MIMF

Greetings,

After a couple of years (literally) of piecing together the required hand tools and a couple of machines, I am ready for my first build. I plan on following the Cumpiano book for the most part but will use the dimensions of a dread instead (Stew Mac purchased Herring. plan) . My son is also going to start a build on his own. His build will be a 00/concert size. Can we use the same Solera when building our respective guitars? The part that is a bit confusing is not so much the Solera itself, but the cork rim around the outside that is attached to heavy paper for a perimeter of the solera. Is it just safe to assume that each build would need it's own perimeter 'shim'?

Any reference to a good discussion on the topic is appreciated. I have done some web searches (including this site) but I'm interested in opinions. Thanks in advance for any assistance offered.

p.s. my build a predictable IRW/Adi dread , my son's build an 00 using Cherry back/sides/neck/blocks. Sustainable ethos at work

The issue to be aware of with Cumpiano's book is he mixes the building of a classical with a steel-string throughout the book. It is hard to separate the two. Soleras are typically only used for a classical guitar. For a steel string you really only need an outside form and the two guitars you mentioned need their own form.

Also, be aware that several of Cumpiano's methods are now considered somewhat dated (even by Cumpiano) so before proceeding full steam ahead, check in here to see if there is not a better method. One such issue is the neck joint using wood dowels is not recommended. Also, most people use radiuses dishes for constructing the top and back, which is a big improvement over the method shown in the book.

Also, welcome to the MIMF.

Tom,
What a great father/son project!
I'll guarantee you will both know each other far better by the end of the project ( and he will probably learn all the words you already know <g>).
I agree with Barry, you will find outside molds a better method for the guitars you contemplate, than a solera. You will each need your own mold shaped for the body style you make. (You don't want to be fighting over one mold anyway).

Making the molds is pretty easy, and a good way to break into the actual building process.

Remember there is nothing you can do that can't be fixed or burned.

I will disagree here a bit with Barry - Cumpiano's book can be confusing at times, but the solara is used for both steel string and classical, and lots of folks build with this same technique and get decent instruments...moldless construction is especially useful for one-offs where the work involved in building an outside mold may not really be worth the time spent. The downside of molds construction is that the body can turn out to be lopsided, out of square, or otherwise untrue, and that can make everything from binding to neck fitting a royal PITA.

The main issue with Cumpiano's description of solara/building board use for steel strings is that he's adjusted his techniques enough such that the book is no longer really reflective of his approach. If you have not been over to his web site and marked up your copy of the book with all his changes and errata, you might consider doing so.

OK - now to agree with Barry: especially for new builders, an outside mold will go a very long way towards a) making sure the body is true and square, b) holding the rim for operations such as gluing in the linings, counterboring neck bolts, etc., and c) safe storage of the unclosed box. While it may take a few hours to make up an outside mold and a bending form, most builders will use those fixtures for more than one guitar, and sometimes for many, so the time spent is more than offset by the reduction in fussing and fretting with neck and tail block squareness.

Unfortunately, there is no good modern construction guide available which covers the techniques and jigs/fixtures that many of us use, including lightweight, outside molds, radius dish top and back construction, and go-bar deck clamping. My suggestion is that you might do a deep dive through the posts here and on other fora to research, then make the call on whether you'll go mold-free or use one of many outside mold systems.

Just a few highlights in terms of how I use outside molds to hold and jig the work:

An outside mold is a frame to hold the rim, and that frame can be clamped into a repair vise to allow access to both sides for linings, tapes, detail cleanup work, etc.
By blocking the mold at a uniform distance off a true surface such as a flat bench top, the neck and tail block can be installed square and true without much in the way of bother.
Storage of the rim is a lot easier...drill a hole and hang from the rafters using a ladder bracket...
When the box is closed (this is an archt. getting closed), the mold stays on and keeps the sides from distorting...the spreaders are either rem,moved through the sound hole (on flattops) or spruce springbars are substituted, then cut and removed through the F-holes.
Another criticism of outside molds (beyond time and cost to fab) is storage...I have lots of open rafter space, so no issue even where I have 2 or 3 of the same mold (people love those SJs...), but broken down, they really don;t consume all that much space.

Thank you for your detailed responses. I have followed several different build threads of amateur, and professional luthiers. I also found a very good photo essay on the techniques used by Froggy Bottom.
There are so many ways to accomplish any one task. The more I read, the less certain I become it seems.

I'll start with what I'm sure of: ( I think)

Side bending: silicon/rubber blanket from omega with router speed control for temperature variance. (home made form/ springs/blocks etc) and I'll have some practice pieces.

Jointing top and back: hand planing edges on shooting board, simple work board with cauls on outside and weighted in center to clamp together.

Thickness top, back and sides: hand planing, scraping

Question: to joint the back, I would like to have a back strip. Is it better to joint and then rout/inlay or to glue a back strip between halves? I've seen both ways done.

What I'm less sure of:

Attaching the braces: (attempting a 28' radius top and 20' radius back)
Questions:
1. Easiest for beginner?
method 1: cam clamp the curved braces to top and back forcing top or back to conform to the shape of the brace
method 2: use a go bar deck and radius dish in conjunction with radius-ed braces

2. radius dish versus radius board? (meaning a radius front to back and side to side using a dish, or radius board meaning radius from side to side only)

3. could a D, OM, and 00 all use the same top and back radius? Or would the smaller bodies use a different radius. Assuming I am going for the Martin design style.

4. If I choose the radius dish/go bar deck method to attach the top and back bracing, are those same dishes then used to sand the edges of the respective top and bottom of the sides?

5. If I don't use a radius dish method, but instead choose to cam clamp all my bracing, what is the best way to prepare the sides and blocks in order to accept the top and back?

Thanks in advance if you are able to assist. I will make rather than purchase any molds, radius dish/boards, etc.
Seriously considering the outside mold rather than Solera approach.. I probably will build the outside molds and turnbuckle spacers, etc.

"Question: to joint the back, I would like to have a back strip. Is it better to joint and then rout/inlay or to glue a back strip between halves? I've seen both ways done."

I just sandwich and exercise some care until the back graft is on and reinforces the seam.


"1. Easiest for beginner? method 1: cam clamp the curved braces to top and back forcing top or back to conform to the shape of the brace
method 2: use a go bar deck and radius dish in conjunction with radius-ed braces"

Either works, but the cost of enough cam clamps to get even pressure distribution for bracing is going to be somewhere around $360 (10 x 4", 6 x 6", 4 x 8" @ about $18 per clamp for good ones) if you want to do two braces at a time, while a deck, dishes, and bars will run a little more (still under $400). The go-bar deck will handle bracing clamp-ups as well as closing the box, so pretty useful...and considering that something like 30 cam clamps is closer to what you'll need for closing the box ($540 if you by them and hours of work to fab them), you'll save some money downstream.

"2. radius dish versus radius board? (meaning a radius front to back and side to side using a dish, or radius board meaning radius from side to side only)"

I prefer the radius dish, which if purchased with 80 grit sandpaper cover sheet also handles the final radiating job for the rims. A dish makes the job pretty quick and easy, although the Cumpiano method is not that bad.

"3. could a D, OM, and 00 all use the same top and back radius? Or would the smaller bodies use a different radius. Assuming I am going for the Martin design style."

I use 15" and 28" on everything except arch tops, small ukes, and Weissenborns - Size 5 to jumbo/Grand Aud/dread. Works well. Radius the X, tone bars, bridge plate, and fingers to 28' and the UTB to 60'...glue all braces in except the UTB on the 28' rush, then glue UTB in on a flat surface...this gets the extension lined up properly with the top.

"4. If I choose the radius dish/go bar deck method to attach the top and back bracing, are those same dishes then used to sand the edges of the respective top and bottom of the sides?"

Same dish...just use 3M 77 or PSA 80 grit paper...when bracing, I keep a sheet of white butcher paper on top to protect the sandpaper surface from glue. A dish with 80 grit will last 5-6 years before you'll need new paper...I would bite the bullet and by the dishes in 1" Extira Waterproof MDF from Luthier Suppliers...$170 + $24 shipping for your 20' and 28' dishes complete with sandpaper. Order your bars from Goodwinds...96 x 24" x 3/16" bars and vinyl caps are about $85 delivered, and the ply and hardware for a free-standing deck is about $80. Best thing about go-bars - consistent 8 lb pressure with a 24" x 3/16" bar...and with 96 bars, you'll get much more even pressure on the glue line than cam clamps.

"5. If I don't use a radius dish method, but instead choose to cam clamp all my bracing, what is the best way to prepare the sides and blocks in order to accept the top and back?"

Cumpiano covers this in detail...do the rough profile as described (find the point 2" below waist, lay out the upper bout wedge after laying out the lower bout cut line...trim to that line and then clean up as described with a sanding board.

Thank you very much for your detailed response to my questions. I appreciate the help.

Best Regards,

Another possible workboard for one off construction is to draw the outline of the guitar on a piece of plywood and screw wooden "Ls" around the perimeter. The sides can be clamped to the Ls to keep things aligned. When a new model is chosen a new outline can be drawn and the Ls moved as necessary.

I started my tool / jig building first with a solera. After doing some extensive research, and listening to the guys on this forum, I changed directions and decided to go with radius dishes, outside frames, and a Go-Bar Deck.

The outside frames were pretty easy. I used 3 layers of 3/4 Baltic birch plywood. I used a band saw to cut the shape out, being careful to leave the cutout piece of wood intact, for making the bending mold.

I also built the Go-Bar-Deck using 2 pieces of plywood, 24 x 24. Drilled holes in the corners and bought some 5/8 threaded rods, long enough to hold the top high enough to glue the box together. I used wing nuts and can also lower the top low enough for gluing braces using the same rods.

I then built a side bending machine patterned after some of the ones I saw on YouTube. I just watched the videos, making notes about how the machine worked, thought it through and built it. It works very well.

The radius dishes I purchased from LMI. More work than it was worth to me. I went with a 15 ft. and a 25 ft.

There are a lot of videos out there to get ideas from, including some from our friend Todd Stock.
Blues Creek also has some nice instruction vids.

Welcome to the forum, and best of luck in your first build.
I'm certain you and your son will remember this always.