[Boatanchors] Plexiglass

[Wilson Lamb]

Being an admirer of my own advice, I decided to check on this.  Not many 
people would salvage old microwave ovens and even fewer would admit it, but 
I do, having finished six now.  I'm after the transformers, two of which 
will make a KW power supply, but there are lots of other things in there 
like microswitches, hardware, and quite a bit of nice hookup wire.  I'm no 
longer taking everything, since I have enough, but did have a carcass in the 
basement with the door still on.

The door has a piece of probably tempered glass backed up by a panel of 
perforated metal with thin plastic laminated on.
This was a classic, old, high end unit, for over the stove use, so a little 
larger than some.  the glass is 19.25X7.75 inches, so needs cutting if for a 
standard panel.  I'm guessing a regular glass cutter would do it.  The 
perforated metal is quite heavy gauge and would make a great viewer for the 
old rig, as well as let in air.  It's a panel screwed into the door, with 
the perforations inside the frame part, so you'd have to trim the perforated 
part out with a saber saw.

I wouldn't be surprised if modern units are a little simpler, but don't 
know, since I recycled the other five, doors and all.  You can likely break 
off the door at the hinges, if you don't want to bother going inside.

BTW, of the six HV xfmrs, two are a good match and the rest scatter from 
1900-2600V!  You can use the filament winding to buck or boost the voltage 
by about 2%, if you have a pair that are close.  These are cheap xfmrs, 
optimized for the oven service, so they draw about 4-5A with no load.  The 
power factor unloaded is 0.1, so it's not many Watts and doesn't seem to 
create heat, to speak of..  You have to use two, because one end of the 
secondaries is grounded and may not be sufficiently insulated to run above 
ground if lifted.
There's a ref or two I'll provide if anyone wants, or you can search the QST 
archive for microwave oven.

73,
WL
----- Original Message ----- 
From: "Wilson Lamb" <infomet at embarqmail.com>
To: "BOATANCHORS" <BOATANCHORS at puck.nether.net>
Sent: Saturday, February 18, 2012 11:10 AM
Subject: [Boatanchors] Plexiglass


> You might find something in a microwave oven door, but I'm pretty sure the 
> home stores sell Plexi or Lexan for windows, pictures, etc.  You could 
> even use real glass glass, which they will cut for you.
>
> Nice project.  I have a long running project with a whole rack of 30s 
> circuitry, partly on wooden chassis Email if interested.
> Wilson
> W4BOH
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