[Cob] a cob bathtub

[Amanda Peck]

Nicely.  Although it may take a while.

It can be put INTO your plaster or floor mix, or applied afterwards (in 
coats, mixed with mineral spirits to increase penetration) on things you 
want to have extra abrasion resistance or waterproofing.

You want BOILED linseed oil.  You want to BUY boiled linseed oil.  And you 
want to take extraordinary care to prevent spontaneous combustion.  Your 
rags and even the t-shirt you were wearing need to be spread out single 
layer on something that won't burn, or into the spontaneous-combustion proof 
container.  And boiling your own apparently can result in unwanted fires as 
well.

For those and other reasons most of my furniture making friends are using 
tung oil mixtures.  I've no idea how they work on earthen plasters.  But 
I'll probably do a sample one of these days.

A couple of years ago I did a teensy floor sample in a paint roller pan.  
Let it dry, coated with three or four layers of (decreasingly diluted--this 
may be wrong, by the way--the stuff did pool in spots) linseed oil.  Got 
told that it was too bleeping small to tell me anything (you don't want to 
work with that guy!), just set it out in the weeds in the fall.  Next 
spring, after the fall rains, well into the spring floods, I took a look at 
it.  If I took it OUT of the container, I could chip the corners fairly 
easily.  But it had held together nicely, the suface was dark and shiny.
.................
Carmen wants to know:
Does the linseed oil harden...?