cutting blower noise, the poor mans way

So, my friend has a box I designed for him. It has a frame of 2x4s, roughly 6 inches apart, then within that, another frame of 2x4s, running across the others, to mount the walls. the walls are made of 1/4" OSB, and the interior lined with a recycled plastic version of FRP and trimmed/caulked. The side wall has electrical built in, one outlet split and connected to seperate digital timers, and four "always on" plugs. the walls, floor, and ceiling are all insulated, IIRC it was R-14. At final measurement, the side walls are 6" thick. "But why the hell would you do that? sounds like overkill to me!" most likely it is. But, the best feeling in the world, is standing there with the door open, pumps humming and buzzing away, water sloshing, and then I shut the door, leaving just a very faint hum if you stand right next to it.

Well, my stomach sank yesterday when I installed the blower. on 12v, it was ridiculously loud, vibrated the whole box, Basically too loud to be useful. So, I switched it to 5v. Quieter, yes, but still too loud. It still made an obnoxious humming sound. I shut everything down. luckily I'm still testing.

So, I was trying to think of what to do, when I thought "dynamat!". I previously read of people using something called "peel n seal" or "quickroof" to sound-deaden their cars on the cheap, this stuff is damn near identical to dynamat, it is an asphalt and butyl rubber based aluminum-backed roofing underlayment/flashing, and is found in the roofing section of lowes/home depot, under 20 a roll.

So, I wrapped the blowers plastic housing twice with this stuff, and put two layers on the face of each mounting foot, and two on the back of each mounting foot, then put the screws through it. the results...

12v is still too loud for my liking. I think I will find a way to dial it down to somewhere between 7v and 9v, or maybe the restriction on the intake will quiet it a bit. But, at 5v, with the door shut, the ceiling fan runs louder than the exhaust is now. It seems adding mass to the plastic housing and mounting points of this blower nearly eliminated the vibrations and whatever other noise this thing was putting out.

Now, the cons. Some people in the car forums report that there was a strong "new paved road" asphalt smell that came off of this, but after applying, and heating it with a heat gun to set it, I still smell nothing. It is good up to 200 degrees according to the package, so it should be fine.

Hopefully, my discovery can help you with your loud blower issues...