I have expanding foam questions

[Ballatician]

Hey ATOT - I will be doing a little demonstration for kids aged 7-12 this weekend and wanted to use expanding foam for one activity.

I haven't decided yet if I will just do one big demonstration or have them each do a little one for themselves.

I know it can come in a can form but for my purposes it would work a lot better if I could mix the two materials together in front of them and that brings me to my first question.

What are the materials that I need? Are they dangerous, where can I get them, how do I clean up afterwards?

 

[Crono]

I love the sulfuric acid + sugar reaction demonstration, but I guess that's not what you are looking for.

 

[Ballatician]

Not quite but I looked it up and it was pretty cool to see that carbon build up.

 

[IronWing]

Maybe explain how the new-fangled foamy soap dispensers work. It's like a liquid in the dispenser but a foam when it hits your hand. A great mystery to be solved.

This demo has a true hands-on aspect for the kids and also means the little germ bags will be less likely to pass on H1N1 or gout or something to you.

 

[Rubycon]

Sulfuric acid and sugar seems harmless however you need concentrated sulfuric acid which is quite dangerous. The reaction is also considerably exothermic which means the contents of the mixing vessel will get very hot. It's generally OK to do indoors near a ventilated hood.

Tide in the dishwasher is always fun but it makes a bubble monster too!

There is an expanding foam packaging material with two parts that get mixed together and it expands. It's really sticky too - even worse than candy apples!

 

[chusteczka]

Not quite but I looked it up and it was pretty cool to see that carbon build up.

sulfuric acid and sugar reaction with video

"How to use expanding foam" by TAP Plastics

Chemistry experiment with expanding foam

 

[Evadman]

You can get the A and B parts separately, but they are usually much bigger quantities than you probably need (200 sq/ft and up). You can get them at larger builder supply houses or online. Here's a few places:

http://www.energyefficientsolutions.com/sprayfoam.asp
http://www.sprayfoamdirect.com/prod...category_id,6/option,com_virtuemart/Itemid,1/
http://www.eco-distributing.com/Foa...urethane-Spray-Foam-Insulation-Kit_p_209.html

 

[Ballatician]

Thanks for all the help. I found out that the experiment I was thinking about used hydrogen peroxide mixed with dish soap and using potassium iodide as a catalyst. Alternatively people have reported using active yeast as a catalyst as well.

Searching elephant toothpaste was the trick.

Anybody know where to buy potassium iodide? I hope the drug store has it otherwise I'll plan on trying the less vigorous yeast version.

 

[Ballatician]

sulfuric acid and sugar reaction with video

"How to use expanding foam" by TAP Plastics

Chemistry experiment with expanding foam

Thanks, I watched those yesterday but watching them again today led me to read the comments and find out I should be searching for "elephant toothpaste"

 

[Rubycon]

Running each component at each other from opposing sides of a hog intestine (natural casing for sausage) - think trains heading toward each other in a tunnel, single track. How big would it get? What would the final shape be?