Tube, from your post
Pumice! Yeah, I didn't have to buy Spill Magic--I could just get some pumice! I can't remember what I did next: I'm sure I searched the Internet for a source of pumice in Seattle. Eventually I found Seattle Pottery Supply. My memory is that they told me that they labeled their pumice as "volcanic ash."
it sounds like you were using pumice all along rather than actual volcanic ash - and knew that. You've accused Melissa of not following your directions, but nowhere do I see where you told her to use pumice. Throughout this thread
http://www.bigfootforums.com/index.p...c=11363&st=225)
when she started her experiments, you repeatedly told her to use volcanic ash, not pumice.
I've asked her to comment and this was her reply:
"I could find no reference to him telling me to use Pumice,(May 19 2006, 03:31 PM I received the Pumice tip from an employee of the pottery store, who said I could look at pumice which is material from a volcano, but its not as fine as volcanic ash (I was told that over the phone and thats when I typed this post)
May 17 2006, 08:44 PM
Ok tube - I will do this "challenge" --- question ,, what if I get the same results?
In fact - I have an idea. Ok, to the store I go this weekend ...
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(I actually went over to the store on a week day.)
So, I went to this pottery store and after reading what Tube had written about the substrate being lightweight, and the consistancy of Powdered Sugar - I knew this wasnt the stuff (or so I thought). Thats when I posted the very first post you see from me dated May 18th "As Fate would have it".
I was jazzed by the idea of the Pumice (although tube never said a word to me about it) but even the store owner who does all the measurements said whomever told me over the phone that Pumice was comparable to Volcanic Ash, was wrong. He showed me Pumice - and I didnt think in a million years that stuff would work at all. Wish I knew then what I know now.
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May 17 2006, 07:47 PM Post #208
Tube
We don't have the original cast. I accept that the copies I've seen and own are accurate representations of the original. Therefore I examine
the copies to try to understand how the textures on the original arose.
I'm satisfied that the textures on the original cast arose entirely as a result of the casting artifact process. Now exactly what the mechanism of
this process is, I'm still trying to work that out. Perhaps the expansion of these cements is involved. I'm satisfied that wicking, lack of
adhesion, and plasticity of the substrate are all necessary conditions.
I propose that you will understand how ridiculously simple this all really is by simply doing this test for yourself. Zip on down to the local
pottery supply store and buy 10 or 20 pounds of volcanic ash. Dump it into a big turkey roasting pan you buy at the local Goodwill for $3.50.
Put rubber gloves on. Lightly tamp down a big foot shaped depression into the volcanic ash. Include toes so you will see the "ridge flow
pattern" as it winds around the pressure ridge that separates the toes from the ball. Mix your plaster of Paris slightly on the thick side and
keep mixing for a minute or so longer than normal. Pour into the center of the "track" and keep pouring into the same spot in the center of the
track until the track is filled with slurry. Pull the cast an hour later. Let cure overnight. Very gently remove any remaining ash. You will see
"dermals" for your very own self, and hopefully you will get a "ridge flow pattern" that closely resembles the Onion Mountain cast.
You will know the truth, and the truth will set you free!
Good luck!
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May 18 2006, 08:05 AM Post #215
Melissa:
Tube - As fate would have it - I can not just simply "Pop" into my local Pottery Supply store and pick up a 20 pound bag of Volcanic Ash
Yes, this does frustrate me.. lmao. I already had the roasting pan - so that was the easy part.
But, this is not over, just a minor bump in the substrate. LMAO. (I crack myself up!!)
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May 19 2006, 01:43 PM Post # 241
Tube:
No, I've yet to get to the point of doing splash casting. I made the copy just by pouring the slurry into the mold. I did make a mistake which I
mentioned earlier in this thread in using too much "Pam" brand nonstick spray as a release compound. This resulted in a couple of hairline
fractures on the cast. Fortunately this did not affect the ridge textures that concern us.
Since an elastomeric female mold will not wick or deform as would real world soil, you really don't need to go to "splash casting", you can
just pour the slurry right in.
Good luck on your volcanic ash casting tests! Since I don't work with pottery, I don't know the ins and outs of the pottery business. The
volcanic ash I'm buying here in Seattle is very fine, at least as fine as powdered sugar or wheat flour. Make sure what you get is a very fine
powder.
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Tubes first post after Melissa's first set of tests with TriCalcium Phosphate
May 20 2006, 02:59 PM Post #246
Tube:
Some substrates will allow formation of casting artifacts and some will not. This is why I recommended you try volcanic ash, as it has worked
for me. I have no idea if this other material would work or not.
Remember, at some point you need to run a control, in which you create a foot shaped "track" using gloved hands so the track has a known
smooth texture. Any surface textures that result from the cast you make in the track must be artifacts.
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Post 261 May 22 2006, 01:35 PM
Excerpt from post
Tube:
Also, I would reiterate that you should experiment with substrates that indeed can create casting artifacts such as volcanic ash (which may also be sold as pumice, I believe) or fly ash. You live in Texas so I know you have no shortage of dry soils to test too. If you absolutely can't find volcanic ash where you are, I can arrange to send you some from here in Seattle. Fly ash you should be able to obtain cheaply at places that sell concrete and concrete supplies. Fly ash will produce casting artifacts with Hydrocal B-11 but not plaster of Paris or Ultracal 30."
Now, what about those directions?