Tips and techniques for replacing holder light trap?

[keithostertag]

I have several 5x7 film holders which need the felt light traps replaced. Could someone give me some tips on how to proceed?

These are old Kodak and Graflex wooden holders, so easy to access light traps by removing four screws.

The felt is wrapped around the brass spring material (along with a protective plastic? strip) then crimped by the tight fold of a metal strip. As you can see in the attached photo, when using a small flat head screwdriver to pry apart the fold I create small indentations in the metal. Hmm... that doesn't look like it will be easy to crimp back flat and tight.

What kind of tool(s) do you use to properly open and reseal this crimp/fold that holds the felt in place? Seems that if I don't pry the crimp apart and just pull the felt out then I won't be able to get the felt stuffed back up there... there must be some technique I'm not thinking about. I've seen several posts in the archives which suggest people see this as a common easy thing to do but don't state any type of tips or instruction.

Also, I've read that some folks use adhesive to glue the felt in place... if that's advisable, which type of adhesive is best? One person commented that some adhesives will off gas or leave an oily film that can possibly damage film.

Also, recommendations for exactly what type of felt and source for such? The original seems very thin to the types of felt I have and see in stores.

Thanks

Keith Ostertag

153456

[Tin Can]

108 people looked but no answer.

I think you will need to experiment and hopefully document your solution..

I gave up and did not repair the one ULF holder I dissected. It had major destruction from prior "super glue" repair. Looked like somebody poured glue in without disassembly.

Good luck!

[Jim C.]

There was a post in this forum a while back where a member found a replacement for the
the finger strips in the light trap, heck if I can even find the post here. I'll check and see
if I have the link to the supplier bookmarked at home.

In regards to prying the finger strips try using a long thin blade, with a screw driver you're applying prying force in one
point spot and if the metal is soft you'll get those dimples you need to spread out the prying force.
Working on focal plane shutters which have folded metal aperture stays, I used a dull boxcutter blade
and painters spatulas to pry the stays apart just enough to remove them off shutter fabric, the blade was just shy of the width of the aperture stay.
You can also just pull the felt out, it'll actually give you a larger groove to insert a tool to widen the fold enough to slip the new
felt back in.

[Jim C.]

Annoyed me that I didn't have it bookmarked at work, hammered on Google and it's called finger stock.
This is one link - http://www.omegashielding.com/

[Erik Larsen]

I've used the omega shielding products Jim referenced. There is a part # in this link
http://www.largeformatphotography.info/forum/showthread.php?114914-FS-11x14-holders-and-finger-stock-for-holder-light-traps

[Tin Can]

The only thing I can add is the finger stock on the holder I dissected used 2-1/2 pieces of what I think was 5" stock slightly over lapping to maker longer continuous "stock".

I still think Jo Anne fabrics may have good polyester felt.

[Jim C.]

I've used the omega shielding products Jim referenced. There is a part # in this link
http://www.largeformatphotography.info/forum/showthread.php?114914-FS-11x14-holders-and-finger-stock-for-holder-light-traps

You're the member I remembered posting the finger stock source !
:)

[keithostertag]

Thank you gentlemen for your assistance!

I was able to finally get to a Joann's Fabric store today. Looked through a lot of black material which I felt would not work- either not woven tight enough to be light-tight, too thick, not lint-free, or too stretchy.

Finally decided to try a Velvet Ribbon $5/yd, 100% nylon, 1.5" wide, stock #07865488. It is just a little thicker and wider than the original felt but otherwise seems like it will work. The original felt was 1 3/8 wide.

They also have something called Neo Emp Velveteen at $14.99/yd roll stock #01581974 (mostly cotton) which might work: I might try that as a fall back if the ribbon doesn't work.

It may take me a few weeks to get around to putting these together, but I will at that point report back.

Thanks to Jim C. for saying "You can also just pull the felt out, it'll actually give you a larger groove to insert a tool to widen the fold enough to slip the new
felt back in." which for some reason I hadn't thought of.

I don't need the fingerstock, but now at least I know what it is called in case I might need it in the future.

Keith Ostertag

[keithostertag]

Reporting back:

This velvet ribbon, in my opinion, will not work satisfactorily for use in the light trap. As soon as you cut it, it throws out a multitude of fragmented pieces! I suppose one could seal the cut with glue or maybe fingernail polish, but of course that would invite other problems. Also, it is too thick and is the wrong type of weave.

So, I'm still looking for a suitable material.

Keith Ostertag

[Jim C.]

McMaster-Carr has velvet fabric in .030" ( a hair under 1/32" ) thickness.