Salmo sez: after I wrote;
The common denominator for bouyancy or density in foam seems to be pounds
per cubic foot. Do you recall what your EVA weighs?
No, I wish I did know. I work in a lab with fancy digital scales.
I could weigh a square foot at 1/4" and extrapolate....might do that.

Weighing might be a good idea. Unless I'm missing something there is no
other common ground to compare foams. Seems like the industry does not have
some kind of standard numbering system for foams.

The foam I have (almost gone now) I bought in 1991. The guy I bought it
from said it was NOT the lightest possible EVA foam. He said it was the
lightest stuff he had in stock, on the floor of the warehouse right now
(well back then, that is). He probably did tell its bun weight, but
I didn't write it down nor remember it.

Over the last 12-18 months, I've probably talked to or surfed 20-30
speciality foam suppliers and do not recall anybody using "bun weight"
terminology.

He suggested some other resin types too, polyurethane, possibly.
Like you said earlier, seems the more resin, the more cost.

I chose the EVA stuff and it worked well. I've been making unsinkable
grasshoppers for almost 15 years now. The fancy, good-looking hoppers
Rainey sells in fly shops now (with beady eyes and double-strand
kicker legs) look great, but they hardly float. I can mend the line
on my hoppers in FAST water, with a heavy nymph hanging off the back,
which sinks the hopper momentarily. And then voila: up pops the hopper
again. Try that with a Rainey Hopper and it stays down for the count.
Right. She should call her Float Foam, "Barely Floats Foam" g.

Do you recall the manufacturer and the product id? Are they on the web
today?
No, but I did buy it from Industrial Rubber in Seattle. They don't like
to even talk to you, however, unless you want to set up a real account
and make recurring purchases.
Right again. I contacted them also. However other firms will sell limited
quataties of foams with the hopes of you buying big quantaties later.

Y20 and 2# XPE from Specialty Foams www.irfoam.com for example are two
closed cell foams weighing 2 pcf. The Y80 weighs 8 pcf and the 4# XPE
weighs 4 pcf and these may be machinable and shaped but are heavier.

2 pcf sounds pretty light. But I don't really know for sure.

From what I think I heard from talking with sales people, foam "lightness"
or density in closed cell foams is a result of the gas trapped inside the
cells. And they said most cell gas was air, CO(2), both or some other
derivative of the chemical process that formed the foam When I asked if
they could inject the cells with helium or something lighter than air, was
it possible to get foam that weighed less than 0 pcf, they seemed to glaze
over and clam up.

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Is your EVA foam machinable? Can it be sanded? Can it be cut or shaped
by a hot wire? What can it be painted with other than Prismacolor or
similar pens?
Machinable? No. It's too soft.
I cut it with razor blades, paper cutters and/or a fabric cutter.
I lash it onto the hook LOOSELY, and then glue it in place with
ZapAGap. If you wrap it on tightly you collapse the foam and lose
the bouyancy.

Since you can use soft foams, maybe you should look at their Y-20 and 2# XPE
Both are very soft based on the samples they sent me..

The white Y20 and off white XPE for example are soft, non-machinable,
cannot be easily bored to create dowells or cylinders easily formed via
hot wire, IMHO.
You can make nice round little holes with a leather punch.
You can cut it accurately with a straight edge and a circular,
disc-shaped fabric cutter. You can cut it with a hot wire, although
I never do.

Foam for popping bugs has different characteristics, I now see compared to
your hopper and stone fly needs.

It glues nicely (onto anything) with CA glue.

IMHO As poppers get larger than 3/8 to 1/2 inch diameter, especially in weak
material or soft foams, CA glues become less useful as adhesives, even with
thread wapped hump shank hooks. The hook twists loose from the bug body. I
have grappled with this problem for decades! Will be testing a possible
solution that could work with any body material this summer.

Sheet stock 1/4" thick is what you want. You can cut that
down to whatever you need. Or use it at a full 1/4" thick to
make magnum hoppers or giant adult stonefly immitations.

I saw what you mean from the photos in the two links. Did not like his
colors though!

IMHO colors make a difference to fish. Most of the time the strike/catch
rate due to color difference is small or not noticeable to me. But
sometimes, the color match must be exactly right on. Other people can talk
about this more than I can - bass will eat anything g! But even on bright
sunny days in clear water, even BIG ole bass get smarter about colors!
Bright, sharp, clear, flourescent colors seem to work consistently better
for me than dull, off shade, fuzzy dark colors. One color I have tested
over the years and absolutely refuse to use is "Stop sign" yellow. Lemon
yellow beats amber or stop sign yellow hands down every time for bass,
bluegill and yes, even trout. Yep I know lots of stop sign yellow is sold
at drug stores, Wall Mart and other places but flourescent or lemon yellow
just works better.

Colors for popping bugs are getting very exotic. Top and bottom spraying,
fading at overlap, scales, eyes, gills and other steps all require base
coating and spray-on technology are going way beyond handwritten marks-a-lot
colored pens.

Oh, the other problem I had with soft, closed cell foams is getting paint to
stick - either water or solvent based! When I asked the sales people which
worked best on their foam, they said just send them a color swatch and they
could match it and color the foam, for a minimum order. groan There's
that word again! No bucks or guts - that's me!

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Good luck!
John