Radius dish alternatives
 

I am searching for alternative building methods for getting the radius in the back and sides. I know some use a radius stick instead. How well does this work and are there any instructional videos out there? Everything I’ve seen is for the radius dish method.

Check Cumpiano's book.

Stew Mac has instructions on how to do it that way. It wont exactly radius the sides but it will be close enough. The top doesnt need radiusing but the back does a little.

Page 12.

https://www.stewmac.com/freeinfo/i-5295/i-5295.pdf

I feel the top needs a little arch do deal with humidity changes.

Wait... sides get radiused?? :hmm:

Nothing new hear, I got all of this off the innerweb. I use a 15' radius beam/bar/stick for backs and a 28' for tops. After 8 guitars in 5 years I find that it works so well I won't go to dishes and go-bar decks. Just as easy to sand with the beam, and only takes a little longer to glue braces against it. If you build a bunch of instruments or you love to make tooling, dishes and decks are probably a good idea.

I use the beam to 1) draw the curve on the braces, 2) shape/sand the curved side of the braces, 3) glue the braces down against, and 4) sand the rim before and after lining is installed. After 8 instruments I still have not changed the sandpaper.

Shaping the rim takes just 3-5 minutes on each the top and back before the linings is installed, and another 3-5 minutes on each after the lining is installed. Can't see that a dish will save any time here at all. Gluing braces one at a time takes a little longer without a go-bar deck, but only building a few guitars, the time is not an issue, and the storage space in the shape is an issue:

https://www.flickr.com/photos/ruby16...7699022686200/

click left and right, text below

Good luck and Merry Christmas

Ed

I visited a guitar manufacturer who had radius dishes with sandpaper glued on, fastened to potters wheels. They held the guitar body against the spinning radius dish to sand the proper arc into the sides and linings.

I bought a radius jig to sand the radius in the underside of the braces. When it came time to glue down the braces I opted to use clamps and cauls and let the braces dictate the shape of plate.

When it came time to do the rims though, I had to get creative. I ended up tracing the arc from the brace jig on to the side of a 2x4 and cutting it out with a band saw. That would then be my sanding stick. I still haven’t figured out how I will go about gluing the plates to the rims, but I once read about a jig that was made with index cards that I may give a try.

Neil

If you use an outside mold, just put the whole thing on the dish. If for some reason you don't want to that, put the rim in the mold and insert wedges along the bottom edge of the rim every couple of inches to support it against a flat backboard while you glue on the top, then flip it over and do the same with the back. No dish needed. The shot below shows the wedges under the bottom edge of the rim to make the top edge of the rim extend an even amount above the mold.

https://www.flickr.com/photos/ruby16...7649776959267/

Click left and right, text below. I find it impossible to attach a photo to this format.

Merry Christmas

Ed

Ok, I misunderstood. My mold is only half as deep as the body so that’s exactly what I did for my first build. Radius dishes are not required, just lots of cauls. The Decius is already determined once the sanding is all done.

That is exactly how I do it as well, albeit I welded some bars to the base of my pottery wheel to raise it up to a standing height.

Steve

Me too! One of the few things that hasn't changed since I started nearly 20 years ago.

I get some strips of poster board and fix it to my mold with spring clamps. I tilt the entire thing on my radius dish to get my desired taper (even to do a slight "Manzer wedge") then use a thin Sharpie on a compass to scribe onto the poster board. I then remove the poster board, cut the line and trace the profile onto some scrap plywood. From there I have a template I use to either mark and bandsaw, or router off, that I can use every time. Takes only a minute or so with a radius block afterwards to touch up and it's very repeatable.