old canvases

[arches]

As I am a newbie at plein air and am looking forward to failures, is there a way I can recycle old used canvases? Oil paints are very durable once dry. Can I gesso over them, paint over them or just start with new ones? If I were using the new water based oils I could just wash them off but I do not plan on using water base oils to paint outside. Perhaps this has been discussed before here and you might point me in the right direction. Thanks!! Donald O'Roark.

[dbclemons]

Hey, Don. "Looking forward to failures?" That's the spirit, lol! Painting over old oils is a topic that comes up often in the Oil section here. Search through that area and you should see several good bits of info. Here's one link:
http://www.wetcanvas.com/forums/showthread.php?t=246064

I think gesso might have adhesion problems on dried paint (definitely if acrylic gesso,) so a layer of white paint would be my recommendation. The dried water-mixable oils don't really just wash off after they've dried; you'd have to really scrub them down, most likely with solvent.

-DBC

[arches]

David, thanks for the link. I went there and got my question answered. What I meant about waterbased oils is that I guess they can be washed off while they are still wet, but what a mess that might make.Might work ok for quite small paintings if I could avoid water getting on the back of the canvas. Most likely better to let them dry. Don.

[Donald_Smith]

Oven cleaner will remove oil paints from canvas. I don't know how it will affect the longivity of the next painting.

Don

[jimb]

Here's my 2 cents.
I wouldn't even bother painting on canvas unless I was pretty sure that I had the skills to consistently make "Keepers". Use panels made of masonite cut to the size that you want. Give them a coat of gesso on both sides (or even acrylic primer if you wish) paint as much and as often as you can, and if you do get lucky and make a "keeper" it will be on something that is archivally sound. If not, scrape and/or sand off the "mistakes" and start again, or toss the panel. You won't have that much invested in it anyway.
The way to learn is paint, paint, paint, and then paint some more. The above is a good way to make that afforadable while still using good methods.
Not everyone will share my opinion, and I have been in trouble with the art police before, but this makes sense to me.

[arches]

Jim, would you use treated or untreated masonite? I have heard that untreated is somewhat unstable. How can you add a bit of "tooth" to the finish? Thanks! Don.

[jimb]

Actually, that's not too much of an issue these days. Masonite (trade name Duron) is actually pretty hard to come by now. When you could find it in hardware stores it did come impregnated with oil and without (some folks called it tempered and untempered. Most of the stuff found in hardware stores and is commonly called masonite, is not. It is just plain old hardboard. That stuff is just fine and it is stable. Do not confuse it with MDF which is medium density fiberboard. That stuff is not good but you should be able to recognize it easily since it is not nearly as dense as hardboard. Go to the "handy panel" section of the hardware store and you should easily find what you need. If you want a bit of tooth you can put put some pumice or marble dust in your gesso and that will usually give you what most people are happy with.
You can also use plywood panels if you are afraid of the hardboard (no need to be though, LOTS of people paint on them). But you can find 1/4 inch or 3/16 plywood that has an excellent finish on one side and cut those up too. People have been painting on boards or panels for hundreds of years.
In the old days people gave their boards a bit of tooth using real gesso (rabbit skin glue and marble dust). Those surfaces go all the way back to the Renaissance.

My point is that if do a lousy painting (and we all do them) you can scrape, sand, and reuse them, or if they are too far gone, just chuck them. No big loss because they are so cheap.
BUT... if you luck out and your painting really comes together...then you have it on a surface that is sound and readly accepted as a standard surface by the art world. A win-win.

[arches]

Thanks Jim! I do appreciate it. Don.

[dbclemons]

This site has good information about hardboard and fiberboard:
http://www.hudsonhighland.com/woodglossary.htm

I use untempered harboards a lot, and occasionally MDF or birch panels.

-David

[Lorijo]

I like hardboard too, its much stronger than canvas. Down here in Florida the canvas can get mildew on it and it gets even more fragile. I have gotten a few commissions to repair canvas paintings that had holes poked in them and paint flaking off from getting flexed. Lori