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Old 29th Sep 2022, 9:34 am   #1
G6Tanuki
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Default Foam Rubber.

I have a couple of Halliburton flight cases which have served me well transporting and storing my cameras and lenses for more than three decades but the foam inserts are starting to break down and produce dust, which is very much a no-no around optical gear.

S
My question being, where to get replacement foam? The current stuff is grey but has a black layer on the top face which is sort of velvety to the touch rather than having the usual texture of foam Rubber.

Also, how do they cut out the holes in this stuff so cleanly? My attempts in the past using knives have always left a horrible jagged edge. Do they use a Laser or something??
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Old 29th Sep 2022, 12:49 pm   #2
The Philpott
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Default Re: Foam Rubber.

I would suggest expanded closed cell polythene (polyethylene). Relatively inert as far as i can tell, and easy to cut with a blade. I salvage bits of it whenever it comes my way.
Would need to shop around as on a cursory search i can only see bulk purchase, at high prices. (Polystyrene, of course, is virtually given away!)

Dave
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Old 29th Sep 2022, 1:53 pm   #3
Goldie99
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Default Re: Foam Rubber.

Your existing foam sounds like a fairly standard flexible open-celled Polyurethane foam, probably with an additional black velvety fabric layer glued to the top surface.

The flex. PU foam is typically produced in large semi-continuous blocks, ca. 2m wide by 10's of meters long, and post fabricated into a very wide range of products, including mattresses, furniture, packaging, etc. It's no different in essence to the foam blocks / sheets you'll often see for sale on market stalls, for cushions etc. The grey colour probably has no great significance, it just looks nice, and masks any foam discolouration from light / UV exposure. I'd be looking for a relatively high density (say 40 - 60kg/m3), high resilience (HR), grade flexible foam, with medium to high hardness.

Cutting flex. PU foam by hand can be a challenge especially when you move away from straight lines. For smaller circular holes up to ca. 1/2" I use gasket punches, for 1/4" up to ca. 1" I use freshly sharpened cork borers. I've not had to go above ca. 1", but for a camera lens diameter I'd be looking for something like a larger cork borer type tool, e.g., these leather tools, or something in that direction - you want to be cutting the foam with minimal distortion / compression of the foam (or maximum) during the cutting.

https://www.amazon.co.uk/Leather-Cut...82901373&psc=1

The more uneven foam distortion you have during cutting, the more distortion of the final cut surface, e.g., as a somewhat extreme example - these 'egg crate' foams, cut using only a straight knife blade... acoustic pyramid type foams are made in exactly the same way.

https://www.evilmadscientist.com/2014/egg-crate-foam/

As an alternative, you could also cut square lens slots, with the width of the square equal to the lens diameter, and then 'fill' the open 4 corner spaces with glued in triangular foam sections, for a nice snug fit. It wouldn't be as snug as a cylindrical hole, but done cleanly it wouldn't be far off..

For large scale production, the fabric cover may well have been pre-formed to the necessary shape. For one-off home production... a decent spray contact adhesive, and a thinnish fabric, probably pre-cut in several pieces, seems like a viable alternative.

Overall, it'll probably come down to how complicated the internal foam geometry is in terms of cut-outs, how many, depths, etc... a built-up layered approach could be better if it's more complicated.

Alan
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Old 30th Sep 2022, 8:01 am   #4
radiomobile
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Default Re: Foam Rubber.

A bandsaw with a fine metal blade works well. An electric carving knife is another possibility while for round holes a holesaw is very effective, the latter range from 10mm up to 75mm or greater. A piece of metal tube can also be used, first sharpen the edges and file a few notches in the end.
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Old 30th Sep 2022, 5:03 pm   #5
G6Tanuki
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Default Re: Foam Rubber.

Update :: a friend whose business is running photo-safaris [lucky toad!] has pointed me at his pet suppliers of camera transit cases. They have Peli cases at a good price and will cut the foam inserts for you if you tell them the camera bodies and lenses you want to fit inside.

Their laser cut foam inserts look vastly more professional than I think I could achieve..
And he can get me his personal discount along with a VAT offset.

So the old Halliburton cases will be sidelined and probably used to store valves in the bottom of one of the two filing cabinets which I allow myself as a components store. I can hack up some plywood separators to ensure optimum space efficiency.
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Old 30th Sep 2022, 6:22 pm   #6
Goldie99
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Default Re: Foam Rubber.

That sounds like a result
Pricier, but far better quality and finish than is likely by hand.
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Old 1st Oct 2022, 12:16 pm   #7
G6Tanuki
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Default Re: Foam Rubber.

It was a pragmatic solution, I feared that if I had tried to cut the foam inserts myself the results would have looked like they were done by a blindfolded badger using a spoon.

At least reworking the foam in the Halliburton cases to store my stash of 5B/255Ms and 6146s and 811As doesn't need to be elegant.
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