Micro bits?

[gordon stephenson]

Just about to scrap a microwave oven, Still working OK but the interior has deteriorated, With the casing removed there appears to be some decent parts all in good condition, My question is, are there any bits I should be saving as useful for something else?
It has not been plugged in for a week so I presume it's discharged by now!!

 

[KemppiFrog]

Meggatron might be useful for DIY RADAR

 

[mike 109444]

Look up (youtube) homemade spot welder (small though). Turntable motor (low geared motor)

 

[Engineer1964]

Theres quite a few useful things in there Gordon,

You'll find a gigantic capacitor inside the microwave. It looks like a metal tin with two tabs on top. Short it out to make sure it doesn't have any leftover charge on it, before you poke your hands anywhere near. Just put a screwdriver or something metal you aren't connected to, across the two metal terminals, I know you said its been left off for a week but just in case

Making a stick welder from an old Microwave is fun if you've got nothing else to do You'll need at least a couple, One won't be powerfull enough.

http://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/

Another thing is a magnet, They have a magnet in there somewhere which is pretty strong, you can use this to make a welding positional magnet, but adding a couple of bits of 2.5mm or 3mm steel either side like a sandwich.

Have Fun Gordon

 

[MattF]

You'll find a gigantic capacitor inside the microwave. It looks like a metal tin with two tabs on top. Short it out to make sure it doesn't have any leftover charge on it, before you poke your hands anywhere near. Just put a screwdriver or something metal you aren't connected to, across the two metal terminals, I know you said its been left off for a week but just in case

One chap I worked for years ago would have had our guts for garters if he'd seen us short a cap out to discharge it. Best to pop a 1meg or so resistor across the terminals to slowly discharge any remaining charge. Whacking a meter on there is the simplest way to check if it is indeed discharged or not.

 

[gordon stephenson]

Thanks for the help everyone. there looks to be more than one capacitor.What range does a meter have to be set on to discharge them? I can retrieve the magnet, Cant see any particular markings on the transformer but it is quite big and in really good looking condition, Do microwaves normally operate on the same voltage after the transformer?

 

[MattF]

What range does a meter have to be set on to discharge them?

You use the meter to check if there's any voltage still lurking in there, not to discharge it. Digital meters are of such high input impedance that it would take yonks to discharge it. If there is still notable voltage present, (if only several volts, it's not worth bothering), you can short it out as suggested earlier, if you don't have a resistor handy, but make sure you make a quick contact onto the second pin, otherwise it will leave a notable arc point on the connector. Not the best method, but if needs must... I just used to use upwards of a 1meg resistor with some flyleads and clips on, which I made up, for discharging caps. Connect up then just leave it hooked on there for a min or two.

 

[Engineer1964]

Thanks for the help everyone. there looks to be more than one capacitor.What range does a meter have to be set on to discharge them? I can retrieve the magnet, Cant see any particular markings on the transformer but it is quite big and in really good looking condition, Do microwaves normally operate on the same voltage after the transformer?

Unless your going to be using the capicitor just short it will discharge any charge, A meter will not discharge it only tell you if there is a charge.

a transformer will generally lower a voltage, is there not a lable anywher in side or on the back of the microwave that tells the voltage??

 

[tigler]

Defo salvage the transformer, contactor, fuse holders, caps, turntable drive motor etc. The older, Japanese made microwave's had some really nice, high quality components inside.
The magnatron is is only of curiosity value, to try and operate it without screening would be potentially very dangerous.

 

[Engineer1964]

To get the magnets you need to get into the Magnetron, but be aware off disassembling a magnetron! Some types contain beryllium oxide ceramic insulators. Beryllium oxide is very dangerous if inhaled. Lead to berylliosis, an nasty incurable lung condition.

It might be more trouble than its worth just to remove two magnets

http://www.youtube.com/watch?v=2YZuxEtzD9c

 

[MattF]

If magnets are sought, knacked hard drives are a good source of rare earth magnets. Have loads of the things stuck to the ceiling screws in the shed, for when I find a use for them.

 

[tigler]

I've used those for making mag pick up tools in the past. So powerful that they do have a tendency to attract to anything nearby on the way to the target !!
Also good for making super power fridge magnets !!

 

[MattF]

I've used those for making mag pick up tools in the past. So powerful that they do have a tendency to attract to anything nearby on the way to the target !!

Aye, they're devils for that. Last one I made, (I have a few 10mm round magnets here specifically for making pickup tools and similar), I drilled/bored the brass holder so that the magnet is recessed inside by a few mm. Loses a bit of its strength due to the air gap, but saves it clinging on for dear life to anything it meets on the way to the piece.

 

[rtbcomp]

I always salvage the magnets.

There are microswitches, but not always the change-over type. There's a small fan.

The transformer gives out a few thousand volts at about a kilowatt, I scrap these for the copper, but note that the primary windings are sometimes aluminium.

 

[tigler]

I've noticed the more recent microswitches are el-cheapo quality compared to old school Jap stuff. There is also the oven light bulb and holder, useful for drill and lathe lights with a bit of adaption.

 

[Shox Dr]

Don't forget the odd baked bean in the corner

 

[gordon stephenson]

I think i will salvage the transformer, a couple of nice micro switches from the door catch,bulb and holder,cooling fan and motor, turntable drive, capacitors etc, going to leave the magnetron alone if it's a health risk!! also there are a couple of those little "over temp" units but will have to check what temp they are set at,

 

[Shox Dr]

How strong are the turn table motors?

 

[gordon stephenson]

Don't know the answer to that one Shox Dr. Must have some reversing gismo because it changes direction each time it's used.
P.S no hidden baked beans, How posh do you have to be to not have an orange stained poly jug for heating beans in you kitchen cupboard.

 

[rtbcomp]

Turntable motors aren't very strong, they are heavily geared down, I've never seen a reversing mechanism either, the start direction is random.