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Once again, a post of more interest to the newer builders that those with a pile of molds in the corner.

Once I had a template for my OOOO, I though taking a few pics of the mold making process might be interesting. I did not have a sheet of baltic birch, so I used a half sheet of Borg-brand birch ply.

I use a 2" x 2" extension on each end of the mold, so I start the layout of the mold master pattern by placing the body template 4-1/4" or so in from one end of the ply and centerline aligned with one of the straight edges.



After transferring the outline of the body, I use a 2" radius spacer to lay out the outside of the mold.





A quick fillet where the outside of the mold tucks at the waist avoids a sharp, weak corner.



A combination square makes layout of the 2" x 2" extensions easy - the extensions allow direct clamping of the neck and tail blocks, as well as house the carriage bolt and wing nut mold closures.







The inside corners at the ends of the mold halves are best shaped with a 3/4" Forstner bit...so I marked the center point to make things a bit easier.



Once layout is complete, I rough cut around the outside with a jigsaw.





As mentioned earlier, I shape the corners with a 3/4" Forstner, then trim the ends of the blank square on the tablesaw.







A quick pass through the band saw gets things down to 1/8" outside the line.





I do final shaping of the master with an oscillating spindle sander, finishing with the 3/4" diameter sleeve.





I use the finished master template to lay out the other five laminates for the full body mold sections. These get roughed out with a jig saw and trimmed to 1/8" oversize with the band saw.



Some builders use a full bodied mold for both cutaway and non-cutaway bodies. I prefer a mold that is shaped to the cutaway, so rather than try to get bass and treble sides identical in shape, I start with the master mold as a basis for the cutaway.



After adding the cutaway profile from the full body template, I rough trim on the band saw.





I tack the master template to what will be the cutaway master, and pattern-rout the outside and most of the inside up to the start of the cutaway.



After popping the master off, a little cleanup on the spindle sander gets the cutaway master to final shape.





As mentioned, the rough-cut laminates need cleanup on the band saw and a little hand sanding to get rid of any fuzzy edges off the saw.



While the master will function as the center laminate of the bass-side mold sandwich, I needed a duplicate for the treble side. A little pattern routing gives me two net-shape center laminates and four rough-cut outer laminates.





For the cutaway side of the mold, one net-shape master and two rough-trimmed outer laminates complete the prep.



A glue roller makes quick work of getting things ready to nail up without excessive squeeze-out. I use 1-1/4" 18 gauge brads to hold the three lams together, and try to remember to keep nails out of the end sections where my carriage bolts and wing nuts will go.





Once the sandwiches are assembled, I use a pattern router bit to trim the outer laminates to shape.



The final cleanup on the cutaway section consists of slotting the neck/cutaway section so that the sides can be run long to get a good shape through the section. This is one idea that Benedetto suggests and that really works.



A little clean-up on the spindle sander gets rid of any tearout or roughness.



After a quick test fit, I lay out the hole locations for the carriage bolts and wing-nuts, then drill the bass-side mold to function as the reference for holes in the treble-side full body and cutaway mold.





I clamp the bass side mold to the others and transfer the carriage bolt holes, then through-drill to clean up the holes.



I spot prime with shellac, mark the sides for future reference, and do 2-3 coats of shellac to minimize future glue issues. Other than spreaders, the mold is ready to go.



Next up are solid full-body and cutaway bending molds for the OOOO.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Great tutorial!

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Brad
Avon, OH

Thanks Todd - I was wondering how others do this.  Much cleaner than my method of mostly hand work.   How long do you think it took from start to finish?   

 

 

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Time you enjoy wasting is not wasted time.

About three hours from start to finish, including the pictures (45 of them...editted down to 38). The only close work is on the master template and the cutaway section. I think this is a two hour job in a well-equipped shops if you are not documenting the steps.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Some folks write books. Others write for the OLF ... nice work, Todd!

Filippo

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On the web at Morelli Guitars

Filippo -

Chris V. is up tomorrow if you can break away to pick up the screw. Don't think he'll be shooting nitro with the rain, but his OM is close to being ready for it. Probably be binding the Terz.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Right on Todd. Great tutorial. I've got two new molds and bending forms to make and I'll be using your method to make the mold.


Question, is it most common to make the molds 2-1/4" thick versus 3" thick?

I only have two shapes I made, both the molds are 3", heavy MDF and time to re-make them. So I guess I'll have 4 molds to make

Do the jigs ever stop

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My Facebook Guitar Page

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Very nice tutorial, Todd.
Thanks!
This is the same style of mold that I use, and I've found it useful to put a couple of locating dowels in each end, rather than depending on the bolts alone to keep things true- my bolt holes tend to 'wear larger' since I often use the mold halves separately to hold sides, binding, etc when drying. The dowels need only extend 1/2 inch or so into the holes in the opposite side- it's an easy final step to drill for these after you have the two halves bolted together.
Birch ply is the way to go if you don't have a good scrap pile!

Cheers
John

One question Todd. The slots you have put into the mold for the cutaway are a heck of a good idea, based on the trouble I had the the last one I built.

Mine was a mitered Florentine. Do you miter the joint near the neck, or just butt the sides, then bind it? The reason I ask is that I figured there must be and easier way.

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Allen R. McFarlen
Barron River Guitars
Cairns, Australia

Thanks, guys - seems like this topic comes up every few months and I find out folks are trying to line up a bunch of plys after final shaping - tough job that is not necessary if you have a pattern bit and a nailer or brad and hammer handy.

I have one 4 ply mold (4 layers of nominal 3/4" ply) - too thick for anything but a 12 fret dread, and one I'm considering cutting down to 2.5". I have not seen any advantage with the thicker mold in terms of maintaining body shape - on sides that are a little reluctant, a small 3" long block and a 4" Bessey Tradesman clamp do the job to pull things in.

In terms of locating pins, I had them on the first version of this style of mold, but dropped them after seeing how much friction was generated by the carriage bolt/wing nut combo and end/face grain ply mating surface. Going without alignment pins or a close tolerance hole and bolt does require alignment when the mold is tightened after insertion, but I check this anyway. I think John's addition is a good idea, though, given his alternative uses for the mold, and alignment pins are an easy addition - 5 minutes max) to this style of mold.

I've only done one florentine, so if there's an easy way to do them, please advise! I trim the point and shoulder of the cutaway and add maple binding and purflings, then rout the top and back channels - works for me.

The slots on the cutaway are there primarily to allow me to get a very accurate measurement of side length and meeting angle prior to committing the side to the saw, as well as to pull a stubborn side into alignment when I'm gluing the neck block. I don't have a good shot of the SJ florentine mold in use, but the slots are a life-saver. I make the cuts slightly oversized width-wise (.100), and shim with scrap or tape as necessary.

The best thing about this design is the ability to put two 8" deep-reach Besseys on the neck and tail blocks...they act as handles for radiusing the body and linings, and add enough weight to stop any chatter.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

WOW Todd...Very nice tutorial!

So far, I've found myself reviewing this post 3 times...each time I get distracted by the cool tools, equipment and details in the background. I really love that bench...especially the dovetail-detailed vice. There are so many on my list of "Shops I'd Love to Visit", and yours is near the top of that list.

And once again...a superb tutorial on the construction of building molds! Even though I've built my molds differently, I will definitely try this method next time. Thanks for posting!

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JJ
Napa, CA
http://www.DonohueGuitars.com

Thanks, guys - I'm going through flushing the painkillers out of my system after recent surgery, so I can't sleep and won't do anything that can't be easily redone...good time for doing stuff like this.

I've got one more article working on solid molds for blanket bending, then back to work on Tuesday, so back to the rat race. My contribution to world peace and reduced side breakage.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Well, thanks for your therapeutic efforts on behalf of those of us who are beginners.  You have saved hours of "navel contemplation", and lint collection efforts.  You have done a great service to the OLF, and we await your final contribution with trepidation (well at least the trembling part).  We all wish you speedy flushing of your system, and a return to the real world of hurt we all face.

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Waddy

Waddy Thomson Guitars

Waddy's Guitar Build Albums 13 done - #14 in process.

Sound Clip from #1: Barrios' "Una Limosna por el Amor de Dios" (An Alm for the Love of God) -Not me playing! I could never.....!

Awesome, thanks a ton, Todd!  Makes me smile to see somebody work so hard and give such helpful info out for free.

Time to give my printer a workout!

Great Job Todd. Bob Connors from Geelong already has it posted in his RUNNING LINKS OF OLF TUTORIALS.



http://www.connor.net.au/olftutorial/

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http://www.dickeyguitars.com

Thanks, Bruce...Bob's efforts to put all these articles together makes OLF even more of a resource. I'm already pointing folks towards Bob's links when they have questions on 'how to?'

Working on finishing up the bending form article to complete the series. The first curly anigre OOOO side is in the mold already, and the other side goes in later today after I prep the cutaway section. Hope to wrap up the article with a shot of the bent ribs ready for assembly.

Cheers...

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Great post!

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Guitars, guitars and more guitars.

Thanks Todd - Great Tutorial! This will really help when I decide to make my next mold. Great looking shop you have there btw.

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Anderson Guitars
Port Richey,Fl.

Excellent tutorial!

You have made my life a lot easier when it comes to making molds. Thanks a million!

-Rob

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-Rob Eckert
Ann Arbor, Michigan

Thanks again, folks...just documenting common practice for those that prefer photo essays to text.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Todd, thanks for the great, and very clear tutorial.  I have previously bought my molds and bending patterns, but now may have the courage to try building my own shape(s).  Really looking forward to seeing your bending pattern tut. too!

BTW, what type of router table do you have/how do you like it?

Thanks again for the great info!  I look forward to reading/seeing more of your tutorials.

The router table pictured is shop-made...MDF/Formica/wood edge with a FASTTRACK track section and a shopmade MDF fence. Steel angle stock under to keep things flat (but not as flat as I'd like...).

IMO, the two things that make a router table either a dream to use or a pain are flatness and the fence. I really like the Bench Dog Pro Top and Pro Fence system - works great and not too expensive. The CMT and Jessem phenolic tops are pricey, but you could land planes on them...very rugged.

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I'm really starting to think that the whole world is just a patchwork quilt of crazy little cults, all with their own secret spaces, their own records, their own rules.
- Robin Sloan

Awesome Todd
I am about to build my 1st mold for my 2nd guitar
Cheers
Barry

Great tutorial Todd. Thanks!
John