Statue Forum 

Go Back   Statue Forum > Home Grown > Sculptor's Pit Stop

Thread Tools
Old 03-12-2006, 08:35 PM   #1
martin canale
Company Moderator
martin canale's Avatar
Join Date: Feb 2005
Location: argentina
Posts: 604
Old Tutorials

Well I know this was too see already but maybe some Newbie can find something interesting

Sculptors always have a wide selection of tools which he or she feels most comfortable using. In fact, we have lots of modelling and dental tools, but we use to work just with five or six of these whilst sculpting a figure. And don’t you ever forget you have some great tools stuck to the very end of your arms, most useful for the early stages.

Starting off
It’s a fact that preparation is the key to success. You have to make a good research and gather as much reference material as possible. One thing you should keep with you all the time is a book on anatomy, especially when planning the proportions of your figure. This is a crucial part of the process, so take your time, have fun, and do some investigation.
Perhaps you like the idea of having a proportionally correct photocopy of a figure and resize it depending on the scale of the piece you are going to work on. We strongly recommend to use these same resized figures for the armature planning.

An armature is just a framework that provides the basic form and proportions for your figure. It also makes the sculpt much more resistant and lets you to pose it in whatever position you require. We use two sizes of wire to make an armature: for the main part we use aluminium paper (to give volume to the thorax), after that we cover it all with fast action epoxy clay.

You can find many kinds of wire in your local shops but it all comes down to budget and preferences in the end.

We use to work the character’s head and hands separately. Why? Well... these two areas need much more detailed work than the rest. Needless to say, making them individually helps to get to those hard to reach places. First of all we sculpt the head, since it is the focal point of every figure, the most important part of the kit. What does this mean? It means that nothing else matters if the head isn’t right.

For the head we use a piece of wire. We make something similar to a circle in one end, where it will be made the head. Then we cover it with epoxy clay until it gets half its intended size. This way we make a base where we should sculpt all the rest. Once the head has been sculpted, it can be attached to the main armature by cutting the brass tube to the
correct length and slotting it over the neck. This way you can also pose the head and remove it if any correction is needed.

The Main Figure:
Once the head is finally complete and in place you can start building up the clay on the main body of the figure.
You should over exaggerate the pose, since the addition of clay reduces the impact of what it was supposed to be a dynamically posed figure.
Many artist use to bake the sculpt after applying a layer of clay over the armature, but not us. Sometimes further corrections are needed. And we always build up the form as a whole, not in one section at a time cause this way you have more chances of loosing body symmetry, size and/ or proportion.
Again, try to get as much reference material as possible. When you are making the muscles, have in mind that certain muscles take different appearances depending on their orientation and action.

Don’t rush to make further details on the muscles unless you are completely sure they are well placed in the figure. The final result will surely be worth the patience

If you are happy with the basic muscle structure, you can start refining the figure…….

…….and also to start working on the figure’s clothes, that’s why we recommend you to have some reference material about these matters too (a good collection of books may be needed). When we say "refining" we mean the process of smoothing and removing all possible imperfections on the clay. Right after that comes the finishing details addition.

Now, if you want to make copies of your new figure -castings-, there are some considerations you should attend to. Some sculptors make all the figure as a whole and then cut it using a little saw (although this might produce poorly fitting pieces in the final product sometimes). That’s why here, at Gore Group’s headquarters, we use to test-fitting the pieces continually, so as to ensure a perfect fit in all our figures.

This part of the process needs to be explained in detail so as to achieve a good fitting of the figure’s pieces. Talking about a head or an arm (usually these are the pieces to be separated) we had already prepared the wire snap-on. The "female" piece in the base, the "male" piece in the head, arm or whatever.

That’s where we tie the string (try to get from an supplies shop what we use to call invisible string, used for shortening trousers and such. This invisible string has the width of a hair and is almost as resistant as the strings used for fishing) leaving the two ends hanging from the piece, being convenient to unite both ends with a tiny piece of scotch for working freely.

Now we can start working on the figure as if it were a whole, with the advantage once we finish the piece to be separated we have the string (previously inserted trough the wire) for cutting through the fresh sculpey. All we have to do now is to get the string from both ends and cross them until the piece has been completely cut off.

Done this, our figure is ready for the oven. Voila!

Well, hope you can make good use of this brief tutorial, and that we can meet in many others. Let’s sculpt!











Well here some big images about the mold and castings prosses using vacuum and pressure equipment.
I hope this can help you in any way with this prosses method.

And A GREAT Ralphus2 explain text :

Hey Gang, just wanted to rundown what is going on in the wonderful tutorial pics that Martin has been so kind to share with the board.

Martin starts off by figuring out the best way to "hang" the sculpture in the mold box, keeping in mind not to position the sculpt to close to the mold walls. You also have to keep in mind resin flow {for when you are casting resin} if you find possible air traps you will need to add or cut air vents later.

Once you have figured out your box configuration, you build your box out of pressboard or formica covered boards {you can get shelf stock boards at your lumber store.}
Next you drill your holes for your screws. Use a countersink to make the screw heads lay flush to the board.
The reason to use a smooth surface for the mold box allows for a clean surface on the mold exterior. This makes it alot easier to put your box back onto your mold when you are casting. Woodgrain form plywood may not register back exactly.
Once you have figured your sculpt suspension{usually worked into being your pour sprue} you grease your boards with petrolium jelly, or crisco, or other greasy medium, this keeps the silicone from sticking to the pressboard, probably not needed for formica, but sometimes silicone can bond to the most unexpected surfaces.

Now you are ready for silicone, there is a formula to measuring the material, I believe the method was height x width x Depth and then you multply that by the weight of a square inch cube of silicone. I will varify that and get back to the board, I just eyeball the stuff.

Now for the no bubble part. There are two meathods to this. Evacuating your silicone with a vacuum pump, or pressure casting the entire mold assembly in a pressure pot.
First you need a good pump that pulls an absolute vacuum of 29 {outer space is 30} anything less wont cut it, I have tried.
Robinair SPX cooltech 6CFM high performance vacuum pump is great and is available for around 260.oo or less over at EBAY.
You can get a vacuum chamber for around 50.00 over at Ace glass company. It is a plastic chamber ready to rock out of the box.
You can pull 2000 grams in the chamber. Or you can make one out of a heavy duty stock pot and a 1 inch thick lucite top. You will need to add some kind of rubber gasket to create a solid seal. Add some proper fixtures and you can do larger than 2000 grams in this config.
You let the silicone rise and fall, debubble for a few more minutes and you are ready to pour. Pour your silicone slowly and from a very high position to create a thin strem, this will prevent any large bubbles from being placed into your mold thru pouring.

Now many studios skip this step and place the entire mold setup into a large pressure pot and pour the silicone into the box and pressure the entire setup to a pressure of about 40 lbs. This does the same thing that pressure casting of resin does. Basically no bubbles. And the silicone is pushed into every nook and cranny. If you are casting a piece with mega mega detail this is an excellent way to go even if you are evacuating your silicone. You can also do fast cast silicone{ultrafast catalyst added}
Typically you cannot deaire silicone with fast cast additive, the bubbles get trapped in the evacuation process basically your silicone will swell and stay that way, very reminicent to exspensive rubber froth. So you place your set up in the pot and pour, close and wait. You can produce bubble free quickie molds in an hour.

There are two drawbacks to this method #1: if you have Caught an air pocket in your sculpt it can implode under the pressure, so you will have a mold of a wonerfully craced apart sculpt, not fun.
#2 : You must always use a pressure pot that can handle the pressure for 24 hours. If not the bubbles will reform as the pressure neutralizes to regular air pressure. The mold rubber will swell and distort your mold horribly. Best bet is to always keep some extra silicone from you batch in a small cup and lable the time on it and place the cup on the pressure pot. Check it for hardness and demold your molds once the sample has kicked.

Now comes the fun part, surgery:
This usually starts at the mold sprue. Most moldmakers will mark the mold line they want to follow with a sharpey marker.
This makes it very easy to keep your parting line just where you need it, thus giving you a great seam.
We use medical spreaders, they look like scissors with curved forks on the ends and a locking mechanism at the base handle. They click into increments as you spred the mold rubber.
You start with an initial cut, we prefer #12 sheffield steel #12 curved blades as well as # 11 blades both in a milton #5 scalpel handle.
You make your cuts in a zig zag pattern, gently wiggle your blade left and right as the blade glides thru the rubber, the depth of the cut depends on the size of your mold. The zig zags act as tiny resistration points and will keep your mold alignment just right. This takes ALOT of practice, so do so on some scraps not on an official piece. You must be very careful not to cut yourself, these are surgical blades and can cut deep.
Once you have made your initial cut you insert your spreaders and begin spreading your mold and cutting. Spread and cutuntil you hit your sculpt. I like to lubricate the blade after every few layer cuts with vasoline or olive oil, makes the blade glide thru the rubber with great ease. Follow your marker line until you are done.

Now for casting, if you have planned your mold right this is as easy as mix the resin amount and pour, place in pressure pot and close, bring pressure anywhere from 40 to 80 psi <depends on what you are casting,things with thin delicate detail benifit from higher pressure.>
and wait. Pressure casting is the only way to go, far fewer reject factor.

If you find you are catching bubbles then you will have to cut vents into your mold. This can be done with a brass rod the size of the hole you are needing to cut to make the vent function. You countersink the interior of the rod until it leaves a close to razor sharp edge. This can be done with a #11 xacto blade run along the interior brass edge surface until it is sharp.
Now you grease the tube interior and plunge it thru the rubber wher you need a vent. A tube pushed thru silicone will leave a smaller hole than that of the tube diameter so plan on going a little larger to get the right size hole. You can also run the tube thru the mold surface to create a half gouged out hole on the surface as well.

Gang boards are very important for your larger molds, they will support your rubber and keep its original form, and will keep your mold from being tweaked out from rubber bands and mold straps.

As for mold duration it depends on a few factors. The petroleum content of your resin,{resin contains petroleum products that can breakdown mold rubber, if your resin reaks ala BJBs TC 810 it has more oil in it}
You need to use a good quality rubber as well, we use Silicone INC's GI 1000, rubber. It takes 18 to 24 hours at 70 degrees to cure, and will last approx 2 years on a shelf before decay begins, basically on a mold that age you will lose little bits of rubber in your castings until your mold rubber begins to split and then its into the garbage heap. DO NOT use this rubber as cut up filler, it will delaminate from your fresh poured rubber and you will have a mess of a mold.
Martin mentions cutting up discarder molds, this is a great way to conserve and recycle what is the most expensive part of our hobby/ job.
You can also cut up the leftover rubber from the bottom of your buckets.
Just make sure all the rubber has been catalyized and is not tacky.
Wash your recycle rubber down with a little alchohol and you will be guaranteed good adhesion.

Best recommendation I can make is to practice on a gi joe size head at first. Mold it in a paper cup {hot cups are plastic lined} And cut it up the back. Then try another one and cut it up the sides. We mark our sculpts with a sharpie marker, anything that will mark your model will due, like a soft lead pencil. You can then take pins and poke them thru the cup and have them almost touch the model. Lock these in with a little hot glue.
These will give you a trail of micro holes that you can follow on the exterior of the mold as you cut. You start at the neck, cutting to the mold exterior
. Repeat this with the zig zag cuts.
Xacto #11 blades will work fine but are not as sharp as the scapel blades. So you may go thru a few.
As for the clay wall approach, we use it as well, all depends on sculpt shape and mold size. If the part we are molding has archaic lines that would make a mess of a mold to cut open we will do a two piece mold or a matrix mold {mold with jacket} also depends on project schedule and budget. A cut open mold is the fastest mold you can make.
The seams on a properly cut open mold are practically non existant, the reason for this is the lack of any debris , such as minute left over water clay from your mold process. A good mold maker will make you a beautiful seam, but your mold will cost you more.
It really is a matter of choice, I used to clay wall EVERYTHING, but after I saw the lack of seak on a cut open and the speed in which you turnaround a mold, I will cut open where ever I can.
Martin Canale
martin canale is offline   Reply With Quote
Old 03-12-2006, 08:56 PM   #2
The quickest way to double your money is to fold it in half and put it back in your pocket.
leks's Avatar
Join Date: Sep 2004
Location: below sealevel
Posts: 1,384
Wow this must be the mother of tutorials, although I have probably seen most of it already on your site.

I dunno what it is but I always get excited with these kinda tutorials and I have never sculpted in my life, hehe and even more so if it's from such a talented artist.

Strongly get the urge to maybe buy some material and try my hand at it, but than I see your armature buildup tutorial, how meticulous you set that up and all the work involved and that just so to get started, ah man the agony of that alone would leave me dead and buried

Anyway I love to get a stepbystep/behind the scene look and the complete process involved also I am sure many other more talented and more patient members will be extremely happy with this and be able to put it to good use.
leks is offline   Reply With Quote
Old 03-13-2006, 10:25 PM   #3
Kirk Durfey
I used up all my sick days, so I'm calling in dead.
Kirk Durfey's Avatar
Join Date: Apr 2005
Location: San Jose, CA
Posts: 3,889
This stuff is pure gold! I will be spending several hours drooling over these pics - Thanks for posting this, Martin!
Kirk Durfey is offline   Reply With Quote
Old 03-27-2006, 01:32 PM   #4
Crush Mod
Super Moderator
CKinSD's Avatar
Join Date: Aug 2004
Location: once in SD now in NC
Posts: 8,867
sticking this thread due to GREAT information contained inside from Martin!
Recasters suck big time!
Banning is what i do best!!!!
CKinSD is offline   Reply With Quote
Old 11-14-2006, 10:57 AM   #5
A conclusion is simply the place where you got tired of thinking.
Rome's Avatar
Join Date: Oct 2004
Posts: 1,502
That is terrific thank you for taking the time to create this. This is exactly what I"ve needed. Sticking is also a GREAT idea
Rome is offline   Reply With Quote
Old 11-14-2006, 12:29 PM   #6
Mod Assassin
Super Moderator
Bullseye's Avatar
Join Date: Oct 2004
Location: Makena's Kennel.
Posts: 33,932
Fantastic post Martin.
Bullseye is offline   Reply With Quote
Old 11-14-2006, 01:03 PM   #7
Angry Green Rage Monster Mod. SMASH!
Super Moderator
JadeGiant's Avatar
Join Date: Nov 2005
Location: Anger Management
Posts: 43,789
this is the mother of all tutorials! Awesome post.

What ever happened with that batman?
JadeGiant is offline   Reply With Quote
Old 12-13-2006, 02:04 PM   #8
A conclusion is simply the place where you got tired of thinking.
Rome's Avatar
Join Date: Oct 2004
Posts: 1,502
this is a GREAT tutorial. Thank you for taking the time to help us all.
Here is my question however, how do you work in the detail in a sculpt?
for example, looking at the face how do you go from this
to this

and of course the same applies to the details in the body as well.

My problem is that I used some kind of sculpy and the clay was just too soft for me to ever manage fine detail.
can you PLEASE, pretty please with sugar on top make a tutorial that goes over how detail is established in a sculpt?

That would be very appreciated.

thank you.

OOPS NM, it looks like I jumped the gun a bit and asked my question before looking at the whole post.
Actually I had looked at it all before but it looks like more stuff has been added.
I'll have to study it in more detail, but it still looks a bit over my head.
I'm still not quite seeing how the details to muscles and stuff are added.
should I use a harder clay?
when sculpting detail (like shoulder muscle) Am I removing clay or just pressing down to create the shape?
which tool is best to use.
All basic questions. I will go over this post very carefully to make sure the answers are not already there.
in any case THANK YOU VERY MUCH for this.
it's a great help.
Rome is offline   Reply With Quote
Old 12-13-2006, 02:30 PM   #9
A conclusion is simply the place where you got tired of thinking.
Rome's Avatar
Join Date: Oct 2004
Posts: 1,502
Don’t rush to make further details on the muscles unless you are completely sure they are well placed in the figure. The final result will surely be worth the patience

If you are happy with the basic muscle structure, you can start refining the figure…….

…….and also to start working on the figure’s clothes, that’s why we recommend you to have some reference material about these matters too (a good collection of books may be needed). When we say "refining" we mean the process of smoothing and removing all possible imperfections on the clay. Right after that comes the finishing details addition.
This is exactly the process which I was referring to. the "refining" step. How do I refine the the piece?
Rome is offline   Reply With Quote
Old 12-31-2007, 02:34 AM   #10
Yeah, I spend WAY too much time here!
VinReaper's Avatar
Join Date: Nov 2007
Location: Out of my mind! Be back in 5 minutes! (+12517 to the Post Count)
Posts: 56,642

Awesome! What more can you ask for!

I am set with my beginners tools. I hope,

VinReaper is offline   Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Powered by vBadvanced CMPS

All times are GMT -4. The time now is 01:07 AM.

Powered by vBulletin®
Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.