Okay, here my DIY help:
DIY AC Oxalic Acid Vaporizer
Varroa Decimator
Joerg Klempnauer, 20-2-2020
Many options are thinkable and not one design is binding. The result makes the design good or bad.
Notice to reader: You are going to work with electricity, so ground well and work carfully! Stay safe!
The plan is to vaporize the OA, so the temperature needs to be around 380-420°F (194-215°C). Consider a bowl material with good heat conductivity and good strength. My preference is 1 ¼” copper K-type heating pipe, sold in 10’ length. 3/16” copper tube for the vaporizing tube, this (as much as I have found) only comes in coiled form and is initially very soft, but hardens during the first 20 uses.
Let’s try to get a list together for main components needed to build 120 VAC Oxalic Acid Vaporizer. I will start at the extension cable.
- Connecting cable, 10 Amp, 10 to 15’ long, bendable at colder temperatures. Grounded = three prong, 18 AWG
- Optional: switch with LED light that comes on when power is applied to the heating coil (Gardner Bender GSW-42)
- PID (Proportional, Integral, and Derivative) controller (MYPIN TA4-RNR or INKBIRD ITC-106RH)
- Heat Element (PPE MX13705 – 120VAC 300 Watt) this fits around the 1 ¼” copper pipe
- Someone to weld a cap from copper to one side of a piece of pipe cut 2 ¾”
- The 3/16” vaporizing pipe can be made in many ways, straight out the bottom, bottom side, or anywhere up to 1” from the top
- Someone to weld the 3/16” copper to the bowl
- One or two holes in the bottom to mount the bowl to a frame
- K-type temperature probe with ¼” ring end
- Aluminum flat bar, ¼” by 1.5”, 8-10” long(?)
- Box to house the controls – remember you will be heating the bowl and heat will eventually travel along the alu bar to your controls and hands holding this thing!
- 1 or 2 stainless ¼” bolts and acorn nuts to mount the bowl to the alu bar - hint: put the nuts from the inside!
- 2 or 4 small washers to raise the bowl off the bar to reduce heat travel
Silicon type plug with cavity for the OA charge of 2-4 gram (check CAPlugs.com – I use SH-33533 HUP7.5-04 #7.5 ULTRABAKE
Below a wiring diagram for the MYPIN.