Recently it became legal to use Oxalic Acid (OA) in our bee hives as a tool against varroa mites. There are several ways of applying it but the best for both mite control and the bees is to vaporize the OA with a 12 volt wand stuck in the bottom of the hive. Buying a vaporizer was spending and looked and the device looked ripe for building one of our own. I found several ideas cruising the net. The biggest catch was a way to heat the head of the wand. Someone suggested that a glow plug from a diesel engine should work just fine. A quick trip into town and a $10.00 bill resulted in an Autolite 1110 glow plug used by Chev 1973 Diesel engines. Now that I had the heat source I could design the rest of the wand.
Rooting around in the scrap pile I dug out a block of 6061 Aluminum Block about 2"x5"x3/4" to use as the head for this vaporizer.. The Glow Plug had a 10x1MM thread. I knew that I did not have a tap in that size and a check of the local hardware store did not have one either but I was able to by a couple of hex headed 10x1x40MM bolts. Since this head block was aluminum I resorted to and old trick of making a tap from a bolt. See the Thread on "A quick tap to save the day and keep the mites away " That I post also today for more details.
Crudely Marking out the pocket that we need to mill out on the face with a felt tip
Milled out the 0.5" deep pocket with a 1/2" 4 flute end mill on the Mill/Drill took only a few minutes. The pocket is 1 1/2 long by 3/4 of an inch wide roughly and a 1/2" deep.
Setting the block on end I drilled the hole for Glow Plug, Drilling a 13/64 hole 1 3/4" Deep from the left hand side of the block as a pilot and to contain the heat element for the glow plug. Following up I redrilled the hole with an "R" drill 3/4" deep to tap for the 10x1MM thread. I also drilled & tapped a 3/8x16" x 3/4" in the center for the wand handle rod. The other hole was done in incase I needed a 2nd heat source.
After tapping the holes I attached the related parts. The 3/8 threaded rod was about 23" long, threading into the center of the block and putting a 3/8-16 hex nut to lock it in place. The Glow plug fit like a dream and did not need a lock nut. For a handle, I found a 20 1/2 piece of 1" conduit. I crimped the conduit onto the locking nut and then pressed the tube oblong to make all but the last 8-10 inched 3/4 of an inch high. I snaked the positive lead of the 13 volt wire down and through a hole that I ground through the conduit just above the male plug on the Glow plug. I crimped the female connector on to the wire, slid a piece of heat shrink tubing over it and then connected that wire. At the other end, I ground a relief for the wire to come out of the tube and then stripped off enough of the negative wire to wrap around the 3/8" rod. Placing a flat washer over the rod, I wrapped the wire around and finished off with a dome nut. Every thing locked up tight.
Attaching alligator battery clips to the other end of the wire and then those to the battery on my pickup, I put a couple of grams of Oxalic Acid in the trey and in less than 3 minutes had a good vapor going.
Here we are using the vaporizer on one of our hives.