Blasting cabinet heater?

[irishpol]

Before the crash I started a thread on sand blaster problems, well my problem is humidity making the media damp... is there some kind of small heater unit I could install in the bottom of the hopper to keep the media dry? seems like an obvious solution! any surgestions would be welcome.

[CARS]

Until a few years ago, my dad had a large plywood box that stored all of his welding rods (arc). He had a 60 light bulb on inside of it 24/7 for 30 years (well, not the same bulb :rolleyes: ).

The light gave off enough heat to keep the rods dry.

Every blasting cabinet has a light or two. Maybe just leave the light on?? (like Motel 6)

[dauer]

Hi Paul,

Are you sure your moisture problem is coming from the blast media itself?
Most of the time the water comes from the air supply....blasting uses such a high volume of air it can be really hard to keep the condensation out.

Dave

[irishpol]

Yes the bottom few inches in the hopper is damp. I have a water seperator on both the compressor & the blast cabinet.

[oldgoaly]

Paul,
by the way you are describing the problem, moisture is seeking out the sand in the cabinet do to the changes in temperature. A dehumidifier and or air conditioner would help. Another approach would be dry the sand out and keep it in a plastic 5 gallon bucket (s) with a lid (good seal too!) When you need to use the cabinet dump the bucket (s) in the cabinet put the appropriate size screen down before you pour it, might as well get the junk out too! When you done with the cabinet, empty it back into the bucket (s) and seal and you will have dry sand next time. Take care! tt

[irishpol]

What a pain constantly emtying & filling the thing! due to space constraints it lives outside on the patio, I'm sure a simple heater would cure the problem. So back to my original question; can anyone surgest a simple little electric heater element that I can build into the bottom of the hopper?

[CARS]

I think Dave and Terry's advice needs more consideration.

How is your cabinet plumbed (fed)? If you are running all hose, you could have 20 separators in the line and still get moisture. The air doesn't have a chance to cool. Vapor gets through separators. Cool air creates drops and the drops hit the separator and fall to the drain.

I have never heard of a sand heater before. Nor have I heard of anyone needing one. That doesn't mean your idea doesn't have merit though.

[irishpol]

The media is damp before I even conect the air line after not using the blaster cabinet for a couple of weeks. I have no problem with water when using air tools, spraying or my 80lb pot blaster. I just need to keep it dry or dry it out before I start. All I was trying to do is find out if any of the forum members knew of a small heater element I could fit in the bottom of the hopper.

[oldgoaly]

Paul,
You answered your own question, not about the heater but the pot blaster. The pot is sealed, sand is good. Trick now can you seal the blast cabinet to keep out most of the moisture sounds like the easiest and cheapest solution. If you go to a heater, one it will need power, two it will need a limit/thermostat. Common heaters available: birdbath, animal watering, domestic water heater element (dry run type) Hvac compressor crankcase heaters, engine block heaters. How much heat? how much sand do you have? also do you want to leave it on 24 hours a day or just when you use the cabinet. Please note as you drive the moisture from the sand to the air in the cabinet, it may condense and run back down the side of the cabinet into the sand.

[adtkart]

If the blaster cabinet is made of metal, so not easily damaged by heat, there is a way to try to heat it. Get one of those small electric heaters, known as "Milk house heaters", to place outside of the blaster. Place it so it is heating up the outside of the hopper area. The heat on the metal should transfer to the sand, causing it to dry out. You should make sure that the cabinet is not sealed to prevent the moisture from getting out, while doing this.

Aaron Thomas

[CARS]

Aaron, Those "milk house" heaters are not made to be run at an angle or horizontally. The fan will not last. In fact, in the last few years, they don't seem to last more than a couple years when used properly. (made much cheaper than 20 years ago like everything else in the market)

Terry is right, you can heat it with many different items. Is it worth it to pay $$$ to heat a $5.00 bag of silica???

How often do you blast??? Is it really just every couple weeks??? It may be a pain, but if you're having this much of a problem it may pay to dump the sand and seal it up till it's next use.

I would try and ask your cabinet's manufacture or even (and maybe better) your sand supplier what others in your climate are doing.

Or, just try out some elements. I've never heard of it being done or being needed but a frost plug heater or electric frying pan element can be had for a buck at a junk yard or yard sale.

Good luck and keep us posted on what works and what doesn't.

[Rick Mullin]

Perhaps this sounds dumb but... What about hanging a 100 watt light bulb in the cabinet while not in use? It is the same idea as we did as kids to make an incubator to hatch eggs in science class. You don't need a lot of heat just a controlled amount to reduce humidity. When you are ready to use the cabinet, just take the light out. It may not be enough to dry out what is in there but it should maintain a dry condition once established. Simple and cheap.
Just my silly 1.5 cents.

Rick

[Roger J.]

Paul,, not sure if this would work for you or not,, but in a shop that I worked at years ago we used walnut shell and had a bit of a problem with moisture in the hopper. Their solution was to run a short air line from a "T" at the tank (with a valve on that line), and it connected to the bottom of the hopper. If the media would get clogged up, you turned off the valve that pressurizes the tank at it's original point, and cracked open the valve on the line to the bottom of the hopper. This would sorta backfeed the media and blow it up into the tank away from the output point.
Depending on how much I was blasting, I usually had to backfeed it 3 or 4 times in going through a full hopper.

[Mike Rouse]

Hello Paul,
Have you tried changing to another blast media? I use the black coal slag.
The other thing I will suggest is to place a light bulb in a reflector fixture on the bottom of the hopper, may start with 40 watt and increase as needed. Also you may try insulating the outside of the hopper bottom with foam board glued to the outside. I think the sand does not change temperature as fast as the outside air and the cool sand from overninght causes the warm moist air to condense on to the sand. Heat and insulate the mass of sand.
Mike

[Dawai]

Okay.. when you get done with all the other trials..
http://www.completeplastics.com/resource/Images/Cartridge%203R.jpg
A block of steel.. a "cartridge heater" meaning a tube with heat resistant wires coming out of it that slides into the drilled hole in the block of steel.. mount this in the bottom of the blast cabinet.. route the wires outside.. on the cartridge.. it says voltage and watts.. the ones I have here in my hand were for a plasitic extruder.. go into the extruder block..

wiring it.. okay.. hot sand is good sand.. but.. how to keep things like paint chips and "solvents" in the mix from pre-combusting? A lil "overtemp" button like goes into a heater or clothes drier.. it snaps when it gets "way too hot".. Personally.. I'd rig a water heater thermostat on the outside of the box there close or connected to the large steel block and use it to turn it on and off.. perhaps.. a light .. warning light.. of when you are "HOT".. since this thing will increase your hydro bill..

Send me a plane ticket.. we can have a blast.. (whar the white wimmen at?) I'll bring my box of tattoo equipment, my glasses.. some spare changes of underwear... Otherwise I can take a crayon and draw you a picture of how to build it.. if you need?? Simple enough.. just google cartridge heater.. common wiring saftey implies.. do it so you live to do it again.. Okay to take chances.. when they warrant so.. like passing in a corner on a racetrack.. (push him on into the fence..)... put them all through the fence.. and soon you got the track all to yourself..

David.. North Gawgia.. (IBEW JW-instrumentation-robotics union ticket) Learning metalshaper.. (Favors go two ways)..

[Dawai]

My next blast cabinet will be the ass end off a delivery van.. about six to four feet of length, shoved up against the building I work out of..

motorcycle frames.. rear axle housings.. small things..

I scrapped, (sent the china) the steel from four of them old ford vans in a row.. I just was not thinking..

[James(Western Canada)]

David: Funny you should mention that, as there is an independent shop in the west end here that specializes in VW's (always work when that's your specialty :):) Anyways, they have a blast cabinet outside made from the back half of a 70's VW Bus.....

James

My next blast cabinet will be the ass end off a delivery van.. about six to four feet of length, shoved up against the building I work out of..

motorcycle frames.. rear axle housings.. small things..

I scrapped, (sent the china) the steel from four of them old ford vans in a row.. I just was not thinking..

[Dick]

there is also an electrical heating rod for gun safes for same reason - to keep moisture at bay
might work, might not

[James(Western Canada)]

Here is another possibility.....heat tapes used to prevent plumbing, etc from freezing, and I believe that some are even self-adhesive....

http://www.heatersplus.com/pipes.htm

James

[irishpol]

You've given me a few good leads to try, I'll let you know how it turns out.
Many many thanks.

[Jaakko]

There are people using a light bulb to keep wooden gliders / sailplanes dry when stored in their trailers; just a 60 or 100W bulb seems fine for a trailer 25ft long, as not only heat, but air circulation does the trick. I would give that a try...

Remove it from the cabinet before blasting, and afterwards, give it a few minutes for the dust to settle before switching it back on. Dust explosions might be an effective, but not very safe way of drying blasting media...

But there's better media around that won't soak as much as sand does, and - along the way - won't affect your health as much. (Just in case you are using sand...)

Jaakko

[Peter Miles]

Depending upon how much sand you are keeping in the hopper, you could consider building a small box to enclose a low-wattage light or one of the goldenrod - type heaters that are used for keeping boats dry. They are intended to heat air just enough to act as a dehumidifier. People also use them in in gun cabinets, small aircraft, etc.

Another possible approach: a heavy canvas shroud, possibly with a blanket underneath as insulation, to drape over the entire unit and then place a incandescent lamp under the shroud directly beneath the bottom of the hopper.

If you warm the environment much, however, you may draw insects, rodents, and snakes (sounds like a well-rounded biosphere but you may not wish to share!).

[Dawai]

Computer in my cnc will quit about 30 degrees F.. I keep a light bulb in the box with the computer. One day a nice fat possum jumped out the lil rubber flap over the cable entrance.. nasty critter had messed on top of the computer where I had to deal with it.. (warm place to poo and all that)

Another day.. a small rat jumped out of the gear drive head and onto mine. I danced till it was stomped flat. (scared the bejesus out of me)

the rod heater box.. well it was made into a welding table.. snakes loved to curl up on top of it.. a nice dark colored one stayed there for weeks.. I was happy he was keeping the rodents out of the shop, till I figured out he was a water moccasin. Then he had to die.

It's a zoo around here. All enjoying the free heat. Can't much live in a small block of steel with a tubular heater.

[CARS]

I think I may have found the answer to your moisture problem.

The Remington Model 365 Mini Dehumidifier
http://www.remington.com/products/accessories/storage-and-safety/dehumidifier/model-365-mini-dehumidifier.aspx

It is sold by gun dealers, on Amazon.com, and through the sportsmansguide.com

[Dawai]

Chris....

Now ain't that just silicate... you know the lil packs that come in electronics and say "do not eat" on them??

Also.. in air conditioners in that lil can.. saw the bottom off.. get a couple cans of it.. put it into the oven and bake it ever so often.. it sucks and holds moisture from the air.

Been there.. done that in my gun safe..

the ten foot tall six inch pvc pipe in my shop.. I ran my paint supply air through it.. it dried it.. all the water stopped in the bottom of the pvc..(I painted two dozen cars) but.. everyone on the painter forum I was on offered to come "whip my ass for suggesting it"... but you know what?? I still use it at times.. (pvc can explode with shrapnel)..

Cooling the compressor air gives a chance to condense the water out of it.. a dead space where it moves slow.. I've always wanted a row of storage tanks..

Heat.. aww.. I see a place to build a welding rod heater there. Use the escaping heat to dry the sand.. Heah.. in the south.. ever spring.. my machinery gets dew condensing on it.. not much you can do about it.. cover it with a tarp.. put a light bulb under it.. .