Sunday, January 29, 2017

Driving the bus, a couple more coats and some kerf

Over the last few days I have had short bursts of free time each day to work on the guitars.  I first day I spent sanding the top rim in a concave sanding dish.  It is a 25' radius dish which makes the top bow slightly from flat.  Contrary to the name "flat top" of a flat top guitar, the top is not actually flat.  It has a slight outward bow which adds a lot of strength and helps with neck to bridge alignment.  Anyways, when I do this sanding I call it "driving the bus".  Essentially I hold both ends of the mold and twist the entire body inside the dish to achieve the angles needed to hold the top shape.  Since it looks like steering a steering wheel, I call it driving the bus!

The next day I sanded to back rim in the same manner except I used a 15' radius dish.  This makes a more pronounced bow for the back.  Again, it adds strength and helps keep the back from sinking in if the wood gets dry in the future.  In this photo you will notice a small thin shim on the back of the neck block.  As per usual, I somehow didn't get the measurement right and had to add a sliver of wood to fill the gap.  I have had this happen 3 times now and for the life of me I can't figure out where I am messing up with this measurement. 

This afternoon I installed the kerfed linings that I made last week on the top edge.  Lots of clothespins!  I made the linings with my tablesaw and router.  I made a bunch of them at one time so I don't have to make any more for a while!  I pre-bent them in the same bending mold I used to bend the sides so they fit well with no glue.  Speaking of glue, I am using something new on this build, fish glue.  Back when I was building before most builders used either Titebond, LMI white glue or hot hide glue.  I have used all of these and they all have their pro's and cons to them.  Since I stopped, fish glue has come on the scene in a strong way.  It has most of the same properties as hide glue (dries crystaline, cleans up easily, and is very strong) but without the extremely short open time that hide glue has.  So far I am really liking this stuff.  Contrary to the name, it doesn't smell like fish but it is made from fish collagen.   Hide glue is also made from collagen but from animals.  The big positive for me is it has a very long open time which allows me to get things placed without the stress of having to get it done in under a minute that hide glue requires.  It takes a long time to fully dry but for now I am fine with that.


I also have done a couple more coats of tru-oil on the parlor guitar.  It isn't exciting and is a slow process but I love the look.  I am up to 15 coats now.  A couple more and it will be ready for polish and final assembly.

Lastly, I never talked about how my other guitars are holding up.  They are just about 10 years old now and have been moved from a wet climate (NY) to a very dry climate (WY).  Well there have been some issues.  Lets start with the OM since that is the worst.  If you remember, I had problems with the back when I built it wanting to bow backwards.  I could get it to bow back to it's correct shape with dampness but it would  pretty quickly flatten back.  Well moving to WY was not a good thing for this guitar.  The center seam cracked almost from end to end.  One side also cracked.  The back sinks inward heavily unless I keep a lot of humifiers constantly inside and then it will only go flat.  Sadly, that guitar in my opinion is a lost cause.  I will probably use it for repair practice.

Second is the OO.  That one is holding up well.  The back has a small section where the center seam opened up but it will be a fairly easy repair.  Other than that, it is holding up well. 

Third, the SJ.  The guitar itself is holding up beautifully.  I had one issue that happened about 6 months after we moved to WY, the bridge started to pull up.  This was my first guitar that I attempted to glue the bridge down with hot hide glue.  I was able to remove the bridge, clean up the old glue and re-set it with fish glue.  It is holding very securely and should be good for a long time. 

Fourth, one of the twins (which is the only one I have access too) is also holding up well but also suffered the same fate with the bridge pulling up after it had been here in WY for a while.  Again, I had very limited experience with hide glue when I built it so after seeing what the SJ did, I went to check the green twin and sure enough it had pulled just the same.  I re-set that bridge too and other than that, the guitar is holding up well.

My very first build, a Stewmac Dreadnaught kit has surprisingly held up the best of all.  No cracks, no bridge pulls, no neck issues, no nothing.  It is as good (other than some finish scratches and dings from playing) as the day I finished it. 

One thing I had to do with all of the guitars was to flatten the fret ends.  Because the climate is so dry (single digit humidity levels in the winter) the necks have shrunk a touch causing the fret ends to stick out.  Not a big deal and certainly something I expected to happen.  Nothing a bit of filing and sanding couldn't fix. 

No comments: