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Material for septum and darkslide in DIY holder - UK (not Garolite)

RogerHyam

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Oct 7, 2020
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139
Location
Edinburgh, Scotland
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4x5 Format
This is an old chestnut but I'm wondering if someone can help me out from a UK/EU perspective.

I'm thinking of a 4"x10" camera project with my own design of holders. I need a material for the septum (somewhat ridge) and dark slides. Most discussions talk about using garolite xx from McMasters. I can't see this stuff available in the UK or EU. I think it is a US trademark thing or possibly full of deadly chemicals!

What is the equivalent outside the US and where would I get it?

I'm looking at ordering ABS and PVC sheets off eBay shipped from China which look good but until I have them in hand I don't know.

I presume 1mm ABS sheets as stiffer and suitable for both septum and dark slides?

Any experience with this?
 
My first impulse would be to drive to my local hardware store and pick up some 1mm sheets of aluminum or sheet metal, then paint those matte black. The sheet metal will be sturdier but much heavier. The aluminum would warp more easily but could be laminated with some kind of plastic to make it a little less pliable.
 
Garolite is an umbrella term for fiberglass composite sheets. FR4 is probably the most common variety of it and is used for manufacturing printed circuit boards, G10 is afaik the same material without the flame retardants.

I don't know if there's an equivalent term in the UK but looking for epoxy glass laminate or phenolic glass laminate should get you pretty similar stuff.
 
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thinkbrown said:
FR4 is probably the most common variety of it and is used for manufacturing printer circuit boards
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Interesting thought! This makes it available copper-clad, which is perfectly opaque. I think >10" lengths should be available as well, although 100x160mm is a more common size. Should be available from any electronics components distributor and of course AliE.
 

I thought about aluminium but I'm trying to make it as light as possible and painting the septum would be an extra complexity. It is an option though.
 
They also make versions that use a black epoxy, though I'm uncertain how lightproof that is.
 

Ah copper clad! Looking at what was on offer I was thinking FP4 or possibly G10 but they all seemed translucent and painting would be a pain and unreliable.
 
thinkbrown said:
They also make versions that use a black epoxy, though I'm uncertain how lightproof that is.
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Yeah I saw one supplier on eBay but only one size and I'd be worried about how opaque of if they would be available if I went back for more.
 
I have spent ALL Sunday morning and 4 cups of coffee on this now! It is paralysis through analysis. I think I might order some black ABS and see how stiff and opaque it is. It seems to be readily available, cheap and light. The question is how stiff it is (@ 2mm for the septum) and opaque it is (@ 1mm for the slides). It will be a cheap mistake if it is a mistake and I'm sure I'll find some other use for the material.

Now outside for some fresh air - maybe with a camera in pocket.
 
A bit off-base but when I needed some 6x9 dark slides for holders missing them, I found some 4x5 dark slides at a good price and cut them down.
 
RogerHyam said:
Ah copper clad! Looking at what was on offer I was thinking FP4 or possibly G10 but they all seemed translucent and painting would be a pain and unreliable.
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The FP4 stuff should work fine. Btw, it comes in various thicknesses. Default is 1.6mm, but thinner is also available. I don't know about anything thicker, but I doubt you'd need that for this application.
Here's one I could quickly find on AliE for the 1.6mm material in a size that allows you to take 4x10" from it (sadly, at 200mm it's *just* too narrow to make two actual 4x10's): https://www.aliexpress.com/item/1735548546.html
 

Have you considered Plastikard, polystyrene sheet that modellers use to make things with? It's available in many thicknesses and in dense black (or white) and available from all good model shops. Not all is as good as a proprietary brand so beware some eBay plastic card can have blemishes, but these are the people who 'invented' it for modellers,

https://slatersplastikard.com/displayMenuInPage.php?mid=2
 

Ooh I'd forgotten about Plastikard. I remember it from the distant past - maybe modelling as a kid. I've got some ABS on order but I'll look into Plastikard as well. At least I should be able to go to a big model shop and check out what it looks and feels like.
 
Why do the darkslides need to be black? The ones in my horseman roll film backs are unpainted stainless steel, IIRC.
Thinking of making a dedicated slim single sided sheet film holder for my DIY camera (which I use with rollfilm holders with a sort of graflok interface), and am going to use thin model aircraft ply (which you can get from 0.5mm in thickness), or I might use laserboard (resin impregnated cardboard: https://lasersheets.nl/products/laserboard-vel ). Also for the darkslide, or if that is too rough and not strong enough use either aluminium or stainless sheet.
 
Well the ABS has arrived from China. It seems ideal. 1mm thick sheet for the dark slide is opaque to the lights I try to shine through it and also somewhat flexible. 2mm sheet is stiff enough to give rigidity to the holder although I may be able to use 1mm for that too. I'm printing the holder now. It's quite cheap material depending on source. It is quite light.

The proof of the pudding is in the tasting. I'll carry on with the project and see if I can get it to work.
 
Garolite (commonly G10 or FR4) is a high-pressure, thermoset plastic laminate made by stacking layers of fiberglass cloth soaked in epoxy resin and curing them under heat. Nothing trademarked about 'fiberglass' or 'epoxy', just the name itself. Any source of material combining fiberglass with epoxy or any other material that is opaque and structurally sufficiently rigid yet thin works.
 
G10 or FR4 is not inherently opaque, especially in 1mm, you can get PCB materials which are black, but often it is the solder mask which makes it fully opaque.
 
Sorry yes, copper clad FR4 is indeed fully opaque, and available in 1mm. 1.6mm is standard, 1.2mm also, and I thought 0.9 is the step below that, but it is 1mm.
 
You're right though; the unlaminated material is quite translucent and would require some kind of light proofing. For a dark slide or septum, I'd get the double sided stuff since that would eliminate any problems with light piping as well; this could otherwise be an issue if the slide is flipped over to denote the film has been exposed.
As tot thickness; the thinnest I have here is 0.6mm I think; double sided. I use it sometimes for small trinkets.
 
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