Thread: oscillating fan prop

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I want to make a moving prop using an oscillating fan. I've never done anything like this before. I know that I should remove the blade, are there any specific things I should do so the motor won't burn up? Any help or advice is greatly appreciated. Here's the type of fan I want to use. It is one with a stand.

First, make sure it is capable of getting good airflow. They won't last long sealed inside a prop. One other step I like to take, is after removing the fan blade, replace it with a muffin fan blade. That really helps with the lifespan of the motor. Which is indispensable imo.

To do this, you will need a 120mm (approx.) muffin fan that you don't mind sacrificing for the cause. Use the blade assembly/hub for cooling, and cut the center out of the shroud (mounting area for the motor). Leaving the arms intact, and use them to attach the shroud to the oscillating fan motor. Let me know if you need any advice on how to do this, and I'll be happy to follow up w/ detailed instructions if needed.

Thanks for replying! If you can, I probably will need some more detailed instructions.

I do have some inflatable christmas decorations that quit working. Could I take the fan blade out of one of the fans? It looks pretty similar to a muffin blade.

Originally Posted by Mysterious Mansion Fan

Thanks for replying! If you can, I probably will need some more detailed instructions.

No problem. Glad to help! I'm getting ready to work on one myself shortly. So if need be I can show you pics next weekend on how I build the hub to adapt the fan blades for them. Sometimes though, pictures speak better than a million words. Anyway, this is how I do it.

Cut out a small circle of 3/4" wood that will just fit inside the fan hub with a hole saw, and then cut half way through off center of the center hole left by the hole saw w/ a jigsaw. Finally pre-drill a hole from one side to the other perpendicular to the cut you just made, slightly outside of the center hole, and run a screw in to compress the hub on the fan motor shaft which allows you to use it as a rudimentary clamping hub for the fan. Duplicate this hole exactly on the opposite side of the shaft hole, and insert a matching screw from the opposing side (so the heads are roughly straight across to offset the weight. That will bring the fan hub/blade assembly to a nearly perfect balance.

Drill 3 evenly spaced holes in the fans hub, and use screws to affix the blades to the wooden hub. At this stage, now you may have to balance the entire assembly, but the best way to tell is to mount the hub on the fan motor. Run it, and see if there is a detectable vibration. Since it's not in perfect balance, there will be a slight vibration unless the rpm matches the oscillating frequency. In the off chance that the rpm/oscillating frequency do match. I'll walk you through the steps of balancing it to alleviate it. 99.9% of the time, it won't be a problem...so don't be concerned.

I also highly recommend adapting the shroud to the new assembly, which will also keep anything from contacting the blades and breaking them, as well as focusing the airflow on the motor. Anything that can lengthen the lifespan, is worth the extra effort imo.

Originally Posted by Mysterious Mansion Fan

I do have some inflatable christmas decorations that quit working. Could I take the fan blade out of one of the fans? It looks pretty similar to a muffin blade.

More than likely, yes. If you could post a pic of it, I could say for sure.

Ok that will work. Whenever you want to, just PM me the pics. Thanks! I will try to get a picture of the inflatable fan blade soon.

Another thing I found is watch the weight and balance closely. I attached a skull head to mine, then made the stand of the fan into a body for a figure that turned side to side. I extended the arm of the figure so it was pointing and waving a hand. This offset the weight and added too much weight. It stripped the gears that oscillate the fan.

I agree about the weight. I had my animated werewolf working great for a few years using an old fan I had but it eventually burnt out. (never leave it plugged into a light sensor power bar - unknown to me it would start up every night as soon as it got dark and must have ran for several nights non stop before I was alerted by the horrible noises of the gears coming from the basement. So much for that fan.) The new fan was very much like the one you have pictured and whereas the old fan was pretty durable the new one was all plastic and couldn't handle the weight. It snapped in half almost as soon as I had it put together. The werewolf has been static ever since.

http://www.hectorturner.com/halloween/werewolf.html

Good points about the weight concerns. I've never used them for anything other than a scanning head movement, only because I never trusted them to handle anything more than that. From what you all have indicated, it seems like that was a good idea not to give into temptation. That knob has always whispered to me that it needed a crank arm attached... I'm glad I never listened.

I found a fan to use. It has a metal frame. I took a close-up of the bolts used to hold it together. Can anyone show me a step-by-step on how to remove the frame? Thanks!