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My Oxalic Acid Vaporizer

55K views 114 replies 22 participants last post by  Tim B 
#1 ·
Hi all,
I have been researching oxalic acid vaporizers. This is what I built and wanted your opinions on it. I made everythingg from scrap I had in my shop. The box is a shallow supper that I screwed up and cut the boards too narrow. The first two pics show it set up for use with a portable propane torch. The last pic shows it set up for 12 volt use. All the copper fittings are tig welded for an air tight joint.
Let me know what you think,
Thanks all,
Caleb

Green


Membrane-winged insect


Wire Cable management Technology Cable Electronic device
 
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#32 ·
ShadowCW,
I just saw one of my bees with deformed wings so I am looking at doing an implementation using your glow plug system. However I hope to find some fittings to interface to some 1/2" SS tubing I have for an applicator. Once I buy one of the two glow plugs you mentioned I will start the search for interfacing SS hardware (not sure what size or pitch the threads are on the glow plug yet).
Anyway I just finished building four of the D. Coats NUCs that are built from 1/2" plywood and do not have an SBB screened bottom. So my question is when you do the vaporized OA treatment does it kill the mites or just make them loose their grip temporarily. My concern is whether the mites that have fallen to the solid wood floor of the NUC will recover and crawl back up or not.
Thanks for the idea, time and support.
 
#34 ·
Hi,
The OA will kill the mites. There are several debates as to how it kills them. Some say it burns their feet and mouths where they can not eat or crawl. Just remember it does not penetrate the capped brood so several treatments must be applied.
The threads on the glow plugs, Champion CH69 and Autolite 1104, are 12mm X 1.25 metric. to simplify the set-up I just turned the threads off and fasten it with a set screw. I'm machining another set up from stainless steel and aluminum. I'll post pics when I have it finished this week. Would love to see what you build also.


That's a nice set up!
Caution:
1. The oxalic acid will sublime when heated and if you wait for 10 minutes it will precipitate as a very small crystal.
2. Do not pull the unit off the hive to soon because you will expose your lungs to the micro crystals!
Good luck,
Good advice.
Thanks!
 
#35 ·
"and if you wait for 10 minutes it will precipitate as a very small crystal"

It is my belief that the vapor is hydrophyllic. The bees keep the interior of the hive at a very high moisture content due to evaporation and respiration. The vapor hits the moisture and is readily absorbed. This drastically changes the PH of the moisture in the hive to a highly acid condition.

The bees will change out the air in the hive as soon as you open it up. They will set up a fan and move the old air out until the inside air meets their "specs".
So, as long as the hive components are damp, there will be no crystals precipitating. The surfaces will have a low PH but can'[t tell for how long.

Fuzzy
 
#38 ·
I will have the plug tomorrow, and if they don't have it listed I can measure the resistance and use Ohms law to calculate. However was the 10-12 amps for all 6 or 8 plugs? With 8 plugs at 12 amps that is nearly 100 amps without the starter. If it is 1-2 amps per plug my 12 ah battery can deal with it for the 2 needed minutes per hive I think. Oh well just thinking out loud, thanks again for the great idea.
 
#39 ·
I have been following this thread with a particular interest, I plan on building one of these units this winter but for now I was wondering if a battery charger would work as an energy source, set on 12 volt or even 6 volts perhaps?
 
#41 ·
A battery charger with a start function yes, a trickle charger no. Basically you need to look at the chargers output in amps. Usually it will be the larger ones that say quick charge or something like that.

shadow-cw,
OK I will have to think on that one for my implementation. Thanks again for your time and support. I'll probably post something tonight on what I learn. Once I figure out my hardware I will need to decide on a battery or charger since my hives are in my back yard.
 
#43 ·
Some chargers will not deliver any current unless they sense a load of proper polarity. Some glow plugs must be used with their controller or will burn out allmost immediately. I use VW plugs direct on 12 volts and have left them on overnight (not intentionally) and they survive. Mine draw 12 amps each. Best to source a plug type you know will work with direct battery voltage.
 
#44 ·
OK I got my Autolite 1104 today and it measures 0.8 ohms which calculates to 15 amps at 12 vdc, or 17.5 amps at 13.8 vdc. I have checked and if I grind the threads off and it will slip inside some 1/2" SS 304 tubing I have. If I grind 2 short splits in the tubing, no longer than the the threads on the glow plug, wrap the ex-thread area with aluminum foil for a seal, with some plumbers tape for handle attachment and a hose clamp, I think I will have it. Now if the Autolite 1104 unit does not need a controller to keep it from burning out I will have an OA vaporizer soon. I have a 30 amp power supply I can use that also has a current limiter in it.
 
#46 ·
mmmooretx, that resistance measured cold, will increase considerably as the element heats so the current draw will drop. I am quite sure you will be good to go! I spliced a deep socket onto a 1/4 tube to be able to reach and screw the glo plug into the barrel of mine. Your way is a lot easier to install and wire. Haven't used mine yet but will in November.
 
#48 ·
Cool guys, can' wait to see what everyone builds. Hopefully I can post some pics of my new vaporizer set-up tonight. I ran a few more tests on my 12v set-up and here are some numbers:
12V Interstate full sized battery. 575 cold cranking amps and 720 cranking amps.
12.8V in the battery to start
Air Temp was 70*F
15 sec- 75*F
30 sec- 95*F
45 sec- 127*F
1:00- 164*F
1:15- 200*F
1:30- 238*F
1:45- 277*F
2:00- 315*F
At two minute mark I unpluged it from the battery but the aluminum was still transfering the heat to the combustion chamber. 2:20 the temp hit 365*F. So I'm thinking on my unit I need to unplug around the 1:40 mark to keep from burning the OA. The temperature results were pretty much the same as using the small 12v battery on my John Deere Gator.
12.5V in the battery at the end of the test.
Amp draw was 13.8 at the start and dropped to 11.8 at the 15 second mark.
 
#50 ·
Ok, I finally have some pics of my new set-up.
Here's the vaporizer assembled and ready for 12v. Aluminum and stainless steel construction. Everything threads together so I can disassemble it for cleaning.
Auto part Tool accessory


Here it is hooked up for 12v. I have a threaded insert on my box so I can easily remove the vaporizer.
Wire Technology Cable Pipe



And here it is setup for use with a propane torch to heat the OA.
Machine Machine tool Tool accessory


Later on I still have to make a smaller diameter and longer length nozzle so I can use the vaporizer on my nuc boxes. A Nuc Nozzle, lol.
 
#53 ·
Shadow, A couple of questions.
How much clearance is any is between the glow plug element and the aluminum rod?
Did you take into consideration expansion inside the rod when the element heats up or do you want this chamber air tight?
I have the glow plug and aluminum rod and was going to start building one today. But thinking it through I was not sure just what size drill bit to use for boring the portion of the hole for the element to fit into.

Final question. What is a good source for the OA?
 
#54 ·
Hi Daniel,
The tip of the glow plug will expand some when heated. Hook it up and heat it outside the aluminum rod to start. When the plug cools off take some measurements. I didn't want the tip to touch the aluminum but wanted it close to transfer more heat to the aluminum. I did think of air pressure inside the tip chamber, this was another reason I turned the threads off the plug and used a set screw. Gives it just alittle bit of air gap. I have been thinking on some sort of liquid heat transfer system but have not go very deep into it yet. Water will tranfer heat 10X fast/better than air but there might be a pressure issue to deal with.
OA can be found at most local hardware stores. Sold in the paint section as wood bleach. I bought mine on ebay, $12 shipped for 2 pounds.
Hope this helps,
Caleb
 
#55 ·
One of the more sought after features I have seen mentioned is built in air movement. This video is the example I have seen most commented about.

http://www.youtube.com/watch?v=2NoYE2FA6_U&feature=player_embedded

I see your glow plug Acid chamber design is extremely adaptable to many other configurations.

I have seen comments of pipe being permanently installed in hive bodies where the vaporizer can then simply be fit and the acid treatment administered. the pipe is then capped until needed again. Copper or brass pipe was suggested in that design as well. Possibly aluminum tubing would be better.

On the heat transfer issue. My first thought was of a grease that is applied to the back of certain integrated circuits that generate excessive heat. the grease makes the transfer of heat to a metal plate higher so the circuit is protected. I am not sure of what the temperature ranges for that specific grease is but I do know such products exist.

Speaking of heat transfer. Do you have any measurements on the cool down of the chamber after the acid has been vaporized. Everything I have seen speaks of the heat up and time it takes to vaporize the acid but I never see where the time to cool down is added.
 
#56 ·
The heat transfer grease may be a good idea. I'll have to do some research on it. I know some of my high speed flashlights have thermal grease in them.
Read through a couple of pass posts. I wouldn't reccomend brass or copper for the vaporizers. There is a chance of toxic gasses in those two metals.
Everyone has told me to leave the hive closed up for 10 minutes after vaporizing the OA. The aluminum dissipates the heat very fast. It just barely warm to the touch after 10 minutes.
Also I think it would be best to be able to clean the vaporizer from time to time.
A note on air flow too. Once the vapors enter the hive the bees will fan it through out the hive trying to remove it.
 
#59 ·
Shadow I can't say about the anti seize and gassing. But would it matter? The threads for the glow plug at least are outside the chamber. As for off gasing of copper or brass. I have never heard a concern about it for plumbers that sweat copper all day long. often in large volumes in confined spaces. I have seen the concern that the introduction of Oxalic Acid changes the chemistry though. At the very least a concern.
I do beleive the forced movement of the vapors is more of a perception thing to the beekeeper than a necessity. But people are attracted to what they are attracted to. Vapors are goign to pretty much dissipate no matter what. But this is not something the average person is goign to know about or rely on. that it blows around just carries a level of comfort to it. I am pretty thrilled with the design as it is.
 
#60 ·
Glow plugs are pretty robust, I have made 2 vaporizers and have used them on about 40 hives per year for 6 years now, and I have the tip protruding into the crystals with no problems.

The down side is the battery it will only do about 10-12 hives per charge. I know a bigger battery would do more but they are heavy.
 
#63 · (Edited)
Regardless of reactivity, Copper fittings are out due to price. I can actually get SS fittings at a lower or at least equal price.

The main cost with SS fitting is the Flange at $27.00 for a threaded flange. Any suggestions for the connection from the pipe to the box would be appreciated.

Otherwise I am looking at anywhere from a 1 1/4 inch nipple and 45 degree elbow down to the same in 3/4 inch. Price for the set ranging from $17.03 down to $9.01.
As a comparison a single 45 degree elbow in copper (1 1/4 inch is about $10.00) 3/4 inch is not a lot cheaper.

I priced such large fitting because the Aluminum rod I am starting with is 1 1/4 inch diameter but that is a bit overkill for the fittings.

I am looking for other solutions, preferable lower cost for the connection to the box.

Also the 45 degree elbow is threaded at both ends. I can thread the aluminum rod but would rather have this be a slip fitting for ease in removing and reloading. even if it is a slip fitting with a thumb screw as a set screw for added holding power. If nothing else I will turn and thread a piece from aluminum rod. I much prefer to come up with a design that is of the shelf parts so that anyone even without a shop can repeat it. Except for the glow plug / vaporizing chamber.

By far the big cost with these parts would be the flange. I was lookign for a bulk head adapter but am not making much ground there, plus the costs are still coming in fairly high.

Anyway so far my parts woudl run between $55.37 to $36.01 all stainless steel not including the aluminum chamber or shipping. That heats the tar out of $175 I have heard mentioned for other systems. Still let me know what you all think of that sort of cost. With a little more effort I think we can put a dent in that cost with a solution to the SS flange. I am looking for a brass flange since at this point the brass will not be exposed to the acid vapor. but am not having a lot of luck so far.

One solution to the $27.00 flange is a $3 steel one. Since the SS nipple threads inside this flange it is not likely to be exposed to the acid vapor. In the event a portion of it is that can be coated with something like JB Weld or steel putty as long as those products woudl not create gases of their own.
 
#64 ·
I would suggest keeping the mass of your components as low as possible. The more cold metal the more heat it takes to get above the vapor poiint and the more re crystalization as the gas leaves the heat source.
As for the antiseize compound, there may be a bit of initial off gassing as the liquid component evaporates but the remainder is going to stay pretty much in place. That is what it is made to do and is slathered around all nuts, bolts, threads etc in boiler rooms around the world. It did years ago have a lot of lead powder in it but anything modern is pretty innocuous I think. If you want just use teflon joint tape. The oxalic vapor though is a whole 'nother beast! Just a mere wisp inhaled and you will be clearing your throat for a day or two.
 
#65 ·
crofter, good point about the mass of the chamber and components. I am actually looking for more mass in the vaporizing chamber for the exact reason of it being a heat sink. This also causes it to remain hotter to handle longer. I do have an idea of how to solve that. keep the chamber warm but make it touchable.

As for the rest of the components they will be a 3/4 inch 45 degree elbow the same size as a galvanized pipe would be and a 1 1/2 inch length of 3/4 inch pipe. I am not sure the distance can be reduce much more than that unless the chamber itself passes through the wall. I have actually thought up a design that will work that way as well and may build it later today.

Basically it is a section of 2 inch diameter aluminum rod that fits through a hole in the box. and slides in and out like a drawer. The pocket for the acid will be a hole drilled in the side of the rod. There will be a stop at each end of the rod to prevent it from being pulled completely out or pushed to far in. The glow plug can be inserted so that it is directly under this pocket. Overall mass from glow plug to pocket of acid would be very small. And mass from vaporized acid to the air of the hive woudl be nothing. at most the acid sets in a pocket that is maybe one half to three quarters of an inch deep. think of the bowl of a smoking pipe with the acid setting in it waiting to be heated. If it works out that the glow plug can be in direct contact with the acid then there is really no mass between the glow plug and the interior of the hive. Faster vaporization since the heat is applied directly to the powder and the chamber itself does not have to be heated.
 
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