1st Build-OM from scratch and my workbench

Take us through building your guitar step by step. Post pictures and tell us what you're doing.
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MaineGeezer
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Joined: Wed Aug 13, 2014 12:14 pm

Re: 1st Build-OM from scratch and my workbench

Post by MaineGeezer »

I've got a four foot level. I tape a strip of sandpaper to one edge, clamp it to the kitchen counter (flat and smooth), put a 1/4" shim under a half top or back to get it up off the counter and well onto the sandpaper, and slide the piece along the sandpaper taped to the level. It works pretty well for getting a straight edge. I hadn't thought about being unidirectional until it was mentioned, above; that sounds like a good idea.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Talladam
Posts: 123
Joined: Mon Sep 21, 2015 9:43 pm

Re: 1st Build-OM from scratch and my workbench

Post by Talladam »

One direction sanding isn't something I tried! Maybe next time. I'd really like to be able to do it with a plane in the future though.
John J
Posts: 296
Joined: Wed Nov 26, 2014 7:52 pm
Location: Saint Paul, MN

Re: 1st Build-OM from scratch and my workbench

Post by John J »

Definitely agree with the one direction sanding. Much more consistent pressure. And sometimes it's one pass then check. Easy to do too much.
Learning every day.
Talladam
Posts: 123
Joined: Mon Sep 21, 2015 9:43 pm

Re: 1st Build-OM from scratch and my workbench

Post by Talladam »

Well, the build is going at a glacier’s pace, but I thought a quick update was in order, if only to keep feeling like I’m moving along. As mentioned in the previous post, the top, back and sides are thicknessed now. Using my boss’s drum sander proved to be an ordeal. First the sandpaper belt broke, and I had to figure out how to replace it. Then it turned out that the belt on the platen was too loose and the wood would stall part way through its run through the machine. With limited dust control, the dust would build up and glaze the belt a bit. And the drum was off by about .010” from one area to the next. So I got the thicknesses close and I will finish off with my random orbital sander and some 80 grit.

Here are my thicknesses now:

TOP: 0.125” at the thinnest spot. I have no real way to tell the stiffness of my top so I’ll take it a bit thinner, but won’t push it too much. I’m planning to get some help shaping my braces from a local luthier, so hopefully if I’m too thick, we can adjust things then.
BACK: 0.127. I’m planning to take it to 0.110” and just hope that works.
SIDES: 0.095”. I think I’ll take them to 0.085”.

Now I’m making templates and moulds. I copied the plans from the Kinkead book, glued it to some posterboard, and cut out the places where the braces intersected so that I can mark the bracing pattern I’m going to try to make my outside mould from ¾” MDF, and I’m going to try to do it with my jigsaw and router. After the stress with the drum sander I would rather use my own tools when I can. I am also trying to figure out how to make radius dishes. I saw a tutorial on making them by using ¼” mdf and a bunch of little shims to create the dome shape. This appeals to me since my router is a bit small for the task otherwise. Here’s the link: http://forum.ukuleleunderground.com/sho ... ave+higham
I’m a little worried that go bars will punch through the mdf though. Any opinions?
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MaineGeezer
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Joined: Wed Aug 13, 2014 12:14 pm

Re: 1st Build-OM from scratch and my workbench

Post by MaineGeezer »

Your top and back are definitely on the high side for thickness. I think mine are about 0.1", but John can give you a much better indication than I can.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: 1st Build-OM from scratch and my workbench

Post by Diane Kauffmds »

This is what I shoot for when thicknessing: .10" for the top, .080-.085" for the sides, .095-.10" for the back. John Hall advised me to brace the guitar with thinner braces, but taller; this gives superior strength without over building.

I also thin my tops toward the edges to loosen them up a bit, per the advise of MaineGeezer. This is done after the box is closed, when you're doing the final sanding, before routing for binding.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Talladam
Posts: 123
Joined: Mon Sep 21, 2015 9:43 pm

Re: 1st Build-OM from scratch and my workbench

Post by Talladam »

The mold, neck and end blocks are done. The end block that Kinkead calls for is 5/8" which is a bit thin compared to the others I've seen so I'm going to add a maple "appendix brace" reinforcement strip glued cross grain to the block. I'm really loving my little apron plane for the blocks. And I put up a new LED striplight above my bench and a nice sheet of plywood on the wall so I can start hanging my tools and such up. I picked the sheet I did because it seems to have a cool figure to it. I'll sand it and put some oil on it and see what it looks like. The mold took a long time for me. I bandsawed and rasped one side piece and used my router to copy it. It turned out a bit rough, but I spent a good bit of time making sure the neck and tail block areas were nice and smooth and at 90 degrees from the face of the mold. I also made a template for my sides because I decided to cut them close to the right shape before bending. This was a bit of a pain since no information on this is included in the Kinkead book. I ended up finding some OM plans online with a side template, reading some info on another forum and adapting the info for the slightly different shape of the Kinkead guitar. I think I actually did pretty well. I'm going to leave the sides a bit over width anyway, so the profile is just to get close. Next I will cut the sides to shape and use my orbital sander to bring them to final thickness. Then its side bending time! (gulp) Then I have to decide if I can glue the sides to the blocks. My humidity is about 15% higher than it is in the winter here and I know that this is a cross grain glue joint and maybe not the best to do when humidity is high. Any opinions on whether this joint is ok to glue right now?
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nkwak
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Location: Pittsburgh PA suburbs

Re: 1st Build-OM from scratch and my workbench

Post by nkwak »

Nice mold! It looks very similar to mine, which was an adaptation of the Kinkade semi-solid mold that used hardwood spacers instead of solid plywood or MDF that many here use. It looks like you thought through some of the issues but I think you may come up with some shortcomings as I have with my mold.

The first issue is hold tight those two halves will remain when the sides are placed inside and the spreaders are brought to tension. In my mold the stainless steel screws and varying density of the materials in the mold itself caused the two halves to flex as much as 1/8". Don't beat yourself up like I did if that happens though. Since you're working with EIR the sides will hold their bend pretty well. I was working with mahogany which had a good degree of spring back.

From this angle the mold looks to be shallower than the full depth of the body. Again, since you're working with EIR your sides should resist "cupping" but if you are going to reuse this mold for mahogany I'd consider making it deeper. My mahogany sides cupped in places and I ended up sanding and scraping the sides pretty thin once I'd bound the body.

Again, you should be fine but I wanted to make you aware of this type of mold's limitations.
~ Neil
Diane Kauffmds
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Joined: Sun Mar 09, 2014 8:13 pm

Re: 1st Build-OM from scratch and my workbench

Post by Diane Kauffmds »

As far as the depth of the mold, I would make it out of 3 layers of 3/4" stock, minimally, stacked and glued together. This is the thickness that John Hall uses. Also, he likes birch plywood for the mold. Of course, this isn't the Kinkade mold. But, it works for all woods. The cupping that I had, seemed to be caused by the steam that I used to bend the sides, rather than the mold. Different elements of the grain dry at different rates and shrink to different sizes. It took me forever to make my mold too.

Maybe John Hall will comment on the molds.

I have a decent workbench now too. It has a pegboard back and an upper shelf. There is a thin 18" florescent light attached to the underside of the top shelf. It helps tremendously. I'm a pegboard person. I hang everything I can, because I hate going through drawers to find things. Since I have so much work to do, I've had to expand my workroom from the quaint smaller space to 1/2 of the basement. I'm moving my workbench and pegboard into the new digs and I'm dedicating that room for guitars that need repair.

I went from ~ 7x14' to 14x36'. I'll be installing a 1/2 bathroom as well, so I don't have to run up 3 stories to do my thing. I bought a 4x8' pegboard to add to what I've already installed.

I use my low angle small block plane a lot too. I keep it in one of the pockets of my work apron.

I work at the pace of a sloth, so you've joined a large club. Your back is gorgeous; you've matched it very well. It's better to go very slow and get it right, than speed up and have to undo mistakes. I think you're guitar is going to come out really nice.

What kind of finish are you going to use?
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Talladam
Posts: 123
Joined: Mon Sep 21, 2015 9:43 pm

Re: 1st Build-OM from scratch and my workbench

Post by Talladam »

My mold is 4 layers of plywood. I think two of them are 3/4 and two are 5/8. I was using leftovers from work so I took whatever I could get. It ends up at about 2 and 5/8" thick. Most of my problems were related to my inexperience with the router, and not getting the first template smooth and nice enough. Next time I would use 1/2" mdf and make a nice perfect template to start, I think it would be easier to shape than the ply and then you could use it to rout all the plywood bits.

I appreciate the encouragement Diane. At the moment I am leaning towards a french polish finish because I don't mind the effort involved, and it would be easily accomplished in my basement without fumes ect. I just looked at a finished guitar (the one that says "9th guitar finished" with shamrocks) that has a trueoil finish that looks great too, so that could be an option. My confusion is with pore filling. I think Robbie O'Brien's method of filling with shellac and wood dust seems simplest, but the zpoxy guitars I've seen look amazing. I promised myself I'd keep this guitar simple and am always battling the urge to do fancy things. I already caved and decided on curly maple binding and end wedge and I'm wavering on my decision to do a single simple rosette ring so maybe I should keep it simple with the finish.
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