You are not logged in.
... you know, candy coated on the outside and chewy in the inside... years ago, a friend and I made an Egyptian paper mache relief on a 1 inch thick 8 ft. by 4 ft. plyboard. We used solid pulp and it took months and months to dry. We tried to use electric fans, 500 watts halogen lamps, hair dryers, and finally, as desperation sets in, I borrowed my grandfather's blow torch. We only got as far as the outer crust to force dry... thus the Mentos effect...
So for about a month it just stayed there in the middle of my friend's living room like three charred corpses... It was so heavy we couldn't lift it. My friend's Mom couldn't invite her friends in because of our project. It was about in the middle of the second month that we finally moved it standing upright against the living room wall, with a lot of help from friends and neighbors. We gave up any further attempt to force dry it and left it to dry by itself...
We kept the uneven charred finish and only used lacquer varnish (with a mahogany tint?) to seal it. It had an antique effect which is a bit creepy... I think I still have the negative somewhere, I took maybe a couple of lousy black & white photos... early evening, available light with an ASA 100 film without a tripod but I used a cable release on the shutter, I think I placed the camera on a coffee table or a stool and used a couple of books to hold it in place.
I've read here in the forum that Melf uses an oven to dry/laminate his pieces... I was just wondering if it could work on solid pulp... on what temperature and for how long?...
It was only recently that I used bunched up newspapers as the core to my pieces- tied with a string or copper wire to hold it in place. My early pieces I did layer by layer, some solid, but it tends to fall off or sag without the proper armature... wouldn't this be a problem, the metal or wooden armature if baked?...
I kinda got used to using solid pulp... yes, it takes aeons to dry, but I like the weight when a piece is finished... most of the people who have seen what I made were surprised when I tell them
it's papier mache. Most of them thought it was made of wood or resin, some even fiber glass.
Right now I have no access to an oven... still trying to do my homework with your help... I could ask the ceramicists and ceramic printers if they will accept a baking job in their high temp ovens... a managable size wouldn't be that difficult to package securely for the trip... but a big piece... never again!...
Offline
A good story!!! I bet it's still wet on the inside. Lots of lovely micro-organisms? Perhaps they will mutate and burst out some day. Aaaaaargh!!
A way round this is to use hollow containers as fill spaces.
Or - lay pulp in sheets in the sun and allow to dry. Break them up and stack them into the general shape you want, before finishing off with a pulp layer just moist enough to model. That way you get the best of both worlds - a pulp interior that is dry. Your mother might even invite her friends to see it . . . a conversation piece e.g. "What the hell is THAT???"
:twisted:
DavidO
Offline
You don't want high temps to dry PM. I use the lowest oven setting my oven has, about 170F (77C) or so, I think. A ceramic kiln would incinerate your project, which seems pointless...
My first question about your Egyptian piece: what kind of adhesive did you use? Was it pva (white) glue, by chance? Especially on thicker pieces, pva glue tends to form a skin, and the inside stays moist. (Why do THOSE scenes from the move Alien come to mind?) One of the methylcellulose adhesives would probably be better for thick work, as it will eventually dry all the way through.
If I were going to make something that large, I would be tempted to try to do it in individual sections, weighted down on a thick board to dry flat, then attached afterwards.
I would not worry about a wire armature in the oven, unless it is lead, which melts at 158F (70C). Aluminum melts at 1218F (659C), and steel loses its strength at 1500F (816C) and melts at something like 2800F (1538C). Your PM would have turned to gas long before then.
A wooden armature wouldn't bother me much, either, if I were using temperature of 300F (149C) or less. When the surface of wood reaches about 212F (100C), the water in the wood starts to boil, then evaporates. If the temperature of the wood rose as high as 450F (232C), various gases are given off (carbon dioxide, carbon monoxide, acetic & formic acids), but the wood itself wouldn't actually start to burn until it reached about 540F (282C).
But by then, your PM would probably be fully engulfed in flames, as dry paper (we would assume it would be dry by now!) ignites at 451F (233C).
I would recommend temperatures of 200F (93C) or less. You just want to dry it, not cook it.
NEVER dry PM in an oven with plastic or styrofoam inside, as they both give off extremely toxic gases and your food would never taste the same again.
Sue
Offline
Thanks Dave, I will try your pulp in sheets tip when I make a fresh batch of pulp...
You're right Sue... I'll scrap my high temp oven option... so, for a piece about the size of a chicken- baked at 100 degrees Celsius for an hour and if I puncture holes on the papier mache for the heat to penetrate the inside... do you think it'll work? The punctures and crack I can fill later when it's dry... well, there's only one way to find out... I'll try on a smaller scale, maybe a fist size...
... Oh, about your question, no, I dont use PVA, I use cassava or corn starch (wondah powdah as Chef Yan calls it). Both cassava and corn starch are easily available here and they're cheap!... I buy it by the kilo for only a few clams... here's the recipe... if you're making a small piece, half a cup will do. Put it in a pyrex bowl and dissolve it with vinegar. Add the vinegar little by little, just enough to dissolve the starch. Stir with a spoon while adding vinegar. Check the bottom of the bowl for lumps, when there's none add hot water slowly while stirring... and viola!... it's like making gravy... The vinegar is to extend the shelf life for days, without vinegar it tends to spoil within a day... my Grandmother taught me...
What I like about starch (cheap!) is I can customize the mixture depending on the stage I'm in in doing a piece. For basic shapes/initial stage I use gooey to jello consistency. For finishing- a bit watery. It's only a question of how much water to add while making the glue... and yes, the movie Alien pops into mind while I'm preparing glue... I'm not familiar with methylcellulose though... did I spell it right?...
>Eric
Offline
... oh yeah, we used corn starch on the Egyptian relief...
>Ditto
Offline
That's an interesting question on vents to dry the inside of a hollow PM project... Inquiring minds want to know if a hollow object without vent holes will explode when warmed, or if enough moisture would be drawn out, fast enough, through the outer skin to prevent it. Hmmmmm.....
Sue
Offline
There is such way of drying of wood as vacuum.
Probably it is possible to hand make a vacuum dryer and to use it for PM drying.
Offline
... I have no appeal!... my wife wouldn't let me use her oven to try my experiment... she wouldn't even let me touch the toaster oven!... so I guess for now, my experiment is on hold... hmmm... maybe I'll sneak it in when she's not around...
Offline
Screeching, skidding 180-degree turn coming up!
I talked with a friend of mine, and she said she wouldn't have used vinegar at all with the mix, as it affects the starch you were using as your adhesive.
And she said she would just have put the piece in front of a fan at room temperature. She suspects the heat you used actually COOKED the surface and created a kind of vapor barrier.
Now that she pointed it out :oops: , it kind of makes sense, doesn't it?
Sue
Offline
... so David was right!... the Egyptian relief we did years ago is still wet inside... still haven't heard from my friend though if some strange creature burst out of King Mycerinus's and the two godesses' rib cage...
Hi sue!... thanks... vapor barrier... makes a lot of sense... how about if we put vents, puncture holes on the paper mache?... is it the acetic acid in the vinegar that affects the starch?... didn't seem to notice it... the only draw back I find is that after hours of modelling, my hands smell like vinegar... sort of marinated... doesn't PVA also contains acetic acid?...
Offline
8)
Vents and air holes sounds a good idea. Better still, open up a fist width channel and pull out some of the interior. If something inside nibbles your fingers, use a blowlamp on it!!
dopapier
Offline
David! You are advising to stick bare hands inside that thing without knowing what is inside??? Use a flashlight first! Watch for movement. Watch for tentacles....! :twisted:
And you might want to do it outdoors, too. There might be a di-stink-tive odor. :shock:
And let us know if there was anything scientifically interesting inside... like new life forms. 
Sue
Offline
Very funny guys... but this is a... a... a quandary!... in a quest for a quicker way of drying papier maches, I could be incubating unknowingly, some strange creatures contemporary science have never seen nor documented before... it could be a potential threat to life, limb and property... just think of the moral, ethical and scientific implications it connotes...
Doesn't all these sound like a potential plot for a scifi B movie?...
Hi Yura!... please tell me more about this vacuum drying thing... must cover all possibilties...
>Eric
Offline
NEVER dry PM in an oven with plastic or styrofoam inside, as they both give off extremely toxic gases and your food would never taste the same again.
Thanks for mentioning this Sue. I haven't dried my pieces in the oven yet, but since I will be making papier mache again soon - this is really good to know! I'd probably would have made that mistake if you hadn't of mentioned it. 
Offline
OHNOES... :shock: 
Should have read some more before I got started!
I have made some beads using solid pulp around pieces of thin plastic pipe, which I am hoping will stay in the beads to protect the holes as I eventually want to string them on tiger tail.
Will they dry right through? The pulp is only about 1/2in thick at the widest point on each bead, possibly a little less, so am I worried about nothing?
I just don't like the sound of "Mentos beads"...
Offline
I don't think you should have any problems. The original post was very large and thick, then they cooked a 'skin' onto it so it wouldn't dry. It probably would have dried without the skin sealing the moisture inside.
I think you're doing fine.
Sue
Offline
Sue's right... don't worry... the pieces I made are about 6 inches thick... it'll be completely dry in 2 days... .Eric
Offline
Thanks guys, I know that was a really noobish question but I've never worked with paper pulp before, so "AAARGH is it going to work?" moments will come thick and fast over the next few days, or so I imagine.
I must lurk a bit more and pick up some more tips...
Offline
Hi all
I have the full use of using my airing cupboard which is ideal for drying items. But failing that you could make a drying cupboard. You need one old wooden wardrobe a light bulb fitting normal bulb not halogen And fit in a few shelves making vent holes in them so the heat from the bulb rises.
I used to have one to ferment wine (He,He) never tried with pm but they do get really warm inside. I would also suggest having a smoke detector fitted above just incase.
Sue.
Offline
An airing/drying cupboard. I'd love to make myself one of those.
I am a little confused though. Could you please give me more details, snoozysnowshoes or point met a picture.
I do understand the smoke detector part though! *laughs*
Offline
O.K Here goes.
When i made my warming cupboard many moons ago I used an old wooden wardrobe. (free standing cupboard). Inside this i added a few extra shelves. But before i put them in i drilled large holes all the way along the back of the shelves. The holes were about 2-3cm across and the height between the shelves depends on what you want to dry. Then i got two lamp fittings attatched them to the inside base of the cupboard and the other ends were wired up to two seperate plugs ( you could just use two old lamps and put them inside).You just have to make sure that the bulb part of the lamp does Not touch any part of the wood :!: .
The bulbs if using two don't need to be more than 40 watts each and if only using one light 60 watt bulb is enough. I had a timer fitted to the plugs of the lights the sort you use when you go on holiday to turn things on and off.I set them to go off at night more of a safety thing than anything else. so long as your not opening the door every five minutes the heat rises off the bulbs through the holes in the shelves an slowly warms up the cupboard with the top of the cupboard being the warmest place.
I hope this will help and don't forget the smoke detector.
Offline
... great idea!... if I can only find a spot to build one... thanks.
Offline
heh Couldn't this be made with cardboard and pm? *looks around* Now where to put it..... Maybe I should build a new house--from PM!
Offline
Just incase you didn't read the ubove section only use the old style bulbs no halogen. Don't want the drying cupboard becoming the new fire place.
Sue.
PS about building it with pm it will burn just as good as the wood :shock:
Offline
"Maybe I should build a new house--from PM!"
No, too soggy in bad weather. But a lot of people are adding cement to pulped paper and making what they call papercrete homes: http://www.zianet.com/papercrete/
Sue
Offline