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Hello to eveybody!!
I am María, a new user of this intresting site. I don't really know yet how this works, although I think that I am getting there, am I not Charlotte?
I would like to ask all of you a few questions in case you could help me...
I have been asked to make a huge word globe. My boss has thought that it would be great to cover a whole polystyrene ball with papier machè in order to get an earthy surface. Has anyone ever tried to do so? Do you think I should cover that ball first with newspaper strips before putting the papier machè? and last but not least, which kind of paint do you think would be the best in order to get a perfect finish?
Thank you very much for all your future proposals!!!
maría.
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I haven't actually worked on polystyrene but I think the principles that apply to other mediums will work here. It would be sensible to try out this method on something smaller first.
Adhesion will be very important. A coat of diluted (50-50) PVA (white glue) over the whole ball will help give a grip to the next layer. Then a layer of newspaper pieces laid smoothly, with a paste with a higher PVA content than usual (say 50%). That will then give a good working base. Bear in mind that anything you lay on top that has a water content will leach into the base layer so avoid having any more water than you have to.
What you do next rather depends on what level of relief structure you want to have. A fine pulp mix (see Martin Favreau's article on mixes) can be worked to as little as 1mm thickness. Tell us what you have in mind and several people will be able to offer good ideas.
Good luck
DavidO
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Dear Marieta,
like David, I have never actually tried to PM over polystyrene, although I gather it is pretty easy to do and is a very good armature. David's idea of doing a test piece first is a good one.
From what I know of it, polystyrene is not hydroscopic (water absorbing) so it is definitely a good idea to key the surface with pva solution first. I think I would also be inclined to use toilet roll / kitchen paper as the first layer, rather than torn newspaper. You ought to get a more smooth globe that way. For the pulp layer use the a fine finishing pulp, tissue paper mix rather than newspaper.
Half a toilet roll will give you about a fist sized lump of pulp: Rip the paper into very small pieces and soak, then make a soup of this using a hand blender or liquidiser. Squeeze out all of the water, I do this by tipping the soup of water and paper into an old stocking and then squeezing it hard until no more water comes out. Break up the damp mass of pulp into bits and if still quite wet, allow to dry over night, laying it out on a tea towel will do.
Then knead into the pulp your glue of choice, I prefer wallpaper paste and a tablespoon or so of ground chalk, you should have a clay like consistency when you have finished. This is then ready to layer and mould onto your globe. You may get cracks in the surface as it dries but these can be filled in with more pulp.
Good luck, post a picture when you have finished.
Charlotte
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Hi everybody!! and thank you very much for your quick and helpful answers David&Charlotte!!
Here I am again in order to tell you my findings but first of all I think that I should tell you more about my project. I have been asked to cover a 2metres diameter polystyrene ball with PM in order to make a replica of the Earth. I have to carry out this job here in Spain with a group of 15 kids at a time from all over the world... isn't it a challenging project??!! Believe it or not, I have never worked before with PM... that is why I am part of this forum now!!!!!
Now I feel like starting comment on your proposals!
- As you suggested David, I am trying small polystyrene balls for my experiments before giving the big step. Thanks!
- Just as you said Charlotte, polystyrene is not a water absorbing material;
- I wanted to let you know that PM sticks really really well on this kind of surface, without adding any extra glue.
- I must try to use toilet paper or kitchen role to get a more smooth and ligther globe, since newspaper it is very heavy for a globe with such dimensions. It could even be dangerous!
- Just to let you know that I have also been trying a kind of PM that is already made (special for kids) which is lighter- I can get really thin layers- and better when working with kids.
- David, you were asking for the level of relief structure that I want to have. I would like to have a general fine layer although I would like the main world mountainous chains to be highlighted!!
Last but not least, I don't have a clue about which kind of painting would be the best one (bear in mind that kids have to use it)... how do you get that shining surface on your pieces? it is just amazing!!
Again, thank you very much for your proposalS. Without them, this wouldn't work...
CompARTE
(I love this word which means to share, and "arte" obviously means art, so... LET'S SHARE ART!!!!
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What a fantastic project, how old are the kids you are working with?
I am just nearing the end of a project with a group of 7-8 year olds and we have run into the problems with paint. They have used poster paint, the classic school powder paint mixed with water, This is ok, but it does crack and is water soluble after application.
Personally I prefer acrylic as it is still water soluble when wet but has a level of flexibility when dry, it can still crack but they are tiny cracks. I have tried to use a 50/50 solution of pva and water with powdered paint mix. This is ok but leaves a gloss finish.
The only problem I have with children and acrylic is that they can be guaranteed to get it on their clothes (I firmly believe that even if you wrapped all of them in a plastic covering they would find a way to smear paint on their clothes, it is the nature of children and dirt, they are mutually attracted). It is impossible to get acrylic out of cloths.
I would have a word with a local model maker and see what they think. Alternatively message Jackie, the sites founder, I am fairly certain that she has worked on big projects with schools.
Best of luck,
Charlotte
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DeART Charlotte,
Thank you very much again for your words!!
After having a talk with my boss and some other members of the group, we have decided to use finger painting, do you know which kind of painting I am talking about? I know that it doesn't leave a gloss finish but, at least, I will be sure that we won't have any problems with eternal stains on the clothes, and everybody will enjoy painting that huge globe (well, I hope so!!!). After having finished painting, myself and some other collegues will put some varnish on the globe in order to get that finish that I love!!
If you considered this option as wrong, please let me know! and if you talked to that local model maker tell me your findings, ok? . I have still time to change my mind !!
I am going to email Jackie rigth now!
Thank you very much in advanced,
maría.
Ps: the kids I will be working with are from 11 to 17... I know, there is a huge gap!! but we'll get there all together!
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Hi, I'm new on this site. I do basic papier mache with students (more or less adults but complete beginners and not 'arty-ly' (if you don't have a word, be creative!) inclined. We use pva and children's readimix paints, water based, and I have come to the conclusion that the cracking of the paint is related to the use of pva. Sometimes its more noticable than other times, I think when there is too much pva or it isn't diluted enough the problem is worse. I haven't tried pva and powder paint, its an interesting idea. I am coming round to the use of wallpaper type (fungicide free) paste and I think there is less bubbling and its easier to use.
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I agree with you about both of the above, the problem with mixing pva and poster paint is that the plastic and the water conflict and cause surface cracking. I find dying the pva with a powder reduces the cracking. Acrylics also have a tendency to crack over the surface. I suspect its conflicting drying times and different surface tensions are the root cause.
Where abouts are you? I work with children and ran foul of Health and Safety rules on glue with my pm projects. Was stuck with PVA as we are not allowed to expose the children to the fungicides in wall paper paste, and yet because flour and water grow mould in a hot classroom we are not allowed to use that either.
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Hi Newmodeller, what you are saying makes sense. I'm always a bit puzzed that some items craze and others dont, but we are not exactly working in a scientific way so its hard to know. I suppose I could do some test pieces...in my spare time :-)
I work with adults and young adults in a further education situation, some of them would be learning use of art materials etc to, in turn, use them with young children. They might be childcare or special needs assistants. I'm in Ireland and as we are also teaching health and safety we are the ones who have to decide what to use. There is a paste available similar to wallpaper paste but with no fungicide.
I've been playing with a polystyrene cutter this afternoon (research for a different class!) and cut out some nice fine letter shapes, so now I will paper mache them and see how they work. Such a trial!! :-)
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