Raul Alvarez wrote:

> Hi All,
>
> Started working on a seismo vault here.  Plans are to use an old, but
> still water tight, cistern that was on the property when we purchased it
> some five years ago.  The cistern is 4 feet wide, 8 feet long and 5 feet
> high.  The top is about 2 feet below grade. Seems like it would make
> a great seismo vault.
> My guess about it still being water tight is that it was mostly full of
> water but the outside ground is very dry.  Since I pumped it out, water
> hasnot re-accumulated.
>
> My questions are: I want to be sure it will stay dry.  What, if any,
> paintcould be used to seal it from the inside?
> Also, after being in it a while, getting the last of the water and silt
> out,I got to thinking about the effects of the echoes created in such a
> box,
> and how they may affect a seismo.
> Any suggestions, comments ???
>
> Raul
>

Hi Raul,

Sounds like you have indeed struck "gold", as far as a vault.
If there is any cracks, a fast cure concrete usually works fine.
Of course, if possible, some kind of drainage sump pump would
be necessary to prevent equipment damage in the future. You
didn't mention the access, which is the likely cause of the
water entrance...it would have to be built up with some water
proof roof and/or more concrete I expect. I built up my crawl
space entrance afew years back with concrete.  Being as the
new layer of concrete probably won't adhere very well with 
the old concrete, I applied a layer of black thick plastic
type water repellent on in the area....don't remember the exact
brand but its normally used to cover concrete driveways, roofs.
My crawlspace entrance is covered with a pivoting joint cover.
I also used rubber weather stripping between the cover and the
concrete.  The cover also has air vents on the south side, away
from the prevailing northwest weather circulation pattern.  Its
also heavy enough that the winds don't "lift" it, and slam it
around.

The only concrete I've ever painted, was my cinder block
garage...which had several layers of unknown brand paint,
over some 50 odd years.  After wire brushing existing paint
separations, peelings, and filling of minor gaps, I used a brand
called CongoPro.  Its a mixture of acrylic and latex.  Its been
on two years and except for the very bottom edge contact with
water, it seems to adhere better than most paints I've ever ran
across.  This is on the outside of the garage of course.  I've even
contemplated the inside, but as ugly grey as it is, I figure the air
movement helps keep the inside dry, and any paint may actually
weaken the concrete, if water gets in the blocks.  Solid concrete
could be different, and may well work fine with paint on it. Hope
the concrete is not powdering with its ? age.

Outside of the above...is your vertical milling machine working
since acquisition?

Meredith Lamb


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