I heat the chemistry in a microwave. Done it for 30 years. I worked for Amana Appliances manufacturing plant in Amana Iowa. We made commercial and Industrial microwaves, the industrial jobs used something like 35, 100W magnetron tubes. This kind of machine is what is used to cook bacon. The stuff you buy ready to eat.
Anyway, I could get free field test appliances, at one time I had furnace and AC, 3 refrigerators, washer and dryer, 2 microwaves, gas range. It was great. I would test the product for a certain period. Look for defects before the product was released for volume production (RVP) I have a Korean made microwave that I've used forever in my darkroom, just put a partial bit in a beaker give it a few seconds.
Now Amana has been through 3 buy outs. The refrigerator plant where I worked is still there, but all the white collar jobs are long gone. I made it through all 3 buyouts, the last was Whirlpool, lasted 5 years. They moved a lot of the design work to Mexico, China, India, and to HQ in Michigan. Maytag was before Whirlpool, Maytag was a great company. Now it's all gone. Newton Iowa was their HQ, the original Maytag washers built up through the mid 80's, would run forever, usually all they would need is a v belt every decade or so, took about 5 minutes to change.
Anyway buy a cheap microwave, use very small bursts of power. In the cold months I run a electric 1500W oil filled radiator set low, has a thermostat built in, keeps my darkroom and it's chemistry at 68 - 70°F