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UV Curing Chamber from old Microwave
#1
Good evening all,

I have been working on this for some time, just got the last component (a 405 nm UV LED) in today's mail. I got an old 0.7 ft³ counter-top microwave oven from Craigslist ($10), gutted the m-wave stuff (Mgnatron, HV X-fmr and ballast capacitor), and installed a  30 W 405 nm ultraviolet UV and power supply; retaining the microwave's timer/turntable/etc.

The UV LED was mounted (w/ heat sink compound) to an old CPU heat sink, that assembly then mounted in an enlarged hole where the magnetron and it's waveguide had been in the side of the oven. There was plenty of room in the oven's side compartment for the LED, heat sink and LED power supply. There are two screws mechanically fastening the heat sink to the wall, I used metallic duct tape to seal an "pretty" it all up.

The microwave's active cross flow cooling, designed for a 700 W device, is entirely adequate to the 30 W LED's cooling needs.  

I also used a couple of strips of the tape o the oven's door, as the 30W LED is very bright (10-20 seconds will cure anything, were I doing this again I might use a 10 W LED).

Here's a link to the LED on Amazon ($16.29);

And the constant current power supply  ($10.92);

Here are some photos of the finished project;

just a plain 'ol microwave
[Image: Mychamber_Frnt.JPG]

UV LED mounted on an old CPU heat sink and installed in place of the magnetron--the "bump" above the LED is left over waveguide I did not remove.  (I see I need yet to clean up some of the grinding dust from enlarging the hole):
[Image: Mychamber_LED.JPG]


Chrome duct tape on window in m-wave door--I had considered lining the entire interior with foil, however with the 30 W LED the gloss white seems to relect the UV quite well...
[Image: Mychamber_Door.JPG]

LED ON
[Image: Mychamber_LED_ON_bright.JPG]


LED ON, lights off
[Image: Mychamber_LED_ON.JPG]

OEM schematic of m-wave
[Image: UECIDE0-1_Stock.jpg]

As modified schematic of m-wave
[Image: UECIDE0-1_Modded.jpg]
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#2
great idea - will have a look on the bulk rubbish to find a microwave oven ;-)
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#3
I made one out of a 2 gallon plastic tub (for wall texture) with a UV light strip stuck in a helix winding down to the base.  Granted I don't have a turntable - so I flip the model half way through.  But works well.
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#4
(07-01-2020, 11:14 AM)gordon3d Wrote: I made one out of a 2 gallon plastic tub (for wall texture) with a UV light strip stuck in a helix winding down to the base.  Granted I don't have a turntable - so I flip the model half way through.  But works well.

Cool, do you know how many watts the UV strip is? Just curious...
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#5
(07-01-2020, 12:40 PM)cliffyk Wrote:
(07-01-2020, 11:14 AM)gordon3d Wrote: I made one out of a 2 gallon plastic tub (for wall texture) with a UV light strip stuck in a helix winding down to the base.  Granted I don't have a turntable - so I flip the model half way through.  But works well.

Cool, do you know how many watts the UV strip is? Just curious...

Doesn't say but I reckon less than 20W - its a 2A x 12V power supply.  LEDs d
on't get very warm.
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