Clay is for padobe. Clay and portland cement don't get along well. Do you have sand on site? It will minimize shrinkage and will not swell when wet like clay does.
Another approach, which I use, is to just oversize everything to allow for the shrinkage. Once you get your mix defined, you can measure the amount of shrink and keep it consistent. Similar to what you do with pottery or metal casting.
spaceman
prrr.t21@btinternet.com wrote:
Hi everyone I'm new to the group, and have read the last month's postings with interest, and found lots of useful tidbits. I'm looking to minimise shrinkage of papercrete so I can use it to replicate shapes. I see adding clay helps, but for reasons that are a mystery to me, clay seems rather expensive to buy, and I cant harvest it on site. I want to avoid a high price mix if possible, and probably all the ingredients will need to be bought in. In principle I could compress the stuff to prevent shrink, but I presume that would greatly slow down production rate. So in summary I want it all and preferably for nothing! If anyone has tips on minimising shrink I'd love to hear. thanks, NT ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/papercreters/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/papercreters/join (Yahoo! ID required) <*> To change settings via email: papercreters-digest@yahoogroups.com papercreters-fullfeatured@yahoogroups.com <*> To unsubscribe from this group, send an email to: papercreters-unsubscribe@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
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