Runboard.com
You're welcome.

runboard.com       Register for a free global account (learn about it) | Log in: (), globally (lost password?)

Page:  1  2 

 
youngbat Profile
Live feed
Blog
Friends
Miscellaneous info

Caped Crusader
Global user

Registered: 02-2004
Posts: 1182
Reply | Quote
Plaster Primer


This tutorial originally posted on LOH.



On our new website we will run some .mpgs. I will try to get Klocket over here with his digital camera, and see if we can get some footage of this down.

I will take more pictures of these molds. I want you to see the leg on the other side. The "secret" behind short work time in making the mold is preparation and not using burlap. You only need two layers of plaster. NO more.

The secret behind cutting your labor time in making the mask is having a good mold. By having a good mold I mean having a mold that eliminates problems and does the work for you instead of you having to jump over hoops each time you run a piece of latex.

To eliminate problems you first gotta know what they are. First you have to know your working time with plaster. This is based on how much MASS is contained in a given area. More contained the mass the shorter the work time as this stuff reacts to a cross-linking reaction, one molocule reacts to another which then reacts to another. i.e. If you poured a bucket of plaster out on the floor it would take more time to harden than if you let it sit in a bucket. This is important.

So how much time do we have to get the plaster on the sculpture? Depends on the amount of plaster/water, and size and shape of the container we mix in.
     
You want to have two buckets of water ready to go right next to the BUCKET of plaster. Never leave your plaster in a bag. If moisture gets to that plaster, you gotta dump it. Put it in a nice clean plastic garbage can with a lid.

Have the sculpture, plaster, buckets of water, reinforcement material, and hand drill with a mixer within inches of each other before you actually start. You don't have time to go searching for your hand drill, or anything in the middle of this.

You want the mixing container to be 5 times the volume of the water/plaster combined. You want a lid with a hole for the mixer to go through so you can pop the lid on and SHEAR the water/plaster. Let's cover some points.

1. Mixing time: 1 1/2 minutes max.

2. Beauty coat application of a piece slighty larger than a human head. about 2 minutes. Get it on gently pushing it into any nooks and crannies. Watch tips of noses, ears, using rubber gloves of course.

3. Without a pause mix the second coat. After mixing for 30 seconds add 3 sixteen ounce cups of chopped fiberglass per gallon of water/plaster, pop lid back on and shear for another minute.

Stop. Pull lid off. (This keeps the plaster from spraying all over the room. get a GOOD plastic lid, a cheap one will shatter.)

4. Apply to the reinforcement coat by hand gently working the mix onto the first coat. The first coat should still be a bit "wet" looking.

5. As the second coat starts to thicken and harden, dip your hand (in rubber gloves) in water and groom, packing the material on nice and tight. Keep grooming and keep your hand wet with a cup of water nearby.

This will take you into the remaining 15 minutes. During this time is when you will have stuck on a leg(s). Putting on one leg is pretty easy, there is a trick to doing two or more. You can use metal spatuala to pack and groom, I just my hand with a latex glove.

It doesn't have to be beautiful, but the material should be packed in tight with no internal bridges, and the outer surface not real lumpy, or sharp/jagged.
 
6. Never dump unused plaster in the sink. it goes in the garbage. All pails, buckets should be re-usable.

Again the best way to show all this is by video, which I don't have a the moment.
 
So now we have a mold of an item slightly larger than a human head (cowl?). After we pulled the clay out, we have baked it a 100 degrees and completly got all the internal water out. It stands up in the middle of the floor all on its own unable to easily tip over. It weighs approximately 10-15 lbs. When we tap it with a small hammer we hear a nice "clang".

Now we are going to fill this thing with an inexpensive, durable, material that contains a rather nasty type of AMMONIA.
 
Now here we have a couple of choices. we can either just breathe the stuff (not good). Or we can protect ourselves in a couple of ways. The easiest way is to get an ammonia respirator. But you will have to store it in a clean tupperware container, alway remember to use it.

Another way is to put a lid on that mold. Now you can open the 1 inch nozzle on the 5 gallon pail of latex, pour it into the mold through a 1 inch opening at the top of the lid. Plug the hole on the mold lid (urethane rubber cork - hardware store). You got a minimum of ammonia hitting you in the face. Let it sit for four hours. Time spent. 2 - 3 minutes. I will discuss making a lid for your mold later.

Emptying out the mold shouldn't be too heavy for a mold this size, but if you are making say, large mascot heads like you see in football games, the mold will obviously be bigger, and the weight of the mold plus the latex to fill it will require a hinged cradle so you can tilt the whole mold to empty it out with just the lift of a lever. That's another tutorial.

One thing I like to do is wipe a smear of latex in the mold before just dumping it in. this eliminates air bubbles caused by surface tension if your sculpt is "smooth". or has no detail. Some like to spray a mist of distilled water in the mold prior to filling it. Remember the longer you let the latex set in the mold, the thicker the piece will be.

This is a short brief explanation of the mold in the picture above. Again I really need to get this on tape to illustrate the fine points. But let me say this. I think that plaster and latex are rarely used to thier full potential. I use plaster where and whenever possible and use only other materials if REALLY neccesary.

The nice thing about latex and plaster is that it makes a CLEAN mess, i.e. one that you can clean up off the floor, that doesn't require chemicals like alchol, and acetone to wipe up unmixed portions off of tables etc... The only real nasty danger here is the AMMONIA. And do fear that stuff.

One other point, I always say weigh out the plaster and water, but you can covert this to by volume and it works just fine. The thing you want to avoid is EYEBALLING the mixture. Get it down so that you know how much water and plaster it will take to cover a piece of a given size for each coat.

Again I am sort of glossing over the whole spectrum. But this should basically explain the mold above. To recap:

1. Molding should take 15-20 min. max. for a piece the roughly the size of a human head. This time starts the minute you hit your hand on the hand drill until you walk away.

(Not included is your preperation, trips to the hardware store. or getting out of bed, etc...)

2. After you demold, bake it out at 100 deg for 2 days.
 
3. Build a "cover" for the mold (optional). I personally like this method of eliminating the exposure to ammonia.

4. Another key point - Your sculpture should be sitting on a lazy susan so that you can spin it around to get at all areas without having to walk around, or reach around the back. Man does this help.

5. Get used to the idea of using ONLY 2 coats of plaster. And stick a clock in front of you so you get your time down (so you don't get on the phone, or distracted). Eventually this rythm will become second nature.

6. This time is for a Single piece mold mind you. A two part mold of this size would be 7 min. on each side, plus the time it takes to build a dividing wall, remove the dividing wall from the first half, clean it up, etc. The mold above is a single piece mold done in one shot.

Other related issues - Backing up your skin with Polyfoam v.s. reticulated foam. What are the benefits of backing up a skin with polyfoam and is there a better cleaner way to insure the skin keeps it's form on the wearer?

What we care about:

1. Safety.

2. How does the piece look on the wearer, standing still and when we move.

3. Durability.

4. Longevity of the piece.

5. Shrinkage of latex.

6. Exposure to ammonia.

7. Attachments.
 
8. Lightweight molds.

9. Durable molds.

10. Molds that make producing a piece fast, easy, safe, fun, & clean.

11. Molds that suck - Heavy molds. Brittle molds. Chalky molds. Molds that tip over constanly. Molds with sharp jaggedy edges that rip our skin. Molds that do not allow us to properly fill it with latex. Molds that have spots thinner, or thicker than 1/2". Molds of roughly a human head size that weigh over 18 lbs. Molds that are two parts when one would have been better, and molds that are one part when two would have been better.

12. Molds that rock - Any mold that makes the process easier. Produces X no. of great pieces. Lightweight. Easy to store. Easy to move. Doesn't tip over. Has a nice "clang" sound. Feels almost like metal to the touch. Looks fairly nice. And has a lid to keep the ammonia from blasting us in the face. Molds that make us feel like we could almost do this wearing nice clothes.

Last edited by Deadly Lemur, 3/18/2006, 11:23 pm
8/8/2004, 1:49 pm Link to this post Send Email to youngbat   Send PM to youngbat
 
youngbat Profile
Live feed
Blog
Friends
Miscellaneous info

Caped Crusader
Global user

Registered: 02-2004
Posts: 1182
Reply | Quote
Re: Plaster Primer - by request.


Here is another shot of the same mold, a little bit better angle. Here you can see that the mold is just a little bigger than the sculpture. This is the simplest piece to add a leg as you only need one, here I used a 1 1/2" steel race car chassis tube. You don't need anything this big, it was a piece of scrap that was handy. One thing that would've been nice would be the addition of a handle to pour back the latex. You sure a heck don't wana lose your grip when pouring back the latex and have it end up on the floor. You can see it even a little under 1/2" thick if you look at the edges. Sorry the picture is sideways.

--Log in or sign up to see linked image content--

edited to include image emoticon

Last edited by The BlackBat, 8/8/2004, 2:37 pm
8/8/2004, 1:57 pm Link to this post Send Email to youngbat   Send PM to youngbat
 
youngbat Profile
Live feed
Blog
Friends
Miscellaneous info

Caped Crusader
Global user

Registered: 02-2004
Posts: 1182
Reply | Quote
Re: Plaster Primer - by request.


Then Brin asks a question and I reply:



To answer Brins question: It's about the consistency of the plaster. i.e. if it's too watery it will all slide down. If it's too thick chances are real good you will bridge somewhere. So, again you gotta weigh this stuff out. The big thing is consistency each time you mix.

If your beauty coat is all sliding down even though you weighed it out, chances are you are putting it on too thick in one shot, and the weight of itself is pulling it all down. Remember 1/2" thick ain't very thick. that's about 1/4" or less for the beauty coat, which just a freckle past a thick layer of paint.

One other thing, if you put on the reinforcement coat too soon, you will get print through of the reinforcement coat. If you put it on too late and push on the beauty coat too hard, you could crack the beauty coat and end up with hairline cracks everytime you pull out a mask.

If that beauty coat goes totally flat and non-wet looking, over time the inside of the mold will start to chip (de-lamination). Timing, experience, practice.

Also I use Hydrocal B11, not Ultracal 30 (30=30 min. set time, 60=60 min. set time.) I WANT this stuff to set up fast, cause I want this to be over quick, AND Hydrocal sucks up the water in latex fast.

My suggestion would be stick to one or the other (know your choice of material intimately). Your timing will be based partly on which type of plaster you use and of course, how much you are mixing.
      
One thing here - If I were to hire someone on a big project, one that could cost me money and a reputation if it failed, I would rather hire someone who knows the crap out of a few select methods and materials, as opposed to someone who has dabbled in a zillion different types of stuff. Be patient and stick to one method/material situation until you are a freakin guru at it...

Sculpting is the same thing. There are people who sculpt natural wildlife like you can't believe, but don't know a crap about Batman. Same goes for making silicone heads, I sculpt em' but I could not at this exact moment in time do what Bob Causey does with these heads. He has spent the last two years doing mostly this. It's an aquired skill, i.e. one that has formulas but, the real excellence comes in just doing it over, and over, and over, and over. And ultimately the gifts that are born with enter into the mix.

Last edited by Deadly Lemur, 3/18/2006, 11:26 pm
8/8/2004, 2:00 pm Link to this post Send Email to youngbat   Send PM to youngbat
 
youngbat Profile
Live feed
Blog
Friends
Miscellaneous info

Caped Crusader
Global user

Registered: 02-2004
Posts: 1182
Reply | Quote
Re: Plaster Primer - by request.


Then the disclaimer:

One thing I should add. this is the situation according to Bob Dullam. There are always many ways to approach a given situation. Based on my experience, whatever inate talent I have, this is what I conclude makes the most sense to me. I can't guarentee you will like the method, or be successful at it. Everyone sees things different. Hell, there could be a kid down the street who could come up with a method that makes more sense than anyone could've ever imagined...
8/8/2004, 2:03 pm Link to this post Send Email to youngbat   Send PM to youngbat
 
Jants Profile
Live feed
Blog
Friends
Miscellaneous info

Banned user
Global user

Registered: 02-2004
Posts: 2291
Reply | Quote
Re: Plaster Primer - by request.


"The Man", nuff said. :up

---

8/8/2004, 2:15 pm Link to this post Send Email to Jants   Send PM to Jants
 
The BlackBat Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 01-2004
Posts: 8469
Reply | Quote
Re: Plaster Primer - by request.


Guys, this is a wealth of information at your fingertips...

Bob, thank you so much for sharing this with us all. Janty summed it up nicely. :up

~Tim :batfly

---
"We all walk in the dark and each of us must learn to turn on his or her own light."

8/8/2004, 2:30 pm Link to this post Send Email to The BlackBat   Send PM to The BlackBat
 
Deadly Lemur Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 01-2004
Posts: 3661
Reply | Quote
Re: Plaster Primer - by request.


hey bob, very cool of you to post this! it must have taken you awhile to write it all out, and i'm sure many people will be grateful for this.

i can't see you pic though... i don't know if it's on your end or mine. let me know if you need me to host pics for you or anything. :)

---
~Heather~

~i don't need a compass to know which way the wind shines!~


8/8/2004, 2:31 pm Link to this post Send Email to Deadly Lemur   Send PM to Deadly Lemur
 
Blackwood Bat Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 02-2004
Location: ummm...the Batcave
Posts: 6009
Reply | Quote
Re: Plaster Primer - by request.


You are the MAN Bob! :up
As Heather said,thanks for taking the time to write all this out. :)

John :flapbat

---
"Wile E. Coyote is my reality,Bugs Bunny is my goal."

8/8/2004, 2:42 pm Link to this post Send Email to Blackwood Bat   Send PM to Blackwood Bat
 
youngbat Profile
Live feed
Blog
Friends
Miscellaneous info

Caped Crusader
Global user

Registered: 02-2004
Posts: 1182
Reply | Quote
Re: Plaster Primer - by request.


I made a correction to point #4, instead "beauty coat", it should have said "reinforcement coat".

Heather, I can see the picture here, but if it doesn't come through for others, go ahead and copy it from the LOH, and re-post it. I have had some problems with my picture hosting thing.. mrbats has these as well.

some related topics.

1. keys: gutter keys, ribbon keys, the shim method, water clay, pre-made keys.
2. one part molds: When not to, When to, how to.
3. clamping edges: building good ones v.s. bad ones.
4. multi-part molds: How to determine the need.
5. seaming rubber (making seams go away).
6. armatures. good ones v.s. bad ones. what type to use in what situations.




Last edited by youngbat, 8/8/2004, 3:41 pm
8/8/2004, 3:32 pm Link to this post Send Email to youngbat   Send PM to youngbat
 
Deadly Lemur Profile
Live feed
Blog
Friends
Miscellaneous info


Global user

Registered: 01-2004
Posts: 3661
Reply | Quote
Re: Plaster Primer - by request.


no worries, looks like tim got your picture up for you already. :wink

---
~Heather~

~i don't need a compass to know which way the wind shines!~


8/8/2004, 6:51 pm Link to this post Send Email to Deadly Lemur   Send PM to Deadly Lemur
 


Add a reply

Page:  1  2 





You are not logged in (login)