Microwave ovens are a gold mine of useful parts that can be salvaged and reused in other projects. However, they also contain components that can cause serious harm if handled incorrectly.
Let's safely disassemble this one I found abandoned at the side of the road and harvest anything useful.
⚠️ Safety warning
Taking apart a microwave can be dangerous. These operate at very high voltages and you should never attempt to repair or disassemble one while it's plugged in or switched on.
Even after it's been unplugged, some components inside can still store a potentially lethal charge, while others, like the ceramic insulators on the magnetron, can be hazardous if crushed or damaged.
If at any point you feel uncomfortable, stop and do another project. It's just not worth the risk!
What's inside?
The first step is to remove all of the screws around the outside holding the outer casing in place - you’ll likely need some Torx security bits for a few of these. Once these are gone the casing should just lift straight off to reveal the internal components.
The exact layout might vary slightly depending on the make and model, but all microwaves have the same fundamental parts:
- Microwave Oven Transformer (MOT)
- High voltage capacitor
- Cooling fan
- Magnetron
- Main PCB
Discharging the capacitor
Before doing anything else, we need to discharge that capacitor. These can store thousands of volts in them even after the microwave’s been unplugged, enough to stop your heart. Modern capacitors often include an internal resistor that’s designed to safely discharge them over time, but these can fail, so you should always assume that the capacitor is charged until confirmed otherwise.
The safest way to do this is with a suitable high power resistor to short the capacitor in a more controlled manner. But if you don’t have one of these, you can take a pair of pliers that are well insulated, and bridge the two contacts together for a short amount of time. It’s best to do this while the capacitor is still in place if you can, and whilst wearing thick insulating gloves.
Be prepared to see a flash or hear a pop if there’s still a charge - again it’s better to do this in a more controlled manner if possible, as this can damage both the capacitor and the tool you’re using.
Once it’s discharged, it can be safely removed it from the microwave.
Magnetron myth-busting
Next let’s turn to the magnetron. This is what generates the microwaves that cook your food, though there’s no risk of radiation now it’s powered off. Carefully unscrew this from its housing and remove it.
It’s a common myth that the white or pink ceramic insulators at the side of the magnetron are made from beryllium oxide, which is extremely harmful if crushed as the dust is carcinogenic and can lead to an incurable lung disease if inhaled.
Unless the microwave is very old, this is far more likely to be made of the cheaper, less dangerous aluminium oxide instead. The pink colour just indicates it’s been doped with chromium oxide, which makes the ceramic pink for the same reason rubies are red!
That being said, neither material is good for your health if you breathe it in; so like the capacitor, treat this with respect, and never cut or damage it.
Dismantling the magnetron
Providing you're confident you won't damage the ceramic material, the magnetron contains two large magnets inside that can be salvaged. These aren’t as powerful as neodymium magnets, but they are quite strong.
The top plate can be levered free with a pair of pliers and a large flat-head screwdriver. From there you can remove the top magnet, which might take a bit of force.
Then you can do the same at the other side: lever apart the bottom plate, cut the tube free, and then you can remove it from its housing and get to the bottom magnet.
Again, be careful when you do this, as you don’t want to damage the ceramic insulator.
Removing everything else
Now we can safely take the rest of the microwave apart. The most valuable piece we can salvage is the high voltage transformer inside, which will probably be near the bottom as it’s very heavy.
These can often be reused in projects that require high current, such as homemade spot welders. The original high-voltage winding is replaced with a low-voltage, high-current one. Or they can be simply sold for scrap.
After that it’s just a case of going through and unscrewing everything left and removing the parts. Don’t forget to flip the microwave over and remove the turntable motor at the bottom, this can be reused or stripped apart for the coil inside.
Once finished you should have an array of parts you can reuse in other projects.
