Dealing with Dead Case Foam

[Gwhite]

Between my own pistols and those owned by the college where I coach, we've got over 50 pistol cases with foam glued into them. Over time, the foam first gets a little crunchy, then it begins to disintegrate into dust, and in some instances, it also gets sticky. I suspect a lot of the exact failure mode depends on amount & type of oil that may have been used on the pistols. At some point, the foam no longer provides any cushioning for the pistol, and it also leaves dust or bits of foam stuck to the guns.

The vast majority of the cases used by European gun makers come from Negrini in Italy. Walther (& Hammerlis built by Walther), Pardini, Steyr, Morini, MatchGuns, Benelli, FAS, etc. all use Negrini cases of one sort or another. Negrini uses a very strong rubbery glue to attach the foam into the cases. Over the years, I've tried various techniques to get the old adhesive out, which usually has enough foam stuck to it that trying to just cover it with new foam doesn't work very well. I've tried scraping it off, cutting it off, solvents & heat without much success.

I finally came up with an approach that works remarkably well that I thought I would share. The next time I do this, I will try to make a video, but I'll describe it as best I can now.

The adhesive is stretchy, but if you try to just pull it off, it will snap if it is stretched more than a centimeter or two. The secret is to pinch a piece of the adhesive and pull up slowly so it begins to peel off the inside of the case. Once it's up a finger width, pinch it with the fingers of the other hand, and continue pulling up slowly. Keep switching fingers/hands in the fashion, kind of going hand over hand, but on a smaller scale. The adhesive will come up in a black sticky mess, but it will come off, leaving almost no residue on the inside of the case. One you've got a ball the size of a large marble, it's usually best to break it off and get rid of it. The adhesive prefers to stick to itself and other objects more than fingers, but not by much. You can't just "throw" it away, you need to stick it to some sacrificial surface you can pitch.

Continue pinching & pulling along the zig zag pattern of glue until it's all up on one half of the case. Flip the case over and do the other half in the same manner. I did a Benelli case last night, and it took about 15 minutes a side.

Because I have a lot of the same sized cases to deal with, I've made cardboard templates for the case foam. You can use a sharp knife like a snap-blade cutter to cut the foam, but I have a hot wire foam cutter that makes it go very quickly. The one I have is a commercial one, but there are lots of plans on-line as well.

The foam I use is grey "egg crate" foam. It comes in various stiffnesses & thicknesses. You don't want it too thick, or too stiff, or you will have difficulty closing the case, possibly even breaking the hinges. The best foam I've found for the thinner hard plastic Benelli cases is "1 pound" density, and 1 1/2" thick (nested) from this outfit:

https://www.cameronpackaging.com/egg_crate_foam.html

For the thicker polypropylene cases used by almost everyone else, you can use slightly stiffer & thicker foam. This place has 1.3 lb density foam, in 1 1/2" thickness that works well:

https://www.foambymail.com/EC/eggcrate- ... -foam.html

Caution: The way the two companies measure thickness is different! Cameron measures the thickness of two pieces nested with each other, where Foam By Mail measures one piece from the back to the peaks. As a result, 1 1/2" thick foam from Foam By Mail is thicker than 1 1/2" thick from from Cameron.

If you find that the foam is still a little thick/tight in spots, you can cut the peaks off in that area, like where it presses against a grip. I cut the foam slightly oversized so it will stay in place in the case without glue. This makes it easy to replace, and I can store thin parts, patches & manuals under the foam.

[dulcmr-man]

Thank you for the tutorial, GWhite. This is what I like about this forum - lots of folks willing to share tips and tricks for the general good.

Dennis, aka Dulcmrman

[GaryN]

THANK YOU !!!
I have been wondering HOW to fix some of my cases where the foam is disintergrating to dust.

[Gwhite]

I've got one more Benelli case at the college that is getting pretty disgusting. When I tackle that, I'll try to take some pictures at least.

I'm not convinced the replacement foam I've found is as long lasting as whet Negrini uses, but at least once the glue is gone, it's SO much easier to replace. I've got a dwindling supply of pre-cut Benelli foam. Now that I know what weight & thickness I need, I may see if I can find some that is more chemical resistant.

[Wile E Coyote]

Another method to cut foam that works well is an electric knife.

[Rudi]

For the main part of my case, I use an inch thick EVA-50 foam. Egg box style foam on both sides just makes for too much compression on the foam and over time, it just looks bad. After a year, there isn't a mark on it, or even a tiny area of wear.
I laser cut mine, it results in clean and sharp lines, less pressure on the case and hinges especially with match grips since the pistol sits 2.5cm lower than before.. It also means the case can always be a little more organised with no chance of a magazine or tools rolling around on the pistol.
It's not for everyone, and I'll redo the design now that I've had it a year and put it in case thats not so wide.
Under the foam is a high quality 1cm thick blue yoga mat piece, which I also use on my workstation table.

[Gwhite]

Very nice! Do use a commercial laser cutting service, or do you have a laser of your own? Some places also cut foam with waterjets.

The EVA should hold up a lot better. The advantage of egg crate foam for the college pistols is that it doesn't care if the current shooter has an XXS grip or an XL grip. Over the course of a decade, that can change quite a bit. For my own pistols, a close fitting cut out foam liner would make more sense.

[Rudi]

This first one was done by a company in Haarlem with a laser, before I got my own 700x500mm bed 80W co2 laser, and I ran the next one myself.
It fits a medium Rink, and the original Large walnut is a little more snug. I did the vector layout for the cut myself, and you are welcome to the svg file any time. the EVA 50 is great, firm but has plenty of "squishiness" left. Has been very resistant to Remoil, Balistol and general grubbiness of the pistol and magazines.

[Gwhite]

I have access to a laser at the college "maker space", so I may play with this. The Benellis we have are all in the previous case version with the built in combination lock, which is thinner and a different shape. I assume you use a DXF file to drive the laser, which would give me a head start on all the other cases that are of the newer polypropylene design. If you could share that, I'd appreciate it!

Thanks!

[Rudi]

Sorry, I thought I had replied. I use lightburn to send all cuts/engraves to the laser, with it's own internal format, but you can of Course import and export dxf. I tend to work with SVG in general, for a little more compatibility with my other design software. I've attached an exported dxf as well as the SVG. This was for a case with internal dimensions (for the top of the main foam) of 440mm X 193mm so if you use the svg file in your design program, select everything, and scale the elements (locking the x and y) to a width of 440mm. Then you can design around the gun and magazine shapes with your own case size. I used the same outline to cut a 1cm piece for under the main foam.

Case-440x193mm.zip

(45.63 KiB) Downloaded 71 times

[Gwhite]

Thanks!

As promised, I made a (crude) video of the process of getting rid of the old foam & adhesive:

https://youtu.be/gXS6eC9ZLnw

At some point, I will also try to make DXF's available of the case outlines I use. All I have at the moment are the cardstock templates I made, so I'll have to measure and copy those into a CAD program. The older Benelli cases require two templates because the bottom is reinforced with a liner that also covers up the combination lock hardware.