Hi all, I am new here but thought this would be a good place to share a bit of my modeling experience.
I make many foam models in the design process, and since becoming a professional (rather recently) I have learend a few tricks to expedite and refine my technique.
Firstly, I use pink foam. Its the same as Blue foam but made by Corning not DOW and it is readily available at the Home Depot's around me (NYC). Secondly, I NEVER paint my foam models. its takes far too much time and will never look as good as a denser modeling foam, acrylic, or even hardwood. Pink foam models for me needs, are to quickly ideate a 3-Dimensional form, understand proportions, and experience ergonomic features. Though I am new at my firm, they have never had issue presenting clean pink or blue foam models in their natural color to clients.
Once I understand my geometry and have my Elevation and Plan templates I cut appropriately sized pieces of foam "stock". I true them up on the bandsaw (make sure everything is 90 degrees) so that my geometry lines up.
If I need to laminate the foams together to make a large chunk, (this I have to do to more often than not) I go to the bandsaw and remove the film of "skin" on both faces of the sheet of foam, I have found it behaves funny when i glue my layers and also the print on the film can leave strange black lines on the finished model when you cut through them. I tend to remove this film regardless of laminating a large block or not, it doesnt sand nicely and is not flat or true. I use photo-mounting spray to laminate the layers and clamp them for 15 minutes in a large vice or between two pieces of plywood. I find the photo-mounting spray has less solvents than super 77 or equivalent heavy duty spray, and is less likely to melt the foam, causing nasty pockets when i cut through them.
I make my stock pieces a bit larger than the Elevation and Plan templates so that I can, for example, cut my Plan profile, tape the pieces back together, rotate the block 90 and cut the elevation. This is a pretty standard technique, but I have learned it is critical to make your stock larger than the final product or this becomes difficult. I leave a hair of extra material when cutting to my line, for sanding off, but cut as cleanly and accurately as possible. Always keep your bandsaw tuned and check for a 90 degree bed/blade relationship before cutting, never take for granted that it is square, especially if you work in an office with multiple people using the equipment.
Finally, I use various rasps and sanding blocks or pads to sand to my final geometry. a Block of foam with sandpaper and foam handle glue to it make for a good large scale sanding block and gets nice crisp lines where surfaces intersect, an important visual element in any design. Foam sanding pads are great for more organic surfaces.
Double stick tape is an absolute gift from the model-making gods. Keep many different varieties on stock, they are indispensible for attaching various elements together. Also, long T-pins like the seamstresses use are great for attaching elements.
Anyway, I hope I added something to the conversation!