Form for laminating guitar sides

[Keith Howell]

I have been looking at this old thread in the library:http://www.mimf.com/library/Laminating_ ... -2007.html

What is best? Building an Inside or an outside form for laminating over?

Cutting an outside form for the usual glue up of the sides head tail block etc and then using the cut out internal waste pieces for an inside form suitably cleaned up and glued would make the most efficient use of material I suppose but what is the best for laminating the sides?

[Barry Daniels]

I tried them all and finally settled on an outside form with a bunch of eye bolts and steel bars for the cross members.

[Randy Roberts]

And just to make things difficult to decide, I've been happy with the results using an inside form. <g>

I pre-bend the veneers on an inside form, then do the glue-up as a sandwich on the inside form of:
wax paper
veneers with 24 hour epoxy
wax paper
layer of cork sheet (1/8 inch ?), or closed cell (neoprene like) foam
strip of wacky wood (several names for flexible plywood that has the grain of all plies running parallel to each other so as to be flexible and bend easily)
Clamp from both sides of the form with regular squeeze clamps.
The trick is to take the pads off the clamps to fit as many as possible around the base of the inside mold.

Haven't had a problem with gaps, etc., (yet)

either should work, and I can see advantages to using the outside mold.

[Clay Schaeffer]

"What is best? Building an Inside or an outside form for laminating over?
Cutting an outside form for the usual glue up of the sides head tail block etc and then using the cut out internal waste pieces for an inside form suitably cleaned up and glued would make the most efficient use of material I suppose but what is the best for laminating the sides?"

Hi Keith,
What I would consider "best" at this point in time is to make the outside form for holding the sides during construction and using the "waste pieces" to make a block form for laminating the sides over. If carefully done, after sanding and smoothing, the gap between them will be about the thickness of the finished side. I use kerf kore as an outside caul on the block form and numerous clamps to compress the laminations. Vacuum bagging might also be effective if you are set up for it.
To create the "flattest" most stable laminations I have found drying the veneers out completely (using heat) to be beneficial.

[DJ Parker]

Hello All,

As the traditional construction method for Gypsy Selmer style guitars is to laminate, I have used both inside and outside bending/laminating jigs. My first jigs were an inside type that I had copied from Michael Collins' book and videos. This worked well although a little cumbersome when it came to flipping it over to add clamps. It uses a body form and an inside caul.

My second jig, an outside type as pictured herein, is taken from the original Selmer jig as shown in Francois' Charle's book on Selmer guitars. Their jig was a rusty, well-worn apparatus with lots of character so I decided to replicate it. Mine is built using aluminum and single press clamps. I like this so much more than the inside jig and it produces a good, even clamping pressure. Yea, it seems a bit much for my small non-production shop but I had the materials and some time and it was fun to build. It should last until I'm long gone!

The picture looks sideways so click on it and it'll open up.

Regards,
DJ

[Bill Raymond]

laminatingform.jpg (26.03 KiB) Viewed 13932 times

Here's my take on a side laminating form.

[Darren King]

Hi, as a first time poster to this forum I am new to actual guitar making (not the concept) but not to vacuum pressing so, when I eventually got around to making my first guitars in January of this year laminating backs and sides was the natural route for me to take. I made high density polystyrene formers for the laminating part of the process and CNC machined an external mould with internal clamp blocks for the assembly and sanding stages all of which worked pretty well. I am now building a Selmer Petit Bouche following a similar method but I must say I really love your jigs. What lay up of veneers are you using? One issue that i found using epoxy was the massive amount of squeeze through to the surface that occurred. I have subsequently gone over to using a urea formaldehyde liquid resin and powder hardener with what is called an 'extender' powder. Misleadingly this has no effect on the cure time but does stop nearly all squeeze through which makes cleaning up the veneer a lot quicker. It has a long open time and a single mixed batch can comfortably be used to glue up a back and two sides. Once I have created small file size versions of my pictures I'll post a few.

[Bill Raymond]

Usual layup for a Selmer-style guitar is from inside to outside: African mahogany, poplar, East Indian rosewood; though there are other woods that can be used for the outer layer, e.g. mahogany, walnut, pau ferro, et c. I used Titebond for my laminations without trouble, but Weldwood would work, too. I imagine that Selmer probably used hot hide glue, but it would be a hassle to keep the glue from gelling before you got everything aligned and clamped up--still, in a hot environment, with preheating the laminations, it certainly would be doable.

[Brian Evans]

What thickness of veneers are you using, and where do you source them?

[Bill Raymond]

Standard thickness--whatever that is. Veneers can be obtained from Constantine's or Certainlywood, among others. A Google search will turn up many, many sources of supply. I believe they're about 1/32 inch thick, but poplar crossbanding runs closer to 1/16 inch.

[Barry Daniels]

I get the best deals for veneer from eBay. Standard veneer thickness is 1/42".

[Carl Dickinson]

Here's what I put together... outside mold bolted together with a spacer and extension to go in the vise. Inside waist and lower bout spreaders bolted with spacers and other scraps glued to make the cauls, clamped with 25 HF clamps.

An addition for the next time I use it will be a sheet of scrap formica to even out the clamping pressure.

Carl

[Darren King]

Hi Carl,
Different approach but here are the moulds and sides I vacuum laminated in white ebony. PTFE coated cloth on top of the polystyrene mould and a similarly coated caul of 0.8mm birch plywood on the outside. The lamination of 5 layers of veneer (three long and two cross grain) were bonded with a UF resin which has about an 8-10 hour cure time so no worries about it starting to go off before everything's under pressure. The small amount of spring back takes no effort to push back to the mould shape.The three internal layers are mahogany and i have used figured sycamore fo the inside and it should all look fairly pretty when its finished I think.