Woodglue? Plasti-dip? PVA glue? Sealing EVA Foam on the Cheap: an experiment

There is a lot of talk on the internet about different ways to seal EVA foam.  I’ve always used plasti-dip, a product readily available in the USA in spray form or “dip” form.  A whole suit of armor could easily use 5+ cans, and at $7.00 or so a can, that can add up.  Honestly, because of cost, I’ve never put on as many coats of the stuff as I needed to to get a really clean, shiny surface.

I’ve seen it recommended on the internet that you can seal foam using a mysterious substance called PVA glue.   What is PVA (polyvinyl acetate) glue?  Well, I haven’t really determined that.  Some people say it’s woodglue. Other’s say it is white glue.  Still others say that it is a specially glue that you can buy to bind books.  Honestly, I’ve googled and googled and haven’t come up with a definitive answer.   So I went to the craft store, and then to the home improvement store to buy some of this PVA glue, but not one bottle of glue said PVA anywhere on it.

In the past I’ve tried sealing foam with both woodglue, and modge-podge, and both produced cracked undesirable results.    But maybe I was just doing it wrong?  Some people recommend diluting the glue, 1:1, 1:3, 1:10 – I’ve seen all variations.    And then recently, I saw someone recommend using a combination: woodglue topped with plasti-dip.

So before launching into another project that would inevitably cost me $50 in plasti-dip, I decided to run my own experiment.

 

Experiment

Products Used:

 

products-used

  • Elmer’s Carpenter’s Wood Glue interior
  • Elmer’s Glue-All Multi-Purpose Glue
  • Elmer’s Craft Bond Tacky Glue
  • Plasti-dip in spray can form
  • Rust-oleum Bright Coat Metallic Finish spray paint in Gold (not pictured)

I experiments on scrap foam I had lying around in different dilutions, applications, and combinations.  Here are my unscientific results:

glue-chart

wood-glue

Here is the woodglue section of my experiment before flexing it.

crackinga

The woodglue cracks after flexing.  Note that the shinier the surface, the worse the cracking.

wood-glue-crack

The 100% wood glue produced the deepest cracking. Note how the crack tore right through the foam, breaking the cosplayer’s heart.

dripping

Tacky glue at 100% concentration got a little drippy and gloppy.

tacky-glue-on-the-bottom-glue-all-on-the-top

The square in the center there is the tacky glue.  Notice the wrinkles but no cracks.  The square above is the glue-all. Notice the same pattern to the wrinkles but these are actually cracks in the paint.

Conclusion:  

  1. Neither the wood glue nor the glue-all are acceptable forms of EVA sealing in any concentration.  Once enough glue was applied to get the desired results, flexing would cause cracks.
    1. Someone might argue that it would be fine on an armor piece that doesn’t flex, but the reality is, that when you are wearing a body suit of EVA foam all the parts need to have a little flex due to the inevitable wear of putting the pieces on and off, bumping into things, etc.  The possibility of large cracks appearing  would be too big of a risk in my opinion.
  2. Adding Plasti-dip to the top of a glue undercoat does NOTHING.  Maybe it would have effect in if multiple coats were used, but at that point, why use the glue undercoat at all?
  3. Tacky glue was the only possible undercoat I would consider.  This is because it is designed to stay flexible when dry.  However, I would want to do more research to ensure that it will stay flexible, and won’t dry out over time.

See Follow-up Post: Tacky Glue: an experiment

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