Class 2 (Thursday Night)

We had a lot of work to do on Thursday, especially since no class on Saturday for the upcoming Labor Day Weekend. The agenda was to attach the sides to the Heel and End Block, then radius the back of the guitar to a 30ft radius, the top to a 15 foot radius and attach the Kerfling used to support the back and front and create the insert for the end of the guitar. We had our heel blocks created and the sides bent from the last class, so our first task was to glue the blocks in place. We had to measure the sides and trim them to fit in the form and not overlap. We were able to do this quickly and set to glueing the blocks.



Cian had to use his "high-tech glue applicator" to apply the glue to the block. While glueing may in and of itself may seem simple enough, it is key to a great majority of the steps in building a guitar. Not enough and you risk jeopardizing the strength of the guitar, and too much you have a real clean-up issue on you hands.

We thought this was too much and ended up reducing the amount considerably, probably too much reduction because once glued there were areas that while I am sure they are secured, you could not see the glue on the edges. So as with everything in life it is a balance that is learned. Just not to be taken for granted.

Here is a photo where both the Heel (neck) and the End (bottom) of the guitar are in place and clamped for the glue to try.

Just a close up of the clamping process. Note that we have clamped it from the top and bottom and removed the sides from the form.

This picture just shows it from another angle.  Clamps on the bottom and top with cardboard protecting the wood of the sides.  You will notice that where the sides meet don't match up exactly.  While it is perfectly ok for them to match up precisely, it is not absolutely necessary as wood is removed to allow for the neck and end piece.  What was a little more critical would be that those sides are parallel and did not have an angle, since any angle at this point produces some 'twist' through the sides.  We had a little, but believe we can compensate with the planing of the guitar later in the process.  But a good lesson for future builds...

Now comes the arduos and "pucker producing" task of planing the guitar.  The two ends are not the same size so there is a general "sloping" that occurs from the end to the neck heel of the guitar.  Using a hand plane the sides width is reduced from around 110mm to around 100mm.  Together with the top and bottom attached the total width of the guitar should be about 105mm.  You need to be very careful that the plane does not grab the grain and create a crack in the sides.  We had two colleagues have this happen.  It can be fixed with application of super glue.

In this photo Cian is checking the radius using a radius dish with assistance from Jim.  These are dishes that have the appropriate radius to them.  You turn the guitar over, lay it in the dish and check for spaces.  The guitar should fit nice and flush and not allow any sunlight through.  This identifies high spots and where to plane.  We did run into an issue here where we had a high spot on one side but when we flipped it to plane that side gets reversed and we were re-planing the low spot instead of the high spot.  Another lesson learned, easy to get confused where your top and bottom, right and left are when you are flipping these around.  We believe it is a minor problem but will probably result in the neck area being slightly more shallow than the plans called for. 

You may notice that there is sand paper in the bowl.  You can take the guitar body and "twist" it in the bowl which will sand it.  We have learned that sanding is useful but only used when needed.  Sanding at this stage will wear out the sandpaper and put a considerable amount of dust in the air.

So that calls for more planing!  I have never used a plane before so I asked for a planing lesson.  The 'trick' is to approach the wood at an angle and when the blade catches continue on the angle keeping the back end of the plane off the wood.  If the rear of the plane rides on top of the wood your cut is very shallow if you get a cut at all...  As with everything practice is needed.

We were not able to get to the Kerfing but are very close.  Some more planing was needed to correct the mistake we had made earlier and we just started sanding.  So another 20-30 minutes and we will be ready to apply the Kerfing.

Here is a picture of one of the students and Robbie applying clamps to the Kerfing using a "high tech Kerfing clamp" (clothespin w/rubber bands wrapped around it).  The Kerfing is sort of like a wooden 90 degree shelf that lines the front and bottom of the guitar and is what is used to glue the top and bottom wood to.

Next week we will finish our planing, sanding and radiusing, apply the Kerfing and start to prepare our back side for mounting.  General feeling this week was excitement as we started to see the guitar take shape and of course some disappointment as lessons learned always carry a little pain with them.  But overall we are very pleased with our progress, have learned a tremendous amount in a short period of time.  We are always a little disappointed when the clean up bell comes.

Dove Inlay

Sorry for the blurriness on some of these photos. Still learning the camera. This was my attempt to inlay a mother of pearl dove onto a piece of Mahogany. I am just starting to learn, having only done one before this and it was a circle at that. I have been getting my inlay precut from Andy at http://www.luthiersupply.com/. Great selection and the quality is superb. I have been very happy with the pieces I have recieved so far.  Above is a picture off of his web site of the dove.  It is quite small and quite thin.  The 1/16th Dremel Routing bit I had was too large for it.  I started by clamping a blank piece of mahogany in my vice.

I start by applying white out over the area I want to route.  The purpose is so when you scribe the shape it will remove the paint and leave a visible outline of your inlay piece.  Several people suggest cementing your inlay to the board while you scribe.  I just use a glue stick and hold it in place.  Much easier to remove that way (IMHO). 

I usually use a scribe (metal bar with a very pointy end), and then go over it with a razor blade to deepen the groove.  In my opinion this part is Extremely Important.  Take your time and do it accurately.  Just doing this small inlay took me a good 15 - 20 minutes to scribe.

I then followed the outline using a 1/4 inch chisel, lightly at first in case I made a mistake. I have a 30 oz rubber mallet that really helps "make a good impression". I am not concerned with removing wood at this point, only providing a nice outline.

Here you can plainly see the outline of the body of the dove.  Now I take my 1mm (yes 1 mm) gouge and starting in the middle working out I began to gouge and remove wood.  I start lightly at first, then a little deeper, loosening the middle by running the razor blade over the outline occasionally.

You can see I have removed the wood with the gouge.  This is where I will start to see if the inlay fits.  I don't force it but apply light pressure.  Where it doesn't fit I either use a razor blade or gouge to remove just a little bit more wood.  Mahogny is fairly soft so you need to be careful.  Work in small increments and try fitting the inlay after each modification.  Patience...

I have purchased a set of sanding heads for the dremmel.  These are metal poles at varying widths that are diamond encrusted.  I have them at grits of 150, 220, 440 and 660.  The whole set was very inexpensive and it has saved me an enormous amount of time.  When I have a rough fit I LIGHTLY run the sanding tool through the outline several times being careful not to really enlarge the route but make it smooth and tight fitting.  These sanding tools were not made for routing or removing more than a fine layer of wood at a time.  If you apply too much pressure they will break.

Here is the dove in the route.  I got a pretty tight fit, but sometimes you have to repair parts.  With Ebony there is a trick where you can take ebony saw dust, mix it in with your epoxy and it covers it up nicely.  I know it doesn't work with maple and doubt it will with Mahogany.  Once I get there I will update the blog to show the glueing process and the sanding...

OK, I was able to complete and sand the Dove down. While I thought it was a good first try, definately not ready for primetime, but that's why I am practicing.  You can cleary see some spacing issues.  I am thinking this was due more to the inscribing process.  When I would run my scribe on the thin parts they were quite flexible and moved.  Then when I tried to fit the piece I widened it to accomodate.  The trick with mahogany was not really succesful either.  I can clearly see the clue lines.  I think I could use this trick but only for minimal areas...

All in all a fun project that I learned a lot from.  I do have another Dove Inlay so I will try again.  Perhaps in Maple :-o

Class 1 (Saturday Lab)

Saturday morning class is a combined class of the classical and steel guitar making courses. There were several TA's on hand which was nice. The objective today was to build the shell of the acoustic guitar. Our sides would be made out of Brazilian Rosewood and we were lucky enough to have very distinctive coloring in our sides. There was a very noticeable red streak running through the middle of ours which turned to a purple.

In order to build the sides we have to bend the sides into the traditional S shape that an acoustic guitar has. In order bend the sides we needed to attach them together to make the frame. We attach the sides what is called a block. There is one for the neck and one for heel (bottom). The dimensions are 70mm wide 32mm thick X around 90mm tall. I had purchased a 8x8x2 block of mahongany the day before so I set off to find a T.A. to get checked off on the band saw. Cian began the work of sanding down the sides. We had planed it on Thursday night (First night of class) in the Safety Planer. The planer simply reduces the width of the board but does not leave it very smooth. Also if you weren't quick enough in pulling the board through the planer it would start to burn so we had a couple of ring marks that we needed to sand off also. After planning it down to 2.4 mm the board was still rather stiff. There were technical difficulties with the sander but once operational, the side was sanded several times until the board was much flexible

Once the side was sanded we had to do two things before we could bend them. We had to locate the beginning and the end of the side and mark them. You can see the white marks toward the end of the board. We had to mark the center point as well. Know that we knew which side was going to be external facing and which end was going to the neck or the heel of the guitar, we needed to adjust for the curvature of the top of the guitar. We found out that the acoustic body actually tapers slightly as it approaches the neck. Funny after all these years of holding an acoustic I never really knew that. To accomondate for the tapering the sides had to have a radius to the side board as it moves toward the neck. You can plainly see the tapering of the board in the above photo.

Now we turned out attention to constructing the blocks. Once we had cut and sanded the blocks to their specified size, we needed to adjust the bottom heel to the curavature of the bottom of the guitar. This was done by drawing the radius on the block and using a planer shave the corners until it fit snugly against the bottom. The neck did not need this adjustment, but the external portion (facing the sound hole) was planed for cosmetic reasons. Next time you have an acoustic look in the sound hole and you can plainly see the block looking back at you. As we were told, the insides tell as much about your ability as a craftsman as does the inside.

Now that we knew which side was up it was time to bend the sides. Bending the sides is done using a press. The board is thoroughly wet down using a spray bottle then placed in between two metal sheets. A "warming" blanket is place on top. This blanket rapidly heats up to about 500 degress. As it increased in heat we slid down the guides to hold everything in place. There are three guides, one on the bottom, one on the waist (middle) and one at the neck.

In the photo above, Jim (T.A.) shows Cian how the mold is put together. Once the sides are bent, they are placed in the mold until a top and bottom are attached to the sides, several weeks from now...

There is a risk of breaking the sides during this process. If this does happen (and it does), then super glue could be used to repair the break. Fortunately no ones has broken yet.

Notice in this picture the top guide has already been pressed into the waist. I am rolling the bottom guide down to bend the bottom of the guitar. Cian will do the neck as soon as the bottom is complete.

That's one side, now we turn off the blanket which is at about 500 degrees. We let it cool to room temperature. Once it is cool it will be placed in the mold and attached to the neck and heel blocks making the outline complete. That will have to wait until next Thursday since we did not have time to complete it.

Welcome

I am new to blogging, so please excuse me while I figure this out. I am hoping to create a central point for family and friends so that we can stay in touch and share photos and information. I am also hoping to create a music space where I can keep information related to playing and listening to music.

Chad