What materials for padding a case?

Construction and repair of Classical Guitar and related instruments
Mode
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What materials for padding a case?

Post by Mode » Thu May 16, 2019 1:56 am

I need some help: my travel guitar is getting all banged up in its gig bag so I would like to construct a rigid case.
For the padding would like to use something semi rigid light and elastic and cover it in soft furry stuff just like a good instrument case?

What are the correct materials to use and how can I source them? (In the US)

Thanks!!!!

M.

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robin loops
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Re: What materials for padding a case?

Post by robin loops » Thu May 16, 2019 3:17 am

Or just buy a better case. They make gig bags that have reenforced sides if you’re set on a gig bag. Or just go with a good hard shell case.
One Ring to rule them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them.
-James-

Mode
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Re: What materials for padding a case?

Post by Mode » Thu May 16, 2019 3:22 am

robin loops wrote:
Thu May 16, 2019 3:17 am
Or just buy a better case. They make gig bags that have reenforced sides if you’re set on a gig bag. Or just go with a good hard shell case.
What I need cannot be bought: this is the guitar I need it for: https://www.classicalguitardelcamp.com/ ... 1&t=127098
Besides, making things is more fun ;)

Cheers,

M.

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robin loops
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Re: What materials for padding a case?

Post by robin loops » Thu May 16, 2019 4:59 am

Wow! Oh okay... I have some ideas. On my way to bed now but will post tomorrow.
One Ring to rule them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them.
-James-

Matthew Masail
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Re: What materials for padding a case?

Post by Matthew Masail » Thu May 16, 2019 9:44 am

Thinking some king of styrofoam.... inside cuts to hold the parts, covered in leather with a 1" thick bottom and a lid.

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souldier
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Re: What materials for padding a case?

Post by souldier » Thu May 16, 2019 10:38 pm

A rectangular case with customized polyfoam/fabric interior similar to violon cases. Polyfoam is good for absorbing impact as well as insulting the instrument from temperature changes. I am of the opinion that very rigid cases such as plywood cases can actually be harmful to an instrument in the event of a hard drop as the shock in transferred straight to the instrument. What often ends up breaking is the neck/headstock since the shock combined with almost 100lbs of string tension is more than a guitar can withstand.
"Success grants its rewards to a few, but is the dream of the multitudes.
Excellence is available to all, but is accepted only by a few." - Christopher Parkening

Mode
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Re: What materials for padding a case?

Post by Mode » Thu May 16, 2019 11:25 pm

souldier wrote:
Thu May 16, 2019 10:38 pm
A rectangular case with customized polyfoam/fabric interior similar to violon cases. Polyfoam is good for absorbing impact as well as insulting the instrument from temperature changes. I am of the opinion that very rigid cases such as plywood cases can actually be harmful to an instrument in the event of a hard drop as the shock in transferred straight to the instrument. What often ends up breaking is the neck/headstock since the shock combined with almost 100lbs of string tension is more than a guitar can withstand.
Matthew Masail wrote:
Thu May 16, 2019 9:44 am
Thinking some king of styrofoam.... inside cuts to hold the parts, covered in leather with a 1" thick bottom and a lid.
Styrofoam looks promising although it's on the stuff side. For the lining I'd prefer the furry stuff.
I guess my question is, what are the materials professional luthiers use when making a modern instrument case and where can I source them?

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souldier
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Re: What materials for padding a case?

Post by souldier » Fri May 17, 2019 12:04 am

Mode wrote:
Thu May 16, 2019 11:25 pm
souldier wrote:
Thu May 16, 2019 10:38 pm
A rectangular case with customized polyfoam/fabric interior similar to violon cases. Polyfoam is good for absorbing impact as well as insulting the instrument from temperature changes. I am of the opinion that very rigid cases such as plywood cases can actually be harmful to an instrument in the event of a hard drop as the shock in transferred straight to the instrument. What often ends up breaking is the neck/headstock since the shock combined with almost 100lbs of string tension is more than a guitar can withstand.
Matthew Masail wrote:
Thu May 16, 2019 9:44 am
Thinking some king of styrofoam.... inside cuts to hold the parts, covered in leather with a 1" thick bottom and a lid.
Styrofoam looks promising although it's on the stuff side. For the lining I'd prefer the furry stuff.
I guess my question is, what are the materials professional luthiers use when making a modern instrument case and where can I source them?
You can always use polyfoam then line it with something thick and furry. If you're going to go custom, anything is possible.

The majority of luthiers don't make guitar cases. They outsource to companies like Hiscox, Visesnut, Hoffee, Karura, Bam, etc.
"Success grants its rewards to a few, but is the dream of the multitudes.
Excellence is available to all, but is accepted only by a few." - Christopher Parkening

Matthew Masail
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Re: What materials for padding a case?

Post by Matthew Masail » Fri May 17, 2019 12:05 am

My intention was leather on the outside, it's tough and keeps the weight down. Inside some kind of velvet for sure. Any kind of firm foam would work if you have a stiff shell but styrofoam would provide a light she'll in itself. That was my first thought anyhow.

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Gorn
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Re: What materials for padding a case?

Post by Gorn » Fri May 17, 2019 7:44 am

Before I laid down my work and moved to an island, I was concerned with exactly such things for more than a decade: putting tools of any kind of shape into polyethylene foam sheets (to put them in drawers or cases). I guess that you can remove the pods? If so, there should be no problem with the size.
Just look up »Hoffmann eForm« on Google for more information. You can generate the shape of your guitar and of each pod with simple photos, load it into a browser-based software (or one of the Hoffmann guys will do), get an offer which might knock you off your feet a little bit and the shape will be milled out of a foam sheet. If your guitar is not higher than 80 mm, everything should be within standard sizes. The cut-out must be made "full sunk-in" (don't know what it's called in the English version of eForm).
I don't know where you live: there's a subsidiary in the USA (Knoxville, Tennessee). You could use e.g. pyramidal foam for the top of the case. I think the best material for the case would be something in flightcase style. Polyethylene foam can be stuck to anything with hot glue.

Mode
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Re: What materials for padding a case?

Post by Mode » Fri May 17, 2019 12:40 pm

Gorn wrote:
Fri May 17, 2019 7:44 am
Before I laid down my work and moved to an island, I was concerned with exactly such things for more than a decade: putting tools of any kind of shape into polyethylene foam sheets (to put them in drawers or cases). I guess that you can remove the pods? If so, there should be no problem with the size.
Just look up »Hoffmann eForm« on Google for more information. You can generate the shape of your guitar and of each pod with simple photos, load it into a browser-based software (or one of the Hoffmann guys will do), get an offer which might knock you off your feet a little bit and the shape will be milled out of a foam sheet. If your guitar is not higher than 80 mm, everything should be within standard sizes. The cut-out must be made "full sunk-in" (don't know what it's called in the English version of eForm).
I don't know where you live: there's a subsidiary in the USA (Knoxville, Tennessee). You could use e.g. pyramidal foam for the top of the case. I think the best material for the case would be something in flightcase style. Polyethylene foam can be stuck to anything with hot glue.
Thanks Gorn, this is extremely interesting! Since it's a one off I'm happy carving it myself from a thick sheet. So you would suggest polyethylene foam? Thanks also for the info about gluing it, I had struggled in the past gluing it but I had never tried hot glue on it.

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Gorn
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Re: What materials for padding a case?

Post by Gorn » Fri May 17, 2019 7:29 pm

Mode wrote:
Fri May 17, 2019 12:40 pm

Thanks Gorn, this is extremely interesting! Since it's a one off I'm happy carving it myself from a thick sheet. So you would suggest polyethylene foam? Thanks also for the info about gluing it, I had struggled in the past gluing it but I had never tried hot glue on it.
Yes definitely. Good quality PE-foam, density 45 kg/m³ (LD 45) is very sturdy and long-lasting. A harder foam does not make sense for a guitar. If you countersink your guitar in the bottom layer you only need a flat piece of cheaper foam (LD 20) or even PU for the top. As soon as the guitar is fully packed into foam, the box needn't be very sophisticated. Maybe thin multiplex + flightcase fittings: that's it.
Tool foams usually have bi-colored materials (laminated, not glued), so you see at a glance, if one tool is still in the engine of an airplane. :wink: That's the original application for it.
BTW: My nickname in the company was "Lord of the Foams" (no kidding!). I can look back on almost two decades of experience and around hundred thousand of different layouts for tools of all kinds (and occasionally some other stuff) in many different drawers/cases/boxes. One recommendation: do yourself a favour and build your case exactly rectangular on the inside!
Enclosed see two pictures of a Sansula foam which I have drawn. The box is a Hoffmann standard multi-purpose tool box.
inside.jpg
outside.jpg
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ernandez R
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Re: What materials for padding a case?

Post by ernandez R » Sat May 18, 2019 7:18 am

Gorn wrote:
Fri May 17, 2019 7:29 pm
Mode wrote:
Fri May 17, 2019 12:40 pm

Thanks Gorn, this is extremely interesting! Since it's a one off I'm happy carving it myself from a thick sheet. So you would suggest polyethylene foam? Thanks also for the info about gluing it, I had struggled in the past gluing it but I had never tried hot glue on it.
Yes definitely. Good quality PE-foam, density 45 kg/m³ (LD 45) is very sturdy and long-lasting. A harder foam does not make sense for a guitar. If you countersink your guitar in the bottom layer you only need a flat piece of cheaper foam (LD 20) or even PU for the top. As soon as the guitar is fully packed into foam, the box needn't be very sophisticated. Maybe thin multiplex + flightcase fittings: that's it.
Tool foams usually have bi-colored materials (laminated, not glued), so you see at a glance, if one tool is still in the engine of an airplane. :wink: That's the original application for it.
BTW: My nickname in the company was "Lord of the Foams" (no kidding!). I can look back on almost two decades of experience and around hundred thousand of different layouts for tools of all kinds (and occasionally some other stuff) in many different drawers/cases/boxes. One recommendation: do yourself a favour and build your case exactly rectangular on the inside!
Enclosed see two pictures of a Sansula foam which I have drawn. The box is a Hoffmann standard multi-purpose tool box.
inside.jpg
outside.jpg
Lord of the foams! That is great. I was nicknamed Carbondez in my heavy composites repair days. I was master of the 250/350F prepreg hot bond. I can't touch the stuff now so I'm building a set of cases out off plywood. It's a work in progress.

My real point was to add that for a one off useing a can of spray foam to mold a shape might be more practical and inexpensive. My plan is to wrap a guitar in protective film of some sort, fill the box with spry foam and set the guitar into it and let it cure. Remove and re apply asmnessasary and carv out accordingly and then glue in a fluffy fabric, I've got crushed velvet in yellow in mind, using a water based non solvent adhesive that stays vary playable. Many glues will react with FP or nitrose so best be cautious.

I started a build thread for these cases but havnt moved it to far forward although I did screw on a hinge the other day to get a better handle on the edge closure structure.

Regardless please post your ideas and progress as it might help me :)

HR
I hate sanding wood or anything else for that matter I just happen to be good at it...

Mode
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Re: What materials for padding a case?

Post by Mode » Sat May 18, 2019 3:27 pm

Gorn wrote:
Fri May 17, 2019 7:29 pm
Yes definitely. Good quality PE-foam, density 45 kg/m³ (LD 45) is very sturdy and long-lasting. A harder foam does not make sense for a guitar. If you countersink your guitar in the bottom layer you only need a flat piece of cheaper foam (LD 20) or even PU for the top. As soon as the guitar is fully packed into foam, the box needn't be very sophisticated. Maybe thin multiplex + flightcase fittings: that's it. ...
Gorn, thank you so much! One of the good things of a forum like this is that there are people with deep experience like you that share their knowledge.
I started looking up for LD45 foam and I could only find a 1"x40x40" sheet for like $160 which for packaging material is nuts and would be barely enough to make the small case I need to make. Is that a rip off or is this material expected to be this expensive?

Mode
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Re: What materials for padding a case?

Post by Mode » Sat May 18, 2019 3:32 pm

ernandez R wrote:
Sat May 18, 2019 7:18 am

My real point was to add that for a one off useing a can of spray foam to mold a shape might be more practical and inexpensive. My plan is to wrap a guitar in protective film of some sort, fill the box with spry foam and set the guitar into it and let it cure. Remove and re apply asmnessasary and carv out accordingly and then glue in a fluffy fabric, I've got crushed velvet in yellow in mind, using a water based non solvent adhesive that stays vary playable. Many glues will react with FP or nitrose so best be cautious.

I started a build thread for these cases but havnt moved it to far forward although I did screw on a hinge the other day to get a better handle on the edge closure structure.

Regardless please post your ideas and progress as it might help me :)

HR
I was thinking the same. I was just hoping to be able to find sheet or plank foam boards to avoid the sticky mess and make use of the "right" material :)

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