Guitar Making

I've been trying to fix up my Toyota Camry so I can take that to the French polishing class in Chicago. It's been sitting on the side of my house for a year needing some work. I've been driving the really cool light blue '91 Dodge minivan my Grandpa gave me. I was unemployed and only needed one drivable car, so I drove the one I didn't have to spend any money on. Anyway, I'm trying to put new front axles and struts on my Camry now, and I hurt my back trying to pull one of the old axles out (and I still don't actually have the axle pulled out, ugh).

So anyway, my lower back is actually glowing red. Luckily, it only hurts when I try to move. When I take a lot of ibuprofin it turns into a soothing blue color which is nice.

So needless to say, this is why I haven't posted much these last few days, haven't felt like hunching over a workbench. And when my back does feel better, I'll be fooling with my stupid car. So I may not post again till I get back from the class. Try to be strong.

A little lunchtime scraping...

This is a rerun, except with a redwood top.

I got my drum sander all adjusted so I can sand wider pieces. The drum is only 10" wide so I have to make two passes to sand anything wider than that.

Here's the back, you can see what the wood looks like a little better since the saw marks are sanded off.


Here's the redwood top. Two years ago I ordered about half a dozen really nice redwood tops from a guy. He had put extra pieces on the top and bottom to protect the rest of the stack. One was chewed up pretty bad, the other was okay and was marked "sample" but was kind of narrow. So I decided since I'm using "second grade" and scrap type stuff for this guitar, these pieces would make a good top for this particular guitar. I'll take a better picture on a sunnier day when I can get some good natural light to get a good closeup shot of the grain. It's really pretty stuff.

No pics today, but some exciting news. Actually, it's not really exciting to anyone but me, but still... I mean, seriously folks, anyone that has a blog has to be a little self-absorbed to even have a blog, am I right people?

I just signed up to take a 3-evening guitar finishing class in July in Evanston IL (northwest Chicago) taught by Marshall Brune in his dad Richard's shop. I'll be learning a technique called French Polishing which is sort of the "old world" way of finishing a guitarthat involves hand rubbing shellac to form a smooth thin finish over the wood. These guys are among the best in the business, so it's a really neat opportunity to learn from a master and I'm really looking forward to it. And I'll have a couple days free to hang out in the Chicago area, so that should be fun, too.

Here's the rosewood back cut to shape.


And here are the sides, I trued up one edge. Then I'll cut it to width on the table saw so I know the edges are parallel.


I also found out yesterday that my Performax drum sander is temporarily out of commission. One of the little clips inside the drum that holds the sandpaper tight is broke. So I'll have to call tomorrow and see if I can get a replacement for that.

This post has a lot of pictures, you people on dial-up are going to hate me.

For a long time now I had planned on using a nice redwood top, I'd already joined it and cut it to shape and posted pics of it here months ago. But I started noticing that visually it didn't seem to me that the color matched well with the cocobolo sides. I asked the opinion of a graphic designer friend and he agreed, so I decided to go with a spruce top and save the other redwood top for something else.

So here's the new spruce top, I joined it and cut it to shape last night.


Now it's time to inlay the decorative ring around the soundhole. It's going to consist of two 1/32"-wide strips of thin black/white/black purfling. Here's my soundhole cutter attachment and dremel router jig from Stewmac. The thumbscrew used to lock in the adjustment wasn't tight enough, so I used some spray adhesive to stick some 600 grit sandpaper so everything would stay solidly in place.


Here's the first channel routed out. I'm using a 1/32" downcut spiral bit.


Here's right after the second one is done so you can see how the circle cutting jig works. It pivots around a 3/16" pin which goes into the workboard underneath. Since it's a downcut bit, it tends to leave sawdust in the channel, so it might be hard to see the second ring.



I ran superglue in the channels, worked the purfling into the channels, and clamped everything down.


Here it is after the glue is dry and ready for scraping.




And after the soundhole is cut out.

I'll try to label the Build Off specific posts so they're easier to sort through later. At some point I'd like to make an index/table of contents page that makes it easier to sort through stuff and find old posts.

Here's a rosewood back I joined last night. This is from an $18 "opportunity-grade" back and side set from Allied Lutherie.

I'm participating in a "Build-off" over at luthierforum.com. We have one year to complete a guitar (actually till March 2006, I joined late) and we'll compete for wonderful prizes and notoriety. Mostly it sounded like fun and will encourage me to keep building. I won't post very much text about that build here, because it would be repetitious and I am lazy. I'll post pics though, since I'm already putting them on The Internets on my build-off thread over at that forum.

My gimmick for this guitar is that it's going to made of cosmetically second-grade cast-off type stuff. Here's the top I joined tonight, made of 2 non-matching redwood plates which were on the top and bottom of a stack of redwood I ordered a couple years ago.

I took the clamps off the other side and realized that my linings are different colors. They were from the same batch, so I didn't even look close. You can especially tell where I patched in pieces at the very end by the tail block, on each side I used the opposite color. I doubt it'll end up being noticable when the guitar's done. Especially the part at the tail block, when the guitar's done you'd have to use a flashlight and a mirror to see it. Still, something to note for the next build.

This is reversed kerfed lining. It'll go around the edge of the sides, and this is what's used to connect the top and back to the sides. It gets glued just slightly proud of the sides, as it will get sanded later by the radiused dish. Other than that, I think the pictures explain it. I need to buy more clothespins so I can do both sides at the same time.

So now that both the neck block and tail block are both glued in, it's time to start profiling the sides in order to prepare for fitting the back on. Right now the sides are the same depth, about 4" deep, all the way around. The tail end of the guitar will be about 3/8" to 1/2" deeper than the end where the neck attaches. So on the back side there will be a taper from end to end. Also, the back will be slightly spherical, with a 15 foot radius. So I need to mark the sides so that I can cut them to the right shape, spherical and tapered end to end. Remember the radius dish I made a couple months ago? Here's where I start to use that.

It may help you to visualize this as if the guitar were complete, it would be face down with the soundhole towards the table.

So I start off with my sides in the form. I've made two small blocks that are the same thickness and set them on the neck and tail blocks. Ignore the pencil line around the sides, I went a little out of order on the pics.


Then I set my radius dish on top of the blocks. If you look at the picture above, you'll notice the neck block is not as tall as the tail block. This is how I'm accounting for the taper from the neck end up to the tail end.


Here's what I'm going to use to mark the sides. It's a Berol brand silver pencil, which leaves marks that are easy to see on dark wood. I put it in a cheapo compass, and use a nut and bolt to lock it in place.


So now I'm transferring the spherical shape from the dish to the sides. It doesn't seem like a precision operation, and it's not. It doesn't need to be, it just needs to get close. So I mark all the way around the guitar. I can't make a continuous line all the way around because the blocks from the form are in the way, which is fine.


Here it is with the profile marked, and I begin to remove everything above the line with a small block plane.


It's almost done, I just bring it to the line and then stop. It doesn't have to be perfect, just close.


Here's a view from the front, if you stare at it long enough you can see the spherical shape, how it's a little higher at the narrow waist. It doesn't have to be perfect right now because I'll finish up by lining the radius dish with sandpaper, and then sand the final profile into the sides and then it'll be perfectly spherical.


And a view from the side.

After I finished up my last blog post, I glued up the tail block. I took it apart over lunch today, looks like I didn't screw it up this time.

The other day I attempted to glue in my neck block, and I glued it on crooked. I meant to take pictures of the screwup and the fix, but I got caught up in fixing it, so I forgot about getting out the camera. My intention is to document my screwups here as well as the stuff I do right. It's a little embarrassing, but the screwups are where you learn the most.

The very general reason that I screwed it up was that I was in a hurry. The specific reason I screwed up is that I didn't do a dry run. A dry run is where you get all the parts together and clamped as if you were gluing it together to make sure everything will go as planned, except there's no glue (thus, dry). I didn't realize until I had glue on the block and had everything partly clamped that I didn't have clamps with deep enough reach to get at the bottom of the block. I also let the block slip a little bit and it went crooked without me knowing it until I went to take the clamps off.

To fix it, I bought a Wagner heat gun from Walmart. They sell it in the paint department, it's used to soften up paint to be scraped off. I heated the neck block and slowly pried through with a paint scraper that I've ground extra thin at the edge. It mostly went well except for I got a few little cracks in the sides. I fixed the cracks with thin superglue and they should be invisible when everything gets sanded. When the neck is on, they won't be visible anyway.

So today I acquired a couple deeper clamps and did a dry run to make sure everything would go together correctly. Here's everything glued and clamped up.



Here's a top view. Be sure to note the waxed paper that keeps the glue away from things that aren't supposed to get glued together. Also, notice I've knocked off a block on my building form to make room for the clamps. I'll glue that back on later.



And here it is with the clamps off. On the inside I used a chunk of plywood as a caul. For the outside I made a flexible caul by slitting some mdf on the table saw. When I clamp it up, it flexes to the shape of what I'm clamping. The cauls help distribute the pressure of the clamps, and also keep you from damaging the actual guitar parts with the clamps.