[GSBN] caulking

[Lawren Richards]

Hi Andy,

I was concerned that any kind of oil might react with my vinyl windows, so I
used raw wool soaked in clay slip for caulking around my windows and doors.
The slip expands when damp and the wool when dry; two years in and there's
hasn't been any shrinkage or issues.  The wool had to be cleaned and carded,
though; it might be easier to do it with recycled wool fabric.

Lawren Richards

Acknowledging that I live and work on the unceded traditional lands of the
Secwepemc People.

-----Original Message-----
From: GSBN <gsbn-bounces at lists.sustainablesources.com> On Behalf Of
gsbn-request at lists.sustainablesources.com
Sent: August 1, 2024 5:00 AM
To: gsbn at lists.sustainablesources.com
Subject: GSBN Digest, Vol 27, Issue 1

Send GSBN mailing list submissions to
	gsbn at lists.sustainablesources.com

To subscribe or unsubscribe via the World Wide Web, visit
	http://lists.sustainablesources.com/cgi-bin/mailman/listinfo/gsbn
or, via email, send a message with subject or body 'help' to
	gsbn-request at lists.sustainablesources.com

You can reach the person managing the list at
	gsbn-owner at lists.sustainablesources.com

When replying, please edit your Subject line so it is more specific than
"Re: Contents of GSBN digest..."


Today's Topics:

   1. Traditional burnt sand mastic recipe & experiences
      (andy at ecodesignarchitects.co.za)


----------------------------------------------------------------------

Message: 1
Date: Wed, 31 Jul 2024 17:00:17 +0200
From: <andy at ecodesignarchitects.co.za>
To: "'Global Sustainable Building Network'"
	<gsbn at lists.sustainablesources.com>
Subject: [GSBN] Traditional burnt sand mastic recipe & experiences
Message-ID:
	<00eb01dae35a$5d4e8640$17eb92c0$@ecodesignarchitects.co.za>
Content-Type: text/plain; charset="utf-8"

Hi good folks
has anyone got experience with making up one?s own traditional burnt sand
mastic for caulking around openings and for providing a flexible seal for
expansion jointing between different materials.


Down South here in South Africa we only get conventional silicone or
polyurethane type joint sealers/caulking agents, which are environmentally
dodgy and unsuitable for natural finishes.  I gather that people in the UK
and US are using a traditional burnt sand mastic with certain suppliers
selling it as a product.

As far as I can tell, you can make your own by roasting or baking a fine
sharp sand to sterilize and drive off all moisture and then about an hour
before use one blends it with a high quality boiled or double boiled linseed
oil. It seems some caulk may also be added to the sand mix, but I am not
sure if this is required or not. 
I was also wondering if you could sun-cure a raw linseed oil rather than use
the boiled type in the same way one sun-cures linseed oil for an earthen
floor.

Can anyone advise?
It would be interesting to hear people?s experiences. 



Many thanks 

Best regards
Andy Horn

-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.sustainablesources.com/pipermail/gsbn/attachments/20240731/8ce
bfd77/attachment-0001.htm>

------------------------------

Subject: Digest Footer

GSBN mailing list
GSBN at lists.sustainablesources.com
http://lists.sustainablesources.com/cgi-bin/mailman/listinfo/gsbn


------------------------------

End of GSBN Digest, Vol 27, Issue 1
***********************************