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Strange question, I know.

I am wanting to try an easy approach to solid linings. Something I can do without needing to build a bunch of jigs. I read a post here, can't find it now, where one persons approach was to put the side struts in full width, put in pieces of lining bent at .100 in between the struts, then laminate a second solid piece, also .100, on top. I'm thinking they were using basswood. I'm using a fox bender, but I'm guessing this would be easier to finesse on a pipe?

I just tried to bend a piece of Sitka at .100, I'll have to wait until the morning, but I'm pretty sure that wasn't the aluminum foil popping and cracking during the bend.

I have some supersoft on the way, which should help, but what would be a good species, suitable for solid linings, that would bend easier at this thickness?

Thanks!
Brad


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I have seen mahogany or Spanish cedar bent for solid linings that looked like a full 1/8" and just a single layer. However, I think it is much easier to laminate the lining from as many thinner pieces as you can bend easily and build up to the depth you want. It is easier, I think, to do the laminating before installing the lining. The jig is not very fancy to do this. An example is Cupiano's (spelling?) book.

I've used koa and mango for solid lining on tenor ukuleles, bent on a pipe, all .10 or more (cutoffs from the sides)....just gotta be careful at the waist. Also, can bend the side, then cut the lining on a bandsaw....good luck.

I've used 2mm (3 layers) Beech myself, has an excellent reputation for steam bending, but Oak, ash, basswood and poplar all spring to mind.
Finessing easier on a hot pipe for a decent fit, differing radiuses.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

That would probably be me Brad since that's what I do. I like to use poplar which I've had more luck bending at thicker dimensions than anything else though I've used walnut, mahogany, Spanish cedar, pencil cedar and basswood. I don't use super soft but that might be helpful if you're used to using it. I usually bend in a fox bender. At .100 I like to soak it for a half hour or so. I do finesse it on a hot pipe and I wet the continuous piece a little right before I glue it. I carve it in place when I'm done. Burton LeGeyt has a different method that works well for him.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Willow. Violin makers use it for linings. Bends real easy.

I haven't tried at that thickness, but walnut is a real treat to bend at side thickness. . .

I do something similar with the full width side supports laminated into the linings but I use 3 layers of thinner stock. Usually around side thickness (0.08ish"). That makes the total thickness close to 1/4". the side support is the same thickness as the first layer and has two layers beneath it. I've been using poplar lately mostly because that is what I have around. bending linings at that thickness is no problem on the pipe and probably faster than setting up my bending machine. I bent a layer close then clamp it in the rim to cool while I bend the next and so on.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

That's a good point. The first layer only has to be as thick as the side strut, which I usually make the same thickness as the sides (usually from sides cutoffs). Maybe I'll try the three layer approach. Do you fight with keeping it all aligned? Any technique to share?

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I make a bunch of lining sticks at the same time so I know I have a pile of sticks the same thickness; the linings and reinforcements are ths same stock. I glue in the side reinforcements and flush them to the already profiled rim. If I am doing a side port, I put the first layer of of backing in at the same time full height running form one reinforcement to the next.

I start bending short sections of lining on the pipe and cut them to fit between each reinforcement strip then clamp them in with clothes pins. Then I bend the next layer close to shape and trim the ends to meet the heel and tail blocks. I clamp those in on top of the first layer with the clothes pins. The third layer is the same process. To glue them in, I take an extra step witch costs time but makes it look nicer. I take the layers out and put some masking tape over the reinforcements then put the first layer pieces back in place. I put glue on the second layer and hold it in place with a few clothes pins while I spread glue on the third layer. When the third layer is going in, I use every clothes pin (BTW these have rubber bands wrapped around them to increase the force) I can fit around the rim and let it dry.

The masking tape prevented glue squeeze out from gluing the second layer to the reinforcements. This allows me to pop the laminated lining our to the rim and clean up the underside (the side opposite what is glued to the top/back). The whole thing pops back in place because the gaps in the first layer key into the reinforcements so gluing them in is a snap.

The bend at the waist on the back can be a little challenging if it is too severe. This is the same challenge with binding the back. Sometimes I cut a little kerf in the lining pieces to make it easier to bend in place. Sometimes I don't need to and just force it in with clothes pin pressure; It really depends on the shape. Once I have used up my current supply of linings, I think I am going to try making the next batch much wider so I can glue them in wide and trim to a consistent height. I don't know if I will like that approach better or not.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Most north american hardwoods bend easily so long as you have good straight grain stock.

The easiest ever is willow. Soak it overnight and you can probably bend it without heat.
Ash and Oak are renowned for being easy to hot bend when wet. I have bent oak guitar sides at 0.150" without issue. It gets hot and flops onto the form.

Straight grained clear Poplar, birch, soft maple, aspen, cherry, and walnut are all very easy to bend as well.

Thanks.

Holly.

Bob

Ok, I have the strips of spruce bent, the side struts in, and the patch in for the sound port. Everything is .070 so I will be doing three layers of linings. I'm laminating in place so the first layer will be between the struts, the second and third layers will go the full length.

I understand the linings will taper, but how do you keep them the right depth while installing? I'm guessing start at the butt end since it will be the full depth, but how do you keep it squared and aligned up toward the waist and neck?

Hopefully the question is clear, and maybe the answer is just eyeball it?


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Scribe a line for depth and a couple layers of tape should keep you in the ballpark, make clean-up a breeze.

It is easier than it seems to fit the body taper (depending on the shape and taper). I start at the tailblock and work forward. There is a fair amount of bendabity to keep it close the the shape of the rim. Using rubber and reinforces clothesline right next to each other allows me to force them to shape. At the waist where the bend in the back stars, you can cut a double kerfs most of the way through the height of the lining if you need to. That can allow a bit more bendability. Usually, I get away with just forcing it. Even if I end up with some small gaps in the lining, it is still way stiffer than kerfed lining. The other option I may try soon is making wider/taller laminate strips and gluing them together then trimming a more consistent height matching the rim before I glue it in.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I'm thinking along the same line, Bryan. I've done a few linings at 3/4" tall, and by the time you get to the head block, they are down to about 1/2" - 9/16" high. Next time around, I'll start them at about
1 1/4" high, and I won't have to force the lining into shape. Mine are laminated, and then installed, though. Either way, they'll make the rims darned stiff.

Alex

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I think you could do one ply at 0.150" willow, oak, or ash and then run with it. Thats thicker than most standard kerfed linings.

Laminated linings are the only thing I've done for all of my instruments. I've solved all of the problems with potential variations in depth and possible gaps. Burton LeGeyt has a different solution that works well for following the radiused sides. You might want to check the archives. I like my method because I build a lot of different sized instruments.

Your linings between the side supports should take care of most of your potential variations in depth. I glue mine in about 1/64" proud of my radiused sides. The next layer(s) don't have to be the full depth if you are going to carve them in place.

To get a tight fit I cut the linings a little long and clothespin clamp them at the waist. Then I see where and how much I need to trim the ends on a shooting board. I repeat the fitting and trimming until I get a good fit. I let in my linings so they don't have to be exact but you might want to take some extra time on this step if you don't.

I dampen the linings before I glue them in. A lot of people will say that's a no-no but it works great and the linings can bend to conform to the basic shape of the radiused sides better without leaving gaps. It also minimizes the glue line. I clamp with fortified clothespins starting at the waist, going on to the upper bout and finishing with the lower bout. I take care to keep them about 1/64" proud as best I can but it's not as critical if you're going to carve them later. Once all the clothespins are in, I replace some of them with special clamps I've made to apply more pressure where necessary, usually about every other clothespin but more in the waist and upper bout.

When they are dry I carve them to a rounded tapered shape and finish with sandpaper.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Ken makes a couple good points that I didn't mention. Actually the first one, I believe I flat out misspoke on. I think I said I start at the tail in an earlier post. I was thinking about when I do the first layer, I start at the tail just because it seems natural. Now reading Ken's remark about starting at the waist, it reminds me that when I am clamping the second and third layers in I do indeed start at the waist and work my way around. Getting the waist clamped in first allows more wiggle room to be spread out around the bout. Secondly, as Ken said, he dampens the linings before clamping them in. Similarly, I bend mine on the pipe and clamp them in while they are still warm and usually a bit damp. This is a big part of allowing them to bend into shape in both directions. By the time I've bent the third layer, the second had already cooled in the clamps and holds its shape.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Brian
I just bent Cypress at 5/16" thick. Just sprayed with water let or soak 5 minutes or so. Heated it to 310 o a fox bender. Bent the waste carefully slowly. Worked like a charm. This is for the tops linings. The back will be kerfed.


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Excuse me. I meant Brad.


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For the first attempt I used Ken's approach of putting the side struts in full height and then piecing in the first layer between them. I used .070 layers of spruce for both the lining and the struts. Not perfect, but they turned out ok.




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Looks good to me. That's pretty much what mine look like. I bet it is rock solid!

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

That is for sure!

Colin asked me on facebook about the padauk that you see in the picture. It looks like I added binding before the top. Below is my explanation. I'll be interested to see how well this works out.

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Let me try to explain what I have going on there. I wanted to do "invisible binding" where the binding is the same wood species as the sides. I thought it would be a nice look if it was not only the same species but the grain lined up as well. So I used the fret slotting blade in the table saw to cut the binding from the side material. That of course makes the sides 2x the binding too short. So I cut pieces of Padauk the same height as the binding and laminated them onto the side. Later this will get removed when the binding channels are cut. Hopefully that is clear.

Of course the radius on the back (15') will make the grain not match up exactly. I oriented the sides so that the back side of the rims, near the neck, where it tapers and the radius is most pronounced, is the lighter wood with less noticeable grain pattern. Hopefully that will hide it.

Something that was a lucky surprise is that by doing this I can visualize the radius on the back and top and now have a better understanding of just how much material is removed by the radius dish.

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Thanks!
Brad

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Looks good Brad. FWIW adding width to the sides before bending is what I do sometimes when the sides are too narrow.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com