Mold Making?

[Fathand]

I am fairly new to acoustic guitar building, on my 3rd, but I have built some banjos, electrics and a couple ukes.

My method of mold making seems to differ from most I have seen and I am wondering if anyone with more experience sees anything inherently wrong with it. In other words, will my guitars likely turn out badly?

I first laminate plywood or chipboard (often from scrap ikea furniture found on the roadside) to 4 to 6" or so thick, 6 to 8 layers, leaving the middle around the outside free of glue. I carefully cut out the guitar shape on bandsaw, drum sand smooth then butterfly the outer unglued part for my female mold, leaving the guitar shaped thick part to bend the sides on. The saw kerf and sanding should leave relief for the side thickness.

Most of what I see are people making one piece and duplicating with a pattern bit then laminating together afterwards. Isn't it difficult to glue all the pieces together accurately?

The shown mold is my recent for a 0 size. I used 1 inch baltic birch for this one.

Comments invited.

[Fathand]

Hmmm any idea why I can't add a pic from Flckr?

[hubcapsc]

Originally Posted by Fathand

Hmmm any idea why I can't add a pic from Flckr?

https://www.flickr.com/photos/419932...tetaken-public

I don't know nothin' about flckr, but it is giving you a url to something that's
not an image...



-Mike

[Bruce Sexauer]

Molds are over rated. Haven't used one for 25 years. Check out my nearby thread in the Custom shop.

To get a picture to show it must be hosted somewhere, and then capture the address in html tags: [img]address[/img]

[Fathand]

Originally Posted by Bruce Sexauer

Molds are over rated. Haven't used one for 25 years. Check out my nearby thread in the Custom shop.

To get a picture to show it must be hosted somewhere, and then capture the address in html tags: [img]address[/img]

Thanks Bruce, I have looked at your reasons before and I don't feel skilled enough.

I did put the address in between tags but maybe the wrong address?

[Fathand]

Originally Posted by hubcapsc

I don't know nothin' about flckr, but it is giving you a url to something that's
not an image...



-Mike

Thanks Mike, how did you do that? I cant even download my own pic from flickr

[hubcapsc]

Originally Posted by Fathand

Thanks Mike, how did you do that? I cant even download my own pic from flickr

I don't have the patience to fight with flickr and photobucket and sites
like that. I made an Amazon virtual host and fired off Apache on it, and
I host my pictures there.

I right-clicked on the broken image icon in your post and copied the link out of it:
https://www.flickr.com/photos/419932...tetaken-public

When you click on that you can see your image, but it is embedded in flickr-goo,
you can't post that link inside of img-tags. I screen-shot your image and uploaded
it to my webserver at:

https://hubcapsc.com/misc/fathands_mold.jpg

Free stuff on the innernet mostly blows chunks

-Mike

[Bruce Sexauer]

Because I have a website, I am able to host my own pictures there. I especially like that because as long as I am in business and keep the bills paid, my pics will always be in my forum posts. If you go back a few years and look around, you will see a lot of dead links.

As far as the skill required to not use molds, I think that it takes no more skill at all, it’s just different than you mostly see. If you were to try it, there are fewer support resources, but there are some . . . Me, for instance. Others have started out moldless, and some have stuck with it. There are serious advantaged where design flexibility is concerned. The only real downside is that until your craftsmanship comes up with practice, there may be a bit less symmetry than hoped for. The guitars themselves may be better though, if that is important to you.

[Shuksan]

Originally Posted by Fathand

My method of mold making seems to differ from most I have seen and I am wondering if anyone with more experience sees anything inherently wrong with it. In other words, will my guitars likely turn out badly?

Most of what I see are people making one piece and duplicating with a pattern bit then laminating together afterwards. Isn't it difficult to glue all the pieces together accurately?

Rather than tell you about something you didn't ask about, I'll take a shot at answering your original questions.

Based on your photo, I don't see anything wrong with your method or the mold you made. The mold looks like it's fully up to the task.

I don't bend sides with a bending machine so someone else who does will have to comment on the suitability of the thick inside piece as a form for bending.

I've built four molds by the second method you described and had no problems gluing the pieces together accurately. The simple clamping setup in the photo worked. The mold pieces are butted to the long block of wood on the benchtop to keep them registered in that direction. This worked fine all four times with no problems. Your method seems like a perfectly good alternative.

[IMG][/IMG]

[Rudy4]

Originally Posted by Fathand

I am fairly new to acoustic guitar building, on my 3rd, but I have built some banjos, electrics and a couple ukes.

My method of mold making seems to differ from most I have seen and I am wondering if anyone with more experience sees anything inherently wrong with it. In other words, will my guitars likely turn out badly?

I first laminate plywood or chipboard (often from scrap ikea furniture found on the roadside) to 4 to 6" or so thick, 6 to 8 layers, leaving the middle around the outside free of glue. I carefully cut out the guitar shape on bandsaw, drum sand smooth then butterfly the outer unglued part for my female mold, leaving the guitar shaped thick part to bend the sides on. The saw kerf and sanding should leave relief for the side thickness.

Most of what I see are people making one piece and duplicating with a pattern bit then laminating together afterwards. Isn't it difficult to glue all the pieces together accurately?

The shown mold is my recent for a 0 size. I used 1 inch baltic birch for this one.

Comments invited.

I do molds by adding one slightly oversized layer at a time, using drywall screws for each layer. I use cheap 3/4" MDF. Cobbling up a mold from materials that are sometimes slightly different in thickness is more trouble than its worth. Flakeboard is absolutely the worst, as the different "flakes" change dimension non-uniformly when they absorb moisture from the glue. Yuck. It depends on if you have lots of excess time to futz the materials. I don't.

Shoot in several screws to register the new layer where you want it, remove them, add glue, replace screws. The screws ensure that the layer registers correctly where you want it to be and it doesn't slip or shift wen the screws are snugged.

After the glue has set I remove the screws and then pattern route the added layer to the previous layer(s). True up the inner walls of the completed form with a vertical oscillating sander. It's the quickest and easiest way I've found to make forms for banjos, guitars, mando-family instruments, etc.

Probably the easiest most trouble-free Image hosting site at the present time is Imgur. I've had zero problems with using it for hosting photos for forum use.

Some of the others I've tried were difficult because viewing permissions were based on being "logged in"... designed to force others to "join" so they get to enjoy all the built-in advertisements.

Imgur link:

[redir]

OP I think that is a fairly normal way to make a mold. That's the way I did it except I think 6in thick is a bit thick. Mine was 4 pieces of MDF.

I built my first few guitars using a mold but then switched to an open work board and never looked back. I would dare say that in fact I found it easier to use the work board especially if it came to designing a new model that would need a whole new mold.

If I did ever go back to using a mold I would probably want one of those adjustable ones that can accommodate many designs. As it is now I have two work-boards and each one has 3 designs on it. Simple outlines with a Sharpie.

[Shuksan]

Originally Posted by redir

OP I think that is a fairly normal way to make a mold. That's the way I did it except I think 6in thick is a bit thick. Mine was 4 pieces of MDF.

The way I read the OP's description of how he built the mold, only the the thick inside piece ends up being 6 inches thick. The outside mold ends up half as thick because he "butterflied" the full stack after cutting the body shape on the bandsaw.

[Fathand]

Originally Posted by Shuksan

The way I read the OP's description of how he built the mold, only the the thick inside piece ends up being 6 inches thick. The outside mold ends up half as thick because he "butterflied" the full stack after cutting the body shape on the bandsaw.

Thats about right. Previous molds were closer to 5" thick depending on what old bookcases and desks I salvaged, butterflied to 2.5" for the female and 5" for the bending mold.
The latest one of Baltic Birch, I used a combination method of laminating to 4 ", cutting out, butterflying to 2" then gluing one more layer to either side and using the pattern router bit to match them up so I wound up with 4" bending mold and 3" female mold.

Thanks for your advice, the gluing jig looks like a good idea.

[Fathand]

Rudy, thanks for the advice. I have used deck screws to help register like that. They come with Robertson heads here that work better than the Philips heads on the drywall screws.

I like your edge sander. I assume it is radiused?

[redir]

Oh I get it now. Actually that's a great idea for making a mold. less waste too.