lens board construction

[chris_4622]

I was wondering if anyone uses baltic birch plywood for lens boards. Any thoughts on the merits of this method would be appreciated.

[MIke Sherck]

Yes, I use it for lensboards for my old B&J 5x7. A local hobby shop carries it: it's reasonable in price, flat as a pancake, appears to strongly resist warping (especially after being primed & painted,) and is easy to work with. I use a coping saw to cut the hole for the lens to approximate size, then sand it smooth and to just the right diameter for the lens I intend to mount. Ditto for the light trap part, and then I glue them together and paint. Fast, cheap, and effective.

Mike S.

[Alan Davenport]

I assume you mean the nice aircraft plywood you can get at hobby stores? IMO there's nothing better. A lens board serves two purposes: it must mount the lens securely, and it must serve as part of the light trap where it mounts. Plywood is strong, lightweight and easy to machine. It readily accepts various finishes. Best of all, it's cheap and easy to find, so you can afford to do prototypes.

[Nick_3536]

I used something the local big box hardware store calls hard board for my last few boards. It's cheaper then plywood. Seems strong. Easy to cut with power tools but I'm not sure about hand tools. Light tight. Comes in both 1/8" and 1/4" thickness. Sheets range from 2'x2' to I think 4'x2'. Maybe bigger.

[Louie Powell]

I recently made a lens board for my Zone VI. Used 1/8" basswood for the outer layer - found it in 4" width in the hardwood section of a nearby lumber yard. Use 1/8" mahogany paneling for the inner layer. The paneling was a damaged scrap sheet used by that same lumberyard to protect the face of the sheet rock they delivered last year and from which I constructed my new darkroom. I thought about using only the plywood for both layers, but the basswood gave a cleaner edge.

I cut the opening in the face layer using a forstner bit - a 1/38" bit is almost perfect for a #0 shutter. The opening for the inner layer was made using a 2 1/2" hole saw. After cutting and sanding the two layers, I glued them together and then did some final trimming on the light trap with a box knife. Stained and varnished the outer layer, painted the inner layer with flat black paint.

[Ernest Purdum]

I agree that this is a very useful material. If you want a fancier finish, you can buy thin sheets (1/32" to 1/4") of mahogany and other woods at www.micromark.com. Sometimes these are also useful building up to the exact thickness you need. They glue easily to the plywood.

[chris_4622]

Thanks for the responses. I am grateful. I am getting ready to build a wood field 5 x 7 camera and I may be tapping you guys on the shoulder with some other questions.

[Mark Sawyer]

Hardwood flooring also makes nice lensboard material; it's tough, resists warping, reasonably priced, prefinished, and readily available. Not being a purist, I use Pergo, a sybthetic laminate with a wood finish.