So not long ago I decided I needed a vacuum distillation kit. Well, to go from 0 to everything you need (glassware, vacuum pump, hot-stirplate, water pump ect.) It costs several dollars. I was looking to save money where I could, and upgrade as I went. I figured I would buy the cheapest hot plate that stirred and it would boil 250 ml under vacuum, right? WRONG!
I got one of these proported 250 watt jobs.
Under -30psi it would eventually barely simmer water. That won't do. I considered my options. Buy a new one, a silicone mat around my BF, a charcoal grill lighter, some coiled heater wire and something to control it.... Rob a cooking hotplate.
Rob a cooking hotplate? 
It's the cheapest route that I knew I could make work, after researching.
I cruised on over to Walmart, and picked up one of these for $15
Then I stripped it.
This is the 8" burner sitting on the 6" base of the stirrer.
I utilized extreme desire and meth to shrink that sucker down 2 inches to fit. (And a quick grip bar clamp. I just went around every couple of inches and clamped it).
As far as the wiring, I left everything for the stir bar and took out everything for the burner. It had a circuit board and when I showed the chip to Google lens. It's a thyrister. It was rated for 4 amps and 600 watts. The coil burner is 1100 watts. I wasn't sure if it would cut the amperage or if it would just trip immediately. It had to go and I rigged up the knob from the mainstays hot plate
The power wires are soldered to the input of the pathetic fuse and to the input of the transformer. The thermistor from the mainstays is fully inclusive, it has a switch that clicks and a metal heat sensitive strip that keeps it all from burning the house down.
To mount the element, I cut the tops off of the legs and the screws hold the bottom blate in. Those are the original mounting holes, cutting the tops off of the legs gained me 1/4" of clearance.
I just cut the led light out of the mainstays (both of them) and soldered one onto the led in the stirrer. These pictures are just to show that they work.
These brackets came with an air conditioner and I just drilled and screwed them in. The other side is under the lip of the plate, so you can't see them or get poked. I don't know where the aluminum tube came from, it was in my junk drawer. The element is insulated from the tube with UV resin and the tube is mounted to the bracket with UV resin. I tested the resin by burning it with a butane torch and it was surprisingly resistant. It wouldn't burn at all or melt. Also in this pic you can see how I chamfered the magnets of the stir mechanism to clear the coil. 99.9% of the time the stir bar stays right between the 2 magnets so this doesn't affect the operation. Another thing you can see here is that the burner is red hot
On the first test last night I was pleased to find everything worked on the first try. When I felt it heating up I got a RBF and put about 250ml of water in it to test how fast it would boil. At about 1:30 the stirring stopped. I figured, "dang, heat soaked the motor that fast" but when I looked what happened was the aluminum plate on the bottom of the burner had sagged all the way down until it stopped the stirring. The water started boiling before I could shut it off, 2 minutes or so.
So, there you have it a hotrod 1100 watt hot-stirplate for a total price of about $50. I'll have to either find a piece of steel or just leave that aluminum plate off, but the screws hold the element so it's not necessary I just figured it would shield the stir motor from the heat. I have a couple of distillations ready to roll today. I'll keep an eye on it and not turn it past 1/2 power and shake it out.
Make it happen. Keep pushing
stir-plate
I got one of these proported 250 watt jobs.
Under -30psi it would eventually barely simmer water. That won't do. I considered my options. Buy a new one, a silicone mat around my BF, a charcoal grill lighter, some coiled heater wire and something to control it.... Rob a cooking hotplate.
Rob a cooking hotplate? It's the cheapest route that I knew I could make work, after researching.I cruised on over to Walmart, and picked up one of these for $15
Then I stripped it.
This is the 8" burner sitting on the 6" base of the stirrer.
I utilized extreme desire and meth to shrink that sucker down 2 inches to fit. (And a quick grip bar clamp. I just went around every couple of inches and clamped it).
As far as the wiring, I left everything for the stir bar and took out everything for the burner. It had a circuit board and when I showed the chip to Google lens. It's a thyrister. It was rated for 4 amps and 600 watts. The coil burner is 1100 watts. I wasn't sure if it would cut the amperage or if it would just trip immediately. It had to go and I rigged up the knob from the mainstays hot plate
The power wires are soldered to the input of the pathetic fuse and to the input of the transformer. The thermistor from the mainstays is fully inclusive, it has a switch that clicks and a metal heat sensitive strip that keeps it all from burning the house down.
To mount the element, I cut the tops off of the legs and the screws hold the bottom blate in. Those are the original mounting holes, cutting the tops off of the legs gained me 1/4" of clearance.
I just cut the led light out of the mainstays (both of them) and soldered one onto the led in the stirrer. These pictures are just to show that they work.
These brackets came with an air conditioner and I just drilled and screwed them in. The other side is under the lip of the plate, so you can't see them or get poked. I don't know where the aluminum tube came from, it was in my junk drawer. The element is insulated from the tube with UV resin and the tube is mounted to the bracket with UV resin. I tested the resin by burning it with a butane torch and it was surprisingly resistant. It wouldn't burn at all or melt. Also in this pic you can see how I chamfered the magnets of the stir mechanism to clear the coil. 99.9% of the time the stir bar stays right between the 2 magnets so this doesn't affect the operation. Another thing you can see here is that the burner is red hot
On the first test last night I was pleased to find everything worked on the first try. When I felt it heating up I got a RBF and put about 250ml of water in it to test how fast it would boil. At about 1:30 the stirring stopped. I figured, "dang, heat soaked the motor that fast" but when I looked what happened was the aluminum plate on the bottom of the burner had sagged all the way down until it stopped the stirring. The water started boiling before I could shut it off, 2 minutes or so.
So, there you have it a hotrod 1100 watt hot-stirplate for a total price of about $50. I'll have to either find a piece of steel or just leave that aluminum plate off, but the screws hold the element so it's not necessary I just figured it would shield the stir motor from the heat. I have a couple of distillations ready to roll today. I'll keep an eye on it and not turn it past 1/2 power and shake it out.
Make it happen. Keep pushing
stir-plate
I made a new one and stuffed a popcan up under the plate for a heatshield, but that didn't work and the electrical tape melted and one of the burner terminals shorted out on the chassis. My wife was sitting there and looked over my shoulder to make sure I bought a new one. I picked up a large 800w stir hotplate used for $100
