Author Topic: Ghetto DIY PCB heaters ?  (Read 2888 times)

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Offline MathWizardTopic starter

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Ghetto DIY PCB heaters ?
« on: August 12, 2022, 10:14:10 am »
Has anyone tried using a coffee machine, pot heater, as a sort of hot plate, or with a shroud, use it more like a hot air/radiative heating thing ?

I would just like something to use to keep a PCB up near soldering temps. I have a toaster oven that worked ok for some pre-heating, IDK how quick it cooled off, but it helped me to remove a 1.25" BGA chip for practice.

And I could get a used coffee maker for $5, maybe put a ceramic tile right on the heater. Or try to make a little shroud, and have a PCB sit over it.

I'd only be going for 100-150C on the PCB, or whatever a common under-board heater does. I'd just adjust the temperature by the distance or air flow, not any electrical control.

Someday I'll get a PCB under board air heater, but I've seen people make rework stations with old electric grills too.


Or what about using a 500W construction lamp, which I have. It feels pretty hot to the hand from a few inches.
« Last Edit: August 12, 2022, 10:21:17 am by MathWizard »
 
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Offline langwadt

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Re: Ghetto DIY PCB heaters ?
« Reply #1 on: August 12, 2022, 10:16:59 am »
halogen lamp
 

Online Ian.M

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Re: Ghetto DIY PCB heaters ?
« Reply #2 on: August 12, 2022, 10:34:33 am »
See https://www.eevblog.com/forum/projects/simple-small-ir-preheater-using-12v-halogen/
and: https://www.eevblog.com/forum/manufacture/small-bottom-heater-for-rework-and-reflow/

My experience is: A MR16 50W 12V Halogen spotlight bulb as an underside heater can easily bring a ~50mm diameter area of most PCBs up to Pb-free reflow temperature, however to reduce stress on the PCB its better used as a supplementary heater.

Mounting the MR16 bulb through a rectangle of drywall board, with its face flush, and minimal gap round it is IMHO important for both safety (the board is fully supported, not just balanced on the bulb, and the only exposed hot area is the bulb's face, when the PCB isn't over it), and performance (minimizes convection heat losses under the PCB).
 

Offline langwadt

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Offline eutectique

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Re: Ghetto DIY PCB heaters ?
« Reply #4 on: August 12, 2022, 11:31:41 am »
Lo-tech: clothes iron.

Hi-tech: clothes iron with added electronics:


 
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Offline Uunoctium

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Re: Ghetto DIY PCB heaters ?
« Reply #5 on: August 12, 2022, 12:11:31 pm »
I'm using an 70'ies "Maybaum" dining warming plate with thermocontrol and 10mm aluminum plate thickness. Heater: 800W
paid 4$ on flea market  :)
same model as
https://www.ebay.de/itm/294429664329?
 

Offline MathWizardTopic starter

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Re: Ghetto DIY PCB heaters ?
« Reply #6 on: August 12, 2022, 12:21:00 pm »
So I should give it a try then, and use some more thermocouples. When I used the toaster oven, I just used 1 hanging in the air.
 

Offline floobydust

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Re: Ghetto DIY PCB heaters ?
« Reply #7 on: August 13, 2022, 04:07:03 am »
I use the low cost "PTC heating plate" for $10 off Aliexpress. A bit harder to find 120V compared to 220V versions.
Although they are scary, mains powered and the 400W I got had crazy inrush 600W cold- but it regulates the plate temperature nicely and settles to 83Wand 230°C after 2 minutes.
The PTC is non-linear and didn't read properly with an ohmmeter. I run it with a fuse + GFCI.
 

Offline Whales

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Re: Ghetto DIY PCB heaters ?
« Reply #8 on: August 13, 2022, 04:54:50 am »
Glad I'm not the only one with a ghetto hotplate :)

https://halestrom.net/darksleep/blog/045_amplifiers/#hotplate

I tried a high wattage lightbulb underneath, but couldn't get the temp high enough.  Perhaps I should have shone the light directly onto a PCB rather than the (relatively reflective) aluminium.
 
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Offline Electroplated

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Re: Ghetto DIY PCB heaters ?
« Reply #9 on: August 13, 2022, 02:39:44 pm »
I use a warming plate salvaged from a 70s hostess trolley that I found years ago, waste not, want not so the saying goes, suits me, being I'm a tight........

--
50 years working with electronics and I still wonder how small parts can have all that smoke inside !
 

Offline robzy

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Re: Ghetto DIY PCB heaters ?
« Reply #10 on: August 14, 2022, 11:21:13 pm »
Fyi Carl Bugeja has done some experiments with PCB heaters

https://www.youtube.com/playlist?list=PLzP6_DqZoxc1of9OfZ4hKAGF9jIvG5vke
 

Offline langwadt

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Re: Ghetto DIY PCB heaters ?
« Reply #11 on: August 15, 2022, 06:26:40 am »
I've used an old lab magnetic stirrer hot plate, just don't forget to tak out the magnet many components are magnetic
 

Offline MathWizardTopic starter

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Re: Ghetto DIY PCB heaters ?
« Reply #12 on: August 16, 2022, 11:11:38 am »
I tried using my herb heater, it's probably only 30W, and it's near useless. I had a monitor PCB mounted up on some cardboard, with air flow right under a 1" BGA chip, and the PCB barely got to 64C after 20min.

Then I tried to remove that BGA with my 858D, and even on max I could not get this 1 after +5min, so I gave up.

For the coffee pot hotplate, I'll try putting a 2.5lb metal dumbbell weight right on the element, and then I'll need some flat plate of metal on top for the PCB to sit on.

I also have a 1000W auto-transformer, I could try using that to control the power.
« Last Edit: August 16, 2022, 11:13:16 am by MathWizard »
 

Offline boneDragon

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Re: Ghetto DIY PCB heaters ?
« Reply #13 on: August 17, 2022, 12:39:49 pm »
there are cheap "led remover ptc heaters" on ebay/ali.
glue k-thermocouple to the bottom with "red gasket", and use temperature controller (rex-c100 or other).
you can also mount several plates in 2x2 or 3x4 pattern, to increase heater area
« Last Edit: August 17, 2022, 12:58:17 pm by boneDragon »
 

Offline Haenk

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Re: Ghetto DIY PCB heaters ?
« Reply #14 on: August 17, 2022, 01:59:32 pm »
Purchased a so called "screen seperator" a couple of weeks ago, which came at only 55,- EUR.
I figured parts alone were more than that, containing vacuum pump, PSU, heater, plate, temperature control module.
My intention was to use it as a low temperature heater to warm up smartphones for easier disassembly.
However temperature control and distribution were like "forget about it" - I measured with a laser thermometer (covered the whole heated plate with the same material to have comperable results) and had very hot areas (like 15C above preset temperature and also 10C less in other areas, reproducable).
Even though it has a rather massive block of aluminium, that's obviously not enough thermal mass. I would guess that's a problem with all the DIY solutions as well. Maybe I'll just add a copper plate on top, that should help...
 

Offline boneDragon

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Re: Ghetto DIY PCB heaters ?
« Reply #15 on: August 17, 2022, 02:23:00 pm »
10-15C difference is not critical for pcb warming.
i've attached 20x3mm alum strips on both sides of heater to increase thermal mass, and insulated container with rock wool - temperature difference decreased, also there is option of fully insulated enclosure, from microwave oven etc
 

Offline Haenk

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Re: Ghetto DIY PCB heaters ?
« Reply #16 on: August 17, 2022, 05:49:39 pm »
10-15C difference is not critical for pcb warming.

Yes, but I wanted to use it to soften the glue holding smartphones together. It's not a good thing to set it to 75C, when in reality it puts out 90C, which might damage the battery and OLED.
 


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