failure gluing ebony

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Brian Evans
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failure gluing ebony

Post by Brian Evans »

I was putting an ebony saddle on the top of a jatoba arch-top bridge a few days ago, and the glue joint failed as soon as I started to work the piece. It popped off with little effort, there was some very small evidence of lifting of the jatoba, but no wood failure at all on the ebony side. The joint was long side grain to long side grain. I sanded both surfaces with 120 grit just prior to gluing, I cleaned vigorously with a clean cloth but no acetone or mineral spirits, I used AR glue, clamped fairly hard, and dry time was around 12 hours. I know that the advice will be hot hide glue, but I build so sporadically that I'm not set up for that yet, any may never make the investment. AR glue has worked for everything else I have done except ebony. Should I be scraping instead of sanding? Use a chemical cleaner like acetone? Any other ebony tips?
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Eric Knapp
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Re: failure gluing ebony

Post by Eric Knapp »

Brian Evans wrote:I was putting an ebony saddle on the top of a jatoba arch-top bridge a few days ago, and the glue joint failed as soon as I started to work the piece. It popped off with little effort, there was some very small evidence of lifting of the jatoba, but no wood failure at all on the ebony side. The joint was long side grain to long side grain. I sanded both surfaces with 120 grit just prior to gluing, I cleaned vigorously with a clean cloth but no acetone or mineral spirits, I used AR glue, clamped fairly hard, and dry time was around 12 hours. I know that the advice will be hot hide glue, but I build so sporadically that I'm not set up for that yet, any may never make the investment. AR glue has worked for everything else I have done except ebony. Should I be scraping instead of sanding? Use a chemical cleaner like acetone? Any other ebony tips?
I have no experience but would like to know if this works.

http://www.lmii.com/products/finishing/ ... teak-epoxy

I was going to try that when the time came. It even refers to ebony so I'm curious.

-Eric
David King
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Re: failure gluing ebony

Post by David King »

I'd suggest that the 120 grit was too coarse. Try sanding to 400. I'd also check the date code on your bottle of glue. Neither of those woods is oily that I've noticed.
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Barry Daniels
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Re: failure gluing ebony

Post by Barry Daniels »

Specifically what brand of glue is this? Is there a possibility that the glue was frozen at one time?

I don't think of ebony as being oily, but it can have a waxy feel which may impede adhesion.
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Brian Evans
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Re: failure gluing ebony

Post by Brian Evans »

it is Lepages Carpenters glue, a pretty high quality AR glue recommended for cabinet making, etc. It's all I've ever used. Oddly I went to their website, which I have never done, and there it says oily woods need to be freshly dressed and de-greased. It was my idea that sanding counted as freshly dressed, I rubbed it pretty hard with cloth to try to get surface oils, but I did not de-grease. I think I am going to try hot hide glue for stuff like this. It's fresh (six months old, which I would think is fresh enough) and never frozen, although it says it can be frozen.

http://www.lepage.ca/en/lepage-products ... -glue.html
http://www.lepage.ca/content/dam/uac/le ... 20Glue.pdf
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Barry Daniels
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Re: failure gluing ebony

Post by Barry Daniels »

DO NOT USE LIQUID HIDE GLUE! That is not what we talk about when recommending hot hide glue.

Rubbing the ebony with a cloth could have been the problem. You took whatever was/oil was present and smeared over the board. Also degreasing wood with solvents is not a good idea. Be careful. There is a lot of mis-information out there about glues.

Most builders use Titebond Original Wood Glue. I've been using it for 40 years and it has never failed me.
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Chuck Tweedy
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Re: failure gluing ebony

Post by Chuck Tweedy »

he said "hot hide glue" Barry
Likes to drink Rosewood Juice
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Barry Daniels
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Re: failure gluing ebony

Post by Barry Daniels »

oops, sorry, I missed that. I think the "frozen" thing mislead me. Freezing of hide glue pearls is not possible since they are already solid. However, the liquid phase of hide glue can be frozen. That is how I prepare it and it keeps in the freezer for several years.
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