While in storage, some sort of greyish-white fungus attacked the metal Graflok back of my Crown Graphic 2x3. Tried to get rid of the fungus but nothing worked, so I ended up sanding the black paint off to expose the metal. Several years have gone by - while in storage the fungus returned. I thought I could just repaint the back. Do I need to worry about fungus re-growth? Any tips for repainting? The camera is in BEAUTIFUL condition otherwise.

Well, besides being in the wrong forum (should be in the Crown/Speed section), it doesn't sound like you've got a "fungus" problem.

If it the metal and not the bellows or glass, it's simple corrosion. I've had the same problem on many backs and they seem to suffer more than any other part. I solve the problem with a good wire brushing to remove as much as possible, then repaint the affected area with a good paint. Several coats applied with a brush and all seems well.

I would have guessed the backs were made of an aluminum alloy, but the corrosion looks more like it belongs to a magnesium alloy? Either way, I've had no problems with paint adhesion. Ordinary model enamel seems to work well as does auto paint touch-up. You can even get a wrinkle paint to match those surfaces. If it does come back, it just means your paint wasn't up to snuff or you didn't remove enough of the original corrosion.

Good luck with it...

Thanks RichS. (Sorry about posting in the wrong forum.)

I'm glad my problem is not as unique as I thought it was. I'm going to the local hardware shop for some black paint. Hope they have the wrinkle paint.

Your explanation makes sense, but I was wondering why corrosion would occur on a painted surface. I always assumed corrosion was like rust, which I thought requires exposure to air.

Well, if you think about it, there aren't any exposed unpainted surfaces. So if it's going to corrode, it'll be under the paint

Unfortunately, once the corrosion starts, it's usually impossible to tell the reason. I see it in the high traffic and contact areas. Normally it starts where the paint is damaged. Even the slightest scratch can allow it to start. Once started, it can creep under the paint and you don't know until a large spot flakes off. Luckily, it does seem to stay under control after a good wire brushing and new paint. I recommend a brass brush as steel does a lot of damage to surrounding paint. After it's all done, a coat of lemon Pledge helps protect it and seal out moisture and further damage, at least to a slight degree...

Get some reuseable silica gel paks and put in the case to control moisture, a catalyst of corrision.

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I would have guessed the backs were made of an aluminum alloy, but the corrosion looks more like it belongs to a magnesium alloy?

Magnesium indeed.