Monthly Archives: February 2012

A Curious Experiment

Today was Mr Thrifty’s birthday and in our typical style we indulged in what some may call “odd behaviour”. There was no fancy dinner out, we didn’t go and see a film- instead we bought a bucket and played with expanding foam.  We must have been the type of children that were cheap to entertain because we were both excited about this experiment for at least a couple of hours. 

You’re probably curious about why we wanted to play with expanding foam and a bucket. The short explanation is because I want to make another “custom” dressmakers model and we didn’t believe the manufactures claims about the expanding foam. Mr Thrifty helped me to make a bust form about 18 months ago and while it turned out very well it wasn’t a full dress form, it stopped just under my bust. When we made the first one we blindly chose a can of expanding foam (I think it was the cheapest) and stuck to it for the whole project. By the end of it we’d used five cans… just for my boobs!

For the next doppelgänger I’ve done far more research into expanding foam. For a long time I’ve contemplated two-part polyurethane foam (aka AB foam) but it’s not exactly cheap, nor is it readily available at the local hardware store. Yesterday, Mr Thrifty and I toddled off to our local Bunnings and took some photos of all the expanding foam they have on their shelves. When we came home I looked them all up online. It seems that not all foams are created equal! Most of them have a 2:1 or 3:1 expansion ratio- meaning one 500ml can expands to somewhere between 1-1.5L, some claim a 10:1 expansion ratio meaning one 500ml can expands to about 5L. None of them seemed to come anywhere near the two-part pouring foam expansion ratio of 25:1.  Continue reading