Control cavity covers - "1 Weird Trick!!"

[bholder]

Ok, so forgive me if this is way too basic, most folks here probably have their own way of doing this, but I thought of something silly stupid that actually worked - large (clean) styrofoam take out containers with large flat sections make excellent control cavity cover templates! Just cut a flat section bigger than the needed cover, cut slightly larger, then press into place to make an outline of the hole above the recess. Cut to that line all around, it should just fit in the hole, riding on the ledge, like a cavity cover would. Now go around pressing the foam against the shoulder of the ledge, to get an impression of the inner hole and screw hole positions. Pop it back out (pushing through pot holes with a chop stick or straw) Carefully poke the screw holes through the center with a toothpick, all the way through, then re-mount it, verify and widen the screw holes to the actual size of the holes. It's a bit delicate, but very accurate and sturdy enough to transfer to a suitable piece of wood or plastic. I should have thought to take stepwise pics, but I didn't think it'd work that well. Anyway, it's slightly sloppy, the cover will need to be edge sanded to fit anyway, here's a snapshot of the resulting foam template:

Pics don't really show the impressions well, but it worked really well - way better than the old tracing paper and pencil or charcoal.

Are there even better ways of creating control cavity templates using just the hole?

 

[Killing Floor]

Smart.

 

[chinjazz]

Nice! Anything done in this “analog” mode would need sanding refinement.

Thanks for sharing!

 

[bholder]

Nice! Anything done in this “analog” mode would need sanding refinement.

Thanks for sharing!

Would I be correct in guessing there's a digital way with the cell phone camera or some such wizardry? That'd be cool, but this has that DIY lowtech reuse "found object" thang goin' on.

And of course, NY basically banned this kind of styrofoam container. There's still plenty of the stuff around, but not like before.

 

[Zooberwerx]

I would just install the styrofoam template as the cover. Bonus points if "#27 Kung Po Chicken" is scrawled with a Sharpie. Free can of soda with lunch special.

Riis

 

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and transferred to 1/4" maple:



Of course, my coping saw and my Dremel kits are all in storage...

 

[bholder]

I would just install the styrofoam template as the cover. Bonus points if "#27 Kung Po Chicken" is scrawled with a Sharpie. Free can of soda with lunch special.

Riis

they probably even make foil-lined styro (for insulation) that'd work for shielding! hehe

 

[Matt Liebenau]

Definitely a stealable idea.

 

[chinjazz]

Would I be correct in guessing there's a digital way with the cell phone camera or some such wizardry? That'd be cool, but this has that DIY lowtech reuse "found object" thang goin' on.

And of course, NY basically banned this kind of styrofoam container. There's still plenty of the stuff around, but not like before.

“There are apps for that” - but there’s still a need to manipulate the file in a CAD system , and the CNC.

I’m still analog but starting to lean into digital.

 

[JeezyMcNuggles]

Ok, so forgive me if this is way too basic, most folks here probably have their own way of doing this, but I thought of something silly stupid that actually worked - large (clean) styrofoam take out containers with large flat sections make excellent control cavity cover templates! Just cut a flat section bigger than the needed cover, cut slightly larger, then press into place to make an outline of the hole above the recess. Cut to that line all around, it should just fit in the hole, riding on the ledge, like a cavity cover would. Now go around pressing the foam against the shoulder of the ledge, to get an impression of the inner hole and screw hole positions. Pop it back out (pushing through pot holes with a chop stick or straw) Carefully poke the screw holes through the center with a toothpick, all the way through, then re-mount it, verify and widen the screw holes to the actual size of the holes. It's a bit delicate, but very accurate and sturdy enough to transfer to a suitable piece of wood or plastic. I should have thought to take stepwise pics, but I didn't think it'd work that well. Anyway, it's slightly sloppy, the cover will need to be edge sanded to fit anyway, here's a snapshot of the resulting foam template:

View attachment 4862505 View attachment 4862506

Pics don't really show the impressions well, but it worked really well - way better than the old tracing paper and pencil or charcoal.

Are there even better ways of creating control cavity templates using just the hole?

I've used tin foil before, and a peice of construction paper.

Stretch it over the cavity, and cut it out with a razor knife along the inner edge.

The construction paper makes a much better stencil because it's much thicker. But, foil cuts so clean and easy. Just have to be delicate when transfering.


But, your idea is pretty ingenious bro. Gotta say.

 

[Slevage]

Nice! Anything done in this “analog” mode would need sanding refinement.

Thanks for sharing!

Digital stuff is only a representation of something in our analog world.

 

[Gilmourisgod]

Ive done it using the "bondo trick", and it worked well, but a little time consuming and messy.

 

[micguy]

Paper taped over the back, rub pencil sideways along the edges, you get a nice template.

 

[bholder]

Digital stuff is only a representation of something in our analog world.

Nah. Reality is just a crutch for those who can't handle virtualization.

Seriously, why should the virtual be limited by the actual? Go Beyond.

 

[Rolling Thunder]

Maybe California will bring styrofoam back. Also, Agent Orange.

Great idea though.

 

[jolthewol]

I will use this!

 

[Gilmourisgod]

Another low-tech approach ive done: stick the body on a copier, works perfect as long as the back of your bass is flat. The one thing I have NOT mastered is cutting the cover out of the same piece of wood that the back is made of, so its literally the same piece of wood. Is there a tutorial someplace on that? I tried a few mockups on scrap with a coping saw, FAIL.

 

[Zooberwerx]

Another low-tech approach ive done: stick the body on a copier, works perfect as long as the back of your bass is flat. The one thing I have NOT mastered is cutting the cover out of the same piece of wood that the back is made of, so its literally the same piece of wood. Is there a tutorial someplace on that? I tried a few mockups on scrap with a coping saw, FAIL.

I have a small table-top skil saw that uses any number of available blades. It's a heckuva lot easier moving a piece of stock against a stationary blade than vice versa. I can also drill small starter holes, drop the blade thru, re-attach and do some rather detailed cut-out work. These home-based hobbyists have made it an art form...you can see plenty of their work at the Arts 'n Craft Bazaars coming to your neighborhood.

Riis

 

[RichterScale]

If you are resawing the back half/layer of the body off a slab, you could always resaw another thin layer off the book matched side of the back for the cover. Not an exact match, but as close as you can get without it being the actual cutout.
It's a very specific scenario, but one option.

 

[Lostgallifreyan]

...large (clean) styrofoam take out containers with large flat sections make excellent control cavity cover templates! Just cut a flat section bigger than the needed cover, cut slightly larger, then press into place to make an outline of the hole above the recess. Cut to that line all around, it should just fit in the hole, riding on the ledge, like a cavity cover would. Now go around pressing the foam against the shoulder of the ledge, to get an impression of the inner hole and screw hole positions.

It's a very nice idea. If you get some 1mm thick acetal (comes in colours various), you could press that against the hole with the foam under it, to get the template, then transfer the result direct to the acetal to make the final result, which might well rival the best original covers.