Polyester-friendly way to remove/dissolve Oasis wet floral foam

December 9, 2012 1:49 PM

How to remove/dissolve Oasis wet floral foam? Problem: must be polyester friendly.

An art project involved sticking some glass rods into wet floral foam (that green stuff they put flowers in at the florist's), pouring polyester casting resin onto the foam, and then letting it set. The desired end result was this:

\     |     /   <- Glass rods
 \    |    /
==\===|===/==   <- Cast polyester plastic
   \  |  /

There was a release agent on the surface of the foam, but some plastic was able to travel down the glass rods into the holes they made in the foam. As a result, the lower ends of the rods (below the plastic layer) are coated in foam, which has been stuck to the rods via hardened polyester plastic.

The foam needs to go, since the glass and plastic all need to be clear. Is there a way to dissolve the foam without hurting the plastic? (The glass we're not worried about... unless you recommend HF. Which we won't use.) Right now we're planning to try and get the foam off mechanically, but that looks like it's going to be a big job.

(Floral foam is phenol formaldehyde plastic, for what it's worth.)

posted by Chef Flamboyardee to science & nature (3 answers total)

My first guess would be acetone. If the polyester resin is fully cured and set, I can't imagine acetone will damage it that much. Even if it does, it will probably eat the Oasis foam much faster. But, this is a guess based on experience dissolving styrofoam cups in acetone in my younger, dumber days.

It should be easy to test, though. Take a piece of foam and a piece of cast resin and put in acetone. My guess is the foam will quickly disappear while the resin will stick around (though it might be softened).
posted by Fortran at 3:42 PM on December 9, 2012

Have you tried just letting the oasis dry completely? Oasis crumbles pretty doggone well when it isn't wet.
posted by St. Alia of the Bunnies at 3:47 PM on December 9, 2012

"There are no true solvents for cured [phenol formaldehyde] resins. Some penetrate the polymer network, softening it to some degree, but it's slow and often not that effective; if there's electronics inside their packaging may be more affected by the solvent than the p-f is. Fenton reagent type mixes and ozone will attack the aromatic ring, eventually cleaving the rings leading to degradation of the polymer network; however this is very slow because only the surface layer is attacked as the reagent can not penetrate into the 3D mesh." http://www.sciencemadness.org/talk/viewthread.php?tid=16240
posted by gregr at 8:19 PM on December 9, 2012