A report on McMaster buna rubber for damping

Felger Carbon · Post by **Felger Carbon** » Sat Apr 22, 2006 5:35 pm

I bought square foot sheets of the adhesive-backed black buna rubber on page 3328: 1/8", 1/4", and 3/8" thick. The advantage of this stuff is that one layer is thicker than Dynamat extreme, which (exclusive of the aluminum backing) is about 1/16" thick uncured buna rubber, which makes it easier to conform to curved surfaces, even fairly sharply curved.

However, I believed that the McMaster stuff would be better on flat surfaces. I have now tried this out.

If you have a really bad enemy, buy a sheet of the 3/8" stuff, give it to him or her, and recommend it for damping material. Leave this stuff alone! Do not approach!

The 1/4" thick stuff is very difficult to cut even in straight lines. I did successfully use some blocks with sizes like 1" by 4", that sort of thing. You have to really want thick damping material in a specific location (such as very near an HDD mount). I used a new utility knife which got used (dull) fast! Not an enjoyable experience.

The 1/8" stuff is almost practical for use on flat surfaces. I gave it the old college try, and did cover portions of a new chassis with it, but it would have been easier and quicker to apply 2 layers of Dynamat Extreme (DE).

Further, the adhesive on the McMaster buna is not nearly as good as the stuff on DE. All in all, you'd want a very good specific reason to reject DE and instead use the McMaster buna. Recommendation: stay away!

(Sometimes a negative report can be of interest.)

Post by **Ralf Hutter** » Sun Apr 23, 2006 7:01 am

1) Using a metal straight-edge as a guide makes cutting this stuff a 1000 times easier.

2) In lieu of a straight-edge, freezing it for a while also helps. Really.

mg1394 · Post by **mg1394** » Sun Apr 23, 2006 11:39 am

Sorry you had the trouble. I have used about 100 sq. ft. of similar material (I use the polyurethane, non-stick, and mount it myself, see p. 3347) over the past year or so and highly recommend it. Ralf's pointers are good for the cutting process. I use the Fiskars rotary cutter - works like a charm. http://www.widgetsupply.com/page/WS/CTG ... tters-45mm

Felger Carbon · Post by **Felger Carbon** » Sun Apr 23, 2006 4:42 pm

Further report on thick rubber including McMasters and DickBlick white stuff that Leo used.

Test samples were scraps about 1" by 2". I used the self-adhesive to attach a piece of 1/8" buna to sheet steel. I used super glue to attach the DickBlick and McMasters 3/8" samples to sheet steel (the front panel where it would be covered by the bezel). I used super glue to attach buna to buna, buna to Blick, and Blick to Blick (all 3/8" thick, not using the self-adhesive on the buna). Went away for 3 hours.

When I checked the bonds, they were all good. The Blick rubber is intentionally brittle (crumbly, you can break the 3/8 stuff up with your fingers if you want to). Still, the bonds held until I deliberately broke them but then the rubber came off in one piece.

Buna to steel and buna to buna, using super glue, was a completely different picture. I had to actually work to get most of the buna off my front panel, and some small pieces got left behind. After a try, I gave up trying to separate the two buna chunks.

On the other hand, the 1/8" buna with the McMaster self-adhesive peeled right off, but it would have stayed if I had not deliberately peeled it off.

Don't use super glue to attach buna to steel or other buna unless you intend that the bond be permanent.