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Juntunen Guitars

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Juntunen Guitars last won the day on November 8 2013

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  1. Looks like I can finally post pictures to this site again so I figured I'd start a build thread. I haven't had much time to work on guitar stuff or my violin builds over the last year and a half and I just took as job as the head repair tech at a shop in Vegas so I'll be moving across the country soon so I'll have to leave some of my projects behind in Minnesota. So in October of 2013 I sketched out a bass guitar and through it in CAD to blueprint it a little. In November or December of that year I started building it. Later tonight I will continue this thread with more pictures. Here's a screenshot of CAD while I was blueprinting.
  2. I think my tops end up thinner than an 1/8th usually but I don't thickness them to a set thickness. I thickness them until the flex with and across the grain feels right. I'm curious to see how the inlay goes as well with the radius in the top. Are you going to inlay it before or after glueing on the top? If I can ever get pictures to post to this site again I will post a picture of a baroque I saw once that the entire back and sides were inlayed in a chevron pattern on every square inch of it... Impressive stuff.
  3. I'm curious how a hard wood will work for bracing. Larson Brothers used laminated braces with a thin hardwood center and spruce on the outside but I've never heard of full on hardwood braces with a full hardwood box. I did get a chance to play an early 1900's Martin parlor guitar that was all koa except for the spruce braces. That was probably the best sounding guitar I've ever played.
  4. Not epoxy! I wish you luck when it comes time to do a reglue on that bridge. Titebond is a big enough pain to deal with on a reglue. Looks like it's coming together pretty nicely so far. I may have missed it but what neck joint are you using, dove tail or bolt on?
  5. Another book to look into if you want wiring diagrams is "The New Book of Standard Wiring Diagrams" by "Les Schatten". For some reason I can no longer post links or anything otherwise I'd link it to you but it's a good book.
  6. Any more progress on the build? How are you going to do a bolt on from the outside, is there a reason for not doing a regular bolt on where you reach through the soundhole? If you want hardware ideas for the bolt on part you can look through my 8 string acoustic build, I did a bolt on with that one but I set it up so the bolts were inside the body.
  7. Try to route with the grain instead of into it. If you keep going in one direction with the router it will always tear out. Fine Woo Working has a video on what I'm talking about but I can't post links anymore for some reason and if I try the forum freezes the link adding thing onto my screen... Google how to route end grain and the video title is "How to avoid router tearout" it's on the Fine Wood Working website.
  8. Just watch how much the top flexes in that area. I think it'll be fine but it's something to keep an eye on. Like I said though, there's a number of builders who have brace patterns like that. What is the x-brace angle?
  9. Great build so far. Couple questions though, why are you running the finger braces off the upper half on the x brace instead of the lower? I've seen builders doing that more now but haven't had the chance to ask them about it. How are you bending your sides? I'm assuming a heating blanket from the water marks on the inside of the bends. On your next acoustic you should try making a rosette like on a baroque guitar in you decide to do another one like the crane one you did here. I'd post a picture of them but I can't post links or pictures right now for some reason, it just freezes my screen if I try but I'm talking about the stacked parchment ones they put inside the soundhole, not the rosette on the top like a steel string.
  10. Oh come on you can get that gluing tops on too, have you seen the top gluing pictures from my builds? Thought I might chime in on the bracing question on the first page. The top braces don't have to be the same wood, it doesn't hurt to have it be the same wood but it doesn't have to be. A friend of mine uses spruce as the x brace and the upper of the two lower transverse braces and cedar for the fingers and lower transverse. When it comes to voicing the top you can get a lot better vibrating top that way it seems. I really like how his guitars sound compared to guitars with all spruce braces. The other thing he does is laminate braces with cedar cores on the bass side and spruce cores on the treble because cedar vibrates more freely it makes for better bass tones. That's part of why I don't scallop the lower part of the x brace on the treble side of my acoustics much. A general rule to go by is the floppier the top the lower sounding it will be and the stiffer a top is the more treble you'll hear (at least those are the terms I use when describing sound) That's why planning your tops/sides/back to a set thickness isn't the better option. Since each piece of wood is different and more or less dense thicknessing it to where it "feels" right is where you stop (obviously don't go until you can see your fingers through it!) I thickness my tops until I can freely twist and flex them pretty loosely across the grain but it is still good and strong with the grain. You can always brace heavier above the soundhole near the neck block if you feel it's to thin since most of the vibrations there are killed off by your upper transverse brace anyways. As to the woods moving separately. This can happen but more so if the wood isn't truly dry or acclimated to your shop and the glue you use will affect this too. With titebond 2 chances are you'll see the braces through the top throughout the year no matter what wood you use since it doesn't let water move as much as titebond 1, avoid titebond 3. Epoxy ... please go jump in a well with cement shoes if you use epoxy for acoustic guitars ... that is all. I like hot hide glue but you have to work fast with it and it will release with heat much faster than titebond. I use titebond on everything in an acoustic except for the neck joint if it's a dovetail, then I use hide glue because it makes neck resets easier (another reason to never use epoxy) the idea of "if you build it right the first time you won't have to worry about it" does NOT work on acoustics.
  11. Couldn't you seal with Shellac and then spray nitro or a urethane over it to give it a harder top coat? That's what I've always been told to do with shellac unless you want a full shellac finish.
  12. I don't know if I would keep the cocobolo raw, I would definitely put a finish on it. Raw wood feels nice but it will soak in our hands oils over time and soften. Cocobolo might take longer because of the oils but I really don't know because of how oily it is. I'd imagine you may run into adhesion problems with any finish you use because of the oils but you never know until you test it.
  13. I used this on my last one. It seemed to be more susceptible to humidity than others I'ved used. I fought blush more often and also tiny pinhole making bubbles. Granted all nitro hates humidity and a garage in Houston ain't exactly dry....but this seemed less forgiving than what I am used to. I did maybe cure a little faster and a little harder...... SR I haven't had any issues yet thankfully. It laid down just fine and smooth for me at least. What are you using to spray it with?
  14. I didn't see any tutorials on the forum on doing burn ins so I figured I'd do a quick write up on it. For those who don't know a burn in is for fixing dings that can't be steamed out. It's pretty common in the furniture repair and finishing industry but is very useful for any type of wood working. I'll show the way I did it on one of my acoustics that had a western red cedar top I dinged on accident. Some things to consider. Burn ins WILL be visible no matter what, a lot can be done to hide them and to make them less visible but a trained eye can find them because they will reflect the light differently than the wood. Some spots that you would do a burn in on may need to purposely be damaged more to work right. If the piece is fractured you may need to chip out the fractured parts and cut the edges flat and square to keep from risking sanding through the burn in. Remember that sometimes it may be necessary to just make a patch to fit into the wood rather than do burn ins. I usually only do burn ins on pretty small spots instead of large dents. Some dents can be steamed out with a soldering iron and a wet paper towel by heating the paper towel from the top and lifting up several times with the soldering iron. Anyways, onto the topic. I dinged this top on accident after I started spraying. You will want some type of finish on that can handle heat relatively well so you don't burn the wood and it just makes the process easier. I'm using nitrocellulose here. Here's what you need. Obviously the burn in stick itself. You can buy these from Mohawk, they are called E-Z flow burn in sticks and you will need a burn in knife. I like the plug in ones but you can get ones that go into a mini furnace but they need to be constantly heated and re-heated, usually you have two to work with. Another option is a butane powered knife but I prefer the house outlet knives just for convenience and they aren't very expensive. You will also need graining fluid and a graining powder. When choosing a color tilt the wood around in the light to see how it matches a stick. Since the stick isn't wood it will reflect light differently. Florescent and incandescent lights will change the look of the reflection so it's good to have both lights handy when doing this. What you want to do is heat the knife up until you can touch the fill stick to it and it melts into a pool of liquid. You want it to be runny and not like a glob of semi melted wax. Once you have a good amount on the knife you turn the side of the blade with the melted stick on it down and pull it across the ding being filled. Don't pull to fast or slow or you will burn or not fill the hole, a steady and light pull will do, you don't want to push to hard or you could mess up the finish even more. Once the filler is in the hole lick your thumb and press down on the fill stick to make sure it's in the dent and not just on top. Once the burn in has cooled sand it down flush with the wood. After you get it filled and sanded down take your graining powder and mix it with graining fluid to get an ink like consistency. Mohawk also sells graining pens. I've never used them so I can't be much help there, I've always used the powders. Once mixed I use a very fine tipped paint brush to paint on grain lines. It helps to practice these on scrap wood. Once the graining lines are painted on spray your finish over it and see how it looks. Here's how small I'm talking for a repair like this typically. When you're done it should look like the wood and like nothing happened. See if you can find the burn in. It gets difficult to match colors when you have streaks in the wood you are repairing, sometimes you just have to go with what's close and deal with it. Also note that the graining powders can be bought in different colors. It's good to have a variety to be able to mix and match from to get the right color. You can also mix burn in sticks to get different colors to match the wood. Like everything though these take some practice but when you can do them pretty well it's a valuable thing to know for repair work.
  15. What are you inlaying into? If it's ebony and you have the gears just route or drill the hole as accurate as possible and use plain old superglue, you will never know the difference. That will actually work on most darker woods too, even some walnut depending on how good your fit it.
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