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-   -   First amateur scratch guitar build, continued: cedar/mahogany medium jumbo (https://www.acousticguitarforum.com/forums/showthread.php?t=228871)

Neil K Walk 09-25-2011 08:25 PM

First amateur scratch guitar build, continued: cedar/mahogany medium jumbo
 
Since the other thread surpassed 300 posts it's time to continue the discussion in a new thread. To sum up, I'm a first timer at building a guitar with very little experience working with wood and I've decided to be ambitious by not even purchasing the molds, templates and other jigs that would make the process easier.

Thanks as always though go to Kitchen Guitars who's graciously allowed me access to his workshop and tools and has provided me with the vast majority of tone woods to work with.

Well, I started last August so it's been over a year and I've made LOTS of mistakes but I'm at a point where I'm making good progress. Here's where I am right now:

1: I've completed the sides assembly which is about 95% ready to accept the top and back.

http://i727.photobucket.com/albums/w...8-17231402.jpg

2: I have a partially braced the top:

http://i727.photobucket.com/albums/w...9-24230912.jpg

3: I have a back that's not quite ready for bracing yet:

http://i727.photobucket.com/albums/w...d/IMG_2368.jpg

I have a plan for next time but experience is teaching me that even the best laid plans can suffer delays - so I won't jinx them by getting specific!

Mary 09-26-2011 04:34 AM

Beautiful work, Neil. Glad to see the new thread has started!

Neil K Walk 10-16-2011 11:18 AM

After 3 weeks away I almost finished up gluing on the bracing last night. My friend Mr. Kitchen was busy too. He was too busy shooting kiddie pics - including my younger son's preschool - and hadn't been in the shop as long as I had been. He hadn't touched his latest build and my top was STILL in the go-bar deck. He also neglected to empty his dehumidifier so the RH went up to 55% which is a little high for gluing but I pressed on. After futzing around with my back plate I marked where my tone bars would fit into the X brace and I notched a slot with a 1/4" chisel:

http://i727.photobucket.com/albums/w...0-15224122.jpg

Then I worked on the bridge plate, which is made of flat sawn osage orange that I thickness sanded to .096". Then I did a dry test fit.
http://i727.photobucket.com/albums/w...0-15232104.jpg

Everything could be snugger but it was good enough for me to proceed after making a caul for the bridge plate:
http://i727.photobucket.com/albums/w...0-16001000.jpg

Hopefully I'll get to glue those last two sound hole braces next time. It's likely that everything will still look like this when I return:
http://i727.photobucket.com/albums/w...0-16001055.jpg

In the meantime I have some homework to do: cutting the braces for the back so that I can glue them up next time too. I'm getting excited because I"m getting close to voicing the top!

Mary 10-18-2011 02:16 PM

This is impressive, Neil. Slow and steady wins the race. I'd rather see you take your time than to stress over a "re-do."

Hang in there little buddy. It really is a nice clean look.

Neil K Walk 10-18-2011 07:10 PM

Thanks, Mary. I sure hope this doesn't end up in the fire pit up on top of my hill! ;)

BTW, I have more downtime this week but I brought some brace wood home to work with. I had a little help today with some "finishing" of my own:

http://i727.photobucket.com/albums/w...0-18110048.jpg

Kitchen Guitars 10-19-2011 04:27 AM

Not so cute when you find it was a brace he took out of your Martin!

Mary 10-19-2011 07:35 AM

Very sweet. He looks like you, Neil. Innocent crayon day with Dad. I love the memory this will make.

Neil K Walk 10-24-2011 07:20 AM

Thanks, Mary. I still had some planing and sanding to do but I tried to keep some of the green crayon there just for sentimental reasons. He scribbled on the lower bout braces so I doubt anyone will ever get to see them once the box is closed but I'll know they're there.

Moving right along, I did the back bracing last night:

First sand the underside of the braces on a radius dish with 80 grit sanding disk. Note that each brace is in a specific spot.
http://i727.photobucket.com/albums/w...0-23225349.jpg

Next, using a template mark where each brace goes and with a Japanese saw and a 1/4" chisel remove a specific section of the centerline graft.
http://i727.photobucket.com/albums/w...0-23231724.jpg

Glue them in with go-bars just like with the top. Note that the waist brace had to be supported. That's because I removed a little too much from the center strip so the brace had a little "wiggle room."
http://i727.photobucket.com/albums/w...0-24000353.jpg

Everything's square and I got the worst of the glue squeeze out cleaned out. Next time they'll be ready to shape.
http://i727.photobucket.com/albums/w...0-24000339.jpg

Thanks once again goes to our illustrious Mr. Kitchen who stayed up late so that I could finish up in his shop with the go-bar deck. He needs his beauty sleep so that he doesn't scare small children on his day job. Hmmm, come to think of it so do I. I can be a bit of a bear in the morning. :-/

PS: since the humidity in my basement here at home has been stable at 37%-42% I've brought the top and sides home so that I can do a little homework. More on that later.

charles Tauber 10-24-2011 07:51 AM

Under the heading of trying to be helpful, I have a few suggestions that might make things a little easier.

I realize that there is no right or wrong method of doing things and each ought to use what works best for them.

If you are using a truly spherical dish to shape your braces, the surface curvature will be the same everywhere on the dish - there is no need to shape certain braces in certain locations.

You may find it easier to cut the center strip using of a sharp knife, such as an Xacto, rather than a saw. It eliminates the potential of scoring the back as you move the saw back and forth. It also allows you to hold the brace in place and score the exact width of the brace onto the center strip, reducing the chances of making the removed section too large.

Your go bars are probably longer than needed, the result of which is that they bend considerably, applying increased lateral forces. (The purpose of the go bars is, of course, to provide downward forces.) With less bend in the bars, the need for "clamps" to prevent lateral movement of the brace being clamped becomes unnecessary. Things being clamped generally stay where clamped.

I learned from Grit Laskin a method for cleaning up the squeeze-out from braces. Take a convenient size and shape of wood, say 1/4" wide, by 6" or so long, by 3/4" high, and use a chisel to create a scalloped end that finishes in a sharp edge. Essentially, you've make a wooden chisel. The "chisel" can then be run along the brace to remove the glue after the glue has semi-hardened. As necessary, use a chisel to pare-back the wooden chisel, giving it a new "sharpened" edge. You can use a soft-wood "chisel" for work on soft woods, or a harder wood "chisel" for work on harder woods. Being not very sharp, the "chisel" won't gouge the surfaces being cleaned the way a real chisel can, but is still effective at removing the squeeze-out.

Anyway, not trying to be critical, just thought these suggestions might be helpful. Keep up the good work.

Neil K Walk 10-25-2011 04:20 PM

Thanks for the ideas, Charles. I hear you on the go-bars. The deck's not mine though I'm building my own for future builds. I don't like the nylon bars at all and am looking for a suitable wood. So far all I've found that's conveniently available is strips of pine that's roughly 1/4" x 1/2" and comes in lengths 16' long.

Good idea with the exacto knife too. Basically what I did this time was to score the top of the center strip then cut down as far as I could with a Japanese pull saw until I scored a piece of Frog tape that I laid down as insurance. After that it was basically chisel work with some sanding to clean out the slot.

For glue clean up, I saved a piece of scrap from the angled cut on one of the braces and wrapped it in a white t-shirt cloth soaked with naptha.

charles Tauber 10-25-2011 07:15 PM

Quote:

Originally Posted by kwakatak (Post 2804373)
I don't like the nylon bars at all and am looking for a suitable wood. So far all I've found that's conveniently available is strips of pine that's roughly 1/4" x 1/2" and comes in lengths 16' long.

Hardwood (e.g. maple) wooden dowels of circular cross section are available at many hardware stores and in several adequate lengths. These work adequately. Better yet, are bars of rectangular cross section. (The rectangular cross section resists the tendency of circular bars to rotate in use.) If you have basic woodworking machinery, these are easy to make using your choice of hardwood. Another option is fibreglass bars of rectangular cross section. Your local building supply store often sells these for use in fencing.

Quote:

After that it was basically chisel work with some sanding to clean out the slot.
Yes, the sanded area is visible in the photo. Local sanding like that can compromise the gluing surface. The back of a chisel, used as a scraper, works well in cleaning the area.

Quote:

For glue clean up, I saved a piece of scrap from the angled cut on one of the braces and wrapped it in a white t-shirt cloth soaked with naptha.
If you leave the Titebond squeeze-out for 5 to 10 minutes it will begin to harden. In that state, it is easy to remove as a rubbery unit, rather than smearing it around with a cloth with water or other solvent. Being water-based, naptha isn't necessary for clean-up - warm water will work, if absolutely necessary. I find that there is more than enough exposure to "nasty" stuff related to woodworking and instrument making that I prefer not to use chemical solvents if something more benign will do the job.

Neil K Walk 10-27-2011 10:59 PM

Today was a mix of mulling things over and getting things done.

The weather's about to change so the RH in my basement has fluctuated. I don't know which hygrometer's reading to trust either. Today one was as high up as 58%. Tonight they seem to agree, though when placed next to my work on the bench below the RH is about 3% higher. FYI: the floor is concrete and this is a basement so some moisture coming through from the ground below is to be expected.
http://i727.photobucket.com/albums/w...0-28004334.jpg

Since the RH fluctuated so much I opted not to glue in the last pieces of my top bracing (namely the sound hole grafts) but I spent some time making sure that they fit snugly for when the time to glue up does come. Instead, I chose to start tapering the ends of the braces:

http://i727.photobucket.com/albums/w...0-28001847.jpg

http://i727.photobucket.com/albums/w...0-28001915.jpg

I'm on the fence on how to proceed though. Do I taper the ends but save the scalloping and final shaping for later in the voicing process when I glue the top to the sides? Or do I just go nuts with the chisel now? Gitnoob's talk of voicing and checking frequencies has me wondering what's best. I'll have to sleep on it. For now I think tapering the ends is best. That will get me closer to gluing the top to the sides.

So I did a test fit after I'd tapered the ends of the X brace on the lower bout. The upper bout is a little more complicated though. The plan is to follow gitnoob's lead and trim the ends of the upper transverse brace so that it locks in flush against the inner face of the bent sides.

http://i727.photobucket.com/albums/w...0-28001440.jpg

Carefully, I flipped it over and laid in on a piece of foam posterboard:
http://i727.photobucket.com/albums/w...0-28002856.jpg

I took note of where the centerline on the plate was located and the one I marked on the underside of the end blocks. Using the neck block extension as a guide I had a rough idea of where the lengths of the two components line up. Looking at the thickness of the plywood and the pre-drilled hole for the truss rod I had an idea to thicken that area. The inspiration was from a plywood Martin neck block that I'd borrowed from my friend who's led me down this path:

http://i727.photobucket.com/albums/w...0-28001743.jpg

I figure that shoring that up like that would help stabilize the area even more and allow me to route a channel for the truss rod after all. I'd been resigned to just having the access point at the headstock, which I wasn't crazy about for aesthetic reasons.

FWIW this area is foremost on my mind because that extension is key to setting the neck angle. At some point I'm going to have to take those sides out of the mold and get that top face planed to the right angle. I have my drafter's protractor ready. I'll be shooting for 91.5° and I'll want the top of that piece of plywood to be dead flat before I even entertain the idea of gluing on that top.

Mary 10-28-2011 03:51 AM

Neil,
This is looking good. I'm glad you have found time for yourself to do this. It's a great therapy as a way to escape mentally.

Neil K Walk 10-28-2011 08:39 PM

You all like pics, right? Here are some close-ups of the brace/rim intersection points:

A: this shot shows how the neck block extension comes up to the upper transverse brace. I've marked the centerline on both the soundboard and the neck block.

http://i727.photobucket.com/albums/w...11-10-28-A.jpg

B: Here's an overhead of the tail block. Note the centerline on the block and soundboard.

http://i727.photobucket.com/albums/w...11-10-28-B.jpg

C: Close up of the intersection point of the upper arm of the X brace and upper transverse brace on the treble side of the body:

http://i727.photobucket.com/albums/w...11-10-28-C.jpg

D: Close up of the UTB and upper X brace arm on the bass side of the body. Having those walnut side braces intersect at that point was pure coincidence. I'm not sure if it's a good thing or a bad thing.

http://i727.photobucket.com/albums/w...11-10-28-D.jpg

E: Close up of the lower X brace arm on the treble side of the body:

http://i727.photobucket.com/albums/w...11-10-28-E.jpg

F: Close up of the lower X brace arm on the bass side of the body. Again, the intersection of the side braces with the X brace was a complete coincidence:

http://i727.photobucket.com/albums/w...11-10-28-F.jpg

Things may still be off a hair so I'll look again once I have the brace ends whittled down a little more.

Mary 10-29-2011 06:12 AM

Are you taking your own pictures or is our photographer buddy? Great shots, Neil.


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