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CA wicking through Shellac?
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Author:  jfmckenna [ Thu Jun 20, 2019 8:57 am ]
Post subject:  Re: CA wicking through Shellac?
Yes you need to seal the end grain or else the thin CA will wick deeply into the wood and stain it. What bothers me is that as you can see the whole purfling scheme and the rosette on the other guitar were done the exact same way, one coat of shellac as a sealer, and no wicking at all but yet on this one rosette it wicked in and it just so happens to be that there are those natural line features adjacent to where it wicked in like it has something to do with it.

To answer your question Banjo... CA is nice to use for this application because once you get everything all set you just zap it in place with the CA. I don't like using water based glues because they cause the wood to swell. I have had it happen a few times in the past where I get a real nice fit for the wooden rosette rings and use Titebond to glue them in and they won't fit becasue the wood swelled. Then you have to clean it up and do it all over again.
Author:  Bryan Bear [ Thu Jun 20, 2019 9:03 am ]
Post subject:  Re: CA wicking through Shellac?
jfmckenna wrote:
I don't like using water based glues because they cause the wood to swell. I have had it happen a few times in the past where I get a real nice fit for the wooden rosette rings and use Titebond to glue them in and they won't fit becasue the wood swelled. Then you have to clean it up and do it all over again.


This will expose me as a hack but so be it. . . I decide what type of glue to use for the rosette based on how good of a fit I get. I try for perfect CA ready fit but if it is just a little bit loose, I use water base glue to get it to swell together. I'm not talking about big gaps or anything just if it isn't as snug as I'd like. Doing it this way, I have to remember to stop and seal the channel with shellac if I decide to go with CA. This thread is probably going to make me use more than 1 application of shellac. If I decide I need to use water based glue, I don't need to seal the channel but I do have to work fast so it doesn't swell too much before I get everything in place.
Author:  Barry Daniels [ Thu Jun 20, 2019 9:17 am ]
Post subject:  Re: CA wicking through Shellac?
Medium CA might be better in this application than thin.
Author:  doncaparker [ Thu Jun 20, 2019 9:34 am ]
Post subject:  Re: CA wicking through Shellac?
JF—

I don’t have any clue about why the streaks are so prominent on that particular top, but I think torrefaction accentuates stuff like that in the wood, in general. Just a notion. You might be right about the streaks being superhighways for moisture. It’s not the strangest idea I’ve heard. In any event, I think you should just go with it as a feature. Maybe use a finish that is heavy on the amber, so as to make everything darker and older looking in general. Torrefaction is supposed to make wood sound old; there’s something to be said for helping it look as old as it sounds. Again, just ideas.
Author:  J De Rocher [ Thu Jun 20, 2019 11:29 am ]
Post subject:  Re: CA wicking through Shellac?
jfmckenna wrote:
Do you think those lines come out as a result of the cooking process? That's kind of what I was wondering. Like it's an internal 'highway' for sap and when it got cooked it all exited there or something. IDK just thinking out loud.


I was wondering the same thing and it reminded me of the paired sequentially cut top sets that Brent posted about in another thread in which one set of the pair was torrified and the other set left untorrified. I noticed in the photos of a couple of the sets on the Alaska Specialty Woods webpage that the torrified top showed dark lines that were much less apparent or absent in the untorrified top. Maybe those lines correspond to places in the wood that had a higher concentration of some component of the wood that gets carmelized by the process. Some of the sets don't have such lines so it may be the combination of torrefaction with specific pieces of wood.

Attachment:
Torrified_Non-Torrified 2 top set ULTRLT - Alaska Specialty Woods.jpg

Attachment:
Torrified_Non-Torrified 3 top set ULTRLT - Alaska Specialty Woods.jpg
Author:  George L [ Thu Jun 20, 2019 11:39 am ]
Post subject:  Re: CA wicking through Shellac?
Wow. That is a bummer. I've never had wicking on channels that have been sealed with shellac. That said, I've never used torrified wood, so ... ?

As for what to do now, I would try a sunburst. If that didn't work, I'd replace the top. I like wood that shows character, but not visible mistakes.
Author:  Barry Daniels [ Sat Jun 22, 2019 9:34 am ]
Post subject:  Re: CA wicking through Shellac?
Thinking about this a bit more and I came up with a theory of why torrified wood would wick CA more. The torrification process dries the resin in the xylem which would cause it to shrink. This would open up the xylem increasing longitudinal permeability. Whether this is applicable to naturally aged wood is the next question.
Author:  jfmckenna [ Mon Jun 24, 2019 9:16 am ]
Post subject:  Re: CA wicking through Shellac?
Barry Daniels wrote:
Thinking about this a bit more and I came up with a theory of why torrified wood would wick CA more. The torrification process dries the resin in the xylem which would cause it to shrink. This would open up the xylem increasing longitudinal permeability. Whether this is applicable to naturally aged wood is the next question.


Yeah this has got me stumped. I've baked wood myself before and you can clearly see the resins rise to the top and make streaking features.

I did a bit more thinking too and it very well may be that I'm jsut a dumb arse and didn't shellac it properly. IT doesn't make sense. Everywhere else on those guitars I used a coat of shellac and thin CA and had no problems what so ever except right there. Occam's Razor... that sort of thing. IDK [headinwall]
Author:  Brad Goodman [ Mon Jun 24, 2019 12:38 pm ]
Post subject:  Re: CA wicking through Shellac?
banjopicks wrote:
I have to ask, why is using CA so important in the first place, if it causes this much trouble?

It’s not..
It’s all what you are used to...
I try to stay away from CA as much as possible.
I’ve glue my rosettes in with yellow glue and have had no problems, once I got my technique down.
You need to have the fit just right so you don’t get a problem with swelling.


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Author:  Jim Watts [ Mon Jun 24, 2019 1:35 pm ]
Post subject:  Re: CA wicking through Shellac?
You might be be able to scrape back and use a pale shellac over the stains and a darker shellac everywhere else in order to blend it in trying to even things out. Using a dark shellac only just darkens everything. Nice looking guitars BTW.
Author:  jfmckenna [ Mon Jun 24, 2019 3:13 pm ]
Post subject:  Re: CA wicking through Shellac?
Jim Watts wrote:
You might be be able to scrape back and use a pale shellac over the stains and a darker shellac everywhere else in order to blend it in trying to even things out. Using a dark shellac only just darkens everything. Nice looking guitars BTW.

That's an idea worth exploring. I already am using a dark button shellac but I could stain it darker too. It might save me a retop anyway...

What's the adage with using colored shellac? I think I remember you want to start off dark and go lighter with each following session? I may have that backwards.
Author:  Clay S. [ Mon Jun 24, 2019 4:48 pm ]
Post subject:  Re: CA wicking through Shellac?
I'm with Don Parker - the more I see it the less it bothers me. If the top didn't have those long dark streaks in it already I might notice it around the rosette, but since it does they really don't stand out.
I wonder how a burst that was dark around the soundhole and faded out towards the edges might look. It might become a thing.
Author:  doncaparker [ Mon Jun 24, 2019 5:23 pm ]
Post subject:  Re: CA wicking through Shellac?
Clay S. wrote:
I wonder how a burst that was dark around the soundhole and faded out towards the edges might look. It might become a thing.


Oooooh! You could call it a Black Hole.

Seriously, though, look for a reverse sunburst in a Google search. Others have toyed with the idea.
Author:  Ken McKay [ Sun Jun 30, 2019 8:08 am ]
Post subject:  Re: CA wicking through Shellac?
I would homogenize the top by spraying toned lacquer over it. To me the long dark streaks need some help blending as viewed from audience level. Vintage amber or the new pale yellow mixed in with your lacquer will do it. I think I would do the while guitar and have a look. Focus away from the very thing you discussed here. If that is not better then a brown burst will be next in my mind.


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Author:  Ken McKay [ Sun Jun 30, 2019 8:10 am ]
Post subject:  Re: CA wicking through Shellac?
Ken McKay wrote:
I would homogenize the top by spraying toned lacquer over it. To me the long dark streaks need some help blending as viewed from audience level. Vintage amber or the new pale yellow mixed in with your lacquer will do it. I think I would do the while guitar and have a look. Focus away from the very thing you discussed here. If that is not better then a brown burst will be next in my mind.


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And I neglected to say that it is absolutely too notch and beautiful.


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Author:  Ken McKay [ Sun Jun 30, 2019 8:10 am ]
Post subject:  Re: CA wicking through Shellac?
Ken McKay wrote:
Ken McKay wrote:
I would homogenize the top by spraying toned lacquer over it. To me the long dark streaks need some help blending as viewed from audience level. Vintage amber or the new pale yellow mixed in with your lacquer will do it. I think I would do the while guitar and have a look. Focus away from the very thing you discussed here. If that is not better then a brown burst will be next in my mind.


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And I neglected to say that it is absolutely top notch and beautiful.


Sent from my iPhone using Tapatalk




Sent from my iPhone using Tapatalk
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