Loose kerfed lining

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bnjp
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Joined: Wed Dec 28, 2011 9:22 am

Loose kerfed lining

Post by bnjp »

I've seen this in other posts, so I'm assuming it's a common mistake. The picture makes the gap look larger than it is, but while the top edge (thicker part) of the lining is tight, but the bottom (thinner part) edge has a gap on some pieces. I can stick a business card in about 1/4".

I don't know if I didn't use enough glue, or if the clothespin clamping method is bad, or if I clamped it poorly. I saw the problem when I clamped the back, so I clamped it slightly different on the front hoping to correct the problem, but even on the front I've got some linings with gaps.

First of all, How should I correct it? Fill the gap with something? pull it all off and reglue it?

Second, How do I prevent the problem happening again? Any thoughts are appreciated.

Image
Bryan :)
johnnparchem
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Re: Loose kerfed lining

Post by johnnparchem »

I turn the mold with the sides upside down and make sure the kerfing on the bottom is tight. If not I adjust my clamps to make it so.

The angle on the kerfing makes it easy to do what you did.
tippie53
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Re: Loose kerfed lining

Post by tippie53 »

http://www.youtube.com/watch?v=HrT4mhbOtYw
here is a video about this. This is one of the details you have to learn. Let me know if this helps you.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
bnjp
Posts: 38
Joined: Wed Dec 28, 2011 9:22 am

Re: Loose kerfed lining

Post by bnjp »

it is helpful John. I think my clothes pins weren't tight enough, since I had the problem on the longer pieces whether I clamped them at the top or bottom. But i didn't check them from the bottom as you did (and as John mentioned). I also may have thought the glue was setting faster and got in a hurry to get it all clamped.

As an aside, What is the purpose of leaving the gap at the neck and tail block?

I'll order some new linings and redo it. This is all for the sake of learning, so I'll be twice as good if i build the darn thing twice! haha :)
Bryan :)
tippie53
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Re: Loose kerfed lining

Post by tippie53 »

you don't want an unsecured joint , it can cause a buzz .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Jim_H
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Location: Bothell, WA USA

Re: Loose kerfed lining

Post by Jim_H »

yea, you'll definitely want to replace the stuff that isn't well bonded.

You might want to gently poke at the rest of it and make sure there aren't any other loose spots.

You'll want to be sure what the cause was and elminate it. If you glue is suspect, you might want a grab a fresh bottle. Otherwise, I'd suggest making a dry run without glue and, then flip it over to make sure you are tight all the way around.

If you are using standard clothes pins, you can re-inforce them with some rubber bands to make more clamping force. Also, you can get bunch of the smallest binder clips at the local office supply store. They apply a lot of pressure. Just be careful, they don't work well on tight curves.
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tippie53
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Re: Loose kerfed lining

Post by tippie53 »

If you are using clothespins put some rubber bands on them. The springs aren't as strong as they were
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
bnjp
Posts: 38
Joined: Wed Dec 28, 2011 9:22 am

Re: Loose kerfed lining

Post by bnjp »

I believe the cheap clothespins are the culprit. I ordered new linings from Stewmac and will pull it all out, clean up the glue, and redo it. I don't want to cut any corners.
Bryan :)
Jim_H
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Re: Loose kerfed lining

Post by Jim_H »

Here is an article at stewmac 'Trade Secrets' that shows how to modify and re-enforce clothes pins to make them ideal for clamping linings.

http://www.stewmac.com/tsarchive/ts0127.html
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tippie53
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Re: Loose kerfed lining

Post by tippie53 »

one more thing
I dampen the kerfing and work it a bit between my fingers to soften it. Then clamp it on the guitar. In about 15 - 20 min it is ready to glue on. The water helps the wood to conform to the side shape. It is also good practice .
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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