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You can view our archived newsletters
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2011/12 Luthierie Camps...
F5/F4/H5/H4
Construction:
April 22-27, 2012
July 15-20, 2012 Oct. 14-19, 2012
Tap Tuning:
Nov. 12-13, 2011
Nov. 3-4, 2012
Tools & Fixtures
Mar. 24-25, 2012
Please visit our website or email Kali for more information about these programs.
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Dear Luthiers, 
Happy New Year to all, and I hope that you and your family had a wonderful holiday season. In response to your luthierie holiday gift needs, Santa's elves worked diligently to ship your items on time. Keeping production up to speed, coupled with Kali being on maternity leave, kept our noses to the grindstone - or should I say, our wood to the sander - and unfortunately we were not able to be as communicative on Facebook as we would have liked. A new video on bending binding has been posted (the videos are on our Facebook page and on YouTube under "siminoffparts"), and another video on attaching binding will be posted in a couple of weeks. Thanks for your patience. January is NAMM month. NAMM stands for National Association of Music Merchants, and its goal is to bring together resellers and manufacturers through various venues as well as hosting two conventions each year. The "winter" event is usually held in Anaheim, California and includes every type and category of musical product manufactured, and Summer NAMM is held in Nashville, Tennessee, which is primarily an acoustic instrument show. Rosemary, Kali, Ken, and I go to Anaheim each year where we meet with our vendors to see the latest and greatest and make decisions about products to bring you in the future. The convention is open only to NAMM members, and this January marks my 39th year of attending (I think I only missed two shows over the years). Of special interest this coming NAMM is for us to participate in a meeting on the current status of NAMM's efforts regarding the CITES embargo and the Lacey Act, both of which have had a serious impact on the ownership, sale, distribution, and usage of certain species of wood (e.g., rosewood, mahogany, and ebony) as lumber and finished goods. This is a very important topic for all of us (builders and musical instrument owners alike), and in our next newsletter we'll report to you on what we learned. We are excited to see your continued interest in mandolin construction. For those of you who are building from scratch, I would be interested to learn if there are any support materials that you wished you had but don't see in our product line. While I believe that we have made available all the necessary templates and ProSeries Drawings for the F5, F4, A5, A1, and H5, there very well could be something we've overlooked. If there is something you feel is missing, please do not hesitate to send me an email directly so that we can consider your request. Also, if there are any luthierie processes you would like to see covered in our instructional videos, please don't hesitate to include those requests in your emails. I welcome your input. Here's wishing you a great luthierie year, and ... thanks for building with us...
Roger |
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The contribution of the backboard
So much attention is given to soundboard woods and to the figure in the backboard and ribs, but little attention is given to the actual contribution of the backboard to the overall sound. It seems that most folks consider it more for its aesthetic attributes than for its acoustical properties.
The backboard is a very important component of string acoustic instruments common to bluegrass music, and there are three basic categories of backboard constructions, each providing a unique contribution to the tonal properties of their respective instrument. These categories are reflector (resonator), closure (lid), and sound-producing medium.
The banjo backboard is called a resonator. Because of its curved shape and laminated construction, the resonator is more of a reflector than a sound-producing member. The resonator produces very little amplitude, especially when held against the body. And, while it certainly plays a role in the instrument's tone (all parts in an instrument's "coupled system" play a role in tone production, but some to a greater degree), it is not a vibrating membrane like the backboard of a mandolin, fiddle, or guitar. Its job is to enclose the banjo's air chamber and to reflect energy forward - toward the inside of the head and toward the apertures.
On a resophonic guitar, the instrument's cone and spider assembly is so efficient and powerful that the contribution of the backboard is minimal by comparison. The backboard on this instrument does contribute to the mid- and bass-response of the instrument, but the instrument can be played on the lap (damping the backboard) or supported on a strap with nothing touching the backboard with almost equal results.
The backboard of the steel-string acoustic guitar contributes to the overall tone, and aids in enhancing the mid- and bass-frequencies of the instrument. And because of the structure of the conventional steel string acoustic guitar and the relative effectiveness and power of its soundboard, the backboard on this guitar plays a greater role in the overall sound than it does on the resophonic guitar. Of further interest on the steel-string guitar is that the backboard is typically cross braced with little or no attempt to graduate or otherwise control the vibrational modes of the backboard.
The violin ("fiddle" to many of us) is an interesting hybrid, and here the role of the backboard is very important. On the violin, the soundboard and backboard are coupled with a soundpost whose purpose it is to stiffen the soundboard and provide a fulcrum for the bridge - with one foot virtually over the soundpost and the other over the bass bar - to rock on. However, as a consequence of the soundpost's connection to the backboard, it serves to drive the backboard, and here we see a greatly elevated role in the backboard's contribution to the overall sound. Of further importance is the manner in which this instrument is held; unlike the banjo, guitar, or mandolin (but like the resophonic guitar) the apertures face upward and the instrument is held out from the body with both the backboard and the soundboard causing waves of compression and rarefaction to emanate up and down from the instrument (and not directly towards the listener).
By contrast to the foregoing instruments, the mandolin features a backboard that is graduated, not braced, and is constructed lightly enough that it can be an effective tone producer. The backboard of the mandolin plays a vital role in the instrument's mid-and bass-response. A heavy backboard delivers a thin-sounding and very treble-voiced mandolin. A properly graduated backboard works in concert with the soundboard and enhances the mid and lower registers. And, if the backboard is tap tuned (so that you know something about its stiffness and specific pitch), the backboard becomes a critical acoustical component of this instrument. Most mandolinists appreciate its contribution and will hold the instrument away from their body, or they will use one of the Tone-Gards® made by our friend and neighbor Tony Pires. For the mandolin, the type of wood used on the backboard is very important, but I'm out of room for this month - so you'll just have to wait until the next issue to learn about backboard woods.
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Product Highlights
 · Calibrated C=256 Tuning Forks - If you are serious about tap tuning and getting the best out of the instrument you are building, you've undoubtedly searched for a way to calibrate your tuners to C=256 (A=431Hz). We offer C=256 tuning forks that have been personally calibrated by Roger Siminoff to within +/- .5Hz. (Note: medical tuning forks are not calibrated even though they are stamped "C=256"). If you want to learn more about why C=256 tuning is important, you can download a free white paper from our web site entitled What Was Loar Hearing? here. Our calibrated C=256 tuning forks are part #821 and are $18.95 plus P&H.
 · New Spool Clamps - We have advanced the development of our spool clamps to provide the stiffer end collars (spools). Our new Siminoff Spool Clamps are constructed with a threaded steel shaft fitted with two hard rubber collars that will not mark the soundboard or backboard. The durometer of the rubber collars permits them to be squeezed during tightening and expand as the glue cures and shrinks - a process that results in constant pressure during the entire gluing process. A fitted nylon insert has been added to prevent the spool from twisting and provide for a smooth turning platform for the wing nut. The spools can be slid in place and will stay until tightened by a single wing nut. Adjustable for use on ukuleles, mandolins, and mandolas. The part number is #3000, and the price per set of 24 is $39.95 plus P&H.
 · Template Sets - Our template sets provide you with the tools to trace highly accurate neck and body shapes onto the wood in preparation for cutting. Included is a neck contour gauge that is held against the neck during shaping to ensure the correct contours of the neck at various fret locations. Each Florentine instrument set (F5, F4, and H5) includes templates for the body, neck side profile, neck contours, peghead, and body scroll centerline. Each pear-shaped instrument set (A5, A1) includes templates for the body, neck side profile, neck contours, and peghead. The F5 set (part #370-KS) is $74.95 plus P&H; F4 set (part #372-KS) is $74.95 plus P&H; the H5 mandola set (part #373-KS) is $77.95 plus P&H; the A5 set (part #371-KS) is $61.95 plus P&H; and the A1 set (part #374-KS) is $61.95 plus P&H.
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Luthier's Tip: Inlay Filler and Crack Repair
The ideal inlay job reveals no gaps between the pearl or abalone and its surrounding background. When installing inlays in ebony or rosewood, our recommendation has been to rout the opening, and then prepare a mixture of powdered ebony or rosewood with some Elmer's white glue to secure the inlays in place. The ebony or rosewood powder can be made by simply sanding either of the woods and carefully collecting the sawdust (or you can purchase some ready-to-go powdered ebony filler mix or rosewood filler mix from us. The rosewood filler mix is comprised of a vial each of black and brown powder so you can match the color as well as darken certain areas of the fill). However, if you prepare your own sawdust, you'll want to pulverize it into a fine powder (an electric coffee bean grinder works well to do this). The glue and powder are mixed to the consistency of buttermilk, and then placed in the inlay's cavity. When the inlay is pushed in place, the mixture oozes around the inlay filling all available space. We suggest leaving the excess in place until it dries and then scrap and sand it flat so the mixture, pearl, and background wood are one level, pot-hole-free surface. 
Sometimes, however, it is necessary to put the inlays in place and get the pieces aligned perfectly before using the filler. This is especially important when doing vines and intricate inlays that have multiples pieces. For these types of inlays, there are two approaches: 1) you can lightly coat the inside of the cavity with either Elmer's white glue, Duco® Cement, or Titebond® Original Wood Glue, and then place the inlays into the glue where they belong and allow the glue to set up; or 2) put all the inlays in place and then flow in some cyanoacrylate glue (Crazy Glue®). Once the inlays are glued in place, you can fill the surrounding spaces with some filler mix. The problem with this method is that no matter how good a job you do trying to fill the void with filler mix once the inlays are in place, there will always be some air pockets or voids, and you will have to make several repeated attempts to fill them. One method I've found handy for filling small voids and cracks, and even for fixing nicks and dings in ebony and rosewood is to put some powdered wood into the void and force it in place with either a spatula or the flat side of a small screwdriver, and then place a drop of cyanoacrylate glue on the powder and allow it to soak in. The cyanoacrylate will dry in five minutes, and then you can begin to sand the area flat. To get a finished product that looks like the original surrounding wood, it is important that you pack in the powder before applying the cyanoacrylate glue. Your goal is to end up with a tight glob of wood bound by the glue and not a dried pool of glue. |
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Our soundboard and backboard carving service has been a valuable asset for many builders who regularly use our service. (To learn more about our carving process, please visit