High mite count

[bobba]

That's interesting hearing how yours behaves on heating too.
I also get some powder on the board. I interpreted that as material knocked out by the bees before it gets hot. If your pan is below the mesh though, that can't be the case. Mmmmmm.
It does seem that it might be better if they heated up more slowly but as I understand it, the really expensive equipment like sublimox actually preheat and then drop the oxalic acid onto the hot bit so quick heating can't be that bad.
Glad you think your new method is working now.

Repwoc - I used Apibioxal my first year but then switched to generic because I was annoyed that apibioxal came with a use by date once opened whereas the other didn't. I get the black residue with both.

Robmort's suggestion of a reaction between the metal and acid sounds reasonable though I do sometimes get bits of material that have to be scraped off rather than just staining.

I was told the powder jumping out the pan can be because of damp powder. So got some new powder and had same problem. Tried the brand name powder too, better, but still happening.

I have seen it happen when test panning in the open. It happens when the vapor erupts, sometimes some powder gets thrown out. I think its because the powder on the bottom of the pan can boil and vape before the top stuff has melted. So I expect that's what the per-heating is to help prevent.

I have found if I make sure any lumps are crushed it seems to help. I think its best to sort of pack the powder down a bit so there are no air voids, but not over pack. And try keep it contestant in the pan.

But what ever I try it still seems to happen sometimes.

I am tempted to try run my pan for 30s, the off for 30s, then back on to vape. To see if I can do a poor-boys per-heat cycle. But dont think I could be bothered with the faf even if it worked. I dont think loosing a little powder is a problem.

I also get the black staining with both brand name and generic, I agree with what Robmort's says.

 

[Murox]

............................I have seen it happen when test panning in the open. It happens when the vapor erupts, sometimes some powder gets thrown out. I think its because the powder on the bottom of the pan can boil and vape before the top stuff has melted. So I expect that's what the per-heating is to help prevent.
I have found if I make sure any lumps are crushed it seems to help. I think its best to sort of pack the powder down a bit so there are no air voids, but not over pack. And try keep it contestant in the pan.
But what ever I try it still seems to happen sometimes................................

I also use a cheap pan heater (aluminium) - I get similar issues - I found that preheating certainly helps reduce "eruptions". Last vape I tried preheating the pan with a gas torch, bit of a faff though it did seem to work at the time. I get the impression that ambient air temperature and humidity and surface area of the pan all play a part as well - the containing area in my pan is quite large so if I heap crystals in it tends to "erupt" more than if I spread the crystals out over the the entire surface of the pan. Consistent even heating seems to be a way forward, how to achieve that in a lump of metal "open to the elements" and heated by a 12v glow plug with questionable power supply is perhaps a problem area.

 

[jenkinsbrynmair]

Robmort's suggestion of a reaction between the metal and acid sounds reasonable though I do sometimes get bits of material that have to be scraped off rather than just staining.

I've had the same varrox irons for nearly ten years and they do guite a few vapes every season - no signs whatsoever of acid degredation in the pans or the surrounding metalwork

 

[drdrday]

I was told the powder jumping out the pan can be because of damp powder. So got some new powder and had same problem. Tried the brand name powder too, better, but still happening.

I have seen it happen when test panning in the open. It happens when the vapor erupts, sometimes some powder gets thrown out. I think its because the powder on the bottom of the pan can boil and vape before the top stuff has melted. So I expect that's what the per-heating is to help prevent.

I have found if I make sure any lumps are crushed it seems to help. I think its best to sort of pack the powder down a bit so there are no air voids, but not over pack. And try keep it contestant in the pan.

But what ever I try it still seems to happen sometimes.

I am tempted to try run my pan for 30s, the off for 30s, then back on to vape. To see if I can do a poor-boys per-heat cycle. But dont think I could be bothered with the faf even if it worked. I dont think loosing a little powder is a problem.

I also get the black staining with both brand name and generic, I agree with what Robmort's says.

I had the same problem of powder jumping out of the pan as it heated, and like you tried new OA that definitely wasn't damp - it made no difference.
I also modified the pan with an extended metal lip around it to stop so much powder from escaping, but I still wasn't satisfied that a full dose was being delivered into the hive.
Between powder escaping, and a 'crust' often forming over the top of the powder that never vaporised I got frustrated and bought a GasVap instead.
Every speck of powder in the GasVap has gone once a treatment is finished so I can be confident it's all been vaporised.

 

[drex]

I only find my pan type vape problematic if the battery is getting low. The usual OA is oxalic acid dihydrate, each molecule of Oa has two of water attached. Hence it bubbles as the water boils off. If battery is good the boiling off happens very quickly.

 

[bobba]

I also use a cheap pan heater (aluminium) - I get similar issues - I found that preheating certainly helps reduce "eruptions". Last vape I tried preheating the pan with a gas torch, bit of a faff though it did seem to work at the time. I get the impression that ambient air temperature and humidity and surface area of the pan all play a part as well - the containing area in my pan is quite large so if I heap crystals in it tends to "erupt" more than if I spread the crystals out over the the entire surface of the pan. Consistent even heating seems to be a way forward, how to achieve that in a lump of metal "open to the elements" and heated by a 12v glow plug with questionable power supply is perhaps a problem area.

I have noticed more powder jumping on colder/damper days too. I keep my pan in a damp shed, witch probably does not help.

 

[bobba]

I had the same problem of powder jumping out of the pan as it heated, and like you tried new OA that definitely wasn't damp - it made no difference.
I also modified the pan with an extended metal lip around it to stop so much powder from escaping, but I still wasn't satisfied that a full dose was being delivered into the hive.
Between powder escaping, and a 'crust' often forming over the top of the powder that never vaporised I got frustrated and bought a GasVap instead.
Every speck of powder in the GasVap has gone once a treatment is finished so I can be confident it's all been vaporised.

I sometimes get the "crust" too.

I had also thought about using some tinfoil to increase the height of the sides of my pan. How did you try modding yours?

I have read studies into OA dosing. And from what I have read the required doses are actually surprising small. So even if you loose 25% of the powder on a 2g dose I expect it will still be OK.

 

[bobba]

I only find my pan type vape problematic if the battery is getting low. The usual OA is oxalic acid dihydrate, each molecule of Oa has two of water attached. Hence it bubbles as the water boils off. If battery is good the boiling off happens very quickly.

As I have said before I can get 2 runs from my battery. I have not noticed any difference between powder jumping on runs 1 or 2. But my battery is an Li that keeps good amps to near flat. So maybe it would be more obvious on a NiCa or Lead Acid.

But if I were to guess, I would expect less powder to jump on the low battery as it would heat it slower. So your observation seems counter intuitive to me! I am not saying your wrong, you have just reported what you have observed.

I will be keeping a closer eye on powder jumping differences between runs 1 and 2 to test your theory though.

 

[bobba]

I got results again from hives Hives 1&2. They just had their 2nd new system vape, and 48h numbers we up (from about 10) to about 30-50. They were the first hives vaped with new system and i think i lost too much smoke. But moving the pan position away from the door and allowing a 2m cool down has made a difference. I do not see any visible smoke coming out the entrance or from the pan when I change it. So am fairly confident the new system is working now.

Thanks again JBM.

But listening to what others say about their pan set-ups. It does seem different set-ups behave a bit differently. So you need to tinker with your particular set up to get the best out of it. There are definitely a few little nuances to this panning lark.

 

[gmonag]

The pan should be cooled in water between applications. This allows time for the water to boil off before sublimation starts and prevent the spitting. It also removes the possibility of overheating the OA and causing decomposition into formic acid.

 

[robmort]

The pan should be cooled in water between applications. This allows time for the water to boil off before sublimation starts and prevent the spitting. It also removes the possibility of overheating the OA and causing decomposition into formic acid.

Doesn't make sense: if it's cooled off how can that allow the water to boil off??
There's negilgible possibility of decomposing into formic acid and even if it did it'd be a Varroa treatment.

 

[gmonag]

The pan warms up from below 100C so the water evaporates slowly. If the OA is put in a hot pan it flash boils and spits.
Your last statement is untrue.