Rubber to silence and cool: TGTBT?

powergyoza · Post by **powergyoza** » Fri Nov 15, 2002 12:53 am

Hey everybody,

After reading up on numano's fanless pc website, I've been tinkering with the idea of enclosing my HD's in rubber. I was worried that I'd have to do a metal-rubber-metal-etc lamination to get quiet and cool, but then I came across these pages. They talk about a flexible graphite rubber that is thermally conductive and absorbs sound too. Check it:

http://www.neseal.com/neograph.html
http://www.dracomech.com/gaskets/flexgraph.htm

Anyone have experience with this material? If no one has had any nightmares with this, I'm prolly gonna try it.... I'll be sure to report back.

Post by **MikeC** » Thu Nov 28, 2002 8:55 am

That's sounds interesting... in the meanwhile, another Canadian at overclockers.com is using plastic food bins

to silence Maxtor drives. For $4 total, it might be worth a try: http://www.overclockers.com/tips00203/index02.asp

powergyoza · Post by **powergyoza** » Fri Nov 29, 2002 6:39 pm

Yeah $4 is really cheap! Yikes! Cheaper than my rubber idea by a long shot.

Right now I'm going to experiment with 3/8" block printing rubber available at a local art supplies store and it's gonna cost me >$30 of material to silence 2 hard drives. That's almost 10x as much $ for maybe a few dB of silencing....

That maxtor in Rick's article looks like an older vintage, might be hotter than my D740x... And he say's it's only warm to the touch. I'll give it a try and take some sound'heat measurements.... and then compare it to my block print rubber idea!!!! My guess is that 3/8" thickness beats ~1/16" hands down for acoustics.

crisspy · Post by **crisspy** » Sat Nov 30, 2002 2:02 am

After reading up on numano's fanless pc website, I've been tinkering with the idea of enclosing my HD's in rubber.

According to numano, silly-cone caulking stuff is a pretty good heat conductor. Seems like a couple extra jumbo contractor size tubes, or more of the normal smaller ones if on sale cheap, would go a long ways in making sheets of "rubber". Probably for less than $15 per drive. Black stuff would even have some carbon, but who knows if it would be enough to help; the clear would be nifty. I think his drive enclosures are strange, but the ideas are good stuff. I have seen a ruggedized laptop hardrive enclosure that is basically a very soft rubber box. Although it's injection-molded-fancy-factory stuff, it seems the home builder could get the same effect easily enough.

First find a small box that is the outside size you want. Maybe a thin walled (single card layer, no wiggly layer) cardboard box. If you used a cut-in-half juice brick or smallish milk carton, you might be able to peel it off later, because of the plastic/waxy inner surface. That might be best.
Goop a bottom layer of the stuff into the bottom of the box, and sqoosh it flat. Then if you wanted to get even fancier you could go 'conformal' by laying in a sheet of seran wrap, and pushing the drive into the goop, thus forming a fairly tight fit. I imagine this would help a lot for heat transfer on the bottom and sides. I think I would wrap the drive in a thin plastic bag (very thin like the rolls of vegetable bags in the grocery store) and suck out most of the air to get a nice tight covering of the bottom. That way you could do the bottom and sides too, all in one peice. When it dried you would have a one peice solution for 5 out of six sides of the drive. If you are really afraid for your drive, substitute a hunk of wood or styrofoam the right size and wrapped in plastic.
I would do the top by laying the drive into the bottom + sides, laying a thin plastic sheet over, and building up a top cover. If you were working in the box, you would have side walls to help too. Once again, if the real drive is used you would get a nice tight fit to the lid for best heat transfer. When the thing is all cured, you could pin the lid on with pins stuck down through into the sides, tape it, elastic bands, tie it with string, whatever.

My 25¢ worth. If I didn't have a Barracuda IV I would probably do it

powergyoza · Post by **powergyoza** » Sat Nov 30, 2002 3:02 pm

Crisspy,

Seems like a couple extra jumbo contractor size tubes, or more of the normal smaller ones if on sale cheap, would go a long ways in making sheets of "rubber".

That's a really neat idea! I'm really torn now as to which idea to try 1st - rubber carving blocks or your "poured-form" silicone caulking idea. You're right, your idea would certainly allow for a tighter fiting enclosure for better heat dissapation. And probably be about the same price too....

Things would be much simpler if I had Barracuda's (or IBM GXP 180's), but I'd be in denial if I didn't say I wasn't having fun...

Post by **MikeC** » Sat Nov 30, 2002 4:01 pm

I'd be in denial if I didn't say I wasn't having fun...

Another delirious addict faces the truth.

crisspy · Post by **crisspy** » Sat Nov 30, 2002 5:53 pm

Just to complicate things, I'm not sure about curing time vs. exposed surface area vs. which type of caulking. A plain cardboard outer mould might be the right thing to allow a proper cure by gassing off, then soak it off afterwards in water and scrub clean.

I'm also not sure about shrinkage vs. which type of caulking. Experiments experiments.

powergyoza · Post by **powergyoza** » Tue Dec 03, 2002 5:41 pm

Crisspy,

I've decided to not complicate things right now. I went with my own carving rubber idea and got at least a 20dB reduction (from 70dB to < 50dB when measuring at < 0.5" distance). My drives are hot, but just within spec.

My 12V NMB exhaust & 4 - 7V panaflo L's are now louder than the hard drives. I'm going to stick with that for now, but I'm curious what other people have achieved in terms of dB reduction. Ie. can anyone top a 20dB reduction with another method?

crisspy · Post by **crisspy** » Tue Dec 03, 2002 8:37 pm

Cool powergyoza, that silently sounds like a pretty great reduction . How did you put them together? We can conclude that the rubber idea works well, and if we need to improve it it's only the thermal issue that might want some help.

you might be able to get a better thermal interface by just putting a thin layer of caulking, maybe ¼" thick, on the bottom and top layers of rubber, then stick them onto the drive. Fill them air gaps! As long as warranty isn't an issue, I would just bond them right on, since there's nothing there you need access to. Same idea aplies to the sides. Alternatively you could try doing a seran wrap conformal layer type trick to give the top and bottom a closer form fitting profile without the pemanence.

After trying to probe my brain about types of caulking to use, I think Mono might be good because it is solvent based instead of acetic acid like true silicone, or water like the latex stuff, so I think it would be less likely to harm the drive. Probably the very best, but more costly, would be a uerethane like they black stuff used for automotive windsheild seams, or marine Sikaflex, both of which will never come off, but cure by absorbing moisture from the surrounding air, instead of drying. Better living through chemistry eh?

I know it's a little late for you now, but conveyor belt rubber can be got used, or probably bought new as small scraps for peanuts, also think truck tire flap rubber. I don't know how the fibers would affect the thermal conductivity though, probably not good.

powergyoza · Post by **powergyoza** » Tue Jan 07, 2003 11:05 am

Crisspy,

It's been a long delay, but I have a little picture to show of the rubber boxes below:

The hard drive would go inside the box (left) and I would close it off with that door (right). The box is very simply built with cut pieces of rubber and glued together with superglue.

I gooped on massive amounts of thermal paste so that there's no air between the HD and the rubber. The rubber boxes are sitting on foam on the bottom front of my case. I placed a 6v Panaflo in front of the 2 HDs to keep them cool.