Expanding foam agents

[greyspace]

I need a simple and cheap way to fill a large hole (1m3)with something like polystyrene. Are there any chemicals that I could mix that would expand and fill the void inexpensively. The material must harden so that it could be removed at some point. The material could have bubbles in it but preferebly <1-2mm dia voids maximum. Just looking for a simple way not really wanting to use a gas mixing system unless this is very easy and reliable. Would also be great if you could tell me how many buckets of each chemical would be required to fill the hole. Thanks

 

[phex]

any reasons not to use polyurethane foam? should be available in adequate quantities, ready for use.

 

[greyspace]

Does polyurethane automatically 'foam' up or do you need to activate it with something. If it dosen't foam up 1m3 or 1000litres sounds quite expensive. I had a look on some suppliers about PU and it seemd to vary from everthing like foam cushions to plastic injection molded parts. Can anyone tell me of a grade that would be fairly stiff so that I could walk on it without it deforming say 5-10mm.

 

[phex]

well, that's the point. PU foam can be customized for what ever properties you need, especially when it comes to stiffness. and yes, you can get ready made mixtures which foam up upon components being put together. i'm sorry, can't help you when it comes to grades, i'd just ask with one of those suppliers you found.

 

[saxon]

greyspace, Check with Mcmaster Carr or WW Graingers. Our Maintenance crews use expandable polyurethane foam to make repairs all the time and is removable. There are various sizes of kits available, from 12 oz. spray cans, up to xyz lb industrial application systems. All you need to know is the volume required.

Hope this helps.
saxon

 

[ihg]

Just bear in mind when you use it, that the isocyanate vapor reacts with water - especially in your lungs. Wear an air-fed mask. I am a bit sensitive about this, as I made the stuff 50 years ago and lost 30% lung function in doing so.
If you are trying to fill 1m3, the rigid foam will be density 0.02 or so; you would want to make it in several batches. Better, get a commercial insulating contractor to do the job; he will have the tools to mix and apply it safely.