We
will keep this a simple as possible with materials and tools
that you should find at Home Depot.
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Wire Cutter |
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Tin Snips |
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4" Drywall Knife
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10" Drywall Knife
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1" Stiff paint Brush
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4" Soft Paint Brush |
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Buckets (about 2 gallon size - convenient
but not critical) |
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If you can grow a third hand or have one
attached by you local doctor this will be useful.
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Step 1: Remove loose
or deteriorated plaster from the edges of the holes, it is good
to vacuum the dust from these edges.
Step 2: Cut some squares of
lathe about 2" larger that your hole - one for each hole. Attach
a piece of wire 4 to 6 inches long to the center of your pieces
of Lathe. Flex and fit into the hole so it is laying on the back
of the plaster.
Step 3: With a 1" paint bush
coat the edges of the old plaster with bonding adhesive. This is
critical: bonding adhesive stabilizes any remaining dust, and
prevents dry plaster from taking the water from the new plaster.
If water is absorbed at the joint the cement does not properly
cure, and you get a weak joint: this becomes a crack in about 6
months.
Allow
drying time of about 15 minutes before next step. The bonding
adhesive should not be completely dried.
Step 4: With 4" knife and
bucket mix a couple pounds of plaster. Start with dry powder,
add water, get out the lumps, bring it to about the consistency
of peanut butter. Toss in a couple handfuls of sand. (amount?
its not rocket science, it just reduces shrinkage and
strengthens the mix, important since this is going on thick).
You are only going to have about 10 minutes working time with
this. It gets hard in about 15 minutes. DO NOT remix or try to
use plaster that has begun to get hard, Throw it out. A few
pennies worth of over-worked plaster will cost you all the labor
of re-doing the job next week.
Wear
your Safety Glasses. This stuff is caustic it will burn your
eyes badly.
Step 5: Now you are on
the ladder, You have a bucket in one hand and your 4' knife in
the other. With your third hand use the wire as a handle to hold
you lathe in place while you pack plaster around the edges and
through the lathe. Your goal is to bond the lathe to the old
plaster. Keep this layer about 1/4" below the surface of the old
plaster. You should be able to let go of the wire, and have
every thing stay in place. At this stage it is good to be rough
and uneven with the fill. Let it get very hard. 15 - 30 minutes.
( good job, have a beer or glass of wine if you are a liberal)
Step 6: Mix another batch.
Fill your hole to 1/8" below the surface of the old plaster.
Take a small piece of lathe and use it as a tool to scratch the
surface of this layer. (now it's lookin' good have another beer
and relax).
Step 7: Mix one more batch.
This time NO SAND. With you 10", knife fill the hole evenly just
above the surface. WAIT until it starts to get hard. Dip your
soft paint brush in water, draw it across the surface of your
plaster followed by your 10' knife. You are wetting the plaster
and lubricating the knife blade as you are cutting off the
excess plaster. Your blade should be at about a 45 degree angle
with enough pressure to take off some plaster but not enough to
break it up. Start with light pressure, use more as it gets
harder. Tip your blade lower to fill any small holes with
accumulated plaster. (Repeat this process until the extra
arm falls off, you no longer need it anyway. ) You are
going to pass over it 5 or 6 times wait a few minutes and
repeat, doing this process until the surface is smooth and hard.
Step 8: Pick up the 3rd arm,
pat yourself on the back. You are probably the only one who will
notice what a great job you did. Drink some more beer, wait 2 or
3 weeks paint with Kilz. Plaster is very alkaline, modern paints
will not stick. This reduces as it cures over the next 2 to 3
weeks, but most paints still will not stick.
