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what materials and methods would you use to fortify cardboard with a resin of some sort?

 In some of make your own halo suit of armor instructibles they briefly go over creating the armor from cardboard and an aqua resin although the description is not detailed enough to grasp. I am aiming to make sculptures out of this cardboard fortified with resin, does any one know how i would go about doing this?

marshon3 years ago
Have a look here, I used normal card to form the shapes and then painted on polyurethane resin used for fibreglass layup but without the matting. Simple two part mix, the card dosen't get soggy and the resin cures in around 12 minutes. I used one coat on the outside and two on the inside.
Most people add bondo to the outside, but I didn't I liked the angular look.

Stage one

Stage two

Finished
Glass cloth and Bondo?
Glass cloth is expensive, about 15 bucks a square meter.
sockless4 years ago
You could use polyurethane to do it, just paint it on with a brush, I'd recommend using corrugated cardboard and sandwiching 2 pieces together with the grains going opposite ways.
puregoldner (author) 4 years ago
good idea
however do u know if the cardboard would be very strong after a coat of the epoxy resin?
It'll probably be stronger.  A friend used this stuff on styrofoam to give it a glass appearance.
Grathio4 years ago
As mentioned, you'll want some kind of two-part epoxy resin.  Your local hardware store will be able to help you out.  I prefer stuff that mixes 1:1 since it's easier to get the mixture correct.  I've also found that it's pretty temperature sensitive.  If it's too cold it will take much longer to set.

You'll probably need to apply several coats to get noticeably improved strength.  Follow the instructions on the bottles, but usually give it 6 hours and a light sanding between coats. Since it's cardboard you want to be careful with the first coat that you don't turn the whole thing into a soggy mess, so try it out on some scrap first.  If the cardboard gets soggy I'd protect it with a couple coats of primer or gesso.  Apply it to all surfaces, even the back, for increased rigidity.

You'll get enough strength to prevent casual dings and dents, but don't fall down or you'll crack it.
Don't forget to make sure you keep parts in a form or hold to a shape. As the epoxy sets (or cures) it may shrink slightly, deforming the cardboard (don't ask how I know this).
puregoldner (author) 4 years ago
thank you for your good ideas
since cardboard has the potential to get soggy and dissintigrate would it be wise to use some other type of craft board like foam board?
onrust4 years ago
I'd use a 2 part epoxy resin.
I would brush on a good first coat because the only strength your going to get is as much that soaks in on the first coat.  ***use caution as the cardboard will get soft.***  If you need more strength add a coat of woven roving.    That you can get in different colors for your sculpture.
How about a polyurethane varnish ?
jeff-o4 years ago
Perhaps they're talking about pour-on epoxy resin.

Nasty stuff to use though.  It's definitely an outdoor activity, or an extremely well ventilated place!
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