Bag Stiffener vs foam vs?

[JC2019]

Just wondering what you guys recommend I use if I ever want to make a backpack or bag more "structured" so it doens't just flop over. I've taken a few older mesh/fabric backpack apart and they seem to use foam?

 

What material do you want to use for leather? Is foam also fine? Or would you recommend something else like "Stiffener"?

 

Thank

[RockyAussie]

Some bags I use just foam to give structure and some have a combination of a stiffener and foam on top. Most of my totes/backpacks  and such use just a foam.

[JC2019]

3 hours ago, RockyAussie said:

Some bags I use just foam to give structure and some have a combination of a stiffener and foam on top. Most of my totes/backpacks  and such use just a foam.

Great thanks. Do you over use left over splits from a hide as stiffener ? 
 

I read a while back that I should stay away from split leather so I don’t really buy it on its own but perhaps it’s valuable still?  Or should I avoid it like bonded leather or do you think they have  their uses? I am trying to stick to top/full grain for the most part but still fairly uneducated. 

 

Edited June 26, 2020 by JC2019

[RockyAussie]

21 hours ago, JC2019 said:

Great thanks. Do you over use left over splits from a hide as stiffener ?

Mostly I only ever use left over split leather from belt backs as a filler in my combination dress belts. In some applications it could be used elsewhere but generally the weight increase compared to the foam is not as desirable. The foam allows more flex as well.

[Scoutmom103]

what type of foam do you use RockyAussie?

 

[RockyAussie]

14 hours ago, Scoutmom103 said:

what type of foam do you use RockyAussie?

 

Quite a few I'm afraid but mostly I use Sekisui foam Softlon 3002. (33kilo per metre) mentioned because that gives you the weight/softness. It is very easy to skive if needed on a skiving machine and takes stitching through it without creating missed stitches on a sewing machine. There are a lot of different densities with foam and thickness and it is a good idea to ask for a sample range to have on hand.

[JC2019]

On 6/27/2020 at 4:40 AM, RockyAussie said:

Mostly I only ever use left over split leather from belt backs as a filler in my combination dress belts. In some applications it could be used elsewhere but generally the weight increase compared to the foam is not as desirable. The foam allows more flex as well.

good to know thank you 

[Scoutmom103]

On 6/27/2020 at 10:50 PM, RockyAussie said:

Quite a few I'm afraid but mostly I use Sekisui foam Softlon 3002. (33kilo per metre) mentioned because that gives you the weight/softness. It is very easy to skive if needed on a skiving machine and takes stitching through it without creating missed stitches on a sewing machine. There are a lot of different densities with foam and thickness and it is a good idea to ask for a sample range to have on hand.

Thank you RockyAussie

 

[johnv474]

You can use a layer of stiffer leather or something like foam. Don't use paper products like cardboard or posterboard because they won't last.

I prefer to use leather.  If a panel isn't stiff enough I just fold the leather over on itself to double the thickness.  If that isn't an option, I use another leather material (it doesn't matter if it's suede, split, or whatever.  I don't use bonded leather because I wouldn't know where to buy it anyway).

You can also buy Cordura, polypropylene or nylon (like they make backpacks and their straps from) or even cotton canvas. A layer glued between layers of leather will stiffen it somewhat, as well as preventing stretch. 

If you want to use foam (the lightweight option), then you probably want to use EVA foam.  This is what they make flipflops from.  EVA is sold, among other places, at places that supply shoe repair materials.  This comes in thickness down to about 1/16th of an inch, but 1/8 inch thick (called "6 iron" for this foam) is much easier to find.  A 16x24 sheet should cost about $11.  This foam is compatible with other materials used in shoes, such as leather, cork, etc., and can be glued or sanded.

EVA foam comes in various densities: regular, extra firm, and light aka cloud. Regular would serve for nearly everything unless you were making hardsided briefcases (which often have wood in them).

They also sell leatherboard, which is recycled leather glued together like bologna.  That is the MDF equivalent of leather.  I don't avoid it, but EVA is cheaper.

If 1/8 inch is too thick, then I would look for cheapo cutting boards from discount stores that are a hard plastic.  They don't glue easily but you can glue the leather all around them and have the stiffener held in place that way.