GREGMW Posted December 31, 2006 Report Share Posted December 31, 2006 Hi I am building a Stewmac Kit and have decided to glue the bracing on using a "GO BAR DECK". Do I really need to use a radius dish? In the Stewmac instructions/video they just clamp the braces down onto a flat workboard,and I assume when the clamps are removed the top takes the shape of the braces .. Thanks Greg Quote Link to comment Share on other sites More sharing options...
fryovanni Posted January 1, 2007 Report Share Posted January 1, 2007 That does not sound like a good way to glue radiused braces. I have never heard of it being done that way(stewmac may recommend it???). How did you radius your braces? How are you sanding your radius into your rim(top and bottom)? I know there are many ways to do something. I use my dishes for every component and as a work board later. That way I have all parts referencing the same surface. Another thought... You want to minimise stress as you build and assemble. Forcing parts from flat surfaces seems to contradict that idea. I would just go ahead and make the dishes(shoot the particle boards will only cost you $5 per dish). Peace,Rich Quote Link to comment Share on other sites More sharing options...
SwedishLuthier Posted January 1, 2007 Report Share Posted January 1, 2007 The StewMac video might be for a dead flat top. Flat top guitars can be either that ( dead flat) or slightly radiused. If you are going to use a go-bar deck and make a radiused top a radiused disc is the way to go. There are other alternatives though. You can sand the braces to the radius you aiming for and glue then on one by one forcing the plate to conform to the shape of the brace. David Russel Young describes that method quite well in his book the steel string guitar. For a tutorial on how to make radiused discs go here: http://www.peternaglitschluthier.com/evens...ollow_forms.htm Quote Link to comment Share on other sites More sharing options...
GREGMW Posted January 1, 2007 Author Report Share Posted January 1, 2007 The StewMac video might be for a dead flat top. Flat top guitars can be either that ( dead flat) or slightly radiused. If you are going to use a go-bar deck and make a radiused top a radiused disc is the way to go. There are other alternatives though. You can sand the braces to the radius you aiming for and glue then on one by one forcing the plate to conform to the shape of the brace. David Russel Young describes that method quite well in his book the steel string guitar. Thanks for the info . I think this is the way Stewmac do it. The braces are already radiused. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted January 1, 2007 Report Share Posted January 1, 2007 You can sand the braces to the radius you aiming for and glue then on one by one forcing the plate to conform to the shape of the brace. This is what I did on the Charity Acoustic, using cam clamps. But to sand the radius into the rims, you'll need a dish. I opted to use a radiused 2x4 which worked fine, but next time I'm going to go ahead and make a dish for some go-bar action. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted January 1, 2007 Report Share Posted January 1, 2007 I understand why guys try to get around using some jigs on their first acoustics(I did the exact same thing). I am going to tell you from experience(having done this with and without). MAKE THE JIGS. If you make a jig for routing your braces and matching radiused dishes you will be able to handle the tasks associated with them with ease(accuracy and speed also). This will allow you to focus on carving your braces and getting your soundboard and back sounding the way you want them to. Making the jigs will take you a fraction of the time you are going to waste fighting not having them(unless you go with a dead flat top). Shoot I even use me back radius dish to make my back profile. Make your life easyier and make the jigs(don't make the same mistakes I made and try to fight with out them). P.S. If you are not wanting to spend the time making dishes. There are also alternatives to Stewmac or LMI that offer good prices and very useful jigs. Take a peek at these links- Jigs Tools jigs more goodies even more Great source for wood Peace,Rich Quote Link to comment Share on other sites More sharing options...
eljefe829 Posted January 3, 2007 Report Share Posted January 3, 2007 It is interesting that I found this thread going on at this moment. I just finished gluing up the soundboard braces on my Stewmac 000 kit. The stewmac braces are indeed radiused. The idea is that you clamp them to a flat workboard, and they will spring back to a radius shape when you unclamp after the glue is dry. Trouble is, mine didn't. In fact, the top is slightly bowed in the opposite direction of what it should be. To be fair, many other builders report no problems with this method. However, based on what I know at this moment, I'd say invest the extra time and/or money in acquiring a radius dish. Quote Link to comment Share on other sites More sharing options...
Mattia Posted January 3, 2007 Report Share Posted January 3, 2007 Radius dishes are cheap to make, not that difficult, shouldn't take more than a day (at the utmost...an afternoon will probably be enough), just really messy. What they do allow is a very, very accurate mating surface for top/sides/back, without requiring the builder (you) to think about things all too hard. Ditto a mold to hold the sides. It's quite simply a better way of building. Not just different, actually better. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted January 3, 2007 Report Share Posted January 3, 2007 I just finished gluing up the soundboard braces on my Stewmac 000 kit. The stewmac braces are indeed radiused. The idea is that you clamp them to a flat workboard, and they will spring back to a radius shape when you unclamp after the glue is dry. That doesn't sound right... ...the braces won't spring back to their original shape because it would require the soundboard to slide on the brace surface....except that it can't because it's glued down. Maybe the other side of the StewMac braces are flat, and you're supposed to clamp them up between the soundboard and the workboard with the flat side on the workboard...??? Or maybe it is supposed to be a flat-topped guitar and the radius is for the top of the brace...?? Quote Link to comment Share on other sites More sharing options...
ryanb Posted January 4, 2007 Report Share Posted January 4, 2007 There is one theory (coming from violin makers, I believe) to assemble the braces as mentioned ... glue the curved braces to the flat top, and the braces will pull the top into an arch. The intent (as I understand it) is to make the top more responsive from the start due to the stress on the top. But most guitarmakers seem to agree that this is a bad way to go. Over time, the braces will relax and the top will then fall (flatten) -- so as the guitar ages, its sound will get worse instead of better. Violins are meant to be taken apart and have the braces replaced when this happens, but guitars aren't designed this way. Of course, the easy solution would be to just get rid of the workboard. If you just clamp the braces to the top (cauls are ok, just not a solid workboard) from the center out, the top will curve to the braces just like it will in a radius dish. It is clumsy though. Of course, don't misunderstand me -- I definitely think the radius dish is the way to go without question ... you will need it for more than just gluing braces, and everything will be more accurate. Quote Link to comment Share on other sites More sharing options...
SwedishLuthier Posted January 4, 2007 Report Share Posted January 4, 2007 Over time, the braces will relax and the top will then fall (flatten) -- so as the guitar ages, its sound will get worse instead of better That can be remedied. Graphite reinforcements have an excellent “memory” and will not conform to the new shape. You can sandwich a thin sheet of graphite between spruce for the braces without adding much weight. Quote Link to comment Share on other sites More sharing options...
Mattia Posted January 4, 2007 Report Share Posted January 4, 2007 I just finished gluing up the soundboard braces on my Stewmac 000 kit. The stewmac braces are indeed radiused. The idea is that you clamp them to a flat workboard, and they will spring back to a radius shape when you unclamp after the glue is dry. That doesn't sound right... ...the braces won't spring back to their original shape because it would require the soundboard to slide on the brace surface....except that it can't because it's glued down. Maybe the other side of the StewMac braces are flat, and you're supposed to clamp them up between the soundboard and the workboard with the flat side on the workboard...??? Or maybe it is supposed to be a flat-topped guitar and the radius is for the top of the brace...?? Nope, its fairly commonplace to do it this way; its called sprung bracing. I don't see the point, so I use a dish. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted January 4, 2007 Report Share Posted January 4, 2007 There are many different ways to build acoustics. I hold to the belief that you should try your best to build in as little stress or "pre-loading" as possible. I try to use the same block of wood to produce my side bending form and mold. I uses the same template to make my bracing radius jig, dish making jig, and so forth. I try to avoid forcing my rim into the mold(I lock it in only to keep it from moving up and down while I perform other tasks). The top and back have to be forced to their radius(because they are flat to begin with and I do not heat and bend them or carve them). When I glue the top and back I don't need or use heavy clamping(rubber bands give it a bit of downward pressure, in the future I hope to use a vac. press *for more even pressure). Things like sanding the base of your bridge so it matches the tops radius(using the actual top as your reference) instead of forcing a flat bottom bridge. The list can go on, but basically ever measure I can take to avoid stress is taken. This is why I use radius dishes during construction. With acoustics there is no one magic element to making a better guitar. It is all about bringing all the elements together, and how all the small changes we make add up to make a better guitar. Peace,Rich Quote Link to comment Share on other sites More sharing options...
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