Cool. I bought a premade one off someone that was made with a water heater element attached to a laundry sink. I'm not sure of the wattage or volume without going out and looking at it, but we used it all last season for chickens and turkeys. We do 65ish birds at a time, four times a year and a batch of 40 or so turkeys for thanksgiving.
The scalder works well enough, although I still keep a propane burner and tank in our abattoir because the electric can take FOREVER to heat up to the right temp and if it cools down too much or you add cold water at any point, forget scalding for at least 45 minutes. Last season, I was waking up several hours before processing started to go fill the scalder with buckets of hot water and then let it sit on for an hour or two before it was ready to scald. Once we got the kinks worked out, it worked really well and I think it made our system more efficient and easier to manage. But, since we did have a few issues, I have been looking into propane thermostats, which are very cost effective, but not quite as straight forward as the plug-in electric ones.
I'm interested in the advertised promise of "heats 5 gallons in minutes" as to what temperature it will heat it to and what is the start temp of the water.
Two more pieces of advice:
1) add some kind of cover to the laundry sink top. The water heats up noticeably faster with a cover - if its foam or insulated in some other way, then all the better.
and
2)always fill the water before plugging in the heater element and always unplug the element before draining the sink. I have a sign next to the outlet ours plugs into that says this so anyone messing with it knows. Your element will melt and be ruined (and may ruin your sink, and also may start a fire) if you accidentally leave it plugged in without being submerged.
Cheers to your project. and I'm looking forward to learning the results of the first test!
