Vodkaman

PoP dryer

35 posts in this topic

Everyone agrees that using the household oven is not a good idea. Commercial plaster operators use drying ovens. There is no reason why the small production/hobbyist cannot do the same. So I have introduced this thread so that we can brainstorm the problem and arrive at a workable solution.

I see the solution as a box, deep enough to mount a household bulb with sufficient air space around it. At the bulb end, a 2 inch dia hole. This is the air inlet. At the other end, a small 12v cooling fan (battery operated), as used for cooling computers. These fans move about 4

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I throw my PoP molds in a 12 in. square cardboard box then set the top of my food dehydrator on it. Run in for 8 hours then pour.

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Guys, How bout using a thermostat controlled heater that you would use in a incubator. I remember as a kid we had a box that we would put duck eggs in to keep them warm untill they hatched.

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It would work, but would take a lot longer without the airflow. The required temperature for ideal drying is 120°F . This temperature is little more than a hot room. The introduction of moving air keep the humidity at the PoP surface low and promote evaporation. All comercial ovens are based around an airflow.

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This sounds a whole lot like the food dryer I built using plans from our local county extension agent. It used aluminum screens built by a local screen repair shop. They kept sets on hand just to fit the dryer.

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Hey Vodka, out in the field on construction sites when we couldnt get a microwave on the job we constructed a hot box, which was a wooded box made of plywood with a hinged lid on top, and took some 1" insultion foam board and glued it to the inside and on the outside of the foam applied aluminum foil so that the box would be lined to refelect heat, and installed a 100watt light bulb into a screw shell lamp holder, just the cheap plastic style thats in your attic, and plugged it into the nearest socket. We would put our food to be warmed up in around 9.00am and by 11.30am its ready to eat,

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Ross, good one. I've used a similar design when I used to do wine making. Heated by a 15w bulb and a thermostat to control the required tempreature.

I did not mention insulation, as the air will be in and out. But I think a lining of ALUMINIUM foil would not hurt any.

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Couldn't you retrofit a large ice chest? It's already insulated, and the plastic ones are cheap.

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This thread reminds me of my brother inlaw. He heats his lunch behind his radiator on his truck. He made a wire rack on the back of the radiator. Wraps his lunch in tinfoil puts it in always has a hot lunch. Dry your mold on your way to work.

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Vodkaman, I am very interested in making a small POP dryer. I do have a question regarding the design. If I am correct the idea is to basically remove moisture. So the dryer the air passing over the mold the more moisture that can be removed. I have access to medical grade air drying chemicals (like dessicants) used for drying nitrogen that is put into auto racing tires. I am thinking of folding up an aluminum sheet metal box with an incadesent light fixture. Then using a computer fan to pull air through this pellatized chemical, to remove humidity, into the box. Then vent air out. Any thoughts, or is there little advantage to drying the air?

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This idea was borne from a discussion on oven drying and its problems. It is based on commercial drying oven design, taken from the internet.

The most important things are to keep the air moving to promote evaporation and don't let the temperature of the air rise above the safe max for the plaster (about 120F, I mentioned it earlier in the thread).

My only concern with the drying chemicals method that you're thinking about, is health and safety. If you can find a solution to these issues, go for it.

You could probably build it so that it uses both methods. Then you can report back with the comparison results.

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I would hold to the basic ideas of 120 degrees and airflow. The idea is simply to pass the incoming air through a pellatized material that absorbes moisture (no health issues, just don't eat eat), in turn drying the incoming air. The drying material is similar to desicant packs that you find inside a pair of new shoes. The theory being that incoming air with high moisture content cannot remove moisture as effectively as dry air. The theory sounds good, I was just curious if anyone else thought it might actually be effective.

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Sounds good, your theory is sound.

Is it possible to dry this substance in the oven, thus making it re-usable? We are talking a lot of moisture, I have noticed 30 - 40% weight reduction of the PoP mold during the drying process.

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That is an interesting question, I do not know if you can recharge this material, that is something I will look into. I am going to get something going on this "easy bake oven" and I will post what I come up with. Thanks for you thoughts.

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Would a cheap toster oven work? That way you don't destroy the boss'es (wife) oven. Would a smoker like the one's in the netcraft catalog work? Could using a chemical to dry cause toxic fumes when you pour? airhog had a good idea simple and works.

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Just my opinion, for what its worth and thats about nothing, but I spent 18 years in the Heating and AC buisiness. A temp controll is cheap and I would think absolutely necesary for what your trying to do. You can get by without the humidity controls but I would bet anything by the time you are done screwing around with different lightblbs and faan speeds and moving it to different locations based on outdoor weather temps ie. sun beating down on it vs shade(assuming this is located outside which it should be).Throw a 20.00 temp control on there and save yourself the frustration. In fact look in granger and you may even find the small fan you need that will be 110volt so you wont need to use 12v either, but thats really not that big of a deal.

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After 18 years in a relevant industry, your opinion is worth a lot. I do agree with you, a temp control would be an advantage. I have designed circuits for temp controls for brewing equipment and for my pet tarantula!

I did not include such a control, because this usually scares people off the project as too complicated, also, I doubt that the temperature is that critical for what we do, considering most members (including myself) dry the PoP in an oven. The temperature references were included because they were quoted in the industrial design article that I based the idea on.

The object was to come up with a quick, cheap and efficient way to dry PoP without using the bosses oven. As I live in a rented apartment from the landlord from hell, I am quite happy to use his oven.

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Isn't that the truth. If you have a landlord from hell like L also do. Just go a head start a POP and worm factory in the house. If the oven craps out the landlord will have to get you a new one. MTfishingrods Has a good idea he also has 12 years over me in the HVAC. I belive he knows what he's talk'in a bout.

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Back to the K.I.S.S principle....

Why not get a small personal heater from (insert you local everything store) with a thermostat? The heating element will dry the air some and it has a fan. Stick your vented box in front of it and set your thermostat. You may have to play with the thermostat and a thermometer until you get the temp the way you want it.(the one I have at home has a thermostat, but it is just a widening line instead of actual temps) This would be simple and cheap.

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I use a kids metal locker I bought at lowes for about 30 bucks made rails along the side to hold the jig holders (two boards with rubber in between to push jig into held together with screws) already has vents and heats to about 150 will try to post a pic well better email me I will still see if I have the pictures works great on lead jigs and have done some crankbaits by using small screws to hang the baits from, The heat comes from a small space heater from lowes will try to get the name and model but it works great it dont shut of either Irun for about two hours using a timer on outlet

szimmerman14@cox.net

pics

well have not figured out how to do pics yet but email me will be glad to send pics:yeah:

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I think I just witnessed the birth of the easy bake oven 2....................

I was pondering a similar idea for hanging lures in to dry after painting. My version had the bulb in a sort of metal can sheild at the bottom and the hanging racks above. I was going to put some holes in the top for air flow. It also needs a hole at the base for fresh air to get in. The air flow to the top has to be deflected so it isnt a direct path. This will stop it from needing a fan. If done properly it is cheap, simple, and efficeint.

I think the hole at the bottom has to have more area than the combined area of the venting holes.

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