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View Full Version : Building the Mold: Not as Easy as I Thought.



sequoia
07-24-2017, 08:15 PM
I've built a bunch of ukuleles using a simple form to hold the sides to glue up the body, but I've always meant to make a proper mold. Below is my old work horse form:

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I figured building a mold would be dead easy and take me an afternoon at the most. Ha! and double Ha ha! I mean how hard can it be? As usual, Murphy's Laws apply: Murphy's Law Number 13: Nothing is as easy as it at first seems.

I basically made it up as I went along. I lined up the plywood layers using dowels and cut each plate out using a band saw and then trimmed off the sides.

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The real challenge here (which is absolutely critical I think) is getting the sides of the mold absolutely plumb and square to the deck. This is where the tricky part came in: To true up your cuts you risk changing the dimensions of the radiused curve you just cut. Using a spindle on my drill press was critical to truing up the sides of the mold. Truing up the spindle on the drill press of course is a huge time sink. Hours wasted finding absolute plumb.

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Making the cauls is its own special time in time wasting limbo la la land. Not as easy as I thought. Below the finished mold with a set of bent sides getting ready to be cut in and lined up. I love it already and it was worth the time. I'm embarrassed to say how long it took me, but something approaching two days would be about right. Who would have thought? I mean how hard can it be? Harder than I thought.

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Timbuck
07-25-2017, 01:37 AM
I started a thread entitled "I'm going to make some concert size ukes" and on page 3 I made a detailed account complete with pictures on how I made a mould.

sequoia
07-25-2017, 08:27 AM
Yes, a good thread. http://forum.ukuleleunderground.com/showthread.php?121329-I-m-going-to-make-some-concert-size-Ukes&highlight=make+concert+size+ukes

cml
07-25-2017, 08:32 AM
Looks really good though!

Rrgramps
07-26-2017, 12:37 AM
I didn't see Ken's mold; it's nice, and has some features I'd like to use on my next mold build. The attachment shows another method, which utilizes shelving board from Menards I got for $4 per board. It takes Two boards to make the mold. Menards sink shelving, from high density particle board is better than their standard under-layment particleboard. But subjection to water will cause either quality to deteriorate. My other molds were made with plywood.
https://imgur.com/gallery/dw0pJ

Timbuck
07-26-2017, 01:51 AM
I made my first mould from partical board , the stuff they use for flat pack furniture..it didn't last long.

Pete Howlett
07-26-2017, 09:08 PM
My enginerring ply forms have been going now for nearly 20 years... if you are an occassional or low volume builder then make 'em out of anything. If you do this for a living, only the best will do :) BTW, it takes me half a day to make an internal and external half template, plexiglass drawing template, internal form and bending jig. I use a bandsaw and a table router to achieve this. I might even have the video of it I shot about 6 years ago :)

Michael N.
07-26-2017, 10:49 PM
My moulds are very minimalist compared to these. I use one layer of 18 mm birch ply. The height is only increased at the two bout areas, also at the top and the bottom block. The outside of the mould follows the shape of the inner form. They are very light, more like a skeleton mould.

Rrgramps
07-27-2017, 03:18 AM
... if you are an occassional or low volume builder then make 'em out of anything. If you do this for a living, only the best will do :)

What Pete said. With my low volume, it will gently hold the sides. They're already bent, they're dry, and should fit well enough that little support is needed. Now if the sides are sopping wet, crudely bent, and needy of lots of pressure to conform; then my molds (hoosier spelling :D) will not last. That said, the latch was the weak link; it was replaced with a more substantial one; then a through-bolt was utilized on the last mold. It's a year old, my other molds are fifteen years old, and although of 2x pine, the materials are still strong as they were in 2001. But I'm not going to argue about materials, maybe I'm wrong, and it will be exploded while we are talking. LOL

Yeah Michael; need to have some kerf clamping room, and thick molds aren't necessarily better. I once scrapped or modified a mold that was so thick it wouldn't allow any work other than hold the sides. But it did that ok.

Last year, my FB friend and mentor, Mark Roberts, showed me a routine for making an outside (with inner core form) ukulele body mold. I used both the process and his choice of materials because I think it's the best routine and method to get it done. He builds frequently, and his build quality is amongst the best. Reminds me of the best here, although he seldom posts here.

Especially important to me, is the practi-nomics (��) of utilizing the center core for the bending machine rib/side form. I've documented the process and put it on Imgur, with Mark's name credit in the first paragraph. It's just that I'm pleased with the results, believe it is a worthy solution to pass on, and may help someone in the future; as Mark's multitude and magnitude of luthier information, Jigs, and pictorial instructional processes have helped me.

Timbuck
07-27-2017, 06:35 AM
I use four Soprano moulds now that I think about it... The first one I use just for marking out the butt joints on the sides....Then one with end cauls for clamping the end blocks; Then a simple one 18 mm thick for fitting the linings and radius sanding; and the 4th is the main one/solera; for fitting tops and backs and lining up the neck...this lot is more or less is an assembly line for sopranos; now I think about it.;)

sequoia
07-27-2017, 07:14 PM
It doesn't surprise me Ken that you have four moulds (we spell it molds) for building sopranos. I'm sure each is a work of art and science... Speaking of molds, I was talking with a person the other day who saw a documentary on 17th century violin maker Guarneri. The only thing that really still exists in perfect form is his old jigs and exquisite mahogany molds. Perfect shape after 400 years. Works of art unto themselves. Perhaps the only thing left after we are gone will be our molds.