You are not logged in.
Those following the slime thread have heard about my adventures with percol, the amazing (probably in a good way) additive used extensively in making paper.
I've got some general questions about papier mache and water that will help me judge my newest amazing experience more accurately and possibly avoid sounding even dumber when I find a paper industry professor or chemist to interrogate.
Does anybody ever mist the surface of almost done stuff with water? I never have so I don't know what ordinary water does.
So far, I've related about the pulp accidentally super charged with Percol that I kept tossing sheets of paper on top and the strips pasted with a more reasonable amount added to the water. (By super charged we're talking about less than a tablespoon added to 8 cups of water and paper shreds, and more reasonable amount possibly 1/16th of a teaspoon per cup of water.)
Last night, I spilled some of the thin paste on top of the paper sheets which had amalgamated into the pulp. The mass gets far smoother each time it comes into contact with any liquid with any Percol. I placed some more sheets on top of it to keep the dog hair off until I could worry about it but when I returned they looked as if I'd smoothed them out.
Meanwhile, the large (4 ft. x 2 ft.) surface pasted with strips had become by far the smoothest area I've ever pasted, and with much less work. One corner, however, which had suffered from a variety of attempts to replicate toilet paper tubes underneath (pulp, small amounts of spackle, etc.) its strip was crinkly and hard. I was about to either spackle it or pry it off, but I tried something that still amazes me.
I took about a teaspoon of the slime water and put it in an 8 oz. spray bottle, filled it with plain water and misted the corner. When I came back about half an hour later, the wrinkly hard paper had softened, smoothed itself and was almost dry (it's in the enclosed front porch with a large fan aimed at the surface.)
So I misted the entire surface and when I returned all seams, waves, high areas, etc. were gone and it had all smoothed out except one tiny crease and was drying so smooth it looked painted. Before misting it was almost dry enough to paint but I'd been giving it more fan time just to make sure. It was way too dry to be "workable".
It was so dramatic that it looked like someone had come it and redone it. The closest thing I can compare it to is having something rough like spread melted chocolate or the surface of spooned ice cream thaw and refreeze to become level and smooth. WITHOUT HUMAN INTERVENTION, except for the misting.
I know chemically how this could work--the Percol makes the water slither into the cellulose cells, taking with it the paste, and possibly rearrange the cells. But its also possible that plain water would have reliquified the paste enough to have the same effect (though it's hard to tell because the paste itself had some Percol in it). Aside from the Percol, the paste adhering the top strips was plain wallpaper paste and methylcellulose, which not being cooked cooked could conceivably reliquify with water alone. (That layer did not have PVA because I was tired of the slightly yellow effect of the carpenters' glue and when I went to the hardware store to get white glue it was cheaper to get a quart of polyurethane to seal the entire finish, which seemed like a nice idea. I think, however, that the absence of plastics in the paste allowed the reliquification at all despite any assistance from the Percol.)
The Percol in the mist was such a tiny quantity--less than 1/64th of a tablespoon per cup of water--that it may be the Percol in the paste drawing the water into the strips.
I'd really appreciate any observations about the behavior of paper and water, and dried paste and water. Someone wrote in an old post about whether dried wet paper shrinks and curls; I know that a common watercolor technique is getting the paper wet and drying it before painting, but it is taped at the edges to force it to dry flat.
My next experiment will be wetting an ordinary sheet with plain water and one with Percol water and letting them both dry by themselves. It would be great if somebody had some dishwasher "drying agent" (Jet), which is also a cationic/anionic agent and affects drying only by making the water "wetter", and could try the same thing with a little.
Offline
Ann,
Borax would act quite differently, I think. It's an alkali, and while it might soften the cellulose (soda ash and lye are used to break down wood and vegetable fibers in some paper-making processes) I do not think it would have the cationic/anionic effect of Percol. But I do vaguely remember something about borax and water from mineralogy, not chemistry or paper-making.
I am now wondering about what salt in paste does to water movement through paper cells and whether it hinders or helps. The reason you're not supposed to cook vegetables in salted water is that the water inside the vegetable cells, which contain vitamins, is attracted to the salt water outside the vegetable and leaves the cells, taking the vitamins with it. It is possible that salt in the paste outside the cellulose cells of the paper impedes the osmosis of water through the cell walls.
I saw the road-fill references and I haven't figured out how it would help, unless it makes the material more liquid or pervasive.
There must be some suppliers of paper-making materials there; see if they sell 'retention aid' and what kind. Craft-level papermaking books may discuss it.
Also it or something like it may be sold as a laboratory supply to aid filtration, and I'm growing more certain that electric dishwasher rinse aid liquid has similar promise.
I figured out an analogy that sort of explains how it works. A dry sponge doesn't absorb water nearly as well as a wet sponge. The cells of the sponge let water travel through them much more quickly once they're already wet. The Percol would vastly increase the attraction water has for the cellulose cells, kind of the way that drafts travel much more easily through badly fitting windows.
This may also explain why some paper works much better than others for paper mache. Aside from weight, sizing and coating, all of which are important, the more calcium carbonate has been added to the paper, the more Percol or equivalent it already has.
It's funny that while I was reading dozens of books about making paper, some very technical, I never really understood what a retention aid meant, and my eyes glazed over during the explanation of how the cellulose and water process works on the cell and molecular level. For handmade paper, it's pretty much enough to know that the fibres stick together and the water drops off. But now papier mache is letting me see it much more clearly.
Since the UK uses a lot more newsprint per capita than the U.S. I think it must be made there (used to work for a publishing co. that was owned by International Paper which was headquartered there). If so, Percol or something like it is available, we just need to figure out how.
Thank you for telling me it's interesting because I've been concerned about droning on, and whether it's too strange or whether it's been a papier mache ingredient for years and I just didn't know it.
Offline
I wonder what effect a water-based paint product would have on that material?
Sue
Offline
That's an interesting question, Sue. VERY interesting and I'm so glad you asked it before I dumped a bunch of water-based polyurethane over my fresh surface.
I was going to blythely answer you that it would depend on whether the papier mache was dried or not and that it might be strange if it were wet. It is supposed to help paper pulp absorb pigment, and I can see how it would. I was thinking earlier that it would be interesting to spatter or drip wet pigment on the wet mache surface.
But until you brought it up I'd just assumed smugly that the poly would seal everything in. It probably will, but I'll do the underside first (was going to do both sides anyway--the main thing I learned in woodworking was treat both sides with whatever finish because if they aren't equal the piece will warp...actually for reasons really similar to our current cellulose/water discussion.)
I'm guessing that if anything, the paper surface will draw the finish in. PVA glue is water based and although an outer layer of Percol paste without PVA doesn't seem to seep through an inner layer paper pasted with PVA, I haven't tried the reverse. I have used paste with PVA and Percol, I just left out the PVA for the top layer because I didn't want the color of the carpenter's glue.
If I have any problems I'll spray paint before I poly...but remember, a lot of paper does have Percol in it (though in microscopic quantities).
Offline