Willem Blees wrote: <<To repair a bridge, if all the wood is still there, use either a super glue, or...>> So far as I know, CA glue (superglue) cures very hard, brittle, and inflexible. When cured it is, in fact, acrylic plastic. Cure a thin layer of superglue on glass, then try to scrape it off with a razor blade and it shatters into dust. Hide glue, which is slightly flexible, had a very long and successful history, but for decades the preferred glues for wood have been aliphatic resin glues ( Titebond yellow glue), and resorcinal glues. Both of these glues dry slightly flexible, allowing for the wood to expand and contract without breaking the glue joint. The glues have been designed for this. It stands to reason that manufacturers think that a slight flexibility is a good thing in wood glues. Try scraping a thin layer of these glues off of glass. They react quite differently than CA glue does. These are "tough" glues. Mr. Blees, - since you recommend CA glue for bridges, I was wondering if you have done any experimentation to show the bridge will still be attached to the board in - say three months or a year? Or,- do you know of a piano manufacturer that has begun putting on all of their bridges with CA glue? Or, have you read any technical material that purports CA glue to be better than aliphatic glue for wood? This is such a new and radical approach to gluing wood, that I was wondering on what evidence you base your advice? Sincerely, Bill Simon Phoenix
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