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Author Archives: Adam Frumhoff

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Inlay Installation

Just as amazing when you know how it’s done:

While a lot of older cheep factory made instruments have stickers on top of or prints under the finish demarcating their logo, nice old instruments, and most new ones have  wood or shell material set into the wood.

Even cheap guitars get inlay work now because it can be made quickly with CNC machines, which cut the inlay with computer guided precision.

We do it the old fashion way – by hand.  Here’s how it’s done:

Fist the design is printed on paper and glued to a sheet of shell material with regular old wood glue. This one is on Alabam, a shell composite material designed specifically for inlay work.

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The shell is then carefully cut out with a jewelry saw and shaped with needle files.

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The finished inlay pieces…

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The pieces are then placed where they will reside on the guitar and traced. A dremel tool is used to carefully cut out the slots for them to fit into to.

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The pieces are then glued in with epoxy and a wax paper covered caul, let to dry for 24 hours, and then sanded down.

The final result:

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Thanks for reading!

Elden Luthiery


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A New Guitar with the Wrong Neck Pitch???

Physics before name brands!

A true story:  In the early seventies the Martin Guitar Co. sent a number of D-18s out the door with the bridge int the wrong place!  And not just a little bit; a full 1/8″. Apparently the bridge locating jig was busted and no one noticed…for a while.

A few years ago I ran into a completely different, but equally baffling, factory error.

This came, strait  from the factory, to the sales department of the shop I used to work at.

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A closer view to see what the issue is…

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Neck Pitch refers to the angle of the neck in relation to the body. With the neck perfectly flat & a strait edge placed on the top of the frets, one can check the projection of the neck. Ideally, the neck should project to  5/16″ above the soundboard @ the front edge of the bridge.  Almost all bridges are 5/16″ tall at the front edge for this reason.

1/4″ is the absolutely lowest acceptable projection. But, 1/4″ projection is something you should only see on a really old guitar that has had the bridge shaved down more than once: A guitar nearing demise, or rebirth (determined by your willingness to spend a sizable sum on repair work).

So here it is. A brand new guitar that projects to  1/4″. We sent it back. 

The replacement was perfect.

Thanks for reading!

Elden Luthiery

 


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Go-Bar Deck Crack Repair

Repairing a Full Length Back Crack with a Go-Bar Deck:

This Guild Jumbo acoustic had one of the most extensive cracks I’ve ever seen. It ran the full length of its back. The cause of this crack was MAJOR dehydration – and years of it. The crack was not only wide open, but the wood had also warped substantially on either side of it.

I unfortunately did not take a picture of the original damage. I was skeptical if the  instruments could be fixed. It required almost a month of prep to reshape the wood for the repair and i wasn’t convinced it could actually be done (and start to blog it) a month in.

Prep work went like this:

1. Intentionally over-hydrate the instrument for 3 weeks.

2. Wet the inside of the guitar along the crack with hot water.

3. Install 2 spreader clamps from the crack area to a a top brace.

4. Clamp the instrument in the Go-Bar deck (See Pic Below) and let sit for 24 hours.

5.  Repeat!

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I did this 6 times before he guitar was ready to glue!

Oh yeah: What’s a Go-Bar Deck?

go bar deck

Go Bar decks are a traditional, and common, clamping system for building acoustic guitars. They come in handy for repairs sometimes too.  Originally the bars were made of wood,  mine are plexiglass (like tent poles) with rubber ends.  Slightly bent they pressure between the bottom & top of the deck.

So, once the wood was made to lie flat and crack closed up I repeated the same process, minus wetting the wood with hot water, with Hide Glue. Same pic as above.

Next came the braces.

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A better view. Go bars sometimes pop off braces. The plexiglass on either side is to protect the top if that happens ( it did twice).

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Please note:  The guitar is sitting on top of carpet on top of a radius dish (the same radius as the side facing it). This was essential to the process.

Reinforcement…

Because of the 3 braces crossing the crack, reinforcement wasn’t a big issue. I only needed to install one cleat near the bottom. Made of mahogany (same as the back),  about 1″ x 3/8″ & 1/16″ thick, and glued cross grain, the cleat helps keep the crack from reopening. It is double stick taped to a magnet, which is used to locate it and clamp it in place.

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Low tack masking tape was used  protect the top and locate proper cleat placement.

3 magnets (kept from tuning in on themselves with heavy duty masking tape) give clamp pressure to the cleat.

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You can see the closed crack above and below the tape, not perfect, but far better.

Thanks for reading!

Elden Luthiery

 

 

 

 

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Taylor Big-Baby Monster Crack Repair

 

A Taylor Big-Baby with a big problem:

This instrument was dropped, inside it’s soft gig bag luckily (if it’s going to happen), on a linoleum kitchen floor. The finish and the wood remained amazingly unscathed. But the shock of the drop caused the top to split and separate from the sides.

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This one took A LOT of clamps. Glue was applied, and clamps installed in 3 sections. From right to left around the edge. There is also 2 spreader clamps inside the guitar under the top crack.

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A view from the side.

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Because I used hide glue – the best option for top cracks – clean up was quick and no color alteration to the top occurred. Here is the finished repair:

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And a view of the top:

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Thanks For Reading!

Elden Luthiery


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Gibson Bridge Plate Repair Blog

Gibson Bridge Plate Repair:

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As you may or may not know, an essential element of acoustic guitar bracing is that of the Bridge Plate. The bridge plate, which rests directly under the bridge on your guitar, executes a number of crucial purposes. It reinforces the sound board under the bridge, provides a surface  for the string ball ends to rest against, & acts as  a tone transfer point (if fitted correctly) between the bridge, strings, top, and braces. The image below is a fairly average x-brace pattern found in most acoustic guitars. The bridge plate is the rectangle with the holes in it fit into the X.

bracing Pattern

Over time,  the pull of the strings against the  bridge plate eventually causes it to wear. Bridge plates are usually made of hard maple (and sometimes rosewood) so that it can handle the constant pressure of the metal string ball ends. At some point, every bridge plate needs repaired or replaced.  I personally feel that, except in the case of a completely cracked though plate, repair is preferable. This Gibson came in for some routine fret work,- but upon assessment I discovered an incredibly damaged bridge plate. The plate was  also made of spruce – not the best material choice!

This picture is taken from inside the guitar. You can see the tremendous damage to the soft spruce bridge plate. The balls had pulled all the way through and were resting directly on the sound board. Another year or less like this and the bridge would have likely torn off, tearing up the soundboard in the process!

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My fist step was to clean up the break area (not shown) and plug it with a new piece of spruce.

Here’s the plug before it went in:

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Once I had the fit just perfect, I used a cam clamp, plexiglass call, and hide glue to install it.

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Using a small sanding block followed by a razor blade scraper I then cleaned it up flush with the bridge plate.

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The next steps  was to make  maple bridge plate overlay. This was especially important on this guitar because  the soft spruce bridge, if left with just the matching spruce plug, would have just worn down and chipped out again .

Step one was to dimension and size the overlay.

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Then to thickness and size a piece of hard maple for the overlay, drill holes for the bridge set screws, and taper the edges..

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I made a custom hardwood caul, rubbed with paraffin wax to prevent sticking, to install it.  Again, hide glue was used.

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Installed with cam clamps, you can faintly see the plexiglass caul on top to help spread the pressure out.

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I let the hide glue set up overnight, cleaned up any excess glue,  reattached the set screws, and then re-drilled the bridge pin holes.

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The final step was to taper the bridge pin holes so the pins fit just right and then establish a groove for the windings with a needle file.

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All Done!

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Thanks for reading!

Elden Luthiery