paper mache dilema!

The other night i decided since i have 87 feet of mountain to make i would go with paper mache over weaved cardboard,since it is pretty much free.Well i started on it with good results,then i noticed i still had a 5 gallon bucket of drywall spackle and decided to dilute it with water and go over all the paper mache to give it a good shell.This is where the problem comes in when it dried it is all cracked! where did i go wrong????? Thanks for the help.

 

sounds like you made the layer too thick..

I am also wondering if the dampness of the plaster, weakened the paper mache.

 

Sorry to tell you, where you went wrong was diluting the spackle with water. Most spackle is "use as is" and the mosture content is set so when it dries it comes out right. By adding the water, you thinned it out (you had less spackle per area, or more water per area) so when it dried, it tried to shrink back to it's original volume, which wasn't enough spackle for the area you covered....and the result is the cracks.

You may have also had a double whammy because the paper mache will suck up moisture from anything it comes in contact with, so it's possible you would've had cracking anyway when the paper mache caused the spackle to "over-dry".

 

Thanks for the replies. So what you are saying is i should leave it alone?

 

I have never tried this, but I would consider doing two things:
One: add another layer over the cracked layer using the stuff "full strength"

Or, or perhaps in addition to the first idea:

Paint over the cracked stuff with cheap earth/tan latex paint to seal it, and then trowel on another thin layer of the stuff.

As I type this, I'd be inclinded to do only the first thing and then see what happens.

Good luck and let us know how it turns out.

 

Putting another layer on to fill the cracks will proably work......but before you put the new layer on, wet everything down as much as possible.... the wetter you can get it, the less chance of the new layer cracking again when the existing layer sucks the moisture out of the new layer too quickly.

 

Dave's right about adding water to spackle,there's only so much "spackle" in there,adding water just screws it up.I'd also go with his idea of wetting everything,but I'd add one more small step..Put some water soluble glue in the water,probably at least 10% of the water volume.That will help anchor any loose spackle...Wet it enough that it can't absorb any more waters,but isn't dripping wet..