Doing the "crease" for a Selmer-Maccaferri model.

[Alain Bieber]

I continue to collect info on the Selmer "large mouth model" since I have the project to start one. I plan to repect the original concept of the "crease" or "pliage" in French of the original. I'd like to avoid a major crac.. noise. What to do. Size of the inner "incision" (English?) for a 2.2 mm Euro spruce top. Heating the top or not, water or not.. Speed of the mechanical application of forces....All advices based upon personal experiences are welcome.

[Craig Bumgarner]

I make Selmer style guitars with the crease or "pliage" as the French call it. There a number of different ways of doing this and I think I tried most of them before arriving at the following very simple method.

I heat the bend area of the thicknessed, unjoined top plates and clamp each to the bench with a block of wood at the bend line and another under what would be the lower bout, to get the angle ala the sketch below. The sketch shows one clamp, but I actually use two, one either side of the 8" wide top plate. This gives me lots of control and a positive bend line. If you want a less visible line, do not clamp hard to the bench. I do NOT score the wood on the inner surface as 1) I have not had need to and 2) I can't help but think this weakens the top in the long run. My finished target is usually 6-7 degrees and I over bend as there is some spring back. I have bent both spruce and cedar tops this way.

I actually use a bit of a hybrid between hard and soft line, making it harder toward the glue line, softer toward the edge. This helps when gluing to the rims, which are usually straight at this point. That is, the sides force the pliage flat where the top meets the pliage, so you might as well bend it that way to start with.

BTW, the top plates should be pretty close to your target thickness before bending as planing or thickness sanding is tougher with a bent top.

For heat, I use either the top of my wood stove or my wife's heating plate for melting aquatint resin on etching plates . You could probably heat a flat metal plate in the oven for this purpose. A heat gun or a clothes iron might do. A traditional side bending iron would do I suppose if it is wide enough for the 8" +/- top halves. Anyhow, I use a just little moisture and get the top piece hot enough to just scorch the interior surface a bit in the immediate area of the bend. Do not heat any more surface area than you have to, certainly not the whole top, just an inch or two either side of the bend. Get the heating done asap and with as little moisture as possible to avoid warping.

I apply the clamps fairly quickly so as to bend while hot. Crank it down over about 15-20 seconds. Listen to the wood. I have only come close to breaking the top once and I heard it well before it caused serious damage.

Try to leave the top set in the clamping jig overnight, but I have pulled them out in as little as 60 minutes and still had success. Over-bending is better than under-bending. Just reheat with heat gun and pull a bit of it back out. The exact angle is less important than that the two top pieces be at the same angle so they can be glued up easily.

Here is a sketch of my setup.

Pliage.jpg (10.46 KiB) Viewed 17326 times

Good luck with your Selmer D. 14 fret to the body I assume? A 14 fret Selmer with a pliage AND a large D sound hole is a potent combination.

CB

[Al Dodson]

I built a clamp from square aluminum tubing (1") that is heated with a torch both top and bottom. This heats a 1" strip which is advanced 1/2" when ready and the clamps screwed down. The top is then bent on a previously scored line and removed from the clamp. The top is thicknessed to .09 - .100" (2.1 - 2.2mm) and scored about 1/3 their depth. I wet the top as it heats. It's been a long time, but I think we tried to get the clamp to around 350F and heated about 1 minute. I have observed that the scoring of the top creates a crush zone for the fibers and helps prevent the top from cracking. By scoring, I mean the fibers are severed but no wood is removed; we used an exacto knife and made a block to control depth. The angle is somewhat greater than Craig mentions.

You will need to let the plates sit a day or two before gluing so the moisture level in the heated area equalizes with the rest of the top. The bent plates are glued up before any dome is introduced but the angles are, obviously, matched up. I have noted that we used a 6.5' radius for our braces; this gives a nice dome to the top.If you check the library you will find some pictures I posted. I also hope that I can post a drawing of the clamping jig. I found the auto cad file of the drawing; it will take a few minutes for me to render it useable here.

[Al Dodson]

This is a sketch of the clamp. I modified a fan shaped torch tip to give two separate flames to feed the tubes. Basically I just squoze (mashed) it shut in the middle! Also the clamp has wing nuts on the top of the bolts for quick clamping.

[Alain Bieber]

Al and Craig. Thanks for your detailed answers. That gives me a good basic info. I will probably decide to make a kind of test top before using my reserve good wood. I understand you both join the two halves AFTER having done the crease? I discussed that with my Maestro here and we made a couple of little tests. We understood the inside Xacto cut should be very light, a couple of tenth of mm... if any.
I suppose you start the rosette work after joining only.. and that a steady little push on the joined plate between the bridge and the rosette is enough to have the plates totally flat in the work area.

[Craig Bumgarner]

...
I suppose you start the rosette work after joining only.. and that a steady little push on the joined plate between the bridge and the rosette is enough to have the plates totally flat in the work area.

I do the rosette after the pliage is bent and top joined. The top will be flat in the rosette area and I just let the bent part below the pliage hang off the bench as I work on the rosette.

CB

[Bill Raymond]

I've made the pliage with a shallow cut in the underside of the top, although I don't think it necessary; from what I can tell, the original Selmers didn't have a cut, but were simply bent over a hot pipe and joined in a special cast iron clamping jig that holds the pliage and dome as the join is clamped. I think SeImer just bent the pliage across the table, but I bend the top more at the center, less at the edge so that it doesn't require so much force to flatten the periphery of the soundboard when gluing to the level sides. I believe there may be a photo of the jig I built in the library, but if not, possibly on the djangobooks.com forum. I cut the rosette channel using a router table with an overhead pin, and glue in the rosette whilst imparting a transverse arch to the rosette area with a clamp I built based on the photo of the Selmer factory rosette gluing jig in Francois Charle's book. The clamp consists of a baseplate with 2 wedge-shaped inserts over which the table cum rosette are clamped via a pair of clamping screws and cauls. The screws are suspended above the baseplate in the cross member of a rectangular frame that is formed by the baseplate, 2 vertical members and the cross member. I might be able to scare up a photo I took of the gluing jig, if it would be helpful.

[Bill Raymond]

Here are a couple photos of my joining jig:



That is, if I have done this image thing correctly.

I wrote in the original MIMF posting: "The jigs were made with an 8mm rise at the bridge position from either end of the top (longitudinal arch). Then I fitted the "horizontal" pieces, arching the one under the bridge 8mm, and the others so that if you put a straight edge down on the ends of the braces, parallel to the centerline, it would contact each of the braces.

I have no "reliable" method of cutting the center join. I tried clamping the two halves together at each end putting a wood spacer in at the bridge position, and planing the two halves together, but it didn't work. So I reverted to the old plane a little, try them, plane a little more... et c. trial and error method...either I am very lucky or very skilled<G>...more likely my success is a testimonial to my luck than to my skill!"

I found it handy to take a little tapered "gusset" out of the seam from the bridge to the butt, to enable the dome to be made a little easier. That is what I was referencing in my comments on cutting the center join.

[Bill Raymond]

Well it looks as if the image posting didn't work.

Try looking here: http://s7.postimage.org/41y9p38bf/raymond_frame.jpg
and here: http://s18.postimage.org/pkkdsg715/raymond_frame2.jpg

[Alain Bieber]

Thanks Bill. I saw the photos of your jig.

[Al Dodson]

I think there may be a lot of difference between the true Macs and the Selmers. By true Mac's , I mean when Mario was working at Selmer. By far the largest number of instruments were built after Mario left so those are the ones most studied. I think Mario saw to it that the tops had a true crease. Later, I suspect there was an attempt to get around this little understood and difficult step.

If you believe, as F Charle contends, that the inspiration for the pliaged top derived from the Neapolitan mandolin, you should study them for a moment. You will note that the pliage is a very sharp and well defined line not a gentle roll as results from bending across a hot pipe. Bending across a score is the best way of achieving this sharp transition that I found. I think the score needs to be a bit deeper than the .2mm you mention; don't be afraid to go at least.5mm. We bent both tops and solid wood backs this way with predictable success.

The plates re pliaged before joining simply for convenience; it would be a daunting task to bend a 16" wide top!

[Alain Bieber]

When I was a very young college boy I walked very often the street of the (at that time) Henri Selmer shop in Paris. A guitar was almost allways exposed side by side with saxophones. If you never visited the "Henri Selmer.fr" web ressource you will discover, in the historical part, many nice photos of this very old wind instruments factory (founded during the Second Empire in Paris). Their guitar involvement did not last very long. Too bad...
A couple of photos show Maccaferri, apparently, working on the guitars. I am not sure he really worked manually on them, could be more marketing stuff than reality <g>. The workers came from Sicilia, according to the usual sources.

[Craig Bumgarner]

As Al suggests, the definitive resource on Selmer guitars is Francois Charle's book, "The Story of Selmer Maccaferri Guitars". It discusses and illustrates the Selmer guitar, history, sales, manufacturing and players very thoroughly. Hundreds of pictures including dozen of closeups and high quality pictures of the instruments themselves. As good as it is, it is fairly short on construction details and methods that a luthier might be looking for. Francois Charles's full size plans of Selmer guitars, available separately, are superb in every way.

Maccaferri initiated the Selmer guitar program (~1932 +/-), designed the guitars, set up the shop and oversaw the first year's production. He then left in a dispute over his contract. After his departure, Selmer continued to build guitars but there was a fair amount of churning as the company sought out what the market wanted. Maccaferri's designs were modified, new designs added. Some were popular, others were not. Charle refers to this as the transition period but by the late 1930s, Selmer seems to have settled on just a few models. The most popular of which was the 14 fret small oval guitar played and popularized by Django Reinhardt. Django's #503 was built around 1940.

The use of the pliage seems to come and go through Selmer's 20 years of building. Some seem to have a very obvious pliage, others do not. I don't recall having seen a hard fold like in a Neapolitan mandolins used on Selmers, but that may well be my lack of experience or poor memory. (I'd love to see a picture of one if someone has one) The pliage was in use to some degree right to the end of the Selmer line. Here is a picture of Selmer #861 (1952), very near the end of production clearly showing a pliage. This appears to me to be pretty representative of the Selmer pliages I've seen.

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As best as I can tell, the pliage was used to stiffen the top in order to 1) better resist the downward force of the bridge and the effects of humidity on dome height and subsequent effect on the string height off the fingerboard (action) and 2) to permit the bridge support bracing to be lighter, making for better response of the top. A pliage, hard or soft, is one way of doing this. Doming to varying degrees, sometimes fairly severe as seen in some old Busatos, is another way. Regardless the aim seems to be to stiffen AND reduce bracing mass. When the right combination is put together, it works very well. Selmer guitars and their copies are famous for their unequaled volume and cutting tone making them popular with acoustic jazz musicians to this day.

CB

[Simon Magennis]

I had a look in the Michael Collins Macaferri book to see how he does it. He bends the top, before joining, over a heat box. The sides of the box are shaped to give the pliage and there are cross bars made from metal piping to support the top. He heats it with a lamp. He damps the underside but doesn't make an incision. He also shows a picture of bending manually but says he prefers the heat box method as it is simpler and is reliable.

I thoroughly recommend the book for anyone who wants to have a shot at building Macaferri style guitar. It details the construction using veneers to create a laminate rather than constructing a solid wood version. Actually he has a quite a few little tricks which are worthwhile for any builder.

[Craig Bumgarner]

Michael Collins book is a great resource. It is sometimes short of the why you are doing certain things and a bit long on production jigs, but very good none the less. No one else even comes close on this kind of guitar.

I found bending a 2.5mm spuce top by hand, i.e. over a hot pipe to be scary as s__t. In spite of having it plenty hot, I was having to throw a lot of weight into to get anywhere at all and the prospect of breaking the top seemed quite likely. Spring back and angle control was also a problem. Course, it is probably just a matter of my lack of technique, but I find the clamp on table method is far more controlled and easy.

Collins' hot box method will no doubt work and I have no argument against it except is yet another piece of gear to be built and stored, something I avoid when possible. The clamp-to-the-bench method described early in the thread involves two clamps and two blocks of wood. I don't even use the same clamps or blocks of wood twice, just whatever I have laying around. A spritz of water in and heat in the joint area. Very simple.

[Bill Raymond]

Ah, the continuing mystery of the pliage! I've not been able to determine whether or not any of the Selmer instruments were scored on the underneath side of the top beneath the pliage. The few photos of the undersides of Selmer tops don't appear to show any kind of scoring. Jon LeVoi has stated that he has seen scorch marks under the pliage, but not scoring, apparently from the bending with a hot pipe. David Hodson opined that these were burns from some sort of router-like cutter used to thickness the top, and that the pliage is imparted simply by bending the transversely arched top to meet the straight sides. Paul Hostetter once thought the pliage was the result of years of tension from the steel strings causing a hunching of the top, but had changed his mind to acknowledge the pliage. Francois Charle has written (in an email to Peter Davies) that the tops were scored by means of a cuter--I will leave it to Alain to translate the word, and perhaps explain how it is different from a canif or a couteau. Max Debelleix told me that the word referred generally to what we know as the Stanley knife or utility knife.

We do know that Maestro Maccaferri was not able to get Selmer to make the guitars exactly as he had wanted, for John Monteleone, who had a friendship with Maccaferri and made at least one guitar according to blueprints drawn by Maccaferri himself, stated that Maccaferri had wanted the backs laminated in a concave form so that the dome would be built into them instead of made flat and domed with braces as Selmer did. Also, Ibanez for a short period made some Maccaferri signature models according to Mario's design that featured a true cranked top, as in a Neapolitan mandolin. I've never seen one of these, but the photos I have seen show a very definite bend below the bridge

Maccaferri himself had referred to the mandolin as an inspiration for his design--could it be that he wanted to make a cranked top all along but wasn't able to get Selmer workers to do it? It certainly seems plausible that this might be the case and that some of his early "prototypes" may have featured a cranked top that was scored under the pliage. (I believe this was also a feature of chitarre battente, but I will defer to Alain's superior knowledge of antique guitars to correct me if I'm wrong.)

There is a good discussion of tops and bracing, including Selmers on Paul Hostetter's site: http://lutherie.net/discussion2.html .

All this is academic, though, as all these methods seem to have worked for various builders.

[Al Dodson]

Craig, the reason we don't see the hard line on the guitar is the dome. This pulls the crease out at the edges unlike the flat top of the mandolin where the crease continues to the side. I agree, your picture illustrates the hard line I'm talking about. Interesting on such a late guitar.

[Bill Raymond]

Al, the mandolin top is not flat, but arched. The photo Craig posted above shows a pliage clearly, but you really can't tell from the photo just how sharp the bend is, as so much is dependent on the lighting angle in photographing the guitar: making 3D judgements from a 2D image is very, very difficult. I will say that the pliage on the Selmer that I examined in Francois Charle's shop a number of years ago was definite, but not sharp like a mandolin; whether or not that was due to a flattening over time from the string pressure on the bridge I can't say.

[Greg Robinson]

Craig, did you take that photo yourself? I ask because we only allow images to be uploaded to our server by their owner for copywrite reasons.
If you did not create the image yourself, you are able to link to a page where it is available.
I have hidden the attachment until you respond.

[Alain Bieber]

Thanks Gentlemen. Let us avoid starting a war on the use of a score or not <g>. I will make a couple of experiments on scraps.. and let my usual attraction for the least effort speak.
For the record, here the generic term for a knife is "couteau". For the commoner a small (usually folding) blade "couteau" is a "canif". BUT for a luthier a very short blade ,not folding, with a rather personalized hand piece IS a "canif". A "cutter" (untranslated, pronounced almost in English, but of common use) corresponds to all kinds of instruments with multiple blades, retractable or not. A "cuter" do not exist in French to my knowledge.
The mutiple tool kind of couteau most often made by Victorinox is logically a "couteau Suisse".
Ah I forgot...do not take risks speaking French outside <G>.
Bill, yes, some, not all, chitarras battentes (Italian to check please) had the pliage. They were transversally flat, most often.