Possible corrosion on rear standard of Graflex Speed Graphic. Cause and Remedy needed

polaroid_memories · Feb 4, 2022

Hi all,
Recently acquired a Speed Graphic from Roberts and when it arrived today I noticed some strange white, hard particles, marks, and clusters on the Graflok back.

Images are here (https://imgur.com/a/JCiUEBm)

My main concern is that this white stuff is stopping me from attaching my Polaroid back to the camera, as the white stuff is raised and not allowing the film back to sit flush, therefore affecting the ultimate film plane.

So how can I remove and clean such marks? Is it corrosion? If so, what caused it? And if it isn't, what was the cause? Is the rear standard of the Graflex made of aluminum?

Many thanks in advance.

monst · Feb 4, 2022

Looks like it would dust off with a stiff brush. Watch where it goes though.

Ian Grant · Feb 4, 2022

I'd remove the back and clean away the corrosion, and repaint it, there's two screws at the top, three at the bottom, and one under the screen holder. I use a chemical to treat the corrosion, then use paint filler, primer and finally black paints, one gives the crinkle finish.

Ian.

polaroid_memories · Feb 4, 2022

Ian Grant said:
I'd remove the back and clean away the corrosion, and repaint it, there's two screws at the top, three at the bottom, and one under the screen holder. I use a chemical to treat the corrosion, then use paint filler, primer and finally black paints, one gives the crinkle finish.

Ian.

Thats amazing advice! Thanks Ian!

Can I ask what particular chemical you use to treat that corrosion? Do you use an epoxy paint?

Ian Grant · Feb 4, 2022

I have some rust remover, however the frame is Aluminium, I use a Dremel and wire brush attachment to remove the worst corrosion, then I use Harpic or a similar lime scale remover, it works well on most metals and is cheap

All the paints are cans, except the filler which is in a tube, you fill any areas wait for it to dry and smooth with wet & dry paper. It's quite a quick job in the Summer but paints take longer to dry in the Winter.

Ian

shutterfinger · Feb 4, 2022

1. the back of crown/speed graphic cameras is MAGNESIUM.
2. soak/submerge the affected parts in CIDER VINEGAR foe 30 to 45 seconds.
3. wash with water!
4.proceed with painting as Ian suggests.

Ian Grant · Feb 5, 2022

The back is an alloy of Magnesium and Aluminium.

While I suggested Harpic, or a similar limescale remover, the alternative is vinegar, cider, white, malt, all work just as well, but I always add a little salt, this forms a very weak Hydrochloric acid solution, My recent experiences are that Harpic is very effective at removing oxidation, also it or an equivalent is a common household item.

Ian

Nicholas Lindan · Feb 5, 2022

Vinegar? Damn it, folks, this is a photography forum.

Use 28% acetic acid diluted 1:4 with water - 5.6%; a special stop bath just for Speed Graphics. Or use glacial diluted 1:15 in water resulting in a 6.2% solution.

Normal stop bath is 2%, vinegar is 4% to 18%.

Possible corrosion on rear standard of Graflex Speed Graphic. Cause and Remedy needed

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