Earl Krueger on sat 29 nov 03
On Saturday, Nov 29, 2003, at 11:42 US/Pacific, Mary Ellen Mason wrote:
> I just built a lovely wedging table a few weeks ago (plaster poured
> onto a framed-in
> tabletop), and I notice that it's growing mold.
Mary Ellen,
Molds can't grow without water, so that is the key to your problem.
From your statement I read that you have a SOLID table top with a frame
surrounding the plaster slab. Correct? If so, then you have created a
well in which the only place for water to evaporate is through the top
surface of the plaster. This is going to be a slow process. The trick
is to get the water to evaporate quicker.
You could try warming the slab by putting an incandescent or infrared
light bulb under the table. This is not the ideal solution but may be
the easiest. Watch out you don't create a fire hazard.
If you still have the sides of the form in place could you remove them
thus allowing water to evaporate from the edges as well as the top?
This might help some but is still not the best.
How thick is the plaster? If you can lift it up off the table top
thereby exposing the bottom surface a lot more surface can be exposed.
Or, could you cut or drill out sections of the table top so the bottom
of the plaster can breathe? Make sure you leave enough table to
support the plaster.
You didn't describe the mold, so if what you are seeing is white fuzzy
stuff then it could be crystals. Calcium sulphate, of which plaster is
made, is very slightly soluble in water and as the water evaporates it
will carry the dissolved salts to the surface where crystals will form.
If this is what's happening then just wipe them off with a damp paper
towel and forget about them.
Good Luck
Earl...
Bothell, WA, USA
Fredrick Paget on sat 29 nov 03
>wedging table growing mold.
>
>Can anyone tell me what to do here? I wipe off the mold, but it
>re-grows. I've
>considered wiping the surface with a watered-down bleach solution,
>but I'm afraid it
>might somehow damage the plaster. Maybe it won't - but I just don't
>want to take the
>risk.
>Mary Ellen
Mary Ellen,
If you don't want to use bleach try Physan. It is a sanitizing agent
used in hospitals, dairies, bake shops, orchid green houses ,etc. I
think the cleaner in Dow Bathroom Cleaner ( Now made by Johnson and
called Scrubbing Bubbles) is the same type of chemical too, plus
detergent, so it will probably work too. Try it out on a small
plaster bat for a test run.
Probably the reason you are getting mold is that the plaster is
still wet and when it dries out the mold will stop any way.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com
John Rodgers on sat 29 nov 03
Be careful what you use. If there is an oily content - Pine Sol possibly
- it will ruin the surface of the plaster table. The plaster will lose
it's ability to draw water from clay.
Regards,
John Rodgers
Chelsea, AL
pdp1@EARTHLINK.NET wrote:
>Hi Mary,
>
>
>You could indeed wipe it down with Bleach...with 'Listerine'
>even, or with 'Pine Sol' , 'Lysol' or the like...
>
>About any dis-infectant should help matters...
>
>
>Phil
>Las Vegas
>
>----- Original Message -----
>From: "Mary Ellen Mason"
>
>
>
>>I just built a lovely wedging table a few weeks ago
>>
>>
>(plaster poured onto a framed-in
>
>
>>tabletop), and I notice that it's growing mold.
>>
>>Can anyone tell me what to do here? I wipe off the mold,
>>
>>
>but it re-grows. I've
>
>
>>considered wiping the surface with a watered-down bleach
>>
>>
>solution, but I'm afraid it
>
>
>>might somehow damage the plaster. Maybe it won't - but I
>>
>>
>just don't want to take the
>
>
>>risk.
>>
>>I guess I could just leave the mold and not worry about it
>>
>>
>so much, but I keep hearing
>
>
>>about 'toxic mold' in people's homes and how expensive it
>>
>>
>is to remove. I have a
>
>
>>fear of this mold spreading.
>>
>>Any advice would be appreciated.
>>
>>Thanks,
>>
>>Mary Ellen
>>
>>
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
Mary Ellen Mason on sat 29 nov 03
I just built a lovely wedging table a few weeks ago (plaster poured onto a framed-in
tabletop), and I notice that it's growing mold.
Can anyone tell me what to do here? I wipe off the mold, but it re-grows. I've
considered wiping the surface with a watered-down bleach solution, but I'm afraid it
might somehow damage the plaster. Maybe it won't - but I just don't want to take the
risk.
I guess I could just leave the mold and not worry about it so much, but I keep hearing
about 'toxic mold' in people's homes and how expensive it is to remove. I have a
fear of this mold spreading.
Any advice would be appreciated.
Thanks,
Mary Ellen
pdp1@EARTHLINK.NET on sat 29 nov 03
Hi Mary,
You could indeed wipe it down with Bleach...with 'Listerine'
even, or with 'Pine Sol' , 'Lysol' or the like...
About any dis-infectant should help matters...
Phil
Las Vegas
----- Original Message -----
From: "Mary Ellen Mason"
> I just built a lovely wedging table a few weeks ago
(plaster poured onto a framed-in
> tabletop), and I notice that it's growing mold.
>
> Can anyone tell me what to do here? I wipe off the mold,
but it re-grows. I've
> considered wiping the surface with a watered-down bleach
solution, but I'm afraid it
> might somehow damage the plaster. Maybe it won't - but I
just don't want to take the
> risk.
>
> I guess I could just leave the mold and not worry about it
so much, but I keep hearing
> about 'toxic mold' in people's homes and how expensive it
is to remove. I have a
> fear of this mold spreading.
>
> Any advice would be appreciated.
>
> Thanks,
>
> Mary Ellen
Jeff Longtin on sun 30 nov 03
Mart Ellen,
Any time I leave a freshly poured plaster piece on a wooden tabletop
overnight I wake up to find the plaster and the wood have all sorts of brown and black
spots (and a few other colors as well sometimes).
I prevent this from happening by elevating freshly poured plaster at least a
day or two.
As I don't deal with it much I don't know a simple solutuion but I would
suggest that you remove the plaster from the wood frame in which it sits. Its very
likely the moldy spots are on your wood frame as much as they are on the
plaster. (It sounds like the wood frame needs to air dry as well.)
As others have mentioned the plaster will need to breath in the future so it
would be best for you to open up this frame thing so air can circulate aroung
the slab in the future.
The mold which is growing in some super insulated new homes is the result of
building materials getting wet and the moisture having no place to go. The
moisture is caused by the home's occupants normal living habits, breathing,
bathing, washing dishes, and the vapor barrier created to prevent air infiltration
is also preventing the interior moisture from escaping. Thus mold is being
created.
I think the reason mold in homes is nasty is that the mold is growing on, and
out of, building materials which have been treated with a variety of
chemicals that were never intended to be air borne and that the mold growth cycle is
causing these chemicals to become air borne. As dried plaster is inert, and
free of preservatives, I don't think there is anything to worry about once your
plaster slab dries.
(Kinda ironic isn't it(?) we came up with all sorts of tricks, vapor
barriers, chaulking, to keep nature at bay but it the end it was nature that
said,"Wait a minute, you can't control me", by throwing us all sorts of nasties!)
take care
Jeff Longtin
John Rodgers on sun 30 nov 03
Mary,
I have been mulling this problem over and believe that what has happened
is that along the way in the construction of your wedging table, the
water in the plaster, and possibly the wood has simply activated the
mold spores in the plaster and on the wood, as mold spores are found
everywhere. They simply float in the air and fall on stuff, and if there
is moisture present, that's all it needs to be activated. The plaster
and wood become the substrate from which they draw their food, by
chemical leaching. All this is very microscopic, of course, but under
the right conditions you can get a a mold "bloom", i.e., a real burst of
mold growth. Since you can't take away the food., i.e., the wood and
plaster, then remove the water. Temperature will also inhibit their
growth as well. If it's to hot or to cold the mold will not grow. But
the easiest way to control it is by removing water.
I build my plaster tables 6 inches thick, using a wood frame, that is
open on the bottom. I make the table frame, put a support strip around
the inside perimeter at the bottom of the frame, and then turn it upside
down on a table covered with formica or other plastic laminate. I do not
put a bottom on the frame. I seal the frame to the table with oil clay
to prevent plaster from leaking before it sets, then I pour the plaster
in. By turning the frame upside down and then casting the plaster, the
plaster forms a perfectly smooth surface against the plastic laminate.
This will be the surface of my table when it is righted. I completely
fill the frame and then smooth it off level with a paint mixing stick.
I install cast iron stanchion flanges to accept steel pipe legs,
although wood legs could be used on the table. I then right the table.
Now the smooth side of the plaster is up, the support strips support the
plaster and prevent it from falling through, and I turn on the fans to
begin the drying process. While quite heavy initially, the water loss
during drying will lighten the table substantially. This rapid drying
with fans, especially if the air is cool or really warm, will prevent
most mold from growing. Then after each use, I turn a fan on the table
to rapidly dry the table. It will lose moisture from both the top and
bottom, reducing the time in the moist material that mold would have to
get started. Rapid drying with moving air is essential to controlling
the mold growth, from my perspective.
One thing I have thought of but have not tried, is to add a bit of
bleach to the water before mixing the plaster. This may help in the
intial stages. I would run a small test first, however, as I have not
actually tried this.
Regards,
John Rodgers
Chelsea, AL
Mary Ellen Mason wrote:
>I just built a lovely wedging table a few weeks ago (plaster poured onto a framed-in
>tabletop), and I notice that it's growing mold.
>
>Can anyone tell me what to do here? I wipe off the mold, but it re-grows. I've
>considered wiping the surface with a watered-down bleach solution, but I'm afraid it
>might somehow damage the plaster. Maybe it won't - but I just don't want to take the
>risk.
>
>I guess I could just leave the mold and not worry about it so much, but I keep hearing
>about 'toxic mold' in people's homes and how expensive it is to remove. I have a
>fear of this mold spreading.
>
>Any advice would be appreciated.
>
>Thanks,
>
>Mary Ellen
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
Janet Kaiser on mon 1 dec 03
>I prevent this from happening by elevating freshly poured
plaster at least
>a day or two.
Oh, dear, Jeff...!?! Sorry for laughing, but the mental image of
you standing holding up a mould for a day or two, maybe hopping
from one foot to the other and whistling, wondering what will
happen if you just let go for long enough the scratch your...
Well... FUN---NY!!
Thanks for the smile...
Janet - Little things please little minds - Kaiser
***********************************************************
The top posted mail was sent by Janet Kaiser
The Chapel of Art : Capel Celfyddyd
8 Marine Crescent : Criccieth : Wales : UK
Centre of Excellence for The Arts
Home of The International Potters' Path
Tel: ++44 (01766) 523570 http://www.the-coa.org.uk
Open: 13.00 to 17.00hrs : Tuesday to Saturday
************** AVG Virus Protected ********************
scott lykens on wed 17 dec 03
I know this is a day late and a dollar short and possibly already discussed,
but these holidays and moving every few months is killin me. so here we go.
while anything touching plaster will slowly erode the surface, even a
casting slip, this is a just wedging table, so I would mix up some food
grade bleach water and have at it.
whenever its old and crappy, hammer it up and dump in another.
_________________________________________________________________
Check your PC for viruses with the FREE McAfee online computer scan.
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
| |
|
