Tarr Mk 2 conversion to Ex-Smoker

[Dr Phibes]

Well, it might be noticed from my other thread that I successfully converted my Mk4 to a Mk2 (by the complicated process of snipping a couple of wires and soldering a couple more ) I also successfully rewired the heater/resistor separately to run directly off the battery via a voltage step-up which was regulating output at 8.1v. This worked wonderfully because the Tarr smoker's heater was activated immediately the tank was powered up. This meant that when the Clark kicked in the proportional fan control produced a nice plume of smoke which bellowed from the exhaust - brilliant.

Problem is being a bit of a thickie at times (quite a lot of times actually) I then went on to run the tank for quite some time and was so taken up with this that I failed to realise that the Tarr smoker was running low on smoke fluid .
The result, and cautionary note for those starting out with similar thickie tendencies, is as follows





Using a voltage step-up is very unforgiving of such oversights too. As can be seen the plastic casing has melted and the wick burned to a crisp, although the heater/resistor is fine. Frankly I'm not too bothered about the Tarr as they are not particularly expensive but had I not realised something was wrong when I did (eventually, doh!) a fire could have spread which would have been much more costly . Consequently, I think I will be using Mk1's (metal) in the future and have just ordered a Mk1 12v as a replacement. This way I can step-up the voltage further with the higher rated heater too.
Given this occurrence I'm thinking I need some kind of fluid level monitor and/or cut out for when the fluid gets too low. Thing is I don't know how long I was running with too low fluid either (note. the cotton wool ball was still damp with fluid?).

[tao]

I like the metal version too..it is smaller as well. I did burn out one wick but those are easy to replace. The little servo switch is a nice addition too..you can turn the smoker off via gear toggle on radio..so with acoustic smoker..I turn if off for a sec so cannon doesn't trigger smoke. But it is also nice to be able to work on things with the smoker off etc. You just wire it into the positive lead on the wire going to the resistor. For fluid level I use small washer so the filler tube I run into it goes about half way down that way I can inject more than needed in and pull the excess out- which will be half full. Not knowing what the level is I just do it after running it for any length of time.

[Tankbear]

Just a note on the 12v TARR smokers it uses a 12v fan, so found some customers have had the idle power of the fan set to low and meant the fan not spinning and the heater burning out within minutes. So I don’t know if the Clark you can change the idle power to the fan, but something else for you to check. I guess if not adjustable, you could swap it with the fan from your burnt out MK1 as that was spinning before.

[Dr Phibes]

Tao, yes, it's a good idea to have a switch on the Tarr heater, which I have but I think as you suggest I will put this on one of the radio channels (it's on the tank at the moment), This won't be a problem as I'm presently using a 10 channel Tx/Rx and I think I got a spare Hobbyking video switch knocking about somewhere (it's easier than using a servo). if not they can be picked up cheap enough and are easy to set up.
I agree too that it's useful that the mk.1 unit is more compact - handy for squeezing into smaller tanks like my Sherman based M36. However the down side is lower fluid capacity which makes monitoring the level more critical if using a constant (stepped up) voltage to the heater. I think what I would like to see is the Mk.2 size in metal, this would be a nice option for Mr Tarr to consider offering (I guess it depends if larger metal cases can be sourced, and demand).

Tankbear, thanks for the info, I didn't think about the fan being 12v too (though it makes sense that it is). I think to avoid problems I'll just swap out the fan with old unit that I just cooked up as you suggest. In this tank (KT) I have a Clark TK24 which has proportional smoker output (the TK22 doesn't) but still doesn't provide control over that output (I think the new TK60 might however). The fan control was working really well so no need to mess with this.
A significant problem, as I see it anyway, is ensuring that the fluid level is sufficient if you are running the heater straight off a dedicated power source. It is important too, and as you point out tankbear, that the fan is running whenever the heater is powered, even at idle or it's clearly going to overheat quickly (depending on what voltage you are pumping through it of course). The Tarr heater/resistor seems to me pretty tough (my cooked one still works fine) but it won't hold out forever if there is nothing to cool it. And then there's the wicks to consider too.

Still, got lots of options and it is fun working all this stuff out

[tao]

The switch is great too when you use the acoustic and if you need to isolate the gun or any sounds other than engine from triggering
smoke output. I may try a second adjustable amp for the Acoustic smoker then i can just cut the sound to that speaker if I want. So one switch to turn heater on/off and other to cut speaker. Overkill probably as just cutting heating element for a few seconds works too

[Dr Phibes]

It's certainly an idea to switch the proportional output as well and would give you total control but it's worth bearing in mind that the fan (or speaker in the acoustic case) use very little power anyway so leaving them running via the proportional control won't hurt anything, unlike the heater. It's horses for courses however, and if that's how you want to do it, then why not.

[tao]

Yes true! It really for cutting the acoustic speaker briefly so the cannon sound won't trigger a plume of exhaust.

[tao]

I was thinking about the small volume and inability to check the level on the TARR 1 in a few of my tanks there is room on the sides of the TARR.. so what about a small pipe (clear tube etc) drilled into/inserted into the side at the bottom leve of the TARR into a small clear reserve cylinder that would also double as a fluid check and refill area?

[Rad_Schuhart]

I need to replace the heating element in one of my HL smoke generators. What do you recommend me to use?

Thanks!

[tao]

I would just replace the whole unit with a TARR unit. The heating element is bullet proof..just a great and reliable unit all around.