Acoustic Guitar Construction

I'm thinkin on getting a dish from Ken and being cheap I'm tring not to buy two. ??? Do some guy's use 15 ft. for D and jumbo's on the back ? Or should I use 20 ft. on my om's and smaller guitar's. I known you can do what you want, but I thought I would throw this out there and see what you guys think.... Oh buy the way is there an easy way to slap sand paper on without spending 30.00 bucks/. ...any info very wellcome.. Thanks Dave

Dave - Ken sells a 15' radius back dish that is not circular, so you can use a spray adhesive (I use Elmer's spray, it works fine) and regular sandpaper.
15' is a dandy radius for D size - I've used it on two of Ken's Ditson kits.

An MDF sanding bar with a 15' radius works as well as a dish and takes only a strip or two of sandpaper, also glued on. Ken sells those as well. I've used one on all 7 guitars I've built.

Thanks bud, I still dont know if I will go wt. the dish or bar. I was thinkin I could sand the braces and make them with the dish. On the five ones I made, I made by hand, But I thought a dish would make braces better. I also used my table top router but the bearing sliped and wrecked my jig. It's not easy making the rad. for jig's like that, and thought a dish might sand a nice brace. There's so many ways to go....and go.... Thanks Dave

Sanding the brace glue surface on a spherical dish is a mistake -- think about it -- you want that surface perfectly flat where it makes contact with the plate -- rubbing the brace on a spherical dish rounds the edges and or tilts the glue surface. The tiny width of the brace is not going to impart any contour along the stiff length-wise grain, but rather if contoured it will gap at the glue line.

I use 15' for all styles all models -- looks nice and is a tiny bit more resistant to cave-ins.

There is no reason you cannot cover a dish with 5" or 6" PSA sanding disks you do not need to cover every single square inch.

Thanks Ken, Thats why I have'nt done the dish thing so- far. But there are still some things bugging me. When I glue the back on , it fits the lower part of the guitar but hangs up in the air over the contured part, toward the neck block, because the rim dives down. I thought maybe if the dish made it more.... like a potato chip..ha ha, the back would angle down more. I have been meaning to ask you this for a while. I am sanding the rim with a homemade 20 ft. bar, so it is fitting the edges, but a go-bar is needed to press the back to neck block. Also Dave B. said you sell a dish that is not circular, is the dish like the shape of the true back, like I see in books. Maybe you can tell me more about the conturing system you sell. This might help others too. Thanks guys ...Dave

First its important to understand that the rim is in fact supposed to impart the contour/radius to the back plate length-wise while the braces impart the contour width-wise. So yes you'll have to apply a bit of pressure to roll the back at the neck block -- if it takes a lot of force the back is too thick.

There is an illustration in this listing

http://www.ebay.com/itm/120810375653?ss ... 1108wt_428

The Mega Mold and Stand Alone Contouring fixtures set angle, location and the actual radius on the rim top or back edge -- a dish or hand held device having no positive locators will not have the ease of process or comparable precision results.

http://www.kennethmichaelguitars.com/contourfixt.html

http://www.kennethmichaelguitars.com/rimslopeMM.html

Thanks Ken, Do You sell the spindle and stuff ? Or do we make our own. I've been reading these for a while, maybe I'm missing some products you sell. Maybe you could send me a message with a way to get a conturing deal... I have the mega mold and templates, sorry to get into business on the forum. Thanks Dave