Marissa Bartz: Hi, my name is Marissa Bartz and I am a Research
Associate here at the National Center for Preservation Technology and Training, and
I am working on a research project where we are trying to prevent efflorescence from forming
on historic [inaudible 00:00:21].
What we are trying to learn is which commercial products work the best in preventing efflorescence
from forming on historic [inaudible 00:00:29].
And the tests I will be showing you today is how we measure the salt concentration not
only on the surface of the wall but also throughout the wall as well.
We will be taking core samples using a drill and then collecting the samples and then running
an analysis on them.
For this test we are using the Mesilla Valley Preservation field toolkit, which they used
on the Adobe structures in New Mexico.
Some of the tools that I will be using is this hammer drill.
Marissa Bartz: As you notice we also have a fairly long drill
bit with a copper tube which we use to collect the core samples as we go in the wall.
I marked the copper tube with half inch increments and we go actually all the way to 16, because
the wall width is eight inches.
I will be drilling the first 12 samples or six inches in the front and then through the
back I'll be doing the final two inches because I found that when I tried to go all the way
through from the front, the last two inches of the wall would actually break off and fall
off, this meaning I couldn't collect the samples.
Another tool that you will need are protective head gear or really just to help with the
noise, because the hammer drill is very loud.
We will need sample baggies properly labeled with whatever your labeling system is.
Marissa Bartz: We will need a ruler or a tape measure, whatever
you prefer, to figure out ... We want to line up the hole from the front to the back.
That's why we need the tape measure.
We also need painters tape, which I will use to apply to the wall.
And because this is our final test on the wall, we're not concerned with the residue
that it may leave behind, but we tape a piece of paper to help collect the sample when it's
coming out of the wall.
We don't want to have any sample missing while we take our test.
We also will need gloves, because the drill does get hot as you're doing it.
That's one of the reasons I actually take breaks every couple inches when I go into
the wall, so that way the drill doesn't overheat.
And finally you will need a little brush, because we will brush out the sample to make
sure that we collect it all as we go through.
Marissa Bartz: And then on this end, I actually tape two
things together, it's a little scraper, because it helps collect the sample into the baggy.
All right, so without further ado, I will show you guys how I drill this.
What I will do is put the piece of paper on the wall and I will tape it to the brick that
I will be drilling.
I tape it to about here and I want a little bit overhang, because it does ... When you
start to drill it does kind of find different directions, so I try to collect it as well
as I can.
And I use a couple of pieces because I want it to be secure.
Marissa Bartz: All right, so we'll be drilling in this square
here, and I don't crease the paper, because it makes it actually harder to collect the
sample, so I just kind of fold it up and then I tape it just like this and it will collect
the sample as it falls out of the hole when we pull back the drill.
All right, so then you create this pocket here, so because especially the first drill
it's going to spin and then the surface will fly off.
It doesn't collect in the tube right away.
That's one of the reasons we do the piece of paper.
Now we will put on the protective noise gear here.
All right, you just line it up with the tip here and then you try to keep it as level
as you can, because it will help you meet the hole on the other side.
While you're drilling, you're going to go up until the line is even with the surface
of the brick, and that's when you know to stop.
You pull the drill back, but you make sure you change the direction of the drill, because
then you'll put it above the paper and you'll spin it in that direction and the powder will
come out whatever's collected in the tube.
And then you take your brush and collect the sample, that's still in the hole.
And I take the sample bag that says number one and I scrape the powder out.
Marissa Bartz: And that's the first sample.
Seal it up, put it down.
And then the other thing I forgot to mention is you also need a Shop-Vac, because I vacuum
out the hole in between each sample to prevent cross-contamination.
I then do a visual check.
Cool.
No powder.
And then I move on to the next sample.
And I will do this for the first 12 and then I will show you again how to meet from the
back.
All right, so now that we finished the front six inches of the wall, I'm going to show
you how I line up the back hole and it's okay if it's not perfect, because we're really
worried about making sure the depth that goes all the way through the wall, because we really
want to understand how the salt goes from the front to the back and everywhere in between.
What I do for this is I have a tape measure and a Sharpie and you may be wondering why
the back of the wall is white is we actually painted it with a water and permeable paint,
that way we could simulate being the exterior of the wall and this being the interior.
That is why this is white.
All right, so I take my tape measure, I line it up and I try to see how far the edge of
the hole is to the edge of the brick.
Marissa Bartz: Then I look it up on the back and I line it
up and I just mark it with a pen, the outermost corner, and then I just see how far it is
from the top.
I get two directions here.
And then I use my two marks that I made on the brick and I just draw a circle and that's
approximately where I'll be drilling.
Then I tape a new piece of paper on just like I did in the front using painters tape.
Then we just again roll the paper up.
No crease.
As I said earlier, it makes it harder to collect the sample when there's a crease in the paper.
Marissa Bartz: The trick is just to hold it as steady as
you can, because it tends to like to move a lot on the back, because of the paint.
Verse the drill bit.
Collect a new sample bag.
And the thing to remember when you're going from the back is the first sample is actually
going to be 16 rather than number 13, because you go one to 16.
Just make sure you label that as the last sample since it's from the back.
And then you again clear out the hole with your Shop-Vac.
The visual check and there's no powder, so you can move on to the next wall or to the
next sample I should say.
Marissa Bartz: As I said at the beginning of this video,
this analytical technique was developed by the Mesilla Valley Preservation Inc, and they
are actually ... They have many videos on how they use this sampling technique on Adobe,
but they also have a video on how they analyze the samples.
And we do it exactly the same way here.
We will put the links below this video, so you ... If you use this tool for your own
research, then you'll be able to see how to do the analysis of these samples.
Also under this video, you'll find links to other analytical techniques that we use here
at the National Center for Preservation Technology and Training, as well as links to other projects
that we may be currently working on.
Thanks so much for watching.
Bye.