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| Endgrain sizing? http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=20322 |
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| Author: | Alexandru Marian [ Sun Jan 04, 2009 11:28 am ] |
| Post subject: | Endgrain sizing? |
Wondering if you guys are sizing the endgrain when doing "spliced" headstocks. I've done my first with LMI white without sizing and worked fine. Since then I built couple solid necks (supplier sent precut solids by mistake). Since then I moved to fish glue, and now starting my number 4; because I read in several places about sizing end grain with a thin layer of glue when using HHG, I was wondering if it might be necessary with fish too... Thanks! |
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| Author: | Kent Chasson [ Sun Jan 04, 2009 4:40 pm ] |
| Post subject: | Re: Endgrain sizing? |
One step that I find essential with a scarf joint is putting on plenty of glue, mating the pieces, then waiting about a minute before applying full clamping pressure. If you clamp right away, all the excess glue squeezes out and the endgrain can soak up enough glue to starve the joint. Waiting a minute lets the endgrain get saturated first. You can't wait that long with hot hide glue which is probably why you need to size it. You can wait with fish glue. |
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| Author: | TRein [ Sun Jan 04, 2009 5:50 pm ] |
| Post subject: | Re: Endgrain sizing? |
Alexandru, Sizing is working a very dilute solution into endgrain, even using another piece of wood to drive it into the endgrain and then letting the piece dry thoroughly. You can then glue with regular hide glue and you will achieve better adhesion of endgrain (i.e. 90 degree cut to face grain) to side grain; the end blocks in a fiddle for example. What you have with a scarf joint is not really end grain. You are gluing skew cut grain to face grain. Your skewed piece would have an angle of 7 to 15 degrees, depending on the angle you have chosen for your headstock. Obviously, the shallower your angle, the less end grain you have. Even at 15 degrees, there is not an overly dramatic proportion of endgrain. I have never seen a scarf joint fail on any classical guitar, even the cheapest ones. And you can be certain the makers of the cheapies don't take any special care gluing the scarf joint. |
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| Author: | Alexandru Marian [ Mon Jan 05, 2009 8:35 am ] |
| Post subject: | Re: Endgrain sizing? |
Thank you for the advise. When doing large areas, I used to paint some glue on both sides, and when done wiggling it all over (i really take my time and insist on this part so it wets the wood well), put more glue and mate the pieces. Fish does have an outrageously long open time. Just unclamped the neck and cut the outer parts, break test is fine, all wood fail. Not sure you can see the joint but it is a bit under the break. |
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| Author: | gozierdt [ Mon Jan 05, 2009 8:11 pm ] |
| Post subject: | Re: Endgrain sizing? |
Alexandru, I love your approach- ask the question to get input, then test it out. You must be an engineer in real life... The tested joint looks very good. Between you and Hesh, you're about to get me to switch to HHG. |
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| Author: | Alexandru Marian [ Mon Jan 05, 2009 8:44 pm ] |
| Post subject: | Re: Endgrain sizing? |
I've been in an engineering school for 2 years (out of 5). My poetical substance couldn't stand it and switched to business school.  I think too HHG is the best glue there is, but with a bit of fish at hand to glue the FB and back without panic attacks. |
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