Water Degradable Materials

Cake Icing.
Del

Bar Soap its a little firmer the icing. Makes for a cleaner job.

Yeah, but it will ruin you doughnuts.
Del

It appears the Del has cake and doughnuts on the mind so to distract him here you go Del:

How about rice paper or purging paper. I've heard of soluble plastics though I don't recall the name they are branded.

I don't know what it is you're doing, how big of an area, etc. But, it seems to me the easiest way to do this is with, (possibly custom made) heavy duty rubber lined canvas air bags. Once cement has set, deflate, remove, wash off and reuse.

If air filled bags are too light, fill them with water and drain after concrete has set.

If you're doing a 24-48 hour soak, a cheapo way to do it would be to just use wadded up newspaper, soak it and scoop it out.

We used to use expanded polystyrene, and then wash it out with acetone, but that is probably frowned on now. You could use it and then dig it out.

That sounds gnarly!

Fill the crevice with salt.

Won't salt have an adverse affect on new concrete?

Salt? Yes.. It will destroy it.. ga?

I thought so, we where always told never to apply salt to concrete period unless there was nothing better to use and it was at least 3 year or older and the amount of salt would be a very small amount.

I liked the toilet paper idea very creative. It's amazing to me how people give out GA to totally wrong answers; I noticed it on several posts.

Assuming you looking for something new in the Oil industry. I guess you will have no access to the void other than pumping/applying water?

Not sure if it works. If you have any free water in your cement it will start eating away your "sugar soap".

Note sugar in cement will delay curing. Salt will cure it faster. What ever you do I think the best idea is to go away from water for your task. Best advice given is the azetone disolveable or similar. Please give more detail of the application so we can make better suggestions.

(Sorry me English - I am from Canada, not)

I've worked with a lot of cement, and when I've needed to do this..

I figured out a way to build my 'melt' away forms out of..

wait for it..

toilet paper. ..it's can be formed and no mater how tightly bound or whatever.. cheap tp will always wash out later with a little soaking and some water pressure.

Thank you very much. It has to be a timed event(may be exposed to water for 12 hours) and stay ridged while water and cement are circulated past it.

It will be exposed to high pressures a swell.(2000psi)

Thanks again.

Regards

Grant george

If you are looking for something to model or to fill space, sawdust mixed with soap or water soluble grease as used in boat shaft seals.

The soap is easier. A water hose breaks it down fast.

Sandy Clay, if available is also applicable.

You can also oil or petroleum jelly the contact areas if the residue is disturbing.

Low density styrofoam if you have access afterwards is also a possibility.

You can cut and scrape it out or dissolve it with most solvents, gas or flame.

Paper bags, filled with small styro particles.

Clay