# DIY Fog Chiller Questions....



## gorehound80 (3 mo ago)

I'm new to the forum, but have building props for years....this year I decided to build my own fog chiller after understanding the concept of how chilling fog works. I have attached some pictures of the basic overall design. I have since added a grate to raise the ice about 3 inches on the exit end of the cooler using a paint roller grate and filled the cooler to about 50-60% with bagged ice. I am using a 1000w fogger and found that the fog is coming out way too fast to stay low. Does anyone have any suggestions on what I can for that? Also, does the fog solution make a huge impact on this? Everywhere online shows nice thick, billowy fog, mine is not. Any suggestions will be greatly appreciated! Thanks!


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## corey872 (Jan 10, 2010)

Welcome to the forum. I see you're decided to dive right in with the 'black art' of fog chilling. I will hit some of the high points. Feel free to read through the Fogger section of the forum for the rest of the encyclopedia of knowledge. 

So first of all, I'd ask - is it really the speed of the fog causing the issue? It might be. 1000W is a lot to force through that small outlet pipe. I have a 400W fogger and I cut a~2" x 12" slot all the way across the bottom of my cooler/chiller. The idea is that you want the fog to flow as smoothly and as laminar as possible. If it is turbulent, then you will have mixing. But also consider, when people make videos to post, it is usually indoors, in a 'room temperature' environment, or even a hot garage in the summer. High heat and dead still air are 'absolutely ideal' for making fog 'stick' to the ground. Everyone builds a chiller and tries it out in the summer - and posts great results. When it comes time to actually run it - on a cool October day, or even worse, chilly Halloween night... the results are less spectacular. The big test would be does the chiller work with small puffs of fog? If it's not even working there, then there might be other issues. Though if small puffs work, you might consider adding 2-3 (or more) outlet pipes to slow the outlet speed. Ideally this would be almost 'natural convection' driven, but the more you try to force it the worse the fog will fan out.

Does juice have an impact? Most definitely yes. The general walmart/dollar store brands are diluted and tend to make a (very cheap) but thin fog. If you switch to a name brand Froggy's (generally highly recommended), American DJ, other 'Pro' brands, they have a higher concentration of active ingredients and make a much thicker fog. There are also 'freezing' and 'low lying' fog juices specifically designed for chillers. While the 'freezing' fogs may not give a dramatic effect over normal quality fog juices, they certainly don't hurt. Definitely stay away from any 'hazing' or 'fast dispersing' products.

Hopefully this will give some things to try. If you can post up some pictures / videos of the action, it might help spot other points to help.


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## gorehound80 (3 mo ago)

corey872 said:


> Welcome to the forum. I see you're decided to dive right in with the 'black art' of fog chilling. I will hit some of the high points. Feel free to read through the Fogger section of the forum for the rest of the encyclopedia of knowledge.
> 
> So first of all, I'd ask - is it really the speed of the fog causing the issue? It might be. 1000W is a lot to force through that small outlet pipe. I have a 400W fogger and I cut a~2" x 12" slot all the way across the bottom of my cooler/chiller. The idea is that you want the fog to flow as smoothly and as laminar as possible. If it is turbulent, then you will have mixing. But also consider, when people make videos to post, it is usually indoors, in a 'room temperature' environment, or even a hot garage in the summer. High heat and dead still air are 'absolutely ideal' for making fog 'stick' to the ground. Everyone builds a chiller and tries it out in the summer - and posts great results. When it comes time to actually run it - on a cool October day, or even worse, chilly Halloween night... the results are less spectacular. The big test would be does the chiller work with small puffs of fog? If it's not even working there, then there might be other issues. Though if small puffs work, you might consider adding 2-3 (or more) outlet pipes to slow the outlet speed. Ideally this would be almost 'natural convection' driven, but the more you try to force it the worse the fog will fan out.
> 
> ...


WOW! thanks for this info! I have an idea to use something like a heavy plastic bag to help the dispersal of the fog by attaching it to my outlet and cutting slit in the bottom of the bag to help it form lower to the ground. Any ideas on how to do this? Or would more 2 inch pipes on the cooler be the answer? perhaps both? I have purchased some pro level low-lying fog solution for freezing, and in my last attempts to test, in all fairness, I didn't fill the cooler up all the way, perhaps more ice would not only slow in the intake of fog but allow it to get colder. If I has gone with a smaller fogger, this coudl all be a moot point, but I tend to go bigger with everything.  Thanks again!


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## gorehound80 (3 mo ago)

corey872 said:


> Welcome to the forum. I see you're decided to dive right in with the 'black art' of fog chilling. I will hit some of the high points. Feel free to read through the Fogger section of the forum for the rest of the encyclopedia of knowledge.
> 
> So first of all, I'd ask - is it really the speed of the fog causing the issue? It might be. 1000W is a lot to force through that small outlet pipe. I have a 400W fogger and I cut a~2" x 12" slot all the way across the bottom of my cooler/chiller. The idea is that you want the fog to flow as smoothly and as laminar as possible. If it is turbulent, then you will have mixing. But also consider, when people make videos to post, it is usually indoors, in a 'room temperature' environment, or even a hot garage in the summer. High heat and dead still air are 'absolutely ideal' for making fog 'stick' to the ground. Everyone builds a chiller and tries it out in the summer - and posts great results. When it comes time to actually run it - on a cool October day, or even worse, chilly Halloween night... the results are less spectacular. The big test would be does the chiller work with small puffs of fog? If it's not even working there, then there might be other issues. Though if small puffs work, you might consider adding 2-3 (or more) outlet pipes to slow the outlet speed. Ideally this would be almost 'natural convection' driven, but the more you try to force it the worse the fog will fan out.
> 
> ...


What about putting a cap on the inlet pipe (vertical pipe) inside the cooler and drilling holes all round the pipe to disperse the fog as it enters the cooler, or what that be too turbulent?


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## corey872 (Jan 10, 2010)

I don't believe the big fogger is 'exactly' the issue - you can always shoot shorter bursts of fog. That is why I asked if it is happening with shorter bursts / right at the very beginning. If so, then it might be more of a design issue. Though if it only shows up after long bursts/heavy use, that could just be the fogger overloading the cooling capacity.

I think adding more outlet pipes would help - that is at least where I would start. It's been my experience that the best fog comes with natural convection. You have an ice box, so there should be a natural flow of cold air through the outlet and trying to pool on the floor. The more you stay close to that natural flow, the more time the fog stays low to the ground.

If you try to force it, either with a fan or large fogger running a continuous jet of fog at a high rate, and especially with a small opening, then the fog doesn't have a good chance to cool down and you may have a 'jet' of fog coming out and dispersing in all directions fairly quickly. (which sounds like what you describe). Though also keep in mind, any ambient air disturbance, cooler temps, dry air, etc all make the fog want to rise and waft away. The bag might help a bit, but if the fog isn't cool to begin with, it will just rise as it comes out of the bag. Plus, anything you add to the 'outlet' side has a chance to allow some fog to condense which means less fog in the air.

On the inlet cap, I don't think that will make too much of a difference. You can always try it and see, but these chillers typically aren't too sensitive on the inlet side. You should keep the fogger back from the inlet opening some. The idea is to let the fog expand, cool off and mix with some ambient air before going through the chiller. That helps reduce the heat load. 1000 watts is about 3400 btu and that is about 0.28 "refrigeration tons". So running your fogger full blast for an hour would melt 0.28 tons or about 560 pounds of ice. Luckily most people don't (can't) run 100% and a lot of that heat gets rejected to ambient air, so the amount of ice needed is less.


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## gorehound80 (3 mo ago)

corey872 said:


> I don't believe the big fogger is 'exactly' the issue - you can always shoot shorter bursts of fog. That is why I asked if it is happening with shorter bursts / right at the very beginning. If so, then it might be more of a design issue. Though if it only shows up after long bursts/heavy use, that could just be the fogger overloading the cooling capacity.
> 
> I think adding more outlet pipes would help - that is at least where I would start. It's been my experience that the best fog comes with natural convection. You have an ice box, so there should be a natural flow of cold air through the outlet and trying to pool on the floor. The more you stay close to that natural flow, the more time the fog stays low to the ground.
> 
> ...


I have been testing it with 2-5 second bursts. I do however have a remote timer that plugs in and allows me to adjust increments and burst length. I will start messing with that, add an additional outlet and lengthen the distance from the fogger to the inlet (right now I place the nozzle right into the outlet).. Thanks for the wealth of knowledge!


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## gorehound80 (3 mo ago)

corey872 said:


> I don't believe the big fogger is 'exactly' the issue - you can always shoot shorter bursts of fog. That is why I asked if it is happening with shorter bursts / right at the very beginning. If so, then it might be more of a design issue. Though if it only shows up after long bursts/heavy use, that could just be the fogger overloading the cooling capacity.
> 
> I think adding more outlet pipes would help - that is at least where I would start. It's been my experience that the best fog comes with natural convection. You have an ice box, so there should be a natural flow of cold air through the outlet and trying to pool on the floor. The more you stay close to that natural flow, the more time the fog stays low to the ground.
> 
> ...


Wanted to post an update on my mods. I adapted a 4inch drainage pipe (non perforated) to the inlet side about 4 ft long (to create a larger pipe and distance for the fog to expand some), and another outlet pipe. I swapped the cheap fog solution for Fog Worx Low Lying solution, and with no ice, it hung lower than about 15-20 inches. With ice, it crawled across the floor! Granted my ice test was with frozen bottles of water and only 1/3 full, but those simple mods made a world of difference! I shortened the drainage pipe inlet down to 3ft, and found that to be the "happy median" for distance on my 1000w and 40qt cooler. I wanted to say thanks for your help and thanks to this forum!


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## corey872 (Jan 10, 2010)

Good deal, glad to know you're making progress. Do you intend to run frozen bottles for the big show? There are some pros and cons to that, too. Once the bottles loose their 'initial freeze' and you have a water/ice mix inside, you start to loose some of the thermal conductivity, so less overall effect of cooling. But the bottles also stay a rigid shape, which (ideally) keeps a lot of passages open for the fog. The 'raw' ice will always have the same thermal conductivity with the fog/air, but as it melts the passageways tend to get smaller and smaller. Then fog flowing around a big lump of ice isn't as good as flowing through all the little holes.

Some people also swear the humidity from the ice helps and there have been some displays (in a warm room and summer) of an 'ultrasonic fog chiller' using just mist from the ultrasonic atomizers. The "Roberts fog chiller" has been discussed on here quite a bit:









Robert's Fog Chiller


I ran across this video yesterday and just knew you guys would find it interesting. This "chiller" doesn't use ice, it works off the theory that it is humidity that causes the fog to lay low, not by cooling it. Pretty cool concept and it appears to work very well. I think this could lead to...




www.hauntforum.com












2021 Fogger Results


This was my yard last year with a hydrosonic cooler. 3k watts of continuous fog filled my neighborhood for 1/4 mile and it stayed under 3' from the ground. Ill add clear fog dams behind the fence this year for a directional change of where Id like the fog to move. This year in 2022 Im building a...




www.hauntforum.com









(likely a bunch more I can't find at the moment)

I think it generally works best if you have hot, dry ambient air and from my experience looses the effect if the air is cooler/wetter to begin with. I suspect the fog particles are absorbing some of the humidity which makes them heavier, and the remaining water vapor is cooling the surrounding air. But if the air is already cool and humid (Halloween night, at least for me!) then it doesn't help much.


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## gorehound80 (3 mo ago)

corey872 said:


> Good deal, glad to know you're making progress. Do you intend to run frozen bottles for the big show? There are some pros and cons to that, too. Once the bottles loose their 'initial freeze' and you have a water/ice mix inside, you start to loose some of the thermal conductivity, so less overall effect of cooling. But the bottles also stay a rigid shape, which (ideally) keeps a lot of passages open for the fog. The 'raw' ice will always have the same thermal conductivity with the fog/air, but as it melts the passageways tend to get smaller and smaller. Then fog flowing around a big lump of ice isn't as good as flowing through all the little holes.
> 
> Some people also swear the humidity from the ice helps and there have been some displays (in a warm room and summer) of an 'ultrasonic fog chiller' using just mist from the ultrasonic atomizers. The "Roberts fog chiller" has been discussed on here quite a bit:
> 
> ...


I'm in North Carolina and the Halloweens here tend to be warm during the day and a light chill at night. Then again, we are typically a very humid climate. The idea with frozen bottles is they'll leave less water in the cooler as they break down and can easily be swapped out. I think for my setup, the results Im getting now will work. Im dressing up as a Grim Reaper (See attachment) so with the fog rolling up to 12" or so will work good for me walking through my cemetery setup. I expect with a full cooler of ice, the fog will hang even lower that what I tested.


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