mixing up casting mixture.

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yowiedan
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mixing up casting mixture.

Unread post by yowiedan » Sat Sep 08, 2012 3:33 pm

hey is there a video out there maybe on you tube or of anyone on here on how to get the casting mixture right so amateur field reseachers can have a look at it.having a video of the actual mixture being done would help greatly.if anyone knows of any such video's please let me know.or any techniques to make it quicker and easier to do.thanks.

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Ray Doherty
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Re: mixing up casting mixture.

Unread post by Ray Doherty » Sat Sep 08, 2012 10:32 pm

Hi Mate

Firstly, visit a friend of mine site, Cliff Barackman. He is on finding bigfoot and one of the leading casting experts in the US> I was fortunate enough to spend a day with him in the field 6 months ago showing me Technics for casting and it has made a massive difference to what I do.

He is producing some stuff in the next few months which will be very useful try his site, www.northamericanbigfoot.com

But in short, you need a mixture that in consistency is akin to pancake mix. For some prints consider using a strip of aluminium as a dam to stop the plaster spilling out. If casting water, get a turkey or chick baster and after damning remove the water. I carry all of these things including water and a mixing bowl in a big pack because primarily thats one of the big things I am looking for. remember, you wont get the whole print in one bowl, you will need and can do two to three depending on size. You need a consistency that will get every nook and cranny of the print but not too watery where is takes house to dry thats why pancake mix is a happy medium, if found. IT should take 20-40 minutes depending on the humidity and direct sunlight and temp

Let me know how you get on

Cheers

Ray
'I want to believe'

NoPolys
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Re: mixing up casting mixture.

Unread post by NoPolys » Sun Sep 09, 2012 2:41 am

Dan;

Also check out this video, there is some good info in it.

http://www.youtube.com/watch?v=zU7m_M6u ... ature=plcp

A couple of caveats to Leigh's video;

Take several before photos and include a GPS for location if one is available.

Notice that Leigh has a forensic right angle piece of card stock for measuring. These are good IF you can find them and you don't mess them up while packing or carrying. I never had much luck with them. I use two steel rules screwed together (Lufkin brand one set 300mm a second one 150 mm). I open them to about 90 degrees (it isn't super critical but a 1-2 degree off angle is ok) then take photos with whichever one is used. They even come with a convenient hole to use!!! (lol) .

In the sandy soil we have over most of Australia, don't use pressureized hairspray, find the high hold Fructus (sp) pump hairspray ( buy at least 2 mine keep gettin borrowed ). Pump the spray over the the casting area, not into or onto it. Less disturbance to the substrates.

If you hear about splash casting methods, try them out. Splash casting takes longer, but ends up with better detail and fewer casting artifacts that can later be misinterpreted.

Always use a dam. Casting material is fragile, if you don't have enough thickness, they will want to break into pieces when lifted. As an aside, I use a roll of the aluminium material tradies use for damp course material.

When you do the final pour (or at the final half if you mixed enough for a single pour) add something to re-enforce the cast. Many people use Al wire. Don't bother with ferrous based wire, it rusts out quickly, wood also is not advised. Again, I'm a bit different and have found plasterboard fibreglass joint tape works well and is less expensive than some other options.

When you lift your cast, keep it dirty, don't take anything off the cast just place it carefully in the paper bag (Again, Leigh uses an "Evidence" bag...... trust me here, any paper bag large enough to handle the cast is good to use). If it won't fit in a single bag, take two or even three bags apart and tape them together with duct tape (seams only!) and cover the cast that way. Don't use any plastic material to cover the cast until it has cured for several weeks/months; there is a lot of moisture in the plaster and it takes time to get out. If you choose to use plastic for storage (plastic bags or "Tupperware") pack some dessicant in with the plaster cast.

Once back home, and after the cast is fully cured then remove the dirt from the cast. When removing dirt, do it over a clean surface. Many times material that was on the foot making the print falls off the foot esp if the print is in wet clay based soil. Hair has been recorded several times as have seeds. Look up "Locard's Exchange Principle" if you are interested in that part of the process.

Casting is a lot of work to do well. After you have a few casts, you may begin to wonder what the worth of a cast is. I'm not certain I can answer that question for you, but it is worth thinking about.

If you have any questions, feel free to contact me or post here.

Good Luck!!

NoPolys
"Everyone is entitled to their own opinion, but not their own facts." - Daniel Patrick Moynihan-

"There are two kinds of people in the world: Those who can infer concepts from incomplete information." -unknown-

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didgmaster
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Re: mixing up casting mixture.

Unread post by didgmaster » Sun Sep 09, 2012 8:36 am

I read somewhere you can speed up the time it takes plaster to set by using hot water, but It would still take time to light fire and boil billy ..

DILLIGAF

Re: mixing up casting mixture.

Unread post by DILLIGAF » Sun Sep 09, 2012 9:19 am

So which type of plaster do you recommend to purchase??

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yowiedan
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Re: mixing up casting mixture.

Unread post by yowiedan » Sun Sep 09, 2012 5:03 pm

gee i didnt know making a cast was so technical lol.after reading all the ways to cast a print im going to take a few casts using my own footprint and use these techiques and see what works best for me.thanks for all the answers to this question and i hope it helps with not only me but others trying to learn.

glenmore79

Re: mixing up casting mixture.

Unread post by glenmore79 » Sun Sep 09, 2012 6:44 pm

A good product is Hydrostone.

Commonly used in garden ornament molding and as light weight as normal plaster

I forget what the combo is but it's something like : 90% plaster 10%cement.
preserves detail like plaster does


cure time is approx 10mins depending on weather, heats up pretty hot while curing but cools fairly quickly.

You used to be able to buy it in 5kg thru to 50kg bags


Barnes sculpting supplies is the company that easily stocks it, they have warehouses throughout each state.
They supply a lot of gear to the film industry.

NSW warehouse is in bankstown. They did have a small store front in Newtown.

DILLIGAF

Re: mixing up casting mixture.

Unread post by DILLIGAF » Mon Sep 10, 2012 8:28 am

Thankyou for that, now I can play mud pies like a professional....

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Ray Doherty
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Re: mixing up casting mixture.

Unread post by Ray Doherty » Mon Sep 10, 2012 11:09 am

I for one found this thread very interesting and love when we have a "how to thread' I picked up some good tips from No Pol and Glenmore I will try to locate that stuff you mention in Brisbane.

Cheers
'I want to believe'

forestguy
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Re: mixing up casting mixture.

Unread post by forestguy » Mon Sep 10, 2012 12:02 pm

Ray Doherty wrote:Glenmore I will try to locate that stuff you mention in Brisbane.
Mate - pls let us know if you do, I had a quick look, but didn't find anyone yet.
"What is reported is different to what is remembered which is different to what was seen which is different to what was present."

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Ray Doherty
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Re: mixing up casting mixture.

Unread post by Ray Doherty » Mon Sep 10, 2012 12:09 pm

Here U go FG


http://www.barnes.com.au/catalog/advanc ... Hydrostone

Will let you know if I find a retail outlet on our side of town

Ray
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yowiedan
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Re: mixing up casting mixture.

Unread post by yowiedan » Mon Sep 10, 2012 12:40 pm

good to see how a simple question can always help others learn more about making casts of footprints.im happy now i asked this question.

glenmore79

Re: mixing up casting mixture.

Unread post by glenmore79 » Fri Sep 14, 2012 8:47 pm

another product is: Easy cast

It's a polyurethane resin and the detail that is retained is 100% "scientifically Accurate"

I used own a company that moulded dinosaur fossils for museums, everything from full size skulls to teeth.
Ultrasil, which is a silicone, was used to make a mould of the original specimen and then Easycast was used to replicate them.
(all fossils in museums are plastic and made this way)



it is exceptionally expensive unless you want to purchase the 200kg drums for about $2000
it comes in 2 parts which is mixed and then hardens in around 5mins with the rigidness and durability of hard plastic.

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yowiedan
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Re: mixing up casting mixture.

Unread post by yowiedan » Fri Sep 14, 2012 8:58 pm

i think i will stick with a much cheaper option lol.

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