An Experiment on Waterproofing Paper Mâché

Soaking in a bowl of water for three hours.

Humidity and outdoor exposure can cause paper mâché to weaken and paint to fade.  Spar varnish and exterior paint can help prevent, but not completely eliminate the problem of fading.  Spar varnish will also prevent some water damage.  But if water finds a way to seep in, the item may still be at risk of water damage to the paper and flour paste.  Mold or disintegration of the paper can result from water infiltration. I was looking at some products that might help prevent the problem.

 

                                                           Removing the foam ball.

 This year I have been experimenting with different types of mixtures for paper mâché mixtures.  Rather than mixing flour and water to spread on the newspaper, I decided to try some other liquids in my mix.  For this experiment, I was using some thin-set mortar ad mix with the flour.  I use this product when mixing grout for my stained glass gazing balls.  It is a form of liquid latex.  My goal was to permeate the paper with the product so that water would not affect the paper.  

                                                 When dry, the ball is still intact.

Please note:  If you replicate this experiment, you should wear proper skin and eye protection and have proper ventilation.  

I mixed together all-purpose flour and the thin-set mortar ad mix.  No water was added to the mix.  I don't generally use a set recipe because I find that flour will hold different amounts of liquid depending on humidity.  I just add liquid and stir until the mixture becomes smooth, with no (or very few) lumps.  If the mixture is hard to spread and lumpy, there is too much flour.  The solution is to add more liquid.  If the solution saturates the paper causing it to rip easily or slip, it is too thin.  The solution: add more flour.  If you work with paper mâché often, you will know a proper mix when you see it.

For this experiment, I covered a Styrofoam ball with plastic wrap, then covered the ball in three layers of  the thin-set/flour paper mâché mixture, letting each layer dry before adding the next.  When the ball was thoroughly dry, I cut the ball open in four quadrants and removed the foam ball and plastic.  After that, I put the four pieces of the  paper mâché back together using hot glue to form a hollow ball.  Then three more layers of the paper and thin-set/flour mixture.  When the ball was dry, it was time to see if it would hold up when saturated with water.  No other sealer was added to the ball.

In the picture, you will note that this foam ball has seen better days.  It has been used in four projects so far.  I try to make as much use of my materials as possible.  In this day of Covid-19, I don't want to have to be out and about looking for supplies or paying exorbitant prices from internet sites.   I tend to reuse my recycle until it screams.

I held the reconstructed ball under running water to make sure it was thoroughly wet.  Then I placed it in a container of water for three hours.  At three hours, the ball was completely intact. When dry, all of the edges of the pieces of paper were still tightly adhered to the ball.  

In conclusion, three hours does not definitely prove that the thin-set admix completely and permanently protects an item.  However, it show that the item will last much longer than if this were just a flour and water mix.  Once painted and sealed with spar varnish, it should add some length to the time that a   paper mâché item will survive in extreme conditions.

I blogged about a different product used for waterproofing earlier this year.  The article was published on July 20th, 2020.    If you are interested, you can read the article at folkartbycaroljones.blogspot.com.

More Pumpkin Projects

 Updated only affects title

Sorry about the picture placement.  This new blog platform will not let me move the pictures around.  I must say it has ruined the blogging experience for me.

Although I have not posted in a while, I have been busy working on my pumpkin projects.  Since Iposted the last picture of a pumpkin in October, I have worked on four different projects.  These projects take a lot of time, and progress has been slow.  Today, I will be writing about one of the more successful projects. 

I have looked at magazine Halloween pictures of yards covered in carved pumpkins.  They look spectacular.  A yard full of pumpkins is also extremely expensive.  Perhaps they get a discount for buying a truckload of pumpkins.  I would like to do a project with a yard full of pumpkins, but alas, even if I could rationalize buying that many pumpkins, I would not have enough interested friends to help me carve them in a timely manner.

My thoughts turned to using the foam pumpkins.  I could work on them all year.  I could use them for multiple years.  However, the foam pumpkins are incredibly expensive.  The craft store near my home was selling them at thirty dollars each for the small ones.  A few dozen of them is out of the question.  

Undeterred, I move to the next thought about making the pumpkins myself from paper mâché.  I have made two pumpkins from a form I made myself.  This form was made from plastic bags stuffed inside a plastic grocery bag, and then filled out with tubes of newspaper to give it more of a pumpkin shape.  That actually worked, but the pumpkins did not have a real pumpkin shape.  I decided that when pumpkins were available, I would purchase one and I could cover it in paper mâché. 

In the fall, we masked up and went to the farmers market.  We did not stay long.  I pretty much had to grab the first pumpkin I saw that had a nice area for carving.  We did not want to stay long in an area with people in it due to the Corona Virus.  I wish I had more time to hunt for the perfect pumpkin, because this pumpkin was a little large.  I would have preferred something a little smaller.  

So I brought home the pumpkin and covered it in three layers of paper mâché.  The pumpkin was heavy, and I could only work on half the pumpkin at a time.  Also, I had hoped to use this pumpkin for a second project, so I used Vaseline to cover the entire pumpkin before I started adding the paper layers.  My first layer of paper was just paper soaked in water.  That helped insure that the paper mâché would not stick to the pumpkin.   Once the first half had dried, I turned it over and did the second side.  

Using a layer of paper soaked with water is a little more tedious than other methods I normally use.  I would add a little water and paper to an area, then go back and layer on some paper with flour paste.  

This was not just an ordinary flour paste.  I was also trying something experimental with the flour mix.  I am not totally sure that this was worth the effort, but I wanted to make sure that the flour paste was water proof.  Instead of mixing flour and water, I used thin-set mortar add mix as the liquid.  This is a form of liquid latex.  In theory, it should make the pumpkin imperious to water.  (I will be blogging about the experiment to check for waterproofing in my next post.)

Once the pumpkin had on three layers of paper mâché, I cut the layers off of the pumpkin using a craft knife.  I ended up cutting it off in quarters.  I had marked it for eighths, but it came off easily in quarters.  There was not enough flex in the paper mâché to take it off in halves.  The trick is to ease it off so that there are no rips and tears in the layers.  (Or at least as few as possible.)  Another trick is to cut some notches as you take it off.  The pumpkin will go back much more easily if you have the notches as a guide.  

Marking some registration marks is a must.  After you get the thing apart, putting it back together without knowing which piece was next to which piece can take up a lot of time.  I usually mark the quarters on each side of the edges using either numbers or the alphabet.  It really took the guess work out of things.

Once the layers have been removed from the pumpkin, I put it back together using a hot glue gun.  I start with two adjoining pieces and glue them top and bottom to make sure the edges meet properly.  Then I continue gluing the edges and notches until the whole seam is glued back together.  I usually glue each half half, then the other two pieces to create a half.  Then I cover those joins in a couple of layers of paper mâché.  It is easier to do at least those two seams while the pumpkin is still open and easy to reach.  Then, I glue the two halves of the pumpkin together.  There are still two seams that have to be covered on the inside.  Cover them, then cover all the seams on the outside.

Once the pumpkin had on three layers of paper mâché, I cut the layers off of the pumpkin using a craft knife.  I ended up cutting it off in quarters.  I had marked it for eighths, but it came off easily in quarters.  There was not enough flex in the paper mâché to take it off in halves.  The trick is to ease it off so that there are no rips and tears in the layers.  (Or at least as few as possible.)  Another trick is to cut some notches as you take it off.  The pumpkin will go back much more easily if you have the notches as a guide.  

Marking some registration marks is a must.  After you get the thing apart, putting it back together without knowing which piece was next to which piece can take up a lot of time.  I usually mark the quarters on each side of the edges using either numbers or the alphabet.  It really took the guess work out of things.

Once the layers have been removed from the pumpkin, I put it back together using a hot glue gun.  I start with two adjoining pieces and glue them top and bottom to make sure the edges meet properly.  Then I continue gluing the edges and notches until the whole seam is glued back together.  I usually glue each half half, then the other two pieces to create a half.  Then I cover those joins in a couple of layers of paper mâché.  It is easier to do at least those two seams while the pumpkin is still open and easy to reach.  Then, I glue the two halves of the pumpkin together.  There are still two seams that have to be covered on the inside.  Cover them, then cover all the seams on the outside.

After those layers are all dry, I give the entire pumpkin three more layers of paper mâché.  It will look like it was never taken apart.  At this point, it would normally be ready for painting, but that is not the plan for this pumpkin.  I plan to cover it in a plastic wrap and then cast another pumpkin on top of it.  Then that pumpkin will be cut off, and the process will continue to complete it as above.  Using this as a mold, I should be able to make a number of pumpkins.  It might take a while, but by October, 2021 I expect to have several pumpkins, each individually carved and painted.