FW: [Cob] a cob bathtub

[Maria Morehead]

-- 
The future you are living into gives you being in the present.

Maria
spiralmother at comcast.net


------ Forwarded Message
From: Bex <cobalot at cpros.com>
Date: Tue, 29 Mar 2005 07:18:09 -0800
To: Maria Morehead <spiralmother at comcast.net>
Subject: Re: [Cob] a cob bathtub

We have done plaster experiments adding the oil to the mix and I like the
results. It didn't seem to matter how the oil was added to the cob.....just
throw some in at any point in the mixing. Amounts? Hmmm My unscientific
records do not say but I would just follow my instincts. I agree that more
oil added when the cob is dry is a good idea.
I find that more clay in the floor mix makes it harder and more resilient.
Of course it makes it more cracky but I just tamped the high clay floor hard
with a small ended tamper as it was drying (for days, just tamped out cracks
as they appeared.) This gave it a nice texture but was lots of work. A very
strong floor....an African idea

I found that with the high sand floors it was best to not do any touch ups
while it was drying as that somehow broke the natural finish of whatever
rose to the top. ie wasn't so shinny where I touched up.

Becky
 
Groundworks
PO Box 381
Murphy, Oregon 97533
USA

1-541-471-3470 voice mail

www.beckybee.net
cobalot at cpros.com


> From: Maria Morehead <spiralmother at comcast.net>
> Date: Mon, 28 Mar 2005 12:30:02 -0800
> To: Becky Bee & Sequoia <cobalot at cpros.com>
> Subject: FW: [Cob] a cob bathtub
> 
> Hi Becky & Sequoia!
> 
> Would you be able to comment on this issue from your perspectives?  I know
> when I was down there last summer you had started experimenting different
> methods on the floor of the sun womb...
> 
> Thanks so much!
> Maria Morehead
> 
> -- 
> The future you are living into gives you being in the present.
> 
> Maria
> spiralmother at comcast.net
> 
> 
> ------ Forwarded Message
> From: "Shannon C. Dealy" <dealy at deatech.com>
> Reply-To: dealy at deatech.com
> Date: Mon, 28 Mar 2005 11:44:34 -0800 (PST)
> To: Amanda Peck <ap615 at hotmail.com>
> Cc: Coblist at deatech.com
> Subject: Re: [Cob] a cob bathtub
> 
> On Mon, 28 Mar 2005, Amanda Peck wrote:
> 
> [snip]
>> Somebody knows this!  Tell us!  How do we add oil to a floor, plaster--or
>> bathtub--mix?  Add it to dry sand, mix well, and go from there?  How much do
>> we add? something on the order of a cup--around .25 liter--to a 5-gallon
>> (around a hundred liters) pail of sand? I've never tried it, and don't have
>> a book handy--it might be quite a bit less than that, more like a cup to
>> three buckets of sand, and one clay.
> 
> I've never found anything written up on this, normally people apply the
> oil after the floor or plaster has been applied and dried.  Because of
> the lack of information, I did alot of experimentation myself as I was
> trying to create a one step floor that would dry as quickly as possible.
> I wasn't expecting it to be sealed when I was done, simply much more
> durable than a straight earthen floor that had not been oiled (I was and
> still am living on the floor surface at the time I was applying it, so I
> needed something that was usable in days rather than weeks).  The problem
> is that clay will not dissolve in the oil, and you really need
> clay in the mix both for it's fine particulates to fill in between the
> sand particles, as well as it's binding strength, technically, the oil
> when dry would probably provide all the binding strength you need,
> however, without the clay it would require massively more oil which is not
> only more expensive, but would take MUCH longer to dry.
> 
> Unless you have a special reason for doing this, I would highly recommend
> going with the more conventional approach of applying layers of oil to the
> dried, finished cob surface.
> 
> Anyway, the best approach I was able to come up with to date was to do the
> usual base/rough surface with a strong good quality cob mix, then figure
> out your best ratios for a very high sand cob mix (just enough clay to make
> a good binder, but nothing more), you will also want plenty of straw in the
> mix, I've been using short straw, though some people I know have started
> using longer straw in their recent floor and plaster mixes.  Once you have
> your ratios, measure an appropriate amount of your clay (or clay soil)
> into a bucket and add enough water to just wet it completely through.  You
> do not want a slip here and there shouldn't be any standing liquid or
> slip on the surface once it has time to absorb the water, you just want
> enough to completely wet the clay while keeping the mix as stiff as
> possible, you will probably want to add water a little at a time, and let
> it sit at least overnight to give it time to fully absorb the water for
> the first batch or two until you know how much water it will take so that
> there are no dry lumps of clay left.  In a separate bucket you will want
> to make an emulsion by mixing one part bentonite clay (I bought a box of
> of generic clumping cat litter which listed only bentonite clay in it's
> list of ingredients), six parts water, and eight parts oil (this was off
> the shelf boiled linseed oil from the local hardware store).  Mix this
> thoroughly, it should end up with a consistency similar to mayonaise,
> probably will do better if after you mix it, let is sit overnight, then
> mix it again.  Finally, mix your sand and clay together, and in place of
> additional water, add the emulsion to get your usual pre-straw cob working
> consistency, and finally add the straw.  I mixed this in a five gallon
> bucket, making batches of about three gallons at a time (using a heavy
> stick to do the mixing).  Keep in mind this is intended to be a finish
> coat, so it is typically going to be less than an inch thick and you
> won't need that much, three gallons would cover six to twelve square feet
> depending on the thickness.  If you dry this quickly (as I did, using a
> fan), expect cracking, though of course you can fill in the small cracks
> with a fine mix.  Once this is dry it is usable and much more durable than
> straight cob, but still somewhat fragile, ultimately it will still require
> multiple coats of linseed oil to finish it.
> 
>> Using it on top is easier, and you probably want to do it this way even if
>> you did use oil in the mix.  Just wipe it on.  Mixed with mineral spirits if
>> you have it.  Let dry, repeat--probably three coats in all.  Then leave out
>> in the rain for a couple of months!
> [snip]
> 
> The way I was originally taught this was to use uncut linseed oil for the
> first coat, then add thinner to linseed oil in progressively greater
> quantities to the succeeding coats (seven was the recommended number as I
> recall).  A number of people I know have just been using the linseed oil
> without thinners in multiple coats.  I think one person used thinner in
> all their coats in order to get deeper penetration into the floor.  The
> basic rule in applying linseed oil to anything is to apply it, give it
> some time to absorb into the surface (ten minutes comes to mind), then
> wipe off ALL the excess (a single drop of linseed oil left standing on
> the surface will not only take forever to dry, but will create a gummy
> mess if you step on it).  With a floor, you can just work slowly,
> and migrate the excess from the treated areas to the untreated areas,
> supplementing with more linseed oil as you go.
> 
> Shannon C. Dealy      |               DeaTech Research Inc.
> dealy at deatech.com     |          - Custom Software Development -
> |    Embedded Systems, Real-time, Device Drivers
> Phone: (800) 467-5820 | Networking, Scientific & Engineering Applications
> or: (541) 929-4089 |                  www.deatech.com
> 
> 
> 
> 
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