posted 11-05-2003 11:01 AM              

The adhesive joint is soft enough that it doesn't interfere with sanding.

posted 11-14-2003 10:30 AM              

quote:

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Originally posted by wondering:
What's the best way to adhere two pieces of yellow polyurethane foam together?

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for quick study models / painted appearance models Super 77 works well. Photo mount spray adhesive works too but isn't as strong which can be good if you have to remove / reassemble the parts for last-minute surface prep. be sure to spray both mating surfaces.

however, if the model you are making will also have weight added, then you should seriously consider using a super-glue type adhesive (Zap-a-Gap CA+)with Insta Set (aka Kicker). Keep in mind that when this glue hardens it will have a density greater than that of the yellow foam. So, if this stuff leaks out to an area that still needs to be finished, you will have a tough time evenly sanding the surface. Be sure to apply it to the pieces allowing at least 1/4" distance from the sanding surface. it is a permanent bond so keep that in mind if you don't plan on taking the model apart.

lastly, for filling and correcting small part-line gaps and dings in yellow foam, here's our little BH secret which i'm sharing for the first time...Future clear acrylic floor polish and foam dust. Squirt about a teaspoon of the polish into a cup and mix in some collected yellow foam dust (be sure its free of any unwanted dirt or other foreign particles) until it has the consistency of wet beach sand. you can then use it to fill gaps and holes in your model and still have a homogenous foam surface. once applied, allow it to air dry prior to sanding. dry time will vary depending on the amount of filling mixture used. the mixture can also be primered / painted when dry. Bondo dries denser and would present an issue similar to that of the super glue when prepping the sanding surface. vinyl spackle is a better sandable gap filler and surface finisher than Bondo for foam study models. if you want a nice foam model without alot of surface prep then you should consider using ren-shape foam. but, what is becoming more common for appearance models, is to spend some time making a 3D model and having an SLA or some other rapid prototype output which can then be painted. the time invested to make that vs. a super-nice appearance model made of foam is almost the same. one added benefit though is you have to make a second model (i.e. if it gets broken)...you'll already have the 3D database that can also be tweaked and then remade faster than your first model.