injecting foam in frame

I don't know about that kind of foam, but this article in VeloNews from a few days ago talks about "a special vibration absorbing material that is injected into the frame". So I guess there are some circumstances when it will work.

Quoted post said:

Originally posted by cmcdavid64
would injecting foam in the tubes of my aluminum frame work to dampen vibrations? i guess i would use the foam you use to fill cracks in walls.

Be careful what you inject into your frame. That stuff expands like crazy. Enough force to snap 2x4's if you put too much in. I would imagine that it would crinkle aluminum if too much.

Matt

I injected some water-based insulating foam (brand is Dap-Tex) into a Scandium frame without any problems.

The foam and its expansion will not blow out a tube. The tube is much stronger; besides, the tube ends are open (no bb, headset, seatpost), so there is nothing to contain the foam and therefore there is no increase in pressure. As it expands outside the tubes, you just wipe it off. The foam then dries in a few minutes.

The polyurethane based foam can be very nasty to handle and is NOT water soluble. I'd not recommend that stuff.

I injected from each end of each tube as the foam doesn't travel very far from the tip of the straw-injector. The cans are supplied with 4" plastic straws. Next time, I'd try to fabricate longer straws to reach further down the tube, injecting as I drew back and then only inject from one end.

The tubing is now more dead when you tap on it. We have not built up the frame to try it out so I cannot comment on the ride quality. Posslbly in a week or so we'll have all the parts and give it a test ride.

As for blowing out 2x4, that seems rather unlikely. What it can do if you inject too much in into a wall, is bulge and rip your drywalls, especially if the drywall was installed using nails. Most of it comes out the holes you make for the injector straws and makes a huge mess.

Regards, Robert