Can't close the mould

[Stray Feathers]

I have glued the backs to the rims on the two Kinkead-style OM bodies I am working on, using a mould as described in Kinkead's book. Backs have been trimmed flush. I now want to glue the tops, but find that the rims can't be put into the mould back-down unless I loosen the bolts at the ends of the mould. I can get the partly-completed body into the expanded mould but don't want to close it too tightly for fear of breaking something. Is this something to worry about? Can I just firm it up as well as possible and proceed with gluing and clamping the tops?

[MaineGeezer]

I am clearly missing something. You glued the back on with the rim held in a mold, correct? Why can't you just put the assembly back in the mold the same way? Why do you have to turn the mold over? And why would that make a difference?

Is a Kinkead mold non-symmetric somehow? I'm imagining a mold to be like the ones John sells:
http://www.bluescreekguitars.com/shop/i ... cts_id=206

[Stray Feathers]

Here is a photo of the Kinkead mould. The mould is deep enough to fully contain the sides. Kinkead uses removable blocks in the mould to lift the sides for gluing kerfing (as here) and gluing tops and backs. He uses a guitar-shaped plywood caul (second photo), that presses down on the edge of top or back all the way around when screwed down to the form/mould (using the same holes again and again). I can see that with the mould you describe the top and back are proud on either side, but this would require a mess of cam clamps which I don't have. With the Kinkead mould, you clamp either the top or back using the mould and caul, then remove the assembly and replace it upside down, shimming the blocks as necessary to get it supported on all sides, and screw down the caul again. I am not sure why the trimmed back is too big to fit in the mould (the other side will just wiggle in) and wonder if I use the mould when it is not fully tightened up, if I will end up with a guitar literally bent out of shape.

[MaineGeezer]

Ah! That clarifies things. The only thing I can think of is, is the back trimmed truly flush all the way around. It probably wouldn't take much of an overhang -- hardly visible -- to make it bind. Since the edge will be cut back anyway when you do the binding, you can afford a bit of an over-trim at this stage, to be sure the back isn't extended out past the ribs.

Otherwise....maybe try measuring across from one side to the other, top and bottom, in several places to see if any area is significantly different. For example, the narrowest point of the waist, the maximum distance across each bout, etc.

Assuming the back is trimmed flush and isn't hanging it up, I suspect you could put it in the mold, with the mold loosened, then tighten it down to pull it into final shape. But I'm not there, I'm just guessing, so proceed cautiously!

[ruby@magpage.com]

Like you, I don;t have a mess-o-cam clamps, so here is my solution - works great:

https://www.flickr.com/photos/ruby1638/ ... 130471994/

Check this 3 shot sequence. Also, there should be no need to flip over the mold. Did you make it? I might check with a square to be sure that the top and bottom surfaces of the mold are lined up exactly, as that would be a cause of an asymmetrical mold. Also, the thicker the mold, the more a problem this can be - your mold seems way thicker than it needs to be. Mine are about 3" thick (2 layers of 3/4" plywood with 1-1/2" thick 2X4 spacers) and seem to work, even on the Nick Lucas Special in the shots - it is 4-7/8" thick.

Ed

[Diane Kauffmds]

Interesting. I saw a video on youtube of a luthier that uses 2 guitar shaped culls, one on each side, to clamp the top/bottom. However, instead of clamps, he uses springs. I plan on using the same concept when I build my next guitar. It always gives me the willies when I close the box with gobars; if one gives away, it can really damage a top.

As far as fitting the guitar back into the mold, I can think of 2 things that would cause this.

1. The first is as Ed said; the mold may not be square.

2. The spreader could also be an issue. When you glued the back to the rims, how was the spreader positioned, and how wide is the spreader? The wood used in the spreader may need to be wider to ensure that it distributes an even amount of pressure, top to bottom, on the rims. I position my spreaders on the center of the rims, and I'd have to measure them, but they they're a good 2 1/2" - 3" wide.

There are two solutions:

1. continue building, and close the box; I don't know how much of a gap you have when you try to close the mold. If the gap is tiny, you may be okay.

2. Unglue the bottom and reglue. check the mold and make sure it's squared up on the inside; if it is, then make sure that the spreaders are below the rim of the mold and they're wide enough to ensure that the entire width of the rims are against the mold, top to bottom.

[Stray Feathers]

Thanks to all who replied with suggestions. In the end I went ahead and glued the tops, with the mould open a little, and things seem to be okay (see update in the blog section here: viewtopic.php?f=48&t=7216&p=41207#p41207

In answer to Diane's question, the waist spreader is only an inch and a half, and an additional one in the lower bout is only 3/4". (These were made and used by the friend who passed the stuff along to me.) It's a good thought to redesign those.

I wonder also if the screw-down clamping caul may have distorted the sides a little so I could not close the mould - especially when gluing the backs, which I did first, because of the rather steep curve to the neck block. Unless it is my imagination, I may have a slight asymmetry in the upper bouts. It might have worked better gluing the tops first, as Kinkead recommends. As I go along, I find recommended methods that work for me, and some that I might change for future projects, and this mould and caul system is one of those.

[tippie53]

there are many ways to do things. Always take a few minutes and look at it. See that it makes sense . We have plenty of how to videos on you tube for your to reference and the guys and gals here are always quick to help.
Getting the top and back on without racking the body is very important. take your time on the next steps and don't be afraid to ask all the questions you feel you need