Drying box burst in flames

[Givat]

My not even year old drying box burst into flames today while drying 1.5 kilo red magnalium stars and 800 gram WIn20 stars.

I had alot of luck and I saw the light that came from the box from far away and ran to take care of the fire.

 

Mt drying box before:

http://i1111.photobucket.com/albums/h479/questl/tools/P1010828.jpghttp://i1111.photobucket.com/albums/h479/questl/tools/P1010829.jpg

 

and after:

http://i1111.photobucket.com/albums/h479/questl/tools/2012-03-05175046.jpg

 

apart from the black stains I can't get off the wall and floor there is not a big damage. no one got heart.

 

I think the reason it all burst into flames is my hot plate thermostat was ruin and it kept on heating till the stars ignited.

 

for my next drying box I'll be sure use different box for the hot plate and different box for the comp I dry. (connect both boxes with some PVC tube and computer vent to move the hot air.)

 

I thought I should show it here, so people wont make my mistakes again

[oldguy]

Glad no one was hurt.

You were VERY lucky nothing else ignited.

I use a food dehydrator as a drying box.

 

[warthog]

I use a food dehydrator as well. Mine is a lot smaller than his though but I imagine so are the size of my batches of stars.

 

So you use a hot plate to produce the heat? May I suggest a different way? A ceramic disk heater is a safer way and they have fans on them already. I am in the process of making a larger dry box now. The walls are made of 1/4" plywood that I will attach 1x2's to for holding the screens. The top of the box has a hole in it which I have put a fan that has a sponge filter over both the intake and out put so that sparks from the motor are isolated from the interior of the box, I also used a 90° bed and a foot of metal venting to further isolate the motor and the possible sparks. The heater sits in a regular metal vent, another 90° bend and another foot of vent tube onto which I put some window screen on both ends f the foot of tubing, to keep any sorts of fire out of the box.

 

Maybe I should try to draw it since it isn't finished. Not sure if the description I just wrote is all that clear.

[oldguy]

If you can find a a small 4 disk 1500 watt PELONIS ceramic heater.

They are about perfect for a DIY drying box.

They are a little expensive new, but can sometimes be found cheap at thrift stores.

[Givat]

oldguy, you are right, I was very lucky and I know it.

 

I always looked in this hobby to make everything as chip as I can, everything is homemade. so I don't think I'm going to buy a drying box like yours.

 

In the last hour I tried to think on a design who will be safer and thought about this:

http://i1111.photobucket.com/albums/h479/questl/tools/dryingbox.jpg

 

as you can see it will be made of 2 boxes - one for the the drying substance and one for the heating element. I think this is the safest design I can build.

for a heating element I think to use "immersion heater" like this:

http://www.elitools.com/files/images/463.jpg

 

I will use a dimmer to control the heat output.

 

what do you think?

 

warthdog, I think this is what you talked about too, right? if not please upload some painting of what you had on mined.

Edited March 5, 2012 by Givat

[oldguy]

For heat, I would suggest a simple inexpensive heating pad. Like you use for a sore back or pulled muscle. They are cheap & available about everywhere.

They usually have 3 heat settings (low-medium-high). You can fine tune one with a rheostat (dimmer switch), if you want.

 

Other than that I would suggest a mat type reptile tank heater.

Or, mat type heater for starting plant cuttings.

Any of those will work for heat.

A little air movement speeds up the drying process & any type computer fan will work.

 

 

[allrocketspsl]

mine sits outside sun heats it good vents only no motor strong cardboard form insulation drys the hardest in a heart beat

light bulb turns on if need be

[Givat]

what temp do you want for your drying box?

I used to have temp about 40-70 degree Celsius in mine. was it too hot?

[oldguy]

I use close to 48C, 120F.

[Potassiumchlorate]

Oh, shit! At least only the box was destroyed.

 

But do you really need a drying box in a country like Israel? At least in the summer it's incredibly hot and dry there, isn't it?

[Arthur]

"heating element I think to use "immersion heater" like this"

 

Givat you scare me. Those heaters are for boiling water and will not stand plugging in to power unless they are immersed. If you are lucky the heater will cut out (permanently) if yo are unlucky it will fail and overheat and start another fire.

 

The best dryers have some gentle heat and a dehumdifier of some sort.

[dagabu]

There are many ways to skin this cat but just about all of the large drying chambers I have seen use light bulbs for the heat source with a metal shield over them to keep comp from touching them and a small fan at the top to draw air out of the chamber.

 

I personally use the same thing that OG uses and it drys anything overnight.

 

 

-dag

[NightHawkInLight]

I haven't been keeping up on all of the drying box threads recently so forgive me if this has already been discounted, but have upright oil heaters been considered? Such as this: http://www.amazon.com/DeLonghi-TRH0715-Filled-Radiator-Heater/dp/B000FT1XZW/ref=sr_1_2?ie=UTF8&qid=1330985894&sr=8-2

 

The heating fins contain no electronics, are totally enclosed and sealed with a thick coat of paint, and a box could easily be built in such a way that the electronics and oil heater are isolated on the outside. No chance of electric contact inside the box, and the oil does not get hot enough to ignite typical comps.

[Givat]

PC, in the summer I dont need any dry box....but in the 3-4 month of winter I need one.

 

Arthur, I hear you. I will look for a heat source that is built to work for a lot of hours in the open air.

 

dagabu, You can;t buy heat wire light bulbs over 60W in Israel (a new low started this year). I thought about reptile heat lamp (infra-red one) but I think this won't give me enough heat.

maybe halogen light bulb?

[warthog]

Givat, your drawing is pretty close to what mine will end up like except there are no bends in the ducting. I plan on snaking my ducting between the two boxes like an "S" adding screens of some fluffed up steel wool as barrier against sparks. Mine will have one of those little ceramic disk heaters in it at the bottom blowing into the area where the racks of drying screens will be and a exhaust fan at the top hole to make the air circulate as much as possible. The heater also has a blower on it. The heater's heat element, blower fan and the exhaust fan are all adjustable for speed with a rheostat, the one for the fan I will wire in and the one on the heater is a part of the unit.

 

Am immersion heater will burn up if you just leave it out and heating up. They aren't designed for that sort of heating. I see, you are in Israel, perhaps then the best ay to go is a little space heater. Either use one like NighthawkInLight suggests or one like mine, a ceramic disk heater. These two have no exposed heating elements like a regular space heater. Mine has an enclosed element that heat a thick ceramic disk which then radiates the heat to the room and the others work like an old steam radiator but are filled with oil instead f steam/hot water.

Edited March 5, 2012 by warthog

[asilentbob]

If you want a smarter thermostat / drying circuit you can use a PID controller (Proportional, Integral, Derivative) made for temperature control. They are not terribly hard to use if your good with electronics. You add a thermocouple and use whatever the controllers outputs are to switch on and off the heat source, whatever it is. You may need some external circuitry to be able to control the load, such as electromechanical relays, contractors, solid state relays, etc... Which is where the electronics know-how really comes in. They generally have several modes of control, like on-off switching, 0-100% partial driving, etc... you can also generally set alarm conditions and such so that you can be sure the heating element doesn't reach a certain temperature, and if it does you can get a notification with external alarm circuit, or use the alarm circuit to cut power to everything, or whatever you want... Way overkill probably, but they can be used for all sorts of other projects so people sometimes build them into little portable boxes with AC sockets.

 

However, for a drying box you might not necessarily need a heater. A fan and patience may be sufficient.

 

I just dry with a fan and place it somewhere where morning dew isn't an issue.

[dagabu]

However, for a drying box you might not necessarily need a heater. A fan and patience may be sufficient.

I just dry with a fan and place it somewhere where morning dew isn't an issue.

 

There are a few comps where heat is necessary or they will never dry but I too just use a fan on all BP based items.

 

-dag

[californiapyro]

sodium nitrate

[warthog]

@asilentbob, does it get to -10°F in the part of Texas where you live?

 

There are indeed times where heat is going to be needed to make the stuff dry.

Without heat in the winters here for instance, comps freeze. Once frozen they never dry.

 

I guess you can add a thermostat etc, it would make temp control a lot more precise.

The thermostat on the little heater I have seems to be all I have needed so far.

I have used the heater w/ the box a few times. I used it to heat up my entire work shed and made it my drying box.

That works but my power bill hates it.

Edited March 6, 2012 by warthog

[nater]

can you get regular incandescent light bulbs in Israel? I am not sure what you mean by heat wire bulb.

[Potassiumchlorate]

I think he simply means old fashioned light bulbs. The New Soviet Union EU banned them here in October last year. I bought lots of them just before, not for using in a star dryer but because I like that old fashioned, warm yellow light.

[DanielC]

I use a small ceramic heater ducted into the 4x2x3 dryer box and vented through the top. It works very well, but it still gets pretty warm (around 120F) I did however have a problem with drying some glitter stars a few weeks ago. They started to gas a bit. Unless it going to be below freezing overnight in your work area it is usually best to air dry them for a while before force drying. I love the dryer box because granulated powder dries in less than an hour and stars easily dry overnight even in the middle of winter. Yes, it does get cold in South Carolina.

[Givat]

After one and a half month of planing here is my new drying box:

http://i1111.photobucket.com/albums/h479/questl/tools/IMG_20120331_191819.jpg

http://i1111.photobucket.com/albums/h479/questl/tools/IMG_20120331_192316.jpg

http://i1111.photobucket.com/albums/h479/questl/tools/P1040059.jpg

http://i1111.photobucket.com/albums/h479/questl/tools/P1040060.jpg

 

all the drying box is made out of a 22.5 c"m Dia PVC tube.

The screens are plastic screen for windows.

all the screen go one on another with a rubber to make it "air proof"

The heating element is from food dehydator oldguy sent me (Thanks again!)

as you can see this time I took a lot of space between the drying composition and the heating element......(maybe to much space, I haven't decide how long I want thus PVC tube to be)

 

I'm waiting for 2 computer fans 8 c"m Dia from Ebay to finish this beauty. (to help with the circulation)

 

Givat

[Mumbles]

I hope this works out for you. The one concern I would have is that you'll eventually just be circulating hot moist air around. It could work better with some sort of vent or another way to remove moisture.

[Givat]

it's not air proof....and near the heating element there is a lot of space for air to come and go.