Cob Re: lime:clay ratio

[Mark A Hoberecht]

At 10:24 AM 10/26/98 +0100, you (crtaylor) wrote:
>
>You can use a store bought hydrated type n bag lime, mix 1:3 lime:clay
>(dry) and test some premade batches to see  Harry (CALXA) recommend curing
>small blocks at 140 degrees in the oven for 24 hours to get a 90 day dry
>cure result example. try it before you get to the use stage, then decide,
>it may provide more long term protectiion than straght cob.
>
Charmaine,

Are you sure the lime/clay mix has no aggregrate (sand) in it?  I know a
typical lime mortar mix is <1 lime:3 sand>, and I've used earth plaster
mixes of <1 clay:3 sand> with good success (cob also about the same
proportions, plus straw), but it seems to me that without some type of
aggregate to go with the 3 parts clay (not just 1 part lime), you'll get
some significant shrinkage cracks.  Any thoughts?