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Well, this is my first tutorial. I hope you can bear with me and my explanations make enough sense.

I have been doing my solid linings in a little different manner than some others I have seen and I wanted to share my methods. Part of the process in making them also includes laminating my double sides so I included that as part of the tutorial.

I begin with 2 sets of sides which are laminated to form the double sides and then 3 other sides which are laminated to become the linings. For the double sides I have been making my outer side around .045 and my inner side about .035. I adjust the outer measurement based on things like the weight of the wood or if I know the guitar will be either used roughly or babied. The 3 other sides I thickness to around .095 or so. There are .1 veneers available from http://www.certainlywood.com that work excellent for this application (and the .06 available for inner sides). In this case my outer sides are Guatemalan Rosewood and all other others are mahogany. Here is a photo of one set of double sides and the linings bent to fit within one an other.



The next step involves an outer form of the side template. Mine is made from 3/4 plywood. It should be an exact template of the outside of the guitar and a little wider then your side thickness. In this case all of the sides are roughly 4" wide and the template is 4 1/2.

This next photo shows the 2 sides and the linings being clamped dry to determine where the best position for the clamps will be. I bend them all on a pipe and you can force them to shape a little but the less you have to the better. The waist is the difficult part to get tight. The outer bouts will generally lay down fine if you work from the waist out.



Once I know where my clamps will go I am ready to begin laminating. For the double sides I have been using the Smith's all wood epoxy. I prefer it to the WEST systems because it is quite a bit thicker and easier to control (i.e. not make a mess). I have used this glue, the WEST systems, fish glue and LMI white all successfully for this operation. LMI white was the most stressful because of the quicker set time. For the lining laminations I am using fish glue mostly because it seems like it will add less weight to the guitar in the end and once I slice the linings(this will make sense later) I can correct small gaps if they occur. I use a nice even layer of glue on each mated surface for the epoxy and for the linings I put a heavy layer on the insides of the outer layers and none on the middle layer. Here is a photo of the epoxy spread on the double sides.



When doing these laminations I place wax paper under the double sides and another layer between them and the 3 lining sides. It is helpful to tape the double sides together at the waist and the ends to prevent them from slipping when they are clamped under the lining sides. Here is a photo of all 5 layers clamped up.



And here is another close up. It is worth it to take your time here and get everything clamped and mated as best as you can. The fact that there is no squeeze out means I probably did not use enough glue. I like to see a little bit.



And here is a shot of them all laminated with the double side sitting on top of the lining side. You can see well they mate to each other.



Much has been said about the stiffness of double sides but for me the real benefit is the stability of them while the box is being constructed(and the crack resistance). I feel that the solid linings are what adds the real increase in stiffness.

continued below.....

_________________
Burton
http://www.legeytinstruments.com
Brookline, MA.

Next up is a jig used to cut the inserts for the vertical braces. People have made the point that these are not as needed when using double sides as there primary purpose is the prevent side cracks from spreading around the rims. I still like to use them and this system can certainly still be used with a single side. Here is a photo of the lining side and the jig. Before using this jig I make sure my lining side is flush on both sides and square to the edges.



Visible also are the vertical braces. I cut them to 1/8 x 1/4 quartered on the 1/4 face. The jig has a bosch colt base mounted underneath and a 1/4" spiral bit mounted to come up 1/8 above the main bar. The 2 fences ride along the main bar. They are a friction fit and could be improved to a rolling mechanism. To slice the channels the side is clamped between the 2 fences and passed over the router bit. This photo shows the side clamped in place about to be pushed over the bit. When performing this operation a sacrificial block is used putting force directly down to keep everything tight as it cuts.



Once the slots are all cut the vertical braces are inserted in the slots and the outer square edges are sanded flush to the curve of the side. You have to number the slots and the braces so you will know which goes where later.



Here is the side with all of the slots cut



The next step is to slice up the linings into 4 pieces. This is done on the bandsaw. I generally cut 2 slices at 5/8-3/4 and then I cut the other piece in half. The linings on the bottom will have to begin wider to deal with the taper. Here is a photo of the sliced linings. Note that before slicing them I marked the waist point on the linings and on the inside of the double sides. This will help with fitting them later.



still more....

_________________
Burton
http://www.legeytinstruments.com
Brookline, MA.

Now we have our 4 linings cut and we have to fit them into the side. Before I do this I install the 2 blocks to the sides and I sand the taper into the rims. I am not using the dishes so this may vary for some of you. The top linings are easy to fit. I set them at the waist lines and mark where they would meet the neck block and then remove material until it is snug to the block and tight to the waist line. I undercut the lining at the end block by a bit and shim it after. If it is made tight on both sides it can be difficult to fit in when gluing. For the bottom linings I do the same procedure and then (remember these linings are about 1 1/4" tall now) I set them in so they are flush with the bottom of the side and I pencil in the taper onto the lining where it falls away.



At the belt sander I sand out this overhang and then on the bandsaw I run the lining through with that sanded edge against the fence and cut the whole piece to 5/8 (or whatever height you want). Now you have a lining piece perfectly mated in both ways to your side. Once this is completed for both lower lining pieces I sand a triangle shape into them on the belt sander. The first time I did this I was very nervous about it but I quickly realized it is no big deal. I use a coarse belt and try not to get too picky with making the triangle too pointy at the peak. It is easy to give it an elegant final shape later once it is glued in. Once you have sanded them to shape I tack CA the vertical braces into the top lining piece.



Once they are in I do a dry fit with the lower lining piece locked into the vertical braces also. Once it is snug I mark the overhang of the vertical braces and trim them off.



Here is another dry fit completely prepped for install. You can see the taper in the lining of the piece not installed.



Now I glue the pieces in. I use fish glue here. LMI white works very well too. I use all of the clamps to be safe and get a tight fit as best I can. It will pretty much sit in there perfectly without any clamps. I do use little cauls on the inside and outside for the vertical braces. The wet spots shown here are cleanup of the fish glue. I brush a little water over squeeze out and it dissipates very well and sands out with no trouble later.



That is pretty much it. To finish up I shim at the tailblock and sand everything smooth. Sometimes with the fish glue you will see a little gap that didn't get tight in the original lamination and I will go in and tack those spots here. Here are some shots of a guitar just about ready for final final sanding before the top and back go on. (The large solid piece next to the neck block is to anchor a bevel cutaway)



and a close up of the vertical brace as it nests in the linings



I hope this was helpful for some of you. It made me think more about it to put it together. I came up with a little list of pros and cons. Feel free to add to it.

pros:
very rigid stiffness introduced to the rims(this could be a con too depending on your building style)
perfect mating to the sides/template
ability to change the lining thickness (i.e make it thinner/more active in the lower bout)
clean look
vertical braces extend the full width of the side

cons:
more time consuming than most other linings
rigid stiffness (see above)
slight weight gain from kerfed linings

Thanks for looking. I would love to hear people's thoughts and any improvements you may think of.

_________________
Burton
http://www.legeytinstruments.com
Brookline, MA.

I was looking this over again and I realized that on photo #5 it should have a different caption. This photo is of a different glue up than I was referring to and that is why there is no squeeze out. Once your first glue up is done The triple laminate lining side becomes a perfect caul to glue up your second set of double sides. That is what is being shown in that photo and why there are less clamps holding everything down.

_________________
Burton
http://www.legeytinstruments.com
Brookline, MA.

Thank you so much for producing that tutorial. I really appreciate it. I really like the way you incorporate the verticle braces into the lining.

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http://www.booneguitars.com
https://www.facebook.com/pages/Stephen-Boone-guitar-builder/488208541257210

Burton, that's really impressive. A really well thought out method. Very well put together tutorial, as well.

I love it!

Thanks

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-Clint Beacock

Burton, I'll bet that side/bracing combo is really stiff. That's a good thing in my mind.

Nice tutorial as well. Thanks a bunch!

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Formerly known as Adaboy.......

Well done! Thanks for sharing that. It sure gives food for thought

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John Ressler

Thank you very much for sharing, I look forward to learning here at OLF

Well done and so helpful! Good ideas and execution.

Thanks Burton!

Ed

Nice tutorial Burton , I enjoyed it.

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Ken

Thank you for sharing your process Burton!
Looks like a very well thought out procedure that took some time to arrive at.
Documented very well!

Lots of food for thought here,
Joe

Thanks for the tutorial. I am currently making a prototype with carved sides (using a router and a template) so I was interested to see what you were doing. I am thinking stiffer means better sound.

Nice work Burton. Thanks for sharing!

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JJ
Napa, CA
http://www.DonohueGuitars.com

Great DESIGN and EXECUTION, Butron. Very skillful!

Thanks for taking the time to post this.

Ed

Thanks (again!) Ed.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

That's actually a really neat and elegant idea. I think I'll try it.

This struck me as a helpful addition to Burton's great tutorial.

Dave


SMITH & CO--USING TROPICAL HARDWOOD EPOXY GLUE

Harder woods such as oak, teak, maple, alder, apetong, araki, pau lope, osage orange, etc., may be glued directly with our epoxy adhesives.

For best results any liquid epoxy adhesive should be applied to both surfaces to be glued and allowed to sit long enough for the wood to soak up as much as it wants, so that when the pieces are assembled the wood will not absorb the glue that would otherwise fill the gap between the pieces, leading to a glue-starved joint. Scarf and butt joints are especially prone to soaking glue out of the joint, as it wicks into the end grain of the wood, which is the open ends of the hollow cellulose tubes of which the wood is made. Edges of plywood are notorious for soaking up liquids.

Improper clamping of wood may be the largest source of glue-joint failure.

Poorly-fitting wood elements, clamped to bend them into contact, will have tremendous spring-back forces pulling them apart, as much as a metal C-clamp can develop. Yet, the shear strength of wood is only 200-300 pounds per square inch, and the wood fibers at the glue joint will pull away from their parallel neighbors, often within hours to days after the clamps are removed.

Curved beams are best made by steam-bending the individual laminations, letting them dry in a fixture that sets the new shape, and then gluing them. If steam bending is not an option, cross-grain fasteners or splines (tenon, biscuits) should be screwed or glued at each end, because the curved structure will want to straighten, and the glue joint will fail by cleavage.
Straight, smooth, well-fitting wood elements can yet be made to fail by using excessive clamping force.

Squeezing a glue joint down to zero glue-line thickness forces out almost all the glue from between the pieces, and the natural porosity of wood wicks away the remaining microscopic residue of glue. The result is a glue-starved joint, and they will fail when the clamps are removed, or sometimes days or weeks later. If the failed joint shows no divots of wood pulled out of the opposite side, the cause of the failure is almost certainly excessive clamping pressure and not enough time allowed before clamping. The wood element should be clamped gently: Just enough to squeeze out the excess glue and bring the wood pieces into contact at the microscopic high points of the joint. Thick pads of soft rubber under the clamp faces ensure gentle, even clamping forces.

Most adhesives, even epoxy adhesives, do not bond hardwoods because the saps and resins in the wood interfere with the bonding chemistry of the adhesive. Our glues are specially formulated (by us - we’re chemists) to overcome this difficulty. We designed a chemical system that would absorb and displace the saps and resins without becoming weakened by the absorbed oils.

Some woods—particularly ebony—contain a wax rather than oils. Saw cutting or dry sanding can smear this wax over the surface, making gluing difficult, especially on end grain or 45 degree bevels. Wet sanding or light abrasive blasting (such as glass bead or 200 mesh abrasive) can clean such material off the surface to be glued and has been found effective in improving the bond strength of such joints.
Side grain bond strength, even with ebony, was found adequate with saw cut or dry sanded surfaces.
It is important to remember that wood is a natural product and varies.

It is also important to remember that surface preparation is at least 50% of adhesive bonding technology.

Our products have fairly long thin-film set times, and so the user has plenty of time to wipe up drips or shape into the desired form before the epoxy gels.

Do not use solvents to “clean” hardwoods before gluing. The solvents are absorbed by the wood and will cause the epoxy bond to the wood to fail. Even solvent cleaning hardwoods after gluing (while the glue is still wet) has in some cases, caused glue-line failures. Wiping up drips with paper towels is safe. These comments apply not only to our glues, but to any glue on any wood.

In mixing two-component products, it is important that the product be thoroughly mixed or it will be physically weak when cured. One of the most dependable methods of ensuring complete mixing of liquids is to mix well in one container, transfer to a second container and mix again.

With all modern products there are certain safety procedures that must be observed if the user is to avoid developing a rash or allergy. Do not get epoxy or other resins on your bare skin. If you do, stop what you’re doing and go wash with soap and water. While casual exposure at infrequent intervals may not be harmful to most people, it is impossible to predict who will become allergic after some exposure. So, be neat and work clean.

MIXING TWO-COMPONENT PRODUCTS

In mixing two-component products, it is important that the product be thoroughly mixed or it will be physically weak when cured. The most important part of the mixing process is to mix it well in one container, transfer to a second container and mix again.

Sophisticated adhesives, sealants and coatings are two-component systems. One part has to be mixed with another part before they are applied. After a while, a chemical reaction takes place, and what is created is a filler, paint or glue with exceptional properties. It is not possible to obtain those properties by taking some simple thing out of a can.
Each of these two parts, whether they are liquids or pastes, consists of very small components called molecules. The manufacturer designed the system so that the individual molecules of each component would react with each other in certain proportions. That is why the instructions say to mix the materials in those proportions.
If the materials are mixed in different proportions, then some molecules of one or another component are left over, scattered among the molecules of both components that did react together. In that case, the material will be softer or weaker than it should be, or will soften in water when it should not. It might be a gooey mess. It is therefore important to mix the components thoroughly, so that everywhere in the mixture the ingredients are in the correct proportions, even down to the individual molecules. Visual appearance of uniformity is not always an adequate guide, as there are millions of molecules in a single inch. A few ounces of material, for example, should be mixed for at least a minute or more, until visually uniform, then transferred to a second container and the mixing procedure repeated, scraping off the mixing tool frequently. This ensures that the small amount of A or B in the bottom corners of the first mixing container has the opportunity to be thoroughly mixed with everything else.
Glues should be mixed by hand, as power mixers can whip in many small bubbles which will give a weak glue joint.
If there are any soft or gooey spots in the final cured product, that is proof that the material was not thoroughly mixed.

Thanks Dave for posting that. I find in reading it some things I feel validated by and others I should maybe pay more attention to. I still use the Smith epoxy and it is always helpful to be reminded of the proper procedure for something you use. I do feel that sometimes switching from one adhesive to another makes me treat them all similarly, and I need to pay more attention to use them correctly.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Burton, thanks for the great tutorial. I am just about to try this and I wanted to ask if you think it worthwhile to make an inside caul for the form?

Hi Edward,

I still have not made one but whether that is laziness or not I am not sure. You can absolutely do it without one. I worried about wanting to change up the thicknesses of my layers at some point and used that as an excuse to not make one. I assumed small discrepancies would matter. They may not though. If you do make one and it works I would love to see it. I would be interested in your results either way, especially what you think of the process and outcome.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

That is a good point. Perhaps make one thin enough that it has play in it, so that there is a small amount of adjustment possible but the caul still forms a more consistent clamp along the whole side and requires less individual clamps?