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Shutter fabric "recoating" idea- need sanity check
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semihemi



Joined: 25 Oct 2003
Posts: 85
Location: Boston, MA

PostPosted: Sat Feb 27, 2010 2:50 am    Post subject: Reply with quote

Thanks, Ian - looking forward to the information.

Semi
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semihemi



Joined: 25 Oct 2003
Posts: 85
Location: Boston, MA

PostPosted: Wed Apr 28, 2010 4:21 am    Post subject: Reply with quote

Just checking in with an update on the shutter recoating project. In summary, let's call it a 'learning experience'. I now have a functional shutter with no flaking or pinholes. This is good. After quite some time in the rolled up position the rubber coating does not seem to be clinging to itself. Also good.

I used Plasti-Dip in the end. I spent some time on the phone with their tech support people, who reassured me that once it was thoroughly cured it would not be prone to self adhesion. They also mentioned that the carbon black loading was around 1%. Not ideal for this project but enough that I was willing to try it. The data sheet on the stuff calls out 70 durometer. Kinda soft - but not really all that soft. More on that later.

I experienced two major headaches, one of my own making. The other, I am not yet sure. Headache number one came after applying the first two coats of the Plasti-Dip (PD). I had been thinning the PD quite a bit for the first couple of coats. I was getting really good control of flow and thickness, but I was not building opacity as quickly as I had hoped. So I foolishly tried applying the stuff full strength. Major blunder! I way overshot my thickness target by around 0.003 inches. This is enough to upset the spacing of the curtain windows, so I had to go back in and strip off a couple of thousandths of the bloody PD. This cost a couple of hours at least. Very frustrating! But in the end I achieved a uniform, photo-opaque layer of PD over the entire curtain surface.

That's all for this installment. More to come soon.

Best,
Semi
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camz



Joined: 15 Apr 2004
Posts: 123
Location: Southern CA

PostPosted: Thu Apr 29, 2010 7:01 pm    Post subject: Reply with quote

Great! This parallels my own experienced with PlastiDip.

Are you using the spray or liquid?
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semihemi



Joined: 25 Oct 2003
Posts: 85
Location: Boston, MA

PostPosted: Fri Apr 30, 2010 2:50 am    Post subject: Reply with quote

That was liquid Plasti-Dip in the can. I was impressed with the stuff overall, but not for this application. There were a couple of other issues also. I am not sure of the genesis of a shrinkage problem that I encountered. Basically, after finishing the application of the PD, I noticed that the width of the curtain was less at the midpoint between the apertures than it was at the apertures themselves, which are of course held constant by the metal stays. I suspect the PD shrinks when it dries, as do many curing thermoplastics, but it is also possible that the nasty solvent that I used for the stripping step caused the fabric to shrink. I am leaning towards the PD as the most likely cause but I cannot be sure without further testing.

Above and beyond the possible shrinkage, there was a larger concern with the PD. In my opinion, at a 70 durometer, it is just a bit too stiff for the curtain work. Ideally the curtain should be built up to around .008 to .009 inches according to my experience. I thought that the PD curtain lacked suppleness at that thickness. I am guessing that something around a 40 durometer would be much closer to ideal. I think it is worth getting in touch with the PD folks to ask if there is a softer version available. They were very helpful on the phone so I think they are used to calls from fumes-crazed consumers such as myself!

There are some positive takeaways from the whole deal though, as follows.

1 - It is definitely possible to completely strip the old rubber from the curtain by way of a solvent dunk. Strypeeze and MEK both work swimmingly. The MEK was less aggressive against the paint on the stays themselves. In all cases remember that these solvents are really dangerous if handled without appropriate precautions.

2 - The stripped curtain retained its integrity. The fabric did not get brittle or lose its color. The metal stays did not react to the solvent or come loose. As mentioned above I did have a shrinkage issue, but I did not notice if it set in as a result of stripping or recoating. I am leaning strongly towards recoating but I cannot be sure right now.

3 - Even with the problems I ran into, I still ended up with a light-tight curtain that is not sloughing little bits of century-old, degraded rubber all over my negatives! That counts for a lot. If the PD was a bit more flexible, with a touch more opacity, then I think we would have a winner on our hands.

Bottom line, would I use the PD again for my next curtain project? No, not as it is. But having built curtains from scratch and having tried the recoating method, I feel that I would make one more try at recoating before walking away. The posts above regarding the fabric paint are very interesting. After looking at the info on www.goldenpaints.com it does look like some paints are very opaque. My gut instinct is that it would be nice to rubberize the paint a bit so I might play with that idea for my next effort. I think I will contact Golden Paints to ask the actual loading of carbon black in their black poster paint. If interesting, I may branch out from there.

Of course, this entire thread is predicated upon the notion that one's curtain is fundamentally sound, but suffers from crispy rubber. If your fabric is brittle, then you are faced with making a new curtain regardless.

Well, that's all from the front lines. Hope this has been of value to potential Graflex restorers.

Semi
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camz



Joined: 15 Apr 2004
Posts: 123
Location: Southern CA

PostPosted: Fri Apr 30, 2010 2:56 pm    Post subject: Reply with quote

Ultimately, the old fabric is going to fail. Personally, I'd rather invest my time and effort in building a new curtain. Are you using the Aki-Asahi material for a new curtain? And if so, which material do you use?
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Henry



Joined: 09 May 2001
Posts: 1439
Location: Allentown, Pennsylvania

PostPosted: Fri Apr 30, 2010 5:18 pm    Post subject: Reply with quote

Apologies for butting in here (I don't own a Speed and know nothing about them), I seem to remember older posts that discussed using changing bag cloth as shutter curtain material. Just a suggestion....
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semihemi



Joined: 25 Oct 2003
Posts: 85
Location: Boston, MA

PostPosted: Sat May 01, 2010 5:45 am    Post subject: Reply with quote

Hi Camz - I agree that ultimately the old fabric is going to fail. Some shutters do seem to have brittle or aged fabric. But some seem to be quite sound except for the rubber coating. Plus, the new rubber coating is a continuous matrix that will impregnate and reinforce the fabric. My gut sense is that a recoated shutter could last for many more years.

I heartily agree that a new shutter is best, but given a choice between a quick and easy recoating versus the laborious process of building a new curtain, I would choose the recoating. The key words are 'quick and easy'! The all-in effort for this first recoating experience was too much. I think it might have been easier to make a curtain. But I am going to give the recoat idea one more try at least.

I have used the Aki-Asahi (AA) material. At the time I made a bulk purchase from him I think there was only one type: rubber on one side, nylon-like silky material on the other, around .008 or .009 going from memory. The stuff is fabulous for sure. I have compared it to a few other materials and it seems to be the nicest, but I think other folks have successfully made curtains from other materials. Bert is the Master in this area!

The AA is expensive. I did find a bulk quantity of less costly material. It had the same opacity as the AA but not quite the same fine hand. It was just a bit thinner also. I don't have any experience with the latest AA materials, however. If you do it would be great to hear your impressions.

Best,
Semi


camz wrote:
Ultimately, the old fabric is going to fail. Personally, I'd rather invest my time and effort in building a new curtain. Are you using the Aki-Asahi material for a new curtain? And if so, which material do you use?
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semihemi



Joined: 25 Oct 2003
Posts: 85
Location: Boston, MA

PostPosted: Wed Oct 06, 2010 5:10 am    Post subject: Reply with quote

Hi Ian - Did you ever get a chance to identify the type of paint that you used. If it is available over here, then I would rather go right to it rather than trying to ID an equivalent.

Thanks,
Semi

IanG wrote:
Sorry the paint's in the UK, and I'm not back there for 3 or 4 weeks so I can't tell you the brand etc until then, but it has a very high pigment content and so worked perfectly.
If you'd seen the cloth of the Thornton Pickard shutter you wouldn't have believed it could be re-light proofed.
I'll post the details as soon as I can, I have 3 more shutters to rebuild and will be making new cutains this way.
Ian
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IanG



Joined: 04 Aug 2006
Posts: 57
Location: United Kingdom

PostPosted: Wed Oct 06, 2010 9:08 am    Post subject: Reply with quote

Yes, it was Reeves Acrylic artists paint, it's in 75ml and larger plastic tubes, it has a high colour density.

Ian
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45PSS



Joined: 28 Sep 2001
Posts: 3197
Location: Mid Peninsula, Ca.

PostPosted: Sun Mar 13, 2011 8:41 am    Post subject: Reply with quote

I am currently working on a 1915 Graflex 3A for another member. The curtain was reported as non moving. Upon inspection I found the curtain would move if pulled on while holding the M lever down. The curtain is as wrinkled as in Semi's picture on every solid section. Once the wind plate and tension plates were off the camera I was able to gently move the curtain from the lower to top roller and back. I coated the curtain fully with Pledge (yellow can) http://www.pledge.com/domore/ , rolling the curtain onto the top roller and letting it sit for 12+ hours. I was told by the owner that another repair person recommended Black Magic Tire Wet http://www.blackmagicshine.com/tire-wet.php to soften the rubber coating on the shutter curtains.
I next removed the curtain as it was now softer and could be handled without fear of it tearing or cracking in two, coated it again with Pledge, rolled it up in its normal curvature and let it set overnight (12+ hours), wiped it dry with cotton towels, and hung on a film drying line with wooden clothes pins top and bottom and allowed it to dry for 18+ hours.
Result: softer material but cracked rubber coating with a little flacking at the roller ends.
I purchased the Tire Wet and coated the curtain, rolled it up as before and allowed it to sit for 18+ hours, wiped it down with cotton towels, and hung to dry as before.
Result: more flexible rubber but still cracked and full of pin holes.
Next I painted the cloth(oops, I painted the cracked rubber side) side with Tulip Velveteen Black fabric paint https://www.ilovetocreate.com/shop/showproduct.aspx?ProductID=234&SEName=tulip-soft-paint , 1 oz size just covered it. (Matt Ebony should work also.) I used http://artusa.royalbrushstore.com/products/productdetail/part_number=RSET-E3/201.0.1.1 brushes.
Result: Light tight curtain.
Paint is currently curing although it is dry, package says to wait 72 hours before use.

More to follow.
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Last edited by 45PSS on Mon Mar 14, 2011 2:49 am; edited 2 times in total
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Sirius Glass



Joined: 06 Jun 2010
Posts: 123
Location: Southern California & Virginia

PostPosted: Sun Mar 13, 2011 3:13 pm    Post subject: Reply with quote

Semihemi and 45PSS, please keep up your work. It seems that you are the only two doing this valuable research.

Steve
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IanG



Joined: 04 Aug 2006
Posts: 57
Location: United Kingdom

PostPosted: Sun Mar 13, 2011 3:59 pm    Post subject: Update Reply with quote

I've restored 6 more shutters since last February and refined my shutter cloth significantly

There's 5 more shutters to restore when I get back to the UK later this month, the shutter cloths ready and waiting to take with me.

Essentially I've switched to a matt black acrylic paint, made and sold here in Turkey. This gives me a nicer finish and a more flexible cloth. I will need to find a UK equivalent.

It's proved to be far better once the shutter curtains are flaking to just make new ones. The flaking and cracking tends to weaken the fabric and removing the old coating doesn't help either.

I've tested the various cloths I've made, I also make bellows cloth, and if you add a second coat of acrylic on top a a dry layer it can pull off if cloths glued etc.

What's particularly important for shutter cloth is to really work the paint into the cloth and wipe off excess, doing this on both sides. Excess paint compromises the flexibility. I test the cloth as I paint it, coating the first side is enough to make itb light proof, doing the other side as well makes doubly sure

Now I've been using my restored shutters for some time I've begun restoring shutters for others. (Thornton Pickard not Graflex).

Ian
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45PSS



Joined: 28 Sep 2001
Posts: 3197
Location: Mid Peninsula, Ca.

PostPosted: Sun Mar 13, 2011 8:13 pm    Post subject: Reply with quote

Ian,
How do you make or reuse the metal aperture frames?
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IanG



Joined: 04 Aug 2006
Posts: 57
Location: United Kingdom

PostPosted: Sun Mar 13, 2011 9:18 pm    Post subject: Reply with quote

45PSS wrote:
Ian,
How do you make or reuse the metal aperture frames?


The shutters I restore use a thin meta strips, a few use bamboo, I either re-use the original, or when the shutter cloths missing use strips I cut from rigid plastic, I do it without thinking, I'd guess old Ice Cream cartons

Ian
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45PSS



Joined: 28 Sep 2001
Posts: 3197
Location: Mid Peninsula, Ca.

PostPosted: Mon Mar 14, 2011 1:04 am    Post subject: Reply with quote

How do you attach them to the shutter material?

I plan to check out Golden Acrylics Fluid Color at a local store soon.
http://www.goldenpaints.com/products/color/fluid/index.php
Candidates are fluid color Bone Black #2010, Carbon Black #2040, and Matt Fluid Carbon Black #2540 based on your suggestion.
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