Reverse Kerfing

Please put your pickup/wiring discussions in the Electronics section; and put discussions about repair issues, including fixing errors in new instruments, in the Repairs section.
Post Reply
Andrew McSpadden
Posts: 64
Joined: Wed Jan 02, 2013 4:28 pm
Contact:

Reverse Kerfing

Post by Andrew McSpadden »

I am going back to reverse kerfing due to the side stiffening benefits but I was never happy with gluing it on. I don't like the faceted appearance in the inside and outside of curves and the occasional breakage.

Any tips people have on gluing these in would be helpful.

Thanks

Mike Conner
Posts: 146
Joined: Wed Feb 08, 2012 8:12 pm
Location: Murphy NC
Contact:

Re: Reverse Kerfing

Post by Mike Conner »

I lightly dampen the "web" with distilled water (to avoid any chance for discoloration) and that has greatly reduced the breakage. Warming it on the bending iron has helped also. //mike

User avatar
Barry Daniels
Posts: 2665
Joined: Thu Jan 05, 2012 10:58 am
Location: The Woodlands, Texas

Re: Reverse Kerfing

Post by Barry Daniels »

The faceted appearance is unavoidable. The thin web behind the kerf is the only place where it will bend. I suppose you could sand the face by hand or with a sanding drum to remove the facets, but that would just weaken the web, which is not advisable.
MIMF Staff

Alan Carruth
Posts: 1003
Joined: Sun Jan 15, 2012 1:11 pm

Re: Reverse Kerfing

Post by Alan Carruth »

As Barry says, it's inevitable. I don't see how that's worse than the gaps in 'normal' kerfed liners. I suppose if you wanted it to really be smooth you could sand it and then glue on a veneer or cloth tape. That would make it even more rigid. Once you glue the top and back plates on the edge stiffness is the same for either sort of liners, as far as I can see. The added stiffness only counts before that. I do use continuous laminated liners in the upper arm of my harp guitars for strength. With kerfed liners or tentelones the load is all taken by the skins, where continuous liners can contribute strength and stiffness on their own, I think.

User avatar
Randolph Rhett
Posts: 348
Joined: Mon Aug 06, 2012 5:19 pm
Location: San Diego, CA
Contact:

Re: Reverse Kerfing

Post by Randolph Rhett »

If you don’t want facets you need to use solid linings.

Clay Schaeffer
Posts: 1500
Joined: Fri Jan 06, 2012 12:04 pm

Re: Reverse Kerfing

Post by Clay Schaeffer »

Another possibility is "semi solid linings". I have been making linings out of wacky wood (bending ply). It bends easily around the curves and to some degree in all directions - i.e. - it will follow the rise and fall of the sides. It adds a fair amount of stiffness to the sides. It is relatively cheap to make.
Attachments
DSCN2137.JPG

Dave Meyrick
Posts: 13
Joined: Thu Oct 19, 2017 5:24 pm

Re: Reverse Kerfing

Post by Dave Meyrick »

On another forum I saw that Roy Courtnall does kerfed linings in the usual way then glues a thin strip of timber on to the linings thus making a rather stiffer structure. It looks really neat and tidy.

It may also address the OP's concerns with the aesthetics of the faceted look of reversed kerfed linings.

My own concern is the quality of the glue joint of the kerfed linings with the sides around the very tight bends of the cutaway shapes that I like to build. I do reversed kerfed linings and they get very faceted round these curves, but more importantly it is really hard to ensure proper contact of the lining with the side round these tight curves when glueing.


Dave M

User avatar
Bob Gramann
Posts: 970
Joined: Fri Jan 06, 2012 11:08 am
Location: Fredericksburg, VA
Contact:

Re: Reverse Kerfing

Post by Bob Gramann »

When I do reverse-kerfed lining around a tight bend, I often widen the kerf in that area so the lining can make the bend. I have never gotten too excited about the appearance of facets on the lining.

User avatar
Waddy Thomson
Posts: 270
Joined: Fri Jan 06, 2012 8:11 pm
Location: Charlotte, NC

Re: Reverse Kerfing

Post by Waddy Thomson »

This may be laziness on my part, but I just love the A-4 Kerfing that Ryan sells. It's laser cut, bends in every direction and looks great. The only weakness I've found with it is that it is somewhat brittle, so has to be handled with some care. I do stiffen in the lower bout against the top with an outside/inside layer of something - usually Spanish Cedar - not because I feel it isn't stiff, but because I think an added bit of stiffness at the top join gives better projection.
P1080551 (Medium).jpeg

Post Reply