[Strawbale] Strawbale Digest, Vol 8, Issue 1

[Michel Couvreux]

Derek,

I will try not to repeat what I said earlier to Jacek, but I really 
appreciate that you took the time to research more on reworking Hydraulic 
Lime.
Certainly, the environment will affect the period of reworking time.
In the case that you describe, I would not use the NHL 5, but the NHL 2 
would be appropriate, even the NHL 3.5.
I would strongly recommend that you experiment a little with the material in 
order to better understand how it behaves. This would be better than a 
thousand words.
But, we should not forget that the choice for a building material should not 
be dictated for its convenience of use in a workshop, but rather for its use 
on a job site and its guaranteed performance.

Michel

Michel Couvreux
TransMineral USA, Inc.
501 Lakeville Street, Suite F (Physical)
201 Purrington Road (Mailing)
Petaluma, CA  94952
707-769-0661
707-769-0352 Fax
transmin at sonic.net
www.limes.us
----- Original Message ----- 
From: <strawbale-request at listserv.repp.org>
To: <strawbale at listserv.repp.org>
Sent: Thursday, February 01, 2007 10:00 AM
Subject: Strawbale Digest, Vol 8, Issue 1



> Message: 2
> Date: Wed, 31 Jan 2007 13:13:00 -0700
> From: Derek Roff <derek at unm.edu>
> Subject: Re: [Strawbale] Hydraulic vs Hydrated Lime plaster
> To: strawbale at listserv.repp.org
> Message-ID: <01E226545665A2B56C924538 at d00-64-106-126-102.dhcp.unm.edu>
> Content-Type: text/plain; charset=us-ascii; format=flowed
>
>> I would like to make some comments on Derek's statements.
>> Hydraulic lime does not set in a short time. It is a product that can
>> be  reworked up to 24 hours.
>
> I am glad that Michel has come forward to offer his experience and
> expertise.  I will repeat that I am not an expert in lime.  I would
> like to learn more about the reworking that Michel refers to.  St.
> Astier, one of the biggest suppliers of natural hydraulic limes,
> mentions reworking times for various products ranging from 8 to 24
> hours.  8 hours means that mixed plaster could not be applied, if
> stored overnight.
>
> In a workshop situation, I try not to mix any plaster after about 4 PM.
> Any plaster not used will sit until the workshop gets going again,
> usually between 9 and 10 the next day.  So for me to use yesterday's
> plaster in such a situation, I need at least 18 hours of rework time.
> This puts me into the last third of St. Astiers stated reworkability
> range.  Obviously, professionals might work later and start earlier.
> Unlike workshop participants and owner-builders, pros would be fully
> cognizant of their tools, materials, and skills.  Please, Michel, tell
> us more about what you have found with reworking different plasters
> after different periods of time.  How do temperature and humidity
> affect the reworking time, in your experience?
>
> St. Astier mentions the tendency of reworked plasters to be weaker, due
> to higher water content introduced in the remixing.  This can be
> counteracted, they say, by greater physical compression of the plaster,
> increasing its density, during the trowelling.   Michel, can you
> comment on your experience with these techniques?
>
> I agree with Michel that cold joints (where new plaster does not adhere
> well to plaster applied previously) can be a problem with any plaster,
> including earthen plasters.  I did not mean to imply otherwise.  I
> remain convince that being able to store mixed plaster for days, weeks,
> or months is an advantage for most owner-builders.
>
> I think good quality natural hydraulic limes are wonderful products.  I
> think good quality hydrated limes are wonderful products.  I look
> forward to hearing more from Michel.
>
> Derelict
>
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek at unm.edu
>
>
>
>
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> End of Strawbale Digest, Vol 8, Issue 1
> ***************************************
>