Body Mold

[Logan Sarchfield]

Is there a supplier that sells A and F style molds? If I didn't have to make these it would save me a considerable amount of time.

[MikeEdgerton]

Roger Siminoff (http://www.siminoff.net/parts/index.php?main_page=index&cPath=8_29).

[Jim Hilburn]

I would think if you plan to build a mandolin worrying about the time a mold would take to make isn't a good way to approach the project.

[Bill Snyder]

....If I didn't have to make these it would save me a considerable amount of time.

How much time? I have not made an F-style mold, but an A-style mold can be made in a couple of hours with a band saw or a jig saw. The F-style mold should not take a whole lot longer than that.

[buddyellis]

Making a mold was sorta 'scary' at first but really its easier than just about any step of the mandolin process if you have a bandsaw. I make a copy of the body outline (actually print from my PDFized copy of HoGo's plan) and transfer that to a piece of plexiglas for a master body outline template, and then use that to draw the shape on a double thickness of 3/4" MDF (glue two sheets large enough for the mold together) and then cut it more or less right down the middle (tailpiece to neck, but the cuts slightly at an angle, see here: http://www.buddyellis.com/Dudenbostel-mandolin-construction/dude12.jpg for an example) so you can cut the thing out easily, and then cut just inside the line on the body edges, doing final shaping to the line with sandpaper/files/etc. You don't really need the fancy inside spreaders, they can be done any number of ways, clamps on the outside, spreader bolts on the inside, or as simple as a piece of fitted cardboard on the inside.

[Logan Sarchfield]

I will build one if I can get access to a bandsaw. I own a bandsaw but its at my parents house on the other side of the country and I don't really have room for one right now. I might be able to get access to one through a friend of a friend. If I get a chance to do that I'll probably make a mold for both an A and F style. If I can't do that I'll look at buying one.

[Mike Bunting]

Geez, Logan, when I saw the thread title, I thought you had come down with some sort of skin problem! Glad to see you are going to build another mando.

[Bill Snyder]

Logan, before I got my bandsaw I used a sabre saw to cut my molds. I make a template out of 1/4 inch hardboard, mdf or plywood. Cut close to my line with the sabre saw and sand as necessary. I then use the template as a pattern and trace on 3/4" plywood. I cut this out with the saw making sure I don't take the line. Then I screw my template to the plywood to use as a pattern for a flush-cut bit in my router. The bearing rides on the 1/4" template truing up the plywood. For an a-style I do this four times. Stack the plywood 2 high and connect the 2 halves to make a symetrical mold.
It has worked well for me.

[Stephanie Reiser]

[QUOTE=Mike Bunting;645663]Geez, Logan, when I saw the thread title, I thought you had come down with some sort of skin problem!
So did I. That is why I spell it mould. Either way, I guess, is right, but "mold" makes me think of old food and "mould" makes me think of wood moulding. I think a hardware store jigsaw can be used to cut the mould out, and I've done it when I started.

[Sleepy Moon Music]

The first Mando i built was on a budget so to make a mould i went to a local lumber yard and got a piece of 1 1/2" styrofoam . I cut out the shape of my mould from it and built the mandolin .It was cheap because it was a damaged piece they were trowing away . It is inexpensive anyway and it worked .

[D.E.Williams]

I find making molds really easy with my cnc.... a much better way than a bandsaw.
It's just kind of an expensive tool though...:))

[Hans]

Logan, without a bandsaw it's going to be tough to make a mould. I can see why you might want to buy one. The accuracy of your instrument depends on the accuracy of the mould. I just tortured my 14" Powermatic cutting this guitar mould.

[MikeEdgerton]

By the way, anyone looking for Guitar moulds can check out Blues Creek Guitar (https://www.bluescreekguitars.com/catalog/). He used to have them for mandolin if I recall, but they aren't in his current catalog.

[Logan Sarchfield]

Thanks for all the great suggestions. I have done a J-45 mold in the past with a jig saw, and I should have just purchased one. With the guitar I spent more time building the mold, radius dish and side bender than the body itself. Blues Creek Guitar is a great resource for guitar molds.

[grandcanyonminstrel]

Hans:

Just be glad you don't build double basses; the mold for mine was huge!

I'll turn up the heat a bit:

If you just go out and buy a commercial mold, you never really develop a very valuable skill in lutheirie. Depending on the task at hand, I build all sorts of specialized jigs and infrastructure to get the job done. My feeling is that every step of a build, the student or newer builder should be making their own infrastructucture to develop their skills.

This year I had about two dozen students pass through my place. About 50% of them had already spent a Lot of money to attend one of the big name places: Roberto Venn, Timeless, Bryan Gallup's school, and the like. They enjoyed the program and built a nice instrument or two, but they can't really think for themselves. They know how to work a quasi assembly line process in someone else's shop.

Outside of any new instrument information, they come to me for help on how to bridge the gap for themselves: how to pattern route jigs and molds, how to build an efficient, very effective heat blanket bending system, how to go up to Mt Mitchell and split red spruce billets by hand and then resaw them into sets.

With all of it, my feeling is that the more you are in control of the process, the better your end result will be. It also gives you infinite ability to create what is in your head and heart, not being bound by someone else's ideas of what your instrument should be shaped like.

Where do you draw the line on "Your" build? Does the ease of a commercial mold turn into prebent sides glued to the precut blocks with cnc'd plates and an imported Chinwanese made neck glued into subcontracted blocks before you add your own logo inlay and ship it out to the paint specialist???

I know several fantastic classical guitar builders who would tell both of us," What do you need a mold for??? Learn how to bend the sides properly and you can build without one in the Spanish tradition, just like the old masters did; just like I do. Mold; I don't need no stinkin' mold"...

When I relocated my shop to the other side of the country a couple of years ago, I sold all of the power tools I had ( and had a realxing, carefree 4000 mile move...). The first tool I bought when setting up again was a nice small spindle sander. For about the price of a commercial mold, you can get one of the small benchtop models. From then on, your molds will be incredibly precise and you'll use it almost every day for the detail work on your build, all with a smile on your face, especially on the days you are fitting the blocks.

j.
www.condino.com

[man dough nollij]

Great post, James.

You make some good points. I grew up taking things apart and putting them back together, out of natural curiosity. I've always been interested in the way things work, and that has served me well. I'm a "techy" job now (though I've done mostly PM/Engineering stuff), and I see that good troubleshooting skills are essential.

I can see how that would be true in lutherie, too. My process goes a certain way to find out why a piece of equipment isn't working right. Might be the same in a wood shop. "This bender seems to be burning up my side pieces... how can I make one that'll work better?" That kind of thing. The previous posts about inventive ways people have come up with to make body moulds are good examples. Thinking "out of the box" (no pun intended).

I also see a lot of examples of people who (like the students who toured your shop) never developed those mental muscles. In their way of thinking, you just take your car to the shop when it's making a funny noise. If you need a jig or a part, you just buy one. I think it's better to build those skills young (like most things), but it's never too late to learn.

:popcorn:

[Darryl Wolfe]

I got my A-model mold from Blues Creek. It is dead on for a '20's Gibson A-model, including the slight asymetry they have. I think it was around $50

[Hans]

Quote: Just be glad you don't build double basses...
Shudder...
Store bought moulds are fine, and save a lot of time, but try to find a store bought Larson shape!

[Rick Turner]

The lutherie schools just don't have the time to teach that all-important skill of basic woodworking or jig and fixture making.

For molds, just make an accurate template as a half pattern (for an A) or two halves (bass and treble side for an F) in 1/4" Plexiglas. Drill two or three 1/4" holes through (use a rake relieved drill bit) the pattern. Rough cut 3/4" pieces of Baltic birch ply, MDF, or whatever about 1/16" over size, and then pin the Plexi template(s) to the mold sections through the 1/4" holes. Now use either a top or bottom bearing pattern router bit in a table to make accurate parts for your mold. You can make them in 3/4" layers and then pin and glue the layers together to make a mold as thick as you need. And now you've got a set of master patterns for making more molds.

I rarely make a part without starting with a Plexi pattern. With pins, double stick tape, and sometimes even a finish nail gun or hot melt glue, you can do amazing work making jigs and fixtures.

[Bill Snyder]

Sounds pretty much like the process I described using above. I mentioned using 1/4" plywood for the template, but I have a stack of plexiglass I got just for this purpose, I just haven't used it yet.

[fscotte]

For molds, just make an accurate template as a half pattern (for an A) or two halves (bass and treble side for an F) in 1/4" Plexiglas. Drill two or three 1/4" holes through (use a rake relieved drill bit) the pattern. Rough cut 3/4" pieces of Baltic birch ply, MDF, or whatever about 1/16" over size, and then pin the Plexi template(s) to the mold sections through the 1/4" holes. Now use either a top or bottom bearing pattern router bit in a table to make accurate parts for your mold. You can make them in 3/4" layers and then pin and glue the layers together to make a mold as thick as you need. And now you've got a set of master patterns for making more molds.




Logan, before I got my bandsaw I used a sabre saw to cut my molds. I make a template out of 1/4 inch hardboard, mdf or plywood. Cut close to my line with the sabre saw and sand as necessary. I then use the template as a pattern and trace on 3/4" plywood. I cut this out with the saw making sure I don't take the line. Then I screw my template to the plywood to use as a pattern for a flush-cut bit in my router. The bearing rides on the 1/4" template truing up the plywood. For an a-style I do this four times. Stack the plywood 2 high and connect the 2 halves to make a symetrical mold.
It has worked well for me.

I'd like to revisit this older thread. These seem to be two similar methods of using a router and a template to make the inside edges of the mold straight. I guess I don't understand this. If your using a template for the router, what would the template be pinned or screwed to? It seems you would have very little of the mold for the template to fasten to, and as soon as you start routing, you'd lose the edge altogether and the template wouldn't be fastened to it at all?

[Bill Snyder]

The template in my case is screwed to the material I am making the mold out of. I can then clamp it to my bench. At least previously.
Now I use a router table and the router is stationary and I move the mold w/template attached.

[HoGo]

I'd second making plexiglass templates first, and I'd recommend one piece template for F style and making the outside F style mould two piece but not divided at centeline but at diagonal connecting lower point with furtherst part of body scroll. That way you can fully assemble the body in mould and release it easily by opening the mould. I guess you cannot buy mould like this.

[Mike Bromley]

How does one attempt an F-Model without a Bandsaw? Jim Triggs told me it was his most versatile tool.

[HoGo]

I don't own a bandsaw. I made my first few mandolins without a bandsaw but it helps to have at least access to one at friend's workshop for some tasks. Now, I visit my friend for block cutting and neck profile cutting at start of build.
Moulds are easy to do without bandsaw. You can make master template out of plexiglass with precise holes for alignment pins and rout the mould with flush cut bit out of two or three layers of plywood (or MDF). It's much cleaner and perhaps even more precise than bandsawing and spindle sanding.

[fscotte]

The template in my case is screwed to the material I am making the mold out of. I can then clamp it to my bench. At least previously.
Now I use a router table and the router is stationary and I move the mold w/template attached.


Is this for an inside mold or an outside mold? It seems this would be for an inside mold... otherwise, wouldn't you have to make your plexiglass template slightly smaller to counter the width of the router bit?

[Logan Sarchfield]

If you want to build an outside mold you will need to make a template of the outside mold shape that you want to build and then route around it with a bearing flush trimming/ template bit. If you wanted to make an inside mold you would have to make a template of the mandolin body shape and subtract the thickness of the sides then route around it with the template bit.

[fscotte]

If you want to build an outside mold you will need to make a template of the outside mold shape that you want to build and then route around it with a bearing flush trimming/ template bit. If you wanted to make an inside mold you would have to make a template of the mandolin body shape and subtract the thickness of the sides then route around it with the template bit.


Ok, that's what was confusing me. I thought he was referring to an outside mold.

I have access to a router and with a table. If I'm going to be cutting my outside mold out of 3/4" thick MDF, which flush cut bit should I use? One with bearings at the top and bottom or just the top?

[Bill Snyder]

I only use outside molds. I use a flushcut bit. There are also pattern bits. Difference is the placement of the bearing - one on top of the cutter the other on the bottom. The bearing is the SAME diameter of the cutter so it trues up the plywood that is already cut close to the line so that it is about as exact a match to the pattern being used as possible.
I will try to sketch a picture or take a photo or two and post them.

[Bill Snyder]

Maybe the attached drawing will help. I cut both my template and my mold out close to my line. The template I cut as close as I can and true up on my spindle sander. The mold I make sure to leave a bit of extra material. It will trimmed away with the router.
I screw the template to the mold and use the router (with or without router table) to trim it to exactly match the template. The bearing rides along the template and the cutter on the flush cut bit only cuts the mold.
If you use a pattern cutting bit it works the same except the bearing is at the top of the bit so instead of the router base riding on the mold the router base rides along the template.

[fscotte]

That's exactly what I needed Bill. That looks way easy now. Thanks for the clarification!

[resophil]

Logan, check your PMs. I can help you out with a bandsaw...