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Hello all!

My name is Brian and I have been a lurker here for a while. This is a pretty amazing forum and is chock full of my favorite thing, Halloween!

I just thought I would share my project with you all. I have seen the pro Fogscreens many times and like most of us, I couldn't even begin to think about affording one. Even used and beat up from the road, they are still well over $10K on ebay. I decided to try and build one. After seeing a few of them online and the dismal results, I wasn't too optimistic that my results would be any better. I figured I would try anyway. Most of the fun, for me, about Halloween is building my stuff!

So, the basics.... This is using 8,800 7 3/4" x 1/4"d drinking straws in a "honeycomb" configuration.
Overall dimensions are 44"wide x 12" deep x 17" tall. This beast weighs about 160lbs!
It uses 14x Nidec 12VDC 220 CFM fans (which are not running anywhere near that speed). The fans are controlled with a PWM signal generator for speed tuning. I am probably running the fans at 25% of their rated speed, maybe even less. They are WAY overkill for this project. I got them cheap and since I had no idea what I was doing, I wanted to make sure I had ample airflow, if needed. I am eventually going to add a DMX controller so I can run cues to the fogscreen in tandem with my Halloween soundtrack.
As for the fog, I am using 4x 6-head ultrasonc misting foggers along with 2 more Nidec fans to push the fog into the unit.
 

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Here are some vids:





In this last one, being that this was the first time I used my Fogscreen, I didn't know what video would show up well and what wouldn't. Now that I know, I will have much cleaner video that will show up much better.

I know this is a lot for a beginning build post but I thought I would share this with you guys and if any of you are thinking of building one, I would certainly be happy to answer any questions!
 

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Thanks, guys!

Yeah, I am not sure what happened with the pic uploads. I reposted the pics in the post below. These are only some of the build pics, I have more. Anyway, any questions, please ask away!
 

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Everyday I am amazed at the level of craftsmanship on this site. This is just another example. It reminds of of the Davy Jones scene on my favorite ride of all times. Pirates of the carribean. Incredible. How much does it cost to build something like this? Even though I am very sure it is way beyond my scope and skill level.
 

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Everyday I am amazed at the level of craftsmanship on this site. This is just another example. It reminds of of the Davy Jones scene on my favorite ride of all times. Pirates of the carribean. Incredible. How much does it cost to build something like this? Even though I am very sure it is way beyond my scope and skill level.
Thank you very much!

It wasn't too expensive but it was no picnic! I know next to nothing about aerodynamics but after seeing several videos and reading a lot about laminar flow physics, I figured this "shouldn't" be too difficult. If I had to do it all over again, I would not use drinking straws. They were a tedious P.I.T.A. to lay all of them down. There are companies out there that sell custom laminar honeycombs. The only thing about them is, they are not cheap. That was why I used straws for my first one. I would say, all total, this project cost about $600 and about 1 month worth of my time. The most expensive part was the ultrasonic foggers.
 

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Nice work! What is your opinion of the large ultrasonic foggers?Are they worth the money?
Have you tried a glycol fogger with your set up?
Thanks, Pete
 

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Absolom7691,

Fantastic work! I'm am curious why, with that huge bank of straws, the fog is only ejected through a narrow strip in the center. Again, fantastic!
 

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Human Candy Shovel
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Absolom7691,

Fantastic work! I'm am curious why, with that huge bank of straws, the fog is only ejected through a narrow strip in the center. Again, fantastic!
The array of straws is separated by sheet metal into three banks. The outer banks are for clear air, while the thinner central bank is for the fog. The idea is for the outer banks of clear air to keep the fog from dissipating, so it retains a dense form that can be used like a movie projection screen.
 

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Thanks, everyone for the props! :cool: I have seen a lot of the projetcts on this forum and coming from you guys, it means a lot!

Nice work! What is your opinion of the large ultrasonic foggers?Are they worth the money?
Have you tried a glycol fogger with your set up?
Thanks, Pete
I was going to originally use a glycol fogger or maybe a hazer but I didn't like the idea that the fogger would be running the entire time. The heat produced from the fogger would also need to be dealt with which would require a chiller. The other thing is, even with really high quality fog fluid, it will still leave a residue, especially at this constant volume. I'm sure a glycol fogger could work but I think it would need a lot of babysitting. As for a hazer, I think the oil based haze fluid would also leave a residue. Since these are just pushing out water vapor, there is nothing but water to leave behind :)

As for the ultrasonic foggers, they are very spendy but I love the constant output of fog. I am actually thinking of replacing all of my glycol foggers for my yard and eventually moving to all ultrasonic foggers. The fog from them looks more like fog and less like "smoke" because it is the same thing as fog, which is what you'd want for a graveyard. I also like the fact that you can just dump them in a tub of water and let them go. If using distilled water, I doubt you'd even have to clean them. I battle every year with my glycol foggers. I only use them for Halloween and even using decent quality juice, I still have to bust out the vinegar to clean them before they are in working order. I am getting a little tired of the battle!

Fantastic work! I'm am curious why, with that huge bank of straws, the fog is only ejected through a narrow strip in the center. Again, fantastic!
The array of straws is separated by sheet metal into three banks. The outer banks are for clear air, while the thinner central bank is for the fog. The idea is for the outer banks of clear air to keep the fog from dissipating, so it retains a dense form that can be used like a movie projection screen.
Absolutely correct! Without the layers of air, you will have a laminar column of fog that will break down over a short distance. Also, since the fog particulate is translucent, the thicker the screen is, the more mottled the image will be. At the business end of the fogscreen, the thickness of the fog is only 1/2" move about 3' away from the fogscreen and that increases to about 2". You can see it in the video I posted with the text from my laser projector. You can see how the image is extruded looking. This is because of the thickness of the screen. With video from a video projector, an extruded image is a very bad thing. The thinner the screen is while keeping it opaque as possible, the better. You also want it to be a thin veil of fog that you can still see through to give that "hologram" illusion.
 

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Super job on the fog screen. I would like to make one myself.
Do you think using that plastic cardboard that signs are made of and stacking it in layers would work and using one of those large vaporizers like those used when your kids have a cold for the vapor? Those put out a lot of cool steam and should be cheaper than a bunch of the small sonic foggers. Can you put together a how to so we can understand how your array works?
 

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I'll try to get a how-to going. I am going to post up some very basic drawings of how it is knocked together and also some of the steps I went through to build it.

I am not sure about using the sign material. If I am not mistaken, you are referring to the plastics signs that have channels in between the sign surfaces. I don't know how uniform they are, as I am not familiar with that material. The thing with attaining a good laminar flow is uniformity. Even though the straws don't vary much, they vary enough that it affects the flow of air and this is maybe why my fogscreen still looks amateur. The thing about the vaporizer is, I am not sure how much those put out. I am pumping a LOT of fog through this thing. With all 4 foggers running, I am going through 6 litres of water per hour. That is a lot of fog. Depending on how big you make your fogscreen, the vaperizers may not output enough. It's worth a try though, especially if the materials are cheap.
 

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Here are some pics during the setup from my 2013 haunt:

No butt jokes, please.... I know I need to knock off a few lbs!
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20131031_153325.jpg

Since I had not yet firgured out how to mount the foggers overhead, they were on the ground and I had to pipe the fog up, 8'. This required me to use 6x 6 head foggers instead of 4. It still worked fine
20131031_161215.jpg
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20131031_171335.jpg
 

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Since I had not yet firgured out how to mount the foggers overhead, they were on the ground and I had to pipe the fog up, 8'. This required me to use 6x 6 head foggers instead of 4. It still worked fine
A trough. A section of gutter mounted inside the box, extending out the side. The end extending out, you want to epoxy a piece of plexiglass on the end instead of the usual bit of sheet metal. You'll also want to make some sort of lid over the section extending out so the fog doesn't escape that way. Foggers go in the trough, fill with water, use a few fishing bobs at the plexiglass end to see where the water level is.

In fact, you might be able to get away with the piping you're already using, assuming the foggers will fit inside the tube - swap the elbow outside the box for a T pointing up, plexiglass over the one side to provide the water monitor, and a slip fit cap on the end pointing up to make refilling easy.

However, in doing so, I'd also ditch the PVC pipe scaffolding for black iron gas line piping. That PVC pipe looks unhappy holding up the fogscreen as it is, I don't think it wants to deal with 100 lbs of extra weight from water. The gas pipe will also allow you to use rebar pounded into the ground for extra anchoring.
 

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A trough. A section of gutter mounted inside the box, extending out the side. The end extending out, you want to epoxy a piece of plexiglass on the end instead of the usual bit of sheet metal. You'll also want to make some sort of lid over the section extending out so the fog doesn't escape that way. Foggers go in the trough, fill with water, use a few fishing bobs at the plexiglass end to see where the water level is.

In fact, you might be able to get away with the piping you're already using, assuming the foggers will fit inside the tube - swap the elbow outside the box for a T pointing up, plexiglass over the one side to provide the water monitor, and a slip fit cap on the end pointing up to make refilling easy.
I have seen a few pictures of the pro fogscreens and they are configured very closely to what you're describing (the trough idea). I am working out something like this as we speak. Thanks for the ideas! Piping the fog up was very inefficient.

However, in doing so, I'd also ditch the PVC pipe scaffolding for black iron gas line piping. That PVC pipe looks unhappy holding up the fogscreen as it is, I don't think it wants to deal with 100 lbs of extra weight from water. The gas pipe will also allow you to use rebar pounded into the ground for extra anchoring.
Actually, there is a lot going on in those pictures. The ABS pipes are only a canopy frame for some black dropcloth. I needed to create a "tunnel" to keep the wind from playing havoc with the fogscreen. The fogscreen is supprted by some lighting truss. It's rated up to 250lbs and I also added some of my own lock pins. The ABS pipes were only bowed because of being in a hot shed all summer, not because they are supporting any weight ;)
 
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