Weight of outside mold?

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Morecowbell
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Weight of outside mold?

Post by Morecowbell »

Finishing up my OM mold and spreaders and it feels pretty heavy - so I weighed it and its tipping the scales at about 19 lbs. The shipping weight on John's OM mold is 11 lbs, with spreaders its 13 lbs, so mine's a bit chunky. I can definitely take some weight off - but was just wondering if anyone else has used one that's as heavy as 19 lbs, and if its an issue. After bending my first sides I don't want to bust them with an overweight mold. Sort of answering my own question but I'm bored and wanted to post something!
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"Facts seldom sway an opinion." - John Hall
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tippie53
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Re: Weight of outside mold?

Post by tippie53 »

think of what you want to do with the mold. Clean the shape so you can get clamps on the top and back to glue up. My molds are about 9 to 10 lbs
you don't need so much
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
tippie53
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Re: Weight of outside mold?

Post by tippie53 »

you also won't need all those spreaders . I screw the neck and tail blocks in through the outside of the mold and a waist spreader. The key is in how you trim the sides. You do look like you made a nice mold and it will do the job well. thanks for posting
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Morecowbell
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Re: Weight of outside mold?

Post by Morecowbell »

Thanks John!
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
Bob Gleason
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Re: Weight of outside mold?

Post by Bob Gleason »

John- Just curious. Do you glue the neck and tail blocks in using the screw through the mold as a clamp, or are you just using the screw to hold the sides centered in place after gluing the blocks? And how does the screw deal with the split line on the mold, or is the screw offset? Stay safe.-Bob
tippie53
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Re: Weight of outside mold?

Post by tippie53 »

I don't use the screw so much to glue in the blocks but to get things set up
as for the joint line here is my proces
A drill through the mold at the center of the mold for the neck block and on the tail figure the center of the tail block
the first thing is the pre drill the blocks so you don't run the screw through the neck bock. Then set the sides to the mold with spreaders.
the point is to establish centers of the blocks and square to the mold and have the sides trimmed and ready.
B remove the blocks and set in the sides. Pre drill the sides using a backer block so you don't split the sides and set in the blocks and square up so when you do glue you know you have the blocks correct/
C remove the screw and apply glue. I do the neck block first. Apply glue run the screw and apply glue. I use tape over the sides on the neck block and clamp then with the spreaders set I glue in the tail. Allow a few minutes of set time then pull the sides and clamp the blocks. This way I know the sides are set and blocks are square. The screws make for a positive location point so all goes back together as it should
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
tippie53
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Re: Weight of outside mold?

Post by tippie53 »

John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
ruby@magpage.com
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Re: Weight of outside mold?

Post by ruby@magpage.com »

You can reduce the amount of material AND make it easier to use by trimming all the excess off. Measure the clamps you will use to hold the top and back and make the mold that wide

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and here it is in use - replace the DOT with a .

https://www.flickr DOT com/photos/ruby1638/49621452853/in/album-72157678301955987/

This shot is further down the line from the first - sorry, the forum only accepts one URL. Click left and right, text below

Ed
Ed M
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Re: Weight of outside mold?

Post by jread »

I built two molds pretty similar to yours so I'll reply. Weight would only be a minor issue as you move the thing around, it's heavy. I'll spare you pictures and lots of details but mine were 4" thick which created the biggest problem which was gluing on the plates. There wasn't a lot of height left to see the fit. I replaced mine recently with one from Blues Creek and John's overall is far nicer to use. Being thinner, lighter, and with the exterior thoughtfully shaped for temporary clamping, it is just a lot nicer to use. One thing I added to were some well placed screws on the outside to keep the clamps from creeping in some spots. His buckles were a lot more stable than mine too. If I were to make another, I'd try for smaller similar dimensions but at this point, I'm hooked on his cnc molds and there's only one more size I want. :D


ps. I also screwed in both the head and tail block thru the mold and for a change did not remove it until both the top and back were glued on. That helped a lot.
Morecowbell
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Re: Weight of outside mold?

Post by Morecowbell »

Glad my silly question generated some further discussion, every time I’m on here I learn something very useful.

John: screwing the blocks sounds like a great system. I can see that locking things down early on would be a big help, thanks for mentioning that

Ed: I love the way you cut your end/bottom joint! I’d like to not use an end flash, may try that approach

jread: yes, I too have begun to appreciate the joys of the CNC router! I actually have access to one, now what I need is a programmer!

Indiana just got the shelter in place order, stay safe everyone and here's hoping this is on the downside of the curve soon.
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
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