View Full Version : print drying screens---which finish?

John Kasaian
8-Nov-2003, 15:49

I've built some new drying screens. They are made from wood and will be screened with nylon window screen, but before I get to that, I want to give the wood a finish for protection. For esthetic reasons(does anyone else consider esthetics when building drying screens? lol!) I'd like to see the grain. What(for this poject) is the best among these four finishes: 1.Shellac, 2.Tung Oil, 3.Spar varnish or 4.a paint-thinner/linseed oil mix? Are there any other finishes I should consider? Thanks!

Mark Farnsworth
8-Nov-2003, 16:14
Polyurethane is probably the best for this application.

Witold Grabiec
8-Nov-2003, 16:17
John, I would first rule out any kind of oil. Simple reason being it will not evaporate completely and you could just touch the frame while putting your prints on it and ... you've got a nice fingerprinted example of your hours in the darkroom.

Since you seem to care about the aesthetics I will suggest varnish. Spar varnish is basically a generic name. While it implies quality, many times it's not. So get an Epifanes or Interlux Schooner. I've never used the Interlux brand alghough I've heard very good things about it. Epifanes brand is basically a standard in wooden boat restoration. Whichever brand you chose, the application is the key.

1. Wood must be dry and smooth.

2. Dust free for coating: vaccum it well and pass around with a lint-free damp rag (use varnish compatible thinner)

3. Dilute varnish half-and-half with compatible thinner and apply first coat. Let it dry.

4. You can try to sand this coat but it may seem tacky. If so, just apply the second coat with 10% higher varnish ratio. Let it dry.

5. Now you should be able to sand it nicely. Use only a very fine paper of around 400 grid (wetdry type is your choice here, just don't wet it) or steel wool 000. Either available at Wal-Mart or most hardware auto-parts stores.

6. Continue increasing varnish by 10% for each subsequent coat, always let it dry and sand before the next.

7. When you get to full strength you may want get an even finer paper like 600/800 and it would be best to apply at least two full strength coats.

This approach will give you a mirror finish that will last for a very long time. Fine wooden boats are dealt with this way. It's time consuming and never cheap, but results well worth the wait and effort.

Robert C. McColloch
8-Nov-2003, 18:18
Yes, I use Polyurethane. My screens look great after 4-years and four washings.

Kevin M Bourque
8-Nov-2003, 18:43
I'm normally not a big fan of urethane (plastic! yuk!), but it might be the best choice for this application. You'll never have to worry about getting them wet.

Ralph Barker
8-Nov-2003, 20:33
I agree with the polyurethane suggestion for durability in this application. With multiple coats, and sanding with 600 grit wet/dry (wet) in between, you can get a pretty nice, furniture-quality finish after three or four coats, or a utilitarian finish after two. If you don't like the high-gloss look, lightly rub it down with Rottenstone powder and oil in a rag.

John Cook
9-Nov-2003, 06:09
Polyurethane's major claim to fame is abrasion resistance. It is quite hard and brittle. If you plan to walk on your frames this is the best finish. Just for your information, the downside to poly is that it has little resistance to UV, so don't dry your prints in the sunlight or the polyurethane will begin to peel.

None of the oil finishes is good at resisting water. That's why coasters were invented.

Spar varnish is a soft flexible version of varnish, made to resist cracking when applied to wood which may swell and shrink because of exposure to water (like boats). This sounds like a description of print drying frames to me. Spar varnish is also highly resistant to UV but too soft to walk on without soft-soled boat shoes. ;0)

neil poulsen
9-Nov-2003, 11:02
It's also possible to build screens using the standard materials for making out door screens. It's pretty easy to do, and it can be done to any size specification.

John Kasaian
9-Nov-2003, 16:18
Witold & John,

You've built a convincing case for spar varnish. I'm doubt if my douglas fir 1x3s are figured enough to deserve a yacht finish, but I'll give it a shot. I'm sure Polyeurethane would work nicely too(actually, my old screens were finished in clear shellac, gave good service and still look pretty nice) This is going to be one of the winter projects, so (ho-hum) I'm not really pressed for time.(Besides, it would be good practice just in case I strike it big at the casinos in Carson City when I go over to see Jim Galli's exhibit at the Nevada State Library and I have to buy a yacht!) Thanks to you all!

Kevin Crisp
9-Nov-2003, 16:55
Marine spar varnish ("Man-O-War") would work well. I used this on a pine shelf on one end of my darkroom sink. After 8 years of being wet and having all kinds of b&w chemistry on it it still looks very nice. I would think it would be a lifetime finish on a drying screen.

John Cook
10-Nov-2003, 11:23
If you want really classy frames at low cost and little effort, use pre-cut artist's canvas stretcher strips. Really nice corner joinery. Here they are from Dick Blick:


If you really, really want to take the anal approach, Arrow T-50 staples come in Monel, an alloy which will not rust. Neat!