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Dan Spector
Joined:
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02-Jan-2008
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Started On : 06-Jun-2009 at 11:59:19 PM, #Views : 7190
Topic Subject : Re: Re: Re: Re: Re: Re: Alginate volume( |
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Bruce: what is a 'molt'? or phorpous? What is a rotary vibrator?
As a plaster and resin mixer, I can say the Jiffy line of squirrel-
cage mixers is really good. But only if used right, which means
quickly dunking its head under the water's surface before getting it
going. This way it does not drag in air. But your paint store has far
cheaper versions that should be used the same way.
Everybody: please reread your emails before you post!
Dan Spector
901 323 8717
www.lifecast-art.com
dan@archicast.com
On Jun 6, 2009, at 10:10 PM, aliforum@lifecasting.org wrote:
> ------------Silica-Free & Oh So GREEN------->
>
> NEW! MoldGel SILFREE. A revolutionary formula.
> Made with all food-grade ingredients. It nourishes
> the earth when discarded. 3-to-1 mix ratio yields
> twice the volume as those 1-to-1 brands. Delayed
> shrinkage for delayed casting - so creamy smooth, too.
> To learn more about it click here
> ---------------------------------------------->
>
>
> Hello Dan Spector
>
>
> Post Date : Saturday 06th 2009f June 2009 11:04:29 PM
> Posted by : "Bruce Teter" trisquare@verizon.net
>
> Re: Re: Re: Re: Re: Alginate volume(:--
> Dave.
>
> I would question the use of a high speed rotary mixer, as those
> larger ones
> that are used for plaster. These tend to fill the molt full of air
> and air
> whipped molts are very hard to predict end results or hardness. We
> do not
> use whipping for any water or phorpous bases they will and do
> result in first
> surface bubbles that take time to remedy later. I mix everything in
> a rotary
> vibrator using a wisk drugg through the mix to start slow so as not
> to whip
> it. Then the vibration is turned on and it will mix the batch and
> any air
> bubbles are very quickly brought to the top of the batch and
> eliminated as
> they surface. I have sectioned materials under 1600X polorized scopes
> and have not found any air entrapment. Later Bruce
>
>
> 222 aliforum@lifecasting.org
> Subject: A new topic has been added-Re: Re: Re: Re: Alginate volume
> ( Message No. 2235)
> To: trisquare@verizon.net
>
> > ------------Silica-Free & Oh So GREEN------->
> >
> > NEW! MoldGel SILFREE. A revolutionary formula.
> > Made with all food-grade ingredients. It nourishes
> > the earth when discarded. 3-to-1 mix ratio yields
> > twice the volume as those 1-to-1 brands. Delayed
> > shrinkage for delayed casting - so creamy smooth, too.
> > To learn more about it click here
> > ---------------------------------------------->
> >
> >
> > Hello Bruce Teter
>
> >
> >
> > Post Date : Saturday 06th 2009f June 2009 05:46:07 PM
> > Posted by : "Dave Parvin" parvinstudio@comcast.net
> >
> > Re: Re: Re: Re: Alginate volume:--
> > Ann, you are correct, too much water will weaken the alginate.
> Though one might think that a
> > thin or runny mixture would produce a casting with fewer surface
> bubbles because any bubbles
> > would rise to the top and escape the solution with a pour mold as
> you are describing. Also, a
> > runny mixture will have a slower setting time allowing for more
> bubbles to escape. But one would
> > be WRONG. What happens is that those rising bubbles come up to
> and attach to the bottom of
> > of the casting producing "outies" that have to be repaired. You
> can mix the alginate to a
> > consistency that is more runny that optimum for a skin mold but
> make it just runny enough to
> > pour easily. By not delaying the setting time any more than
> necessary, you will also trap bubbles
> > in the alginate away from the skin surface.
> >
> > Another thing that I find helpful is that just before I pour
> alginate over the hands (or feet) or have
> > the model(s) push his/her hand(s) into a container of alginate, I
> scoop some alginate into my
> > hands and rub it over the skin to eliminate any bubbles on the
> skin surface and force it into ever
> > nook and cranny.
> >
> > I agree with Robert, always mix powder into liquid and not the
> other way around. Chefs are
> > taught to do the same.
> >
> > I also use a "jiffy" type mixer and a variable speed drill with a
> seed range of from 0 to at least
> > 2,500 R.P.Ms. It is good to have some power so I want an amp
> rating of at least 7. I start mixing
> > very slowly increasing the speed as the alginate becomes wet. I
> start a timer as soon as I
> > combine the alginate to the water and mix until smooth which
> takes 40 to 60 seconds depending
> > upon the amount. I generally do not try to mix more than 6 pounds
> (2724 grams) of water and
> > the appropriate amount of alginate in one container. If mixing
> more, I divide the water and the
> > alginate into two (or more) batches. Obviously, the larger the
> batch, the longer it takes to mix.
> > Take too long and you may run out of time to get the alginate
> applied. I either mix half myself
> > and have an assistant simultaneously mix the other half; or I mix
> half and as soon as I am done
>
> > have an assistant start the second batch. If my assistant is
> skilled at applying the alginate, we do
> > it the first way. If she/he isn't so skilled and I pretty much
> have to apply the alginate, I do it the
> > second way.
> >
> > The tricky part is getting mixture just right which comes from
> testing and experience. I can't give
> > you universal proportions because alginates really differ
> depending upon the brand. But when I
> > get a new batch, I carefully test a small sample to know what I
> have. Even the same brand can
> > vary somewhat. Not only do I weigh my test samples carefully but
> I use 80 degrees F. (27 C.) so
> > I can verify setting time as well. I then mark the results on the
> container.
> >
> > I usually weigh both the water and the alginate whenever I am
> mixing them to assure
> > consistency. Robert said that he mixes by vol. as well. I do too
> in some applications. Remember
>
> > guys like us have been doing this for a long time and can tell at
> once from experience if we have
> > to make an adjustment. I'll bet that Robert does what I do, has
> both water and alginate handy
> > when mixing just in case.
> >
> > While I sometimes use water warmer than 80 degrees to shorten the
> setting time, I rarely use
> > colder to slow it down. To do that, I use AlgiSlo. Not only is 80
> degrees comfortable for the
> > model, but the published setting time for most alginates assumes
> water at 80 degrees.
> >
> > Ann, this may be more than you wanted to know about alginate, but
> I hope it has helped. I am
> > still planing on finding out how much the vol. of the water is
> increased by addition of the alginate
> > and will post it here next week.
> >
> > Dave
> >
> >
> >
> >
> >
> >
> >
> > ALI is an international organization whose members are engaged in
> the art and creative
> > industries. Its purpose is to promote the art of life casting
> create public awareness of this unique
> > art form, provide its members with forums to exchange
> information, resources to enhance their
> > effectiveness and advance opportunities for their artistic success.
>
>
>
>
>
> ALI is an international organization whose members are engaged in
> the art and creative industries. Its purpose is to promote the art
> of life casting, create public awareness of this unique art form
> provide its members with forums to exchange information, resources
> to enhance their effectiveness and advance opportunities for their
> artistic success.
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