. 1.2 kg *Excluding power cord
Body dimensions Body diameter ?96 × length 302 × height 96 mm
Accessories Filter (PJF-2) × 1
Carbon brush (KBS-2) × 1
3-core captire cord tap x 1


https://www.sure-ishizaki.co.jp/tool/plajet/plajet-pro/pj-230/
 
Yasu
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Posted on 06/22/2022 1:47 PM
If you could just get a replacement heater, incorporate it into a stainless steel pipe, etc., and use it on your current heat gun, it might be cheaper!

Or, if you can get a 220V to 240V transformer or something like that at a second hand store, you might be able to power up to ?240V/220v?^2 x 1940W = 2345w.

https://www.e-aiharadenki.co.jp/products/SPB/index.html
Edited by Yasu on 06/22/2022 3:14 PM
 
renatoa
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Posted on 06/23/2022 2:37 AM
Such transformer is too big and expensive even to consider.
For only 10% is much simpler to remove some turns of the coil.
The question is if it worth the trouble... other machine builds roast 3-400 grams with 1 kW only.
 
Yasu
Top  #18 Print Post
Posted on 06/23/2022 5:49 AM
In my country, 100v to 125v devices are available for about 100 euros, and I used to use a popcorn roaster with 1.5 times more power, so I was wondering if there are similar devices in Europe.

Steinel hg 2320 e is a ceramic heater, so it is difficult to shorten it as easily as cutting a nichrome wire, so I thought it would be easier to increase the voltage. I thought it would be easier to increase the voltage.


https://suzukid.co.jp/transformer-wiring-equipment/portable-transformer/shu-20d/
Edited by Yasu on 06/23/2022 6:04 AM
 
renatoa
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Posted on 06/23/2022 6:08 AM
Yes, available mainly for 230V to 110V conversions, bigger price, in the ballpark of 100 Euro for 1kW.

The problem is that my whole roaster build cost was less than 100 Euro Grin and the power is my least worry, using less than 80% of 1300W heater for one pound roasts, why should I care about mains voltage ? Grin
Energy is no more cheap today, power hungry machines should rethink their principles.
Coincidence maybe, Giesen just today announced their new 15 kg electric roaster ! no more gas for 15 kg is indeed an achievement... especially when no russian gas Grin
 
Yasu
Top  #20 Print Post
Posted on 06/23/2022 6:24 AM
I too am interested in energy issues, especially carbon neutrality.
Gas is the main source for large roasters, but I am not sure how long we will be able to use gas.
I believe that roasters will have to be electrically powered, just as cars will have to be electric.
This is the reason why I decided to use a hybrid roaster.
Now, 40% of the heat can be converted to electric power.
I thought about this in order to reduce gas consumption as much as possible.
I would like to change this ratio depending on the energy situation in the future.
 
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