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Glue behavior and western redcedar
https://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=48152
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Author:  Tim Mullin [ Wed Aug 17, 2016 5:29 pm ]
Post subject:  Glue behavior and western redcedar

I'm using western redcedar for the first time. Fortunately, I selected my worst WRC top, as I'm not happy with the way rosette turned out. It was to be a wood ring with inside and outside purfling. I usually use epoxy for the wood ring, as the channel can never be dead flat and epoxy tolerates a thicker glue line. I then cut the channels for the purfling, seal (this time with lacquer), then install the purfling with CA.
The exposed end grain in the channels has wicked some of the glue -- the epoxy, I think. It turned the cedar a darker colour and looks like crap.
I'm gonna redo this top (will try to salvage the wood ring) but wonder how to avoid the discolouration of the cedar. Seal with shellac/lacquer before epoxy? Use a waterbased glue like TB or hide? Avoid CA completely?
Experiences with WRC and various glues appreciated.


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Author:  Trevor Gore [ Wed Aug 17, 2016 6:11 pm ]
Post subject:  Re: Glue behavior and western redcedar

I've never had a problem using original Titebond.

Author:  Tom West [ Wed Aug 17, 2016 6:17 pm ]
Post subject:  Re: Glue behavior and western redcedar

Same experience as Trevor......!
Tom

Author:  Jim Kirby [ Wed Aug 17, 2016 7:58 pm ]
Post subject:  Re: Glue behavior and western redcedar

WRC doesn't seem to like CA anywhere near it. (Neither does Spanish Cypress - specific disaster story there). If you must use CA, coat the exposed cedar surfaces with a good coat of shellac first.

Author:  WaddyThomson [ Wed Aug 17, 2016 9:56 pm ]
Post subject:  Re: Glue behavior and western redcedar

When I use CA for rosettes in any top wood, I always seal with Shellac first. I do it for fish glue too.

Author:  doncaparker [ Thu Aug 18, 2016 6:37 am ]
Post subject:  Re: Glue behavior and western redcedar

Please don't be offended, but I think you should reconsider the original basis for your glue choice. Yes, the bottom of the channel can be a little rough, but that does not put the rosette at risk of falling out. There are plenty of good contact points that make this a good enough glue joint to prevent full failure. So really, any of the usual glues will keep the ring stuck to the guitar.

If you assume that to be true, then the other factors need to take priority in your glue choice. Biggest on my list is the hassle caused by staining that you see from some glues.

Personally, I try to use hot hide glue as much as possible. I used HHG on a ring rosette installed in a cedar top not long ago, and it came out fine. HHG does not stain.

Of course, for this application, the downside to any glue with water in it is the swelling effect. Just be ready to manage that and you will be fine.

Author:  George L [ Thu Aug 18, 2016 9:52 am ]
Post subject:  Re: Glue behavior and western redcedar

Tim,
I just finished installing a rosette in WRC using original Titebond. I did not seal the channel beforehand and had no issues with any staining.

Author:  Rod True [ Thu Aug 18, 2016 6:39 pm ]
Post subject:  Re: Glue behavior and western redcedar

I've used shellac for sealing channels in WRC many time. I usually do two coats before installing and gluing though.

Author:  doncaparker [ Thu Aug 18, 2016 7:11 pm ]
Post subject:  Re: Glue behavior and western redcedar

I use shellac too, but mainly to minimize fuzz and chipping out while routing. A little extra protection.

Author:  DannyV [ Mon Aug 22, 2016 8:23 am ]
Post subject:  Re: Glue behavior and western redcedar

I always use shellac. If the wood ring will freely come in and out of the channel, TB will help swell the layup to fill the gaps. If I can't easily get it out I use CA. Shellac is your friend.

Author:  mkellyvrod [ Tue Aug 23, 2016 7:44 am ]
Post subject:  Re: Glue behavior and western redcedar

Agree with others, if you're going to use CA you need to apply a couple of coats of shellac to avoid wicking of the glue. When gluing in tiles for a classical rosette, I have found it easier to install the tiles in the channel and then fill with CA but only after learning the hard way that CA will stain cedar and spruce tops if you don't seal with shellac first.

Author:  Tim Mullin [ Tue Aug 23, 2016 8:12 am ]
Post subject:  Re: Glue behavior and western redcedar

Having done some tests on the now-discarded top, I've concluded that the staining I experienced was NOT from the CA applied in step two. At that point, the channel was sealed with lacquer. Although that's the first time I've used lacquer rather than shellac for this purpose, it seems it works fine.

Rather, the staining seems to have originated with the epoxy used in step one to glue in the main ring. This has been my procedure for many guitars with various species of spruce tops, but only in the WRC did wicking of the epoxy into the endgrain cause a dark stain.

As always, I'll continue to seal w/ shellac or lacquer before using CA, but in future I will also avoid epoxy and WRC unless sealed beforehand. More likely I'll use Titebond for the main ring.

Thanks all for the replies.

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