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Hello again fine people 
Is it advisable to seal a PM project prior to base coat painting? We're having a bit of trouble with the paper strips lifting when we apply a base coat of latex outdoor flat paint. Even tried acrylics (stuff used for painting cermanics). Any suggestions on what is wrong or how to prevent the PM from lifting?
**edit**
Guess I should add that these are flour/water paste, with strips of craft paper over cardboard forms.
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or perhaps you haven't boiled your flour/water.
I'd suggest you use wallpaper paste or CMC (75%) with PVA/white glue (25%). Paper strips thus glued should not lift at all, whatever paint you use.
DavidO 
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I don't like flour/water for strip PM for exactly this reason. I usually use white glue or wallpaper paste. The strips lay flatter and don't pull up as easily.
I always seal with generous coats of straight white glue or slightly diluted white glue anyway. This not only seals the piece but it makes it smoother by filling-in the imperfections in the surface. Plus you can sand it and prime it.
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Darn!! Our paste is boiled but perhaps we're not boiling it enough?
We're trying not to use chemicals like glues if we can help it, but seeing how we don't have an all natural paint... *sigh*
Anyone have suggestions on flour/water mix that won't peel up? We've tried some of the recipes on this site, so far everything peels to some degree when base painted.
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:shock: WOT are you doing? With flour, as long as the starch is released, it will be a strong glue. That only takes a moment at high heat.
Don't worry about the chemicals. Methylated hydroxide is produced from natural cellulose and is used in all sorts of products including foods and beauty treatments. PVA is non organic but, as far as I know, not dangerous in any way. I'm sure someone will let us know if it's not.
I have used latex (emulsion in UK) quite frequently and never had any peeling. (Scratches head in bewilderment . . . )
DavidO
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PVA is a plastic, so the main thing is not to try to dry it in an oven, as it does produce toxic fumes.
Sue
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heh Not sure what we are doing wrong to get the peeling. We've a flour/water recipe (boiled) from this site.
We put it on lighter than we used to since it was warping (that usually, not always works).
Then we put a base paint on... latex exterior flat base. I tried using a gloss spray seal, and a matte. Tried using acrylic (for ceramics).
No matter how we do it the paper in spots will peel (always the edges).
*shrug* I've taken to base painting then sanding it down, then painting again which nearly always works. *bangs head on wall* Guess will have to try some glue in there. :?
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heh The problem isn't lifting so much now as even the flattest item (dried) will warp and bubble and ripple when we try to base coat it. Or do anything to it. This happens with our newspaper and with our craft paper projects. Afraid to paint anything now.
I've tried a glue/water coating. Killz coating. A glossy spray varnish which when painted on, it ripples and bubbles too.
What the heck do people use to coat their projects with? I'm about to start running in circles here. 
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Out of curiosity has the paper you use for layering changed. I ran into problems with one form of newsprint (I found that different papers use different papermills and it really makes a difference). When I used the paper from our local free paper I ended up throwing out the finished items. The fibres where too loose to layer effectively without it tearing on application and the ink had so much oil in it that everything was grey and wouldn't dry properly.
May be it is not the glue but the density, stiffness, etc of the paper. Just a thought, hope it helps.
Charlotte
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Success! I managed to get a layer that peeled - not that I wanted to, but it was interesting.
1 I was using a heavier paper, a thicker, brown wrapping paper. It is rather like what those in the US know as red rosin.
2 I used a fairly thick paste of just wallpaper paste, smeared on to the paper.
When the piece was dry, I realised that some edges had not fully adhered. After a light sponging with water, in no time I had peeled every one off. If I had applied a water based paint, or even another paper layer, they would have lifted or even fallen off.
So . . I reverted to my wallpaper paste (or CMC) and PVA mix and all is well.
:idea: DavidO
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The water in the paint must get absorbed by the flour, which reconstitutes it back into liquid.
Well, THAT'S certainly something to know for future works!
Thank you, David!
Sue
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It might be the paper. The newsprint and craft paper we're using is recycled, used material. Which is exactly why we chose the material.
We'll try out some other pastes (non-flour) I guess, see if that helps. Failing, guess it's onto finding a new recycled source.
Any suggestions on sealing would be great. Projects are worthless if we can't stop them from absorbing seals/varnish/paint. Maybe if we yacht varnish it first then paint it. heh
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I've been experimenting with alternatives to traditional gesso (not fancying boiling rabbit skin size). I have found that paste and plaster of paris mixes can give a good ground for painting. I have experimented with wallpaper paste and PofP which is rubbery initially but dries to a good hard finish. This must be mixed carefully with a balloon whisk as it can be lumpy, the viscosity of the paste allows the Plaster to clump :cry:
I have to say that the best result I have so far acheived has been plaster of paris, pva and water mixed up to the consistency of thick double cream. Painted on to the finished article as some speed otherwise the hardener in the PofP makes it unworkable. Once dried this sands well, is not too heavy and makes a lovely surface for painting. Once varnished the finished piece is wonderfully tough and stands a lot of knocks.
I have used this on the dolls I make and they have withstood a three year old and a classroom full of 5 year olds so far
Best of luck
Charlotte.
Re the paper it is possible that your local recycling mill is bulking up it's recycled paper, I know that in the UK they often run out of recycling material.
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Thanks! We've plaster here and I bought some different craft paper. Now for a week or so of testing. 
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