I have a final for class, and I am using foam board for it. It is due next Monday (the 6th).
I only have white foam board and for the purpose of the project, need it to be black. I was going to spray paint it, but now I'm reading that it's not good to do so?
How can I get the foam board from white to black? What paint would be best to use on this? Thanks.
I should add that buying black foam board is not an option. The only place that has it sells it for over $10 a sheet, and I'm going to need at least 5-6 of them.
The problem with paint on foam board is that it will usually warp the board. (it will bow, a little to a lot depending on the size of the board and how wet the paint is)
What are you using the board for? Is it backing for something else (used in a display), or is it going in the art work itself? If you are going to use it as a display backing, I would get a big sheet of black paper and wrap it around the front (tape on the back) or use double sided tape or spray mount (glue) on the back of the black paper to hold them together. But that won't work so well if you are going to cut it up to put into a art piece. (you would have to be very patient)
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If you are going to need 5 or 6 of them, then you are going to need at least 4 cans of spray paint or several jumbo sized bottles of black acrylic paint (if you are talking about 2.5' x 3' sheets of foam board or larger) because you will need at least two coats (probably will need 3) of paint on each board. Turning something from white to black takes a lot of paint, especially on super smooth paper like foam board.
If you don't care how much it warps but want it nice and black, then the cheapest thing to use is big bottles of poster paint. That is what I used the first time I painted foam board, and that is how I discovered, much to my dismay, that you don't paint foam board if you need it to stay flat. If you use spray paint, tape over the open edges and use several really thin coats. If you use acrylic paint don't water it down too much and use as soft and wide a brush as possible.
Covering it in big sheets of black paper, or buying black foam board are your only options if you need it to stay flat.
Why does powdered sugar mixed with sulfuric acid form a black foam?
Sugar is as mentionned by others a carbohydrate (in this case glucose).
The chemical formula of glucose is C6H12O6 (drawing it here is impossible but you may look up "Fisher notation" of saccharides (other name for sugars) to get an idea on how the atoms are connected.
Now let's talk sufluric acid for a moment.
Sulfuric acid is what you call a dessicant. It is a very powerfull water sponge. A lot of energy is formed when water is "absorbed" by sulfuric acid. This means sulfuric acid likes water a lot
In fact if you put a bit of sulfuric acid in water you can get the water to boil!
Now back to glucose (sugar) or C6H12O6. Another way to write this is C6(H2O)6.
So yes, in sulfuric acid, sugar can lose all its water to the acid and what is left of this "hydrate transfert" is wet acid and carbon
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