How deep does a mold need to be?

[LouieAtienza]

Originally Posted by printer2

More like an opinion by a highly accomplished luthier, just because a person feels a certain way does not make it trash talking. He explained why he holds that opinion and his points are valid to a certain extent. It depends on how you approach building, as an assembler of pieces or as an artist of sound. Building as Bruce does is no harder than building in a mold, it just takes a different tact to get where one wants to go. I build without a mold myself, I watching how Bruce builds and it resonated with me so I tried it. It is no harder if you can visualize what you are trying to do.

Just because Bruce doesn't use a mold doesn't mean it that's the only way to skin a cat. The difference between Bruce and myself or many others is that he has decades of experience that allows him to control certain aspects of the guitar by altering the body shape, and also allowing the flexibility of different shapes without the need for dedicated molds. He also may be a bit better than many at precision wood bending. Sure it's undesirable to "make" a rim set fit into a mold and introduce stress, but I feel it's probably far more undesirable to have a mis-shapen rim that needs to be sanded unevenly to achieve an acceptable outer surface.

For the rest of us, it can be helpful to at least remove one variable at least to start, thus we can better understand and identify what other changes can do to the voice of the guitar.

[John Arnold]

I am having trouble with the concept of a mold slowing down the building process. Both Wayne Henderson and I have built guitars in 4 days using a mold.

[printer2]

Originally Posted by Shuksan

" They are really only useful in production situations where relatively unskilled labor is used and a specific product is the necessary result. The mold allows many sins to be obscured, allowing more consistent appearing results, but also permitting more mediocre performing results. "

In my book, this qualifies as trash talking.

'but also permitting more mediocre performing results'

He never said that anyone that uses one gets mediocre results but that it can permit them while visually appearing satisfactory. I have no qualms with that statement. Now if he said all people that use molds get mediocre results I would wonder.

[printer2]

Originally Posted by LouieAtienza

Just because Bruce doesn't use a mold doesn't mean it that's the only way to skin a cat. The difference between Bruce and myself or many others is that he has decades of experience that allows him to control certain aspects of the guitar by altering the body shape, and also allowing the flexibility of different shapes without the need for dedicated molds. He also may be a bit better than many at precision wood bending. Sure it's undesirable to "make" a rim set fit into a mold and introduce stress, but I feel it's probably far more undesirable to have a mis-shapen rim that needs to be sanded unevenly to achieve an acceptable outer surface.

For the rest of us, it can be helpful to at least remove one variable at least to start, thus we can better understand and identify what other changes can do to the voice of the guitar.

Bruce also uses a Fox style bender which helps produce a consistent side. I think the point was to say there was other ways to skin a cat. Whether one would progress further working without one I will let him handle that himself.

[JDatlen]

Obviously there are many ways to get great results. I use a system similar to what Charles Tauber referenced except instead of dowels I use 1-1/4” square stock with the machine bolt. This allow me to hold sides easily with a couple of spring clamps. Well bent sides don’t need much support and I end up only using a couple of the blocks on each side.
I was over at Bruce’s shop a few years ago and he had a sample of two sides glued to a neck and tail block creating a guitar rim. The sides were of different woods and I think it was for a demonstration he may have been doing. One side was Jatoba which was really stiff and was probably sanded down to .06. Not sure what the other side was but it was thicker, probably in the neighborhood of .08-.09. Bruce was manipulating the sides just by flexing the rims to show how easy it is to experiment with different shapes. A simple twist of the wrist and you had an asymmetrical body shape. Following his threads over the years, you see how many different models he produces with very little setup to create them.

[redir]

Originally Posted by Cantelibre

Its my first build. I feel like I need a mold because I don't have all the skills, have never bent sides, but I will look into the Un mold process.

Like Bruce I don't use one either. But I did use one on the very first two guitars I made. What I found was that for me they didn't really help much and in fact made things more difficult. You can force fit the sides to get better symmetry but then you introduce stress into the top. If you are going to build a lot of the same guitar and use a side bender and radius dishes then it's probably good to have a mold.

[Bruce Sexauer]

There are two major Canadian “schools” of lutherie that I am aware of. One is the Larrivee’ school emanating from Toronto, and the other is the Michel Dunn school emanating from Vancouver. The Dunn school is rooted in Spain, specifically in Guitarras de Las Mallorca’s, owned by Canadian George Bowden and where Dunn spent several years as an apprentice in the middle 60’s. Having shared a shop with Michael Dunn in the later ‘60’s, I am of that school. While the Spanish school does build top down rather than top up as in the German school, both methods rely on an outside mold, and that is where I started.

I have never been very patient around jig and fixture work, finding it tedious and beside the point where my love of making Guitars is concerned. My first molds were 3 3/4” tall, but I soon found that 3” worked as well. These were made from stacked layer of 3/4” plywood, and dropping one layer at a time quickly got me to a single 3/4” piece. This offers no side support so I learned to get the side to stand plum to the top, and it wasn’t long before I realized that a pencil line on the top and a good eye was all that was needed, as long as the side were accurately bent. The advent of Charles Fox’s bender made this relatively easy to accomplish.

What makes moldless construction more efficient is the freedom to pursue new designs, and especially to fine tune existing designs. For me, the pursuit of aesthetic perfection is an incremental process. It is only after a guitar actually exists that I am able over time to see what would have made it better, and a fixed template offers a great deal of design momentum which I think twice about changing if it means making a new mold.

Since building Guitars is not about production numbers for me, but rather is about refining the results, moldless construction is a no brainer. If I had initially been exposed to the possibility of moldless construction, as I hope to do for some others, I absolutely believe I would be further down the lutherie path than I am at this moment.

There are many ways to skin a guitar. When one has acquired a high degree of skill, it probably matters little which method is used as far as a single instrument is concerned. But the process is the nature of the life the luthier lives, and commodity production does not have the appeal of the artistic process, for me.

I too can build a guitar in four days, and have done so while documenting it in this very forum. If interested, check out my “MagCat” which I built just before the 2013 rendition of the Healdsburg Guitar Festival.

[tadol]

Oops - I see Bruce already responded, so this may be a waste of pixels -

Bruce certainly doesn't need any of us to defend his technique - anyone who has played his guitars can get a sense very quickly as to how special they are, and its impossible to say his technique is "incorrect" in any way -

There are some inherent problems building with molds, and Bruces main point, about them forcing consistency, is extremely important. Much of the consistency in luthiery is for reasons completely separate from tone and playability. Most of the time guitars are built to specific dimensions is to fit easily available cases - which is pretty unfortunate. It can take as much time and effort to build a good set of molds as it can to make the box. If your goal is to build a number of guitars all the same size, then the investment in time to make a good mold may be worth it. But if you are just starting, its well worth looking at the technique Bruce uses - I guess it can be called Spanish style - because if you can do it, you will find the freedom to build most anything you want. His second point, about unwittingly creating stresses in the build that are detrimental to the "musicality" of the box, is equally important - If you need to force your bent sides into a shape they do not want to be in, and then expect gluing a top and back to them to keep them in that shape for decades, then you are asking for problems. When you build without molds, you really can't "force" anything - you have to make it so it wants to fit - which means you can build lighter, and thinner, and create something that can be much more resonant - not necessarily easy, but a technique that in the long term is very worth considering -

I've seen luthiers use molds as thin as ¾" - I think they are usually thicker to keep the sides parallel to each other more easily. When they are multiple pieces of material laminated together, they can get pretty heavy.

Whatever you decide to try - Good luck on the build!!

[printer2]

What started me building without a mold is I wanted to build a guitar a different shape to accommodate the size of the wood I had. I built a mold for my first few guitars and I wanted a more traditional shape. I did not know how many guitars of this size I was going to build and I thought it would be a lot of trouble doing a good job of the mold for one guitar. I have been following Bruce's builds for a while so I tried building without.

The main difference in the methods is that you are building the sides onto the top rather than building the rim and attaching the top and bottom to it. This necessitates gluing the the kerfed lining or peonies (little blocks) to the top and sides in order for the sides to hold shape. One of the reasons I also used this method was to squeeze a little more width out of the side pieces I had. Since I was going to put binding on the guitar and rout away part of the sides I left the height of the binding free of sides. This allowed me to build a reasonable depth guitar with sides meant for a ukulele (they were 24" sides. It worked out but was a little tricky to do.

The next build I cheated in another way, the sides were wide enough but rather than rely on the peonies to hold the sides to their shape I relied on thin CA and the good fit of the sides to the top. I placed the sides along the line of the shape drawn on the top. I lined up the top and gave a squirt of CA to make the side and top solid. When both sides were on I went back over the joint placing the peonies with Titebond.

The drawback with building this way is you need to get your neck and heel block placed properly (yes and no, it makes your life easier if you do, still can get the job done if they are out, trust me I know), hopefully square to each other. So it takes some measuring and checking that the two blocks are placed parallel to each other and on the same plane. I came up with a simple method of acheiving this, I cut a 2" x 2" to the length of the distance between them and clamped the blokes on either end of the 2" x 4".



So with the blocks clamped you can glue them to a top and then glue a side to ether block and then the other. I found it really convinient being able to see the butt end of the guitar to get the sides perfectly sanded so that I would not need a wedge of any kind.



I have also built the sides onto the end blocks without having them glued to the top. I then glued the kerfed linings onto the top and bottom of the sides as done in a mold. Then I sanded the edges to give the top and back a flush surface to glue to as you would with the rim built up in a mold. So as long as you were not trying to use the form to force the sides to shape or wanted an exact repeatable shape then the mold is not really nessisarily. I guess you can say the 2" x 2" is a stripped down inside form as used in violin construction. You could have some cross members at the wide point of the upper and lower bout as well as the waist to act as an inside form. It will not correct badly bent sides but it is a quick and cheaper way of building a prototype or one off rather than building an outside mold.

Again, just another way to skin a guitar.

[Cantelibre]

Well, perhaps building a nice side bending form would be the better thing to do, and go without the mold.

[redir]

Aren't side bending forms sort of one trick ponies like molds though?

As an example of why I like not using a mold, I'm building an OOO for someone right now and first off I was able to tweak the standard OOO shape to have more curves at the head block. That's one thing but secondly I screwed up the binding and chipped out some top wood which was so bad that I had no other choice to retop the guitar. So I carefully routed off the top and managed to save it so now with the remnants of that top I am making an OO inspired guitar. And all it requires me to do is fudge the sides to fit a bit and I'm done.

[mirwa]

Originally Posted by Bruce Sexauer

I don’t use a mold at all, and haven’t for 20 years. I question the need for them at all. They slow down the building process and rigidify it, getting in the way of creativity and growth.

I use a mold when making a guitar, not even slightly ashamed by it, I also make my own molds, I personally take pride in using a form, as I will shape the sides to achieve that nice flowing look, rather than, the side has a bend in its waist, that’s good enough, I like the consistency of shape it gives to my final product.

Too many times I see guitars cross my bench that are mis-shaped, out of balance visually, have ridiculously large arches that are not even. These builders could have benefited from using a form when building.

That’s not saying everyone fits in the one box, we are all different, it’s that difference that sets us all apart.

Steve

[printer2]

Originally Posted by Cantelibre

Well, perhaps building a nice side bending form would be the better thing to do, and go without the mold.

Depends on your bending method. If you are using a blanket then a mold is a given. I have a blanket and a few molds to bend on but the last couple I used a bending iron instead. I dampened the wood and bent on the iron originally but I had trouble with the wood scorching at times. I can not remember if I saw someone else do it online but now I wet a rag, wring it out and put it on the hot iron. I then put the wood on the steaming rag and slowly rock the wood back and forth. The wood relaxes and you can feel it letting go and you can bend it. The wood doesn't get above boiling so no more scorched sides.



I bend the waist first then do the bouts.





I used the mold I have to hold the sides for when I build the rims the next day, you sometimes get some spring back but these behaved themselves. The damp rag method might not be good for figured wood, I have not tried harder to bend woods on it yet. If you do have the set set aside to be used another day the form to hold the sides does not need to be as finished as the one shown. I used a 2" x 4" with slots cut in it to slide the ends in, also a short piece of the 2" x 4" the depth of the waist in between the main board and the waist with a clamp holding the waist, short board against the 2" x 4". Worked good with some wood, some maple I had sprung back. Just have to touch up the bends again.

Again, just different strokes, each person finds methods they are comfortable with that gives them good results. I will be making molds for some sizes, I plan on making giveaway guitars for kids that can't afford one, which is why I have been messing about with spruce for back, sides and necks. Anyway I just wanted to give you one perspective on building. I hope others share theirs so you can select from the collective wisdom of the people here. Even though we build in different ways we have no problem adopting a method from each other if we think it will advance our efforts.

[hat]

I'll not join the mold/no mold argument. However, I will say that there is something therapeutic in bending sides by hand over a pipe style bender. Feeling the steamed wood give as you work it, watching carefully as the curves and bends form under your guiding touch is something special. Something that I think everyone that wants to build a guitar should experience at least once.

[murrmac123]

Originally Posted by mirwa

I use a mold when making a guitar, not even slightly ashamed by it, I also make my own molds, I personally take pride in using a form, as I will shape the sides to achieve that nice flowing look, rather than, the side has a bend in its waist, that’s good enough, I like the consistency of shape it gives to my final product.

Too many times I see guitars cross my bench that are mis-shaped, out of balance visually, have ridiculously large arches that are not even. These builders could have benefited from using a form when building.

That’s not saying everyone fits in the one box, we are all different, it’s that difference that sets us all apart.

Steve

Good post, Steve.

I would venture to make a comparison with architecture.

2000 + years ago , the ancient Greeks had already figured out the most aesthetically pleasing contour of a column, and the "stasis" of this contour is very precisely defined. Any arbitrary departure from this contour is immediately noticeable, and will be flagged up by any knowledgeable observer as a gross error.

Fast forward 2000 years (or 1833 years) and we are in the premises of CF Martin, whose guitars are the epitome of elegant design. The outline of a 12- fret Martin, of whichever size, is the absolute ideal shape for an acoustic guitar .... from an aesthetic viewpoint. Probably from an acoustic viewpoint as well, but I am not qualified to adjudicate on that.

Fast forward another 60 or so years, and there are luthiers everywhere coming out with weirdly shaped upper bouts and lower bouts (and don't even get me started on headstocks).

In the middle of all this anarchy, there are only two major builders adhering to the aesthetic ideal ... Martin and Collings.