Repair - 1981 Yamaha SJ-180

Some internal pics.

I didn't find an internal date code, only a 3 on one side.


Look at that bracing!!!


For comparison, here's a 1977 FG-336SB.


1973 FG-260.


1967 FG-180.


1972 FG-500.


1971 FG-140.


1971 FG-150.


You get the idea.  The bracing on the SJ-180 is MUCH heavier than earlier models.

Well, I got the neck off.  5 steam sessions, nearly 2 hours!!!  I seem to be in a funk of hard neck removals, each one seems to be harder than the last.  This one is no exception.  Plenty of pictures and discoveries.  

There's no surprise they used epoxy!  LOTS of epoxy!!  Pretty much like they used to use hide glue, on EVERY surface, including the heel to the side of the guitar.  The only way to remove the neck is to saturate all of the wood in contact with the epoxy and the wood pulls away.

Another thing I noticed is there is no heel lamination!  It's solid!  Nothing to unglue and leave the bottom of the heel stuck in the guitar!!  I think that's a good thing!?

I clamped a piece of wood over the neck pocket gap in an attempt to keep the steam in there.



My first attempt of steaming resulted in only a few dribbles of water out of the tip.  I removed it and found a piece of wood jammed in it, when I pushed it into the first hole.  Not a good start!!

The next attempt lasted 4.5 minutes, when the steam ran out, too much water was wasted trying to see if the tip would unclog itself, collected in the steam trap.  The bass side looked to be a little loose on the top side of the heel corner, nothing on the treble side.

Then I drilled deep holes along the edge of the dovetail surfaces.  8 minutes of steaming and the top of the dovetail is definitely loose, and there's water coming out of the bottom, but it's definitely not ready.  I stopped, took the guitar out of the jig, and stabbed the scalpel deeper into the heel corners.

4 minutes of steaming and no change.  Stopped, removed the guitar from the jig, and drilled holes down into the corner of the heel to get moisture close to the heel face where it's probably stuck to the side of the guitar.  And I cut heavily into the heel corners with the scalpel, about 3/4" to 1-3/4" down from the top on both sides.  And broke the blade.

10 more minutes of steam AND IT STILL WON'T COME OUT!!  It's definitely loose at the top, it must be the bottom that's stuck.  I removed the guitar from the jig and cut deeply into the corners of the heel about 3/4" to 1-1/2" from the bottom of the heel.  I had to put a glove on, my  palm and index finger where on fire from all of the digging I've done with the scalpel.

6.5 more minutes of steam and IT FINALLY POPPED!!!  About 1 minute before I thought I should put some steam down the neck pocket to be sure the bottom of the heel was released.  That way have been the last straw holding it.

And I found CLEAR EPOXY!!  LOT'S OF IT!!  The epoxy itself doesn't liquify, the wood softens and pulls away.

And the neck block is plywood!!





You can see a small piece of the heel still stuck to the bottom of the neck pocket.  That may have been the last thing holding it in.


The brown stuff are softened wood fibers where I cut with the scalpel.  They just rubbed off since they were saturated.


Epoxy on every surface!! 

You can see how the holes I drilled were perfectly down the side of the dovetail, on both sides.






I scraped off the epoxy and wood particles.  And a chunk of the dovetail was partially torn off.






In the end, it looks like a pretty clean neck removal.  But it took probably 2 hours!!!






I glued and clamped the dovetail chunk.  The only thing I have to fix, except for gluing the fretboard back on.


And I'll let it sit for a couple of days to dry.  then glue the fretboard back on.  I'm probably going to have to sand the top of the neck, it's a little swollen near the neck joint, and it probably won't go back to normal.

With this experience, I don't know if I'd do a customer neck reset without cutting the fretboard off at the 10th fret to have access to the neck pocket and dovetail and drill extra holes.  There's no way just putting steam down the neck pocket is going to get the moisture to all the areas that need it.

CTGull,   Thank you so much for the pictures and procedural descriptions.  I am planning on tackling a 1973 FG 200 reset.  Do you think I'll have all the trouble you describe here?  I removed the neck from a cheap (China) Harmony parlor guitar but it turned out to be just 3 dowels!  I am gonna bolt it back on to practice my skills but I have not done a dovetail yet.  Any tips on the FG 200 would be appreciated and thanks again for the details you document.
Ron

Well, last night I went for it!  I cut a slot in both sides of the truss rod channel with the .020" saw, 1/8" from the dovetail.






And bent it.




And sanded the top of the dovetail and the truss rod channel.  It needs to be tapered slightly to allow the fretboard to bend down starting where the neck meets the body.





And I fixed the steam holes and reinstalled the 15th fret.  I did something different, I used the .015", .020" & .025" saws to open the slot.  After using the .020" saw I found they cut undersize, I couldn't get a .018" feeler in, so I used the .025" saw and got a nice tight fit for the fret.

This is filling the holes with rosewood dust and dropping in thin superglue.  It looks messy because after I drop the glue in I quickly throw a little extra rosewood dust on it to make the glue cure instantly.  Then I pull the plastic strip (piece of milk jug), cut & scrape the mess flush, and sand (with the grain).


Then I used a file to break the corners of the slots and pounded the fret in.  It actually went in fairly easy vs. the normally clean the slot with a .016" saw and open it to .020" with feeler gages..  I had to crush the fret flush in a couple places in.




Then I glued the fretboard back to the neck, using a 12" radius sanding block as a clamping caul.  The 12" radius vs. the fretboard radius of 16" puts more pressure on the outer edges of the fretboard.

Fish glue.






The slight taper at the top of the dovetail will allow the fretboard to be glued down flush to the top of the guitar.  Maybe I should have used a thinner saw to cut the truss rod channel, the bend looks to be a little too much.  I'll find out later.

It's been a while since I updated this thread.  I didn't touch it for 2 weeks.  I just took a break.

4 days ago I made a new bone nut & saddle.  The saddle slot is .113"/.114", measured with precision gage blocks.  I made the nut with 1.46" string spacing.  I put the guitar in the neck jig and found the action is 9/64" low E & 7/64" high E, the neck relief is good and the neck is centered.  I set the heel tape at .03", filed & sanded to the tape, put it back in the jig and the action is 7/64" low E & 5/64" high E.  Almost there!  I undercut the heel more, set the tape at .020"/.015", filed & sanded to the tape, and the action is a little over 5/64" low E & 1/16" high E.  It's close!  Leave it overnight.





The next night I found the action was up to 3/32" low E & a little over 1/16" high E, which is fine because I left the saddle high, sticking out .235"/.215".  I crowned and sanded the frets.  I wanted to get the neck on tonight but it's getting late and I'm tired. Tomorrow!

2 days ago I buffed around the heel area, touched up any bare spots with marker, glued & sanded the dovetail shims, and glued the neck on with fish glue.

The dovetail shims.




Glued the neck on!






Some glue squeeze out.


Yesterday I found the action still at 3/32" low E & a little over 1/16" high E. Perfect! I'll let it sit for a couple of weeks and check again.

I bought some cheap finger planes to attempt to thin/lower the top bracing.  www.amazon.com/Jiayouy-Bronze-Violin-Planer-Instrument/dp/B08BJVDQ6V/  They're going to need a lot of work to sharpen and set them up.