Ripped Cone repair method

[guitician]

I would like to share a method of patching paper speaker cones that I recently tried on a couple of nice old speakers that suffered unfortunate accidents. I had this glue called Duco Cement that I picked up at a hardware store. And a Tyvek jump suit that I used for working with insulation. I read about people using tissue paper and white glue and thought: Why not try Tyvek and Duco Cement? The Duco has the viscosity of maple syrup and absorbs readily into paper and Tyvek. I cut some patches from the old jump suit and noticed that it is a two ply, like a paper towel. So I separated the plies and one thin sheet has plenty of strength to keep the cone's tear from opening up later. Applying a thin coat to the cone and the Tyvek on one side, with a little added from the other side of the cone, on the tear was all I did. It seems that the repairs worked well for these two speakers. I need to run them through some blast tests later this week to see how well the repair holds up.

[Gtr_tech]

I use wood glue and won't add any additional material if I can aviod it. The added weight will offset the motion of the cone and cause strange behavior.

[guitician]

That's why I used the Tyvek. It is feather light. The wood glues thicker consistency will cause you to use more glue, thus adding more weight.

[Prairie Dawg]

That's why I used the Tyvek. It is feather light. The wood glues thicker consistency will cause you to use more glue, thus adding more weight.

The best thing so far that I have found is a fabric softener sheet AFTER it has been used in the drier. That cooks all the wax off it and what you're left with is a very durable substrate that smells good. I then use rubber craft cement like Elmers' to saturate the repair piece and install.

[guitician]

Yeah, that's another thing that made me think of Tyvek. It's a thin spun(non-woven) fabric, like the dryer sheet. The fibers of the drier sheet are thicker and heaver than the Tyvek though.

[guitician]

Well, the speakers passed the blast tests fine, with no cracks or loosening of the patch. Sonically, since the cones piston movement has been unchanged, and the resonance is very near what is was before, the sound of the speakers has been fully restored.

[jrfrond]

The added weight will offset the motion of the cone and cause strange behavior.

It would have to be a really heavy patch. Speaker cones are precision-made, but not balanced like a tire. A little paper and glue will not affect response one bit.