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Old Dec 18, 2009, 08:47 PM
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Has anyone successfully built their own smoke unit?

I am trying this right now. Being pretty damn handy, I can build a boat , it should not be that hard to build a smoker. I took about 2 inches of cotton fireplace door rope, wrapped about 1 inch of .01 inch diameter nicrochrome wire from a hair dryer around the rope, soaked it in different liquids. First I tried glycerin mixed with distilled water, then liquid (glycerin) for a fog machine from Walmart, last I tried indoor lamp oil. I do get some smoke, but not much. I apply 12v directly to the wire, this is essentially shorting the power supply. The voltage drops from 12v no load to 2v under load.

Any idea's? I prefer to build as much as I can myself, but this is proving to be difficult. Maybe it's the liquid? Not sure what else I can try that is not flammable.
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Old Dec 18, 2009, 08:50 PM
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ken, you can buy water foggers

www.marksmodelbits.com
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Old Dec 18, 2009, 08:55 PM
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http://www.rcgroups.com/forums/showthread.php?t=330647
and
http://www.rcgroups.com/forums/showthread.php?t=272428

I really like the idea of the newer water foggers, as opposed to my original smoker which fogged with theatrical glycol solution- the stuff was REALLY messy. And I really really don't care for old style oil smokers.
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Old Dec 19, 2009, 12:34 AM
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Glycol fogger

Ken nj,
Easy to build. You're on the right track. The key is dia x length of the nichrome to get it hot at the applied voltage, but not red hot. It's a balancing act, but you'll figure it out. Next, you get very little smoke until you cause the glycol that is evaporating from the wick as invisible vapor to start re-condensing into "fog". That is accomplished by blowing cold air across the evaporating vapor stream coming from the heated wick. Low wattage is obtained by having the nichrome coil inside a glass capillary tube (glass is a good insulator) and having the fluid reservoir tube around that. That allows waste heat to preheat the fluid in he reservoir. Aother featue is that the cap tube acts like an old time coffee percolator. You can watch the preheated glycol boil up through the tube to exit off the heated wick, right where you direct the cool airstream to make the fog. Take a look below.

I like this glycol fogger. I think it puts out quite a bit of smoke per watt.
Its an enclosed unit and ay condensate drips back into the reservoir, so I haven't experienced any messiness.
They operate at about 2A @ 12V, or about 24 watts, and depending on the nichrome wire diameter and length, the units can be made to operate at any desired wattage (amps x volts.)

Links to a video and to how-to posts:

http://www.rcgroups.com/forums/showp...0&postcount=83

http://www.rcgroups.com/forums/showp...09&postcount=5

http://www.rcgroups.com/forums/showp...4&postcount=65

http://www.rcgroups.com/forums/showp...5&postcount=86
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Last edited by DanL; Dec 19, 2009 at 12:44 AM.
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Old Dec 19, 2009, 11:23 AM
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Let me also explain what I would like to do. The model this would be for has exhaust ports on the transom. I want to simulate the exhaust coming out these ports with a smoker. I will have to duct, or blow it out these ports, they above the waterline. I suspect pulling the smoke from where the smoke is made would be better than pushing. That can be figured after I get the right amount of smoke generated.

I know I can buy this, but not sure how the water based ones will work in this situation. The water droplets may accumulate along the tubing to the exit, and they require 24v.

DanL, I started reading into your design, looks good from what I saw so far, have to read into it some more and make some adjustments. Seems like I am not using the right fluid. I also tried the baby oil. Guess I'll have to order the right glycol liquid.

The down size from this is all the time spent experimenting when I could just go out and buy one for $75-100. But this is what a tinkerer does, right? Unlike the link in Docktalk now about kids not being able to tinker these days and not building kits or scratch building.
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Old Dec 19, 2009, 11:58 AM
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Quote:
Originally Posted by ken_nj View Post
Let me also explain what I would like to do. The model this would be for has exhaust ports on the transom. I want to simulate the exhaust coming out these ports with a smoker. I will have to duct, or blow it out these ports, they above the waterline. I suspect pulling the smoke from where the smoke is made would be better than pushing. That can be figured after I get the right amount of smoke generated.

I know I can buy this, but not sure how the water based ones will work in this situation. The water droplets may accumulate along the tubing to the exit, and they require 24v.

DanL, I started reading into your design, looks good from what I saw so far, have to read into it some more and make some adjustments. Seems like I am not using the right fluid. I also tried the baby oil. Guess I'll have to order the right glycol liquid.

The down size from this is all the time spent experimenting when I could just go out and buy one for $75-100. But this is what a tinkerer does, right? Unlike the link in Docktalk now about kids not being able to tinker these days and not building kits or scratch building.
If you are going to have it exit the transom, you would be better using the water units. You don't want an oil slick behind your boat!
Regards,
Gerald.
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Old Dec 19, 2009, 02:49 PM
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Glycol smoke unit facts

Ken,

1. "Glycol" is not an oil. It is a water soluble alcohol. So it won't leave a slick behind the boat. (NOTE: the glycol blend in "fog juice"(specifically the ethylene glycol) is highly toxic to pets - and kids. It tastes and smells sweet, so animals are attracted to it. One lick can kill them, same as for the glycol based antifreezes. Keep your glycol secure from pets and kids!) It won't kill fish and ducks because you use such a small amount to produce "smoke".

2. The WalMart fluid is good enough. There are better ones (higher purity, more expensive types of glycols in the blend), but the WalMart stuff will work well. It may just leave more residue on your filamet over time. But sinceyou make your own filament for about $2 and you tinker as part of the hobby, you can make a new one whenever you want.

3. The 1" or 1.5" computer fan (6 or 12V available) that is used to blow cool air over the filament, pressurizes the closed system and forces the fog out the stack, or in your case the exhaust ports on the transom. You don't want a pull sysytem because the fog/vapor wil pass over the fan/blower and condense on it. That would be a mess.

4. The latest design I use is a baby food jar for the reservoir. Cut a hole in the lid and use it to "trap" the funnel/stack assembly. It's removable for heater servicing and condensate drips back into jar with no leaks. Also seals well so you get that slight pressurization that forces out nice stream of smoke.
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Old Dec 19, 2009, 06:20 PM
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DanL, PM sent. I have been looking at 2 of your diagrams.

Diagram 1
For this one I have braided tubing from a dissected hair dryer. How long should these 2 tubes be cut and what length should the nichrome wire be? The diameter I have is .01. And is the brass nozzle from the fan only blowing on the top of the percolator heater assembly or is air also freely mixing into the entire container?

Diagram 2
How different is this from the other one? Is the 3 wires wrapped around the insulator tubes or do they go through the tubes? How long are these 3 wires and the length of the tubes?

In both instances the length of the wire would determine the amperage draw. I suspect the lengths are a trial and error experiment?

For the liquid, I have 3.
1. Walmart Fog Juice which it says is Water & Glycerin but does not specify the ratio. I could add either to play with the ratio.
2. Lamplight lamp oil from Micheal's art's and crafts store. It just says paraffin lamp oil.
3. Baby oil which is just mineral oil.
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Old Dec 20, 2009, 10:58 AM
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Smoke Unit for the Steam Tramp - RC Groups
http://www.rcgroups.com/forums/showthread.php?t=739243
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Old Dec 20, 2009, 06:59 PM
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Brooks, that smoke unit look similar to DanL's unit, then again that seems to be the common design. DanL is going to send me updated info on his, then to the test bench!
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Old Dec 20, 2009, 08:40 PM
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From the tramp steamer thread:
"The smoke lasted for a cruise, about 18 minutes. The batteries (2, 7.2v 2400mah wired in parallel) were depleted"

Calculating the amps from the above, I get an operating amperage of about 14A. (4800mah/0.33hr). At 7.2V, that's about 100W. That should put out a LOT of smoke. Also uses a LOT of battery power.
The oil unit likely operates at a higher temp than a glycol unit since it has to evaporate the oil. Glycol "smoke juice" boils off at only about 450F, vs 3in1 oil BP of 550F. (from MSDS safety sheets). Note that mineral oils like 3in1
have flash points of only about 300F, where they release flammable vapors. Not a good bet for a model boat, I think, since that's well below the temp required to get smoke.

Quantity and quality of smoke from different units is probably hard to quantify unless seen side-by-side, in the same wind conditions etc.

I still vote for glycol - not messy if done right, low watts per smoke output, no flash point/flammable fumes, not flammable, reasonable internal operating temps and low stack temps (due to the blower air flow and the cooling/condensing effect)

I'll post latest design info for a home-made glycol unit soon.
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Old Dec 21, 2009, 01:01 AM
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You could try Capricorn (though he hasn't written for a while), he had a thread with a 1/35th Fletcher class DD and he built his own smoker(s). Let me see if I can find the thread and I'll update this post.
Foo
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Old Dec 21, 2009, 10:21 PM
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DanL, looking forward to your updated design!! I was looking over this design and I see some details I had questions about. So the nichrome wire is wrapped around the fiber tube, then that is inserted into a glass tube, then that assembly is inserted into the test tube.

In addition to my questions on post#8, wondering what the relation is between the length of the wire vs amp draw vs amount of smoke generated. Also the amount of air blowing at the exit of the top of the tubes?

Calypso smoke unit
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Old Dec 22, 2009, 09:16 AM
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Really busy getting ready for Christmas, so haven't had time to finish the write up. Will get it out by day after Christmas.
I'll post the tube construction specifics part later today.
Latest design is wire wound on fiber core, inside a capillary tube, two cap tubes inside a test tube with a small feed hole, test tube inside a baby food jar reservoir. The fiber core is necessary to keep the boiling solution from blowing up thru and out of the tube (and up the stack!) The wire coil is inside the cap tube (vs wrapped around outside) for thermal effeiciency and reduced power requirement. Outer wrap worksb but overheats solution in reservoir and basically wastes energy.
I'll post diagram with specifics added. Here are diagrams I've done so far.
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Old Dec 22, 2009, 11:16 AM
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I think this is the link Foo was referring too.

http://www.rcgroups.com/forums/showt...&highlight=cap
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