Coroplast?

[impressionist2]

As Dustin Hoffman found out in "The Graduate", the future is Plastics.

So, what do you plein airists think of coroplast as a support under canvas? That's the plastic version of corogated cardboard.

We used it for years in the sign industry and I believe, barring fire, it will still be undegradable one hundred years or more from now.

I ask because it's lightweight enough to carry several along on a plein aire trip and for a woman, no saws are required in the prepping. Simply score with a sharp razor and snap.

Have you used it? How would one apply canvas to coroplast? Or are you opposed to it?

Thanks

Renee

[jenrou]

One of the better known artists (Nechis or Engle?) uses coroplast as a board. I've meant to try it. I assume you would need to tape paper to board, or use big clips.

[walden]

I would think you would need to find a glue specifically designed (chemically) for use with plastics. The white Elmer's that I use to glue canvas to sanded masonite says that it is for use with porus (paper, cloth) and semi-porus (wood, pottery) materials. Other than that, I can't think of anything wrong with it.

[LarrySeiler]

I would think my method demo'ed here on WC of attaching canvas to board with acrylic medium would still work with this material, and being plastic in its own nature should be no problem.

Mainthing is, a support is a support. If at some future point the canvas loosened, it should not affect the work but would be re-appliable to another or different support. I can't imagine polymer finding its way into porous matter yielding its grip, but to another nonporous surface...that is an intriguing consideration.

Larry

[impressionist2]

Well, just for the heck of it, since I use coroplast all the time, to bull clip pastel paper to when doing a pastel portrait, I cut some of it up into 8" x 10" boards and used Elmers ( the only glue on hand at present) to adhere some fairly heavy primed canvas to the coroplast.

Seems to be holding for now after squeegeeing it flat with my pancake turner, and placing the big dictionary on top of it for a half hour.

As Larry said, one can always reglue it later to masonite or other wood if anything goes wrong with the coroplast. Nice part is I store a 4' x 8' sheet ( only costs $8. at the sign supplier) anywhere in the basement and it never bows.

I remember someone complaining about it ( possible on NAPPAP, Larry) but I think that it is more of a prejudice, as masonite and/or birch seems to be "worth" more than plastic. As opposed to it actually having non archival qualities.

Main advantage is it's light as a feather.

Renee

[LarrySeiler]

I think Kevin MacPherson, Renee...uses foam core board to adhere canvas to. Heck, don't get lighter than that stuff, and Kevin has worked up one heck of a reputation for his work too.

So, I wouldn't work up a tizzy over it by any means.

I'm a bit old fashion I guess...and something about birch veneer or wood just appeals to me. Its a bit more expensive, but quite light.

On the other hand, I use masonite or as some call it "hardboard" which at 1/8th thick is fairly light and about $10-$13 per 4' x 8' sheet.

Larry

[impressionist2]

Larry, I worked with both materials in the sign biz and if you lean on foam core with any kind of pressure you can fairly easily wind up with a dent that never comes out. Plus, old foam core looks dirty.

Coroplast looks the same four years later and has greater resistance to dents.

Minor points but something to think about.

Renee

[Wayne Gaudon]

What thickness are you using .. the 1/8 seems rather flimsy if you wanted to frame it.

[impressionist2]

Wayne,

This piece measures out 3/16 depth. I got it from a sign supplier.

It takes the pressure of the tense bullclips holding it in place on a wood panel with no problem. No dents.

In fact coroplast only bends if you apply pressure on the corduoroy seams. Feels like it could just float away, it's so light.

Big difference from it's weaker and more destructible cousin, foamcore.

I hope Ross gives it a thumbs up, though I am not counting on it.

Renee

[Wayne Gaudon]

I will try a different store .. looked at it in one but found it bends too easily .. IE .. the masonite is firm but the the coroplast bent like a bow so it would need a back support which would defeat the whole purpose.

[impressionist2]

Wayne, I posed this question to Ross Merrill the conservator for the National Gallery of Art . Now if he doesn't know, no-one does!I will post his reply.

I am not expecting a thumbs up on this support.

Most likely, I will be buying the Ray Mar panels starting soon.

Renee

[impressionist2]

Here's the response from Ross and no-one is more surprised than I am. Didn't expect such good reactions to coroplast except the part about the ribs imprinting on the canvas in time is worrisome. Renee

Ross wrote:

"


Dear Renee,

Coroplast is a first rate material. I have talked to the company and
although they do not recommend applications or procedures, the most
common
adhesive is a heat set adhesive such as hot glue. White glues such as
Elmers is mentioned in their website but there is not much information
about
application, etc. Thermoplastic conservation adhesives might be used but
the Coroplast is heat sensitive. In their website, Coroplast lists
turpentine action on the Coroplast sheet as "slight" which may also be a
cause for concern. There are two major drawbacks. The first is the
"flute"
shape of the valleys between the core structure. As a result, it has a
"washboard" surface conformation. Conservators are concerned that
over
time, this may impart the washboard conformation to the painting. Second
is
cost. It is hard to beat the price of 1/4" plywood. Coroplast has some
advantages since it is virtually inert and light weight. Some plein air
painters use Multimedia boards as a painting support taped to a Coroplast
backing.

Have you used Coroplast as a support? How have you prepared it?

One of the most stable canvas/panel supports is a composite support of
Sunbrella fabric attached to a Lucabond aluminum panel with a
thermoset
conservation adhesive. It is made by Museum Services Corporation in
Burnsville, MN at tele: 612 895-5199.

Ross Merrill
Chief of Conservation
National Gallery of Art
Washington, DC
20565
rmer@cais.com

[walden]

Good grief, Sunbrella? I have a whole bolt of that stuff in my closet that I bought to make a boat awning that I'm never going to get around to. Hehehe, NOW I know what I'm going to do with it . . .

[Wayne Gaudon]

Thanks Renee .. I was in the middle of posting this and we had a big power failure .. I haven't gotten out to find other sourses but as there are a few concerns I think I may rethink my usage on this one.
However, I do like to use wax paper taped to a board for a painting pallett as I don't have to clean the pallett when done. So, with that in mine, I may just get a 1/4 inch piece of this stuff as it will be lighter when used outside (where I have to hold my pallett in my hand) and it should be easy enough to glue a little handle to it's center so you end up with a nice light weight pallett that never needs cleaning.

Thanks,

[impressionist2]

Lisa, I don't even know what "sunbrella" fabric is! However, I will look into this panel and post what I find.

Wayne, I bought a 4' x 8' sheet of coroplast today. It was $6.99 and they cut it twice for free, so I could fit it into my car.

Coroplast is the company's name. That is why there is a big difference in quality in the product. Other inferior companies are Interpro and Stratocore.

I bought a 6yd. x 60 roll of medium weight canvas and a large bottle of Elmer's White Glue All. Each panel will probably average out at a very low cost, when put together.... and I will get a lot of panels out of that four by eight.

The company I buy from is S & F Supplies Inc. , 43 Engineers lane, Farmingdale, LI, NY, 11735

(631) 420-4400 They ship free on an order of $50. or more.

Renee