XRobots
New Member
I'm posting this tutorial by request from another thread that I posted. This is a basic explanation of how to scratch build (build from scratch) an item, by first sculpting it in clay, and then making a piece the same shape as your clay sculpt in a rigid material.
You can either make the finished piece solid or hollow, so this is great for making helmets, weapons, armour or other props and costume pieces. Note that you don't have to use clay - you could make the original out of wood or another material if you wished. Just make sure that the material you use does not absorb water.
From the very beginning, assuming your are starting from scratch:
Step1: If you're making a helmet or armour piece, you probably don't want to make it out of solid clay due to the cost and weight. So start with an 'armature' which is something roughly the right shape. This could just be lots of cardboard or foam/packing material taped together. I started with a cheap polystyrene head:
Since these heads are a bit smaller than a real persons head (hold it up next to your head and look in the mirror), I padded it out a bit with cardboard:
It's also worth covering the entire thing in kitchen foil which makes getting your clay off afterwards much easier if you wish to do so. If you are using a water based clay it will also stop the cardboard getting damp and going too soft:
So, that's your armature ready for the clay.
Step 2: Now you need to choose a suitable clay. It is important that we can make a mould from the piece once it's sculpted, so picking the wrong clay is something you only do once. It's important to use a clay that is 'chemical free', so it contains no sulphur which is found in products like Plasticine. As you may be spending some time sculpting the piece you also probably want a clay that is not air drying, so you can spend weeks or months getting it perfect and it won't harden during the process.
The two major brands of clay that fit the bill are Chavant clays (but not all of them), or Klean Klay - which is widely available in the US and I think they sell it in Walmart, or check out my Sig for a UK/EU supplier.
If the piece you are using is much larger, then you may wish to use a much cheaper clay such as WED clay. WED was specifically designed for the film industry, and although it's mostly water based it contains silicone so it will dry much slower. If you keep the sculpture in a plastic bag when you're not working on it then it will last for months. Although WED is not considered reusable like Klean Klay which can be used time and time again.
Step 3: Make the piece. It's not easy to teach sculpting, so you'll just have to try it. Mainly you need to cover the armature with clay, then stick more on and take some off until it's the right shape for the finished piece:
Covering the head with clay:
And shaping the piece - I used cheap sculpting tools from my local art shop, generally your local clay stockist will sell sculpting tools too:
Hooray, after about 4 days the sculpt is as good as I can get it... although I could have spent 4 months if I wished as I was using Klean Klay.
Step 4: Make a mould. You only get one chance to make the mould, because when you pull it off the clay it will ruin the original sculpt, so make sure you do it right.
My helmet is quite a round shape, so I knew that I could make a one piece mould and it would pull off the clay ok. However, for some helmets or props you will need to at least put a split in the mould at the back to help you get the mould off, or make a two part mould. This was true for my Iron Man legs, so I divided the piece up into two halves, and put a split into each. The easiest way to do this is to stick a line of playing cards (or plastic sheets / copper shims etc) into the clay where you want to divide it.
Here's what I did for the leg, because it was quite a complex shape. However, for simple items, you can continue as shown here.
You will now need to choose a moulding material. If you are planning to make the final piece rigid, then you'll need to make a flexible mould. There are various materials available, including Silicone RTV, Polyurethane rubber, or standard latex. Latex will shrink and deform easily so it's generally not preferred by professionals, but it's much cheaper than Silicone RTV. I personally use Latex along with layers of dish cloths to help build up the mould thickness quickly and also stop it shrinking. I'd suggest that if you are new to this method of prop building, then using Latex will save you a lot of $$$ until you are sure of what you are doing.
***Remember we used a 'chemical free clay'...? Well, this is important as the Sulphur and other chemicals in some clays will ruin the mould material and you'll just end up with a sticky lump***
Firstly I painted about 10 coats of latex onto the clay all over, leaving maybe 1-2 hours before coats, so it will take a few days:
Next was a layer of dish cloths:
Then more latex, and I also made some latex 'lumps' from the inside of bottle tops which will help locate the flexible mould in the support jacket detailed below:
You can continue with latex and cloth until the mould is thick enough - more recently I have started doing at least two cloth layers without 10 latex coats in between.
Step 5: Make a support jacket. Once you've let the latex dry through completely (a couple of days), you will need to make a rigid mother mould or support jacket. This will hold the flexible mould the same shape once the clay has ben removed from the inside. For this piece I made a two part support jacket, but you may need more parts depending on the complexity of the mould. If you already put dividers in the mould (like I did with the leg) then your support jacket can also be divided along those lines. Since my Latex mould has no dividers, I have to make them now:
I used a line of clay to divide the piece into two:
Then I used plaster bandage to cover one half of the piece:
Next, you'll need to remove the line of clay and apply something to the edge of the plaster bandage you've already put on to stop the rest of the bandage sticking to it. I've found that paper masking tape or duct tape will work for this, or you could try a petroleum jelly - but make sure you don't get too much on the latex. Then cover the other half with plaster bandage:
Step 6: Once the plaster has set and dried (a couple of days), you can remove the two halves:
...and remove the latex mould from the clay:
Next you need to put the latex mould back in the support jacket and spend a few minutes making sure it all lines up - this is where the latex 'lumps' are useful, to make sure the latex goes back in the right place inside the support jacket:
Step 7: Choose what you will make the final piece from. There are various choices for casting materials, but prefer the ones that are non-toxic. In the US there is a product called Aqua Resin which is used a lot by artists and prop builders. In the UK/EU you can try Jesmonite which is what I use personally.
Both Aqua Resin and Jesmonite are water based, non-toxic and non-flammable, so you can use them indoors. They are supplied as a liquid and a powder that are mixed 1 part liquid to 3 parts powder. They will start to set within about 15 minutes, set solid within an hour, and achieve full strength after 24-48 hours. Both product ranges also have a Thixotrope gel available to make them thicker so you can make a 'gel coat' - the first coat that you paint into the mould.
I use Jesmonite with standard glass fibre fabric products - chopped strand mat and surface tissue. Sometimes these can be itchy to your skin, so wear gloves.
Step 8: Make the piece. The basic aim now is to coat the inside of the mould with one or two coats of 'gel coat' and leave it to solidify. Then use one or two layers surface tissue with more resin, followed by one or two coats of chopped strand mat, depending on how strong it has to be.
I don't actually have a picture of this process for the helmet, but here's one of a shoulder bell which has just had the surface tissue applied - you can see that some of the tissue is overhanging the edges, but this can be trimmed later:
If you are making a helmet, you may not wish to use glass fibre products at all. Glass fibre dust and loose fibres are very bad for your respiratory system (lungs), so you should make sure that you seal the inside of the piece very well with resin if you are making a helmet, so there are no loose bits falling off it. For my helmet I used more blue kitchen cloths layered up with Jesmonite resin so that there was no glass fibre at all, so this is something to try.
Step 9: Remove the mould again to revel the piece. If the mould is hard to pull off then wait 24-48 hours before doing so, otherwise the resin will not have set properly and the piece may crack or break. Once you are sure the resin is ready you can remove the support jacket and peel the latex off to reveal the hollow item which is the same shape as your clay sculpt:
At this point you will probably find that your clay sculpt wasn't quite as smooth as you thought it was, so you will need to do some work on sanding and filling the imperfections.
***WARNING: always wear a suitable face mask when sanding items reinforced with glass fibre products. As I said before, loose glass fibres and glass fibre dust is very bad for you.***
Here's the piece after sanding and priming (still not perfect):
That's the end of the tutorial - Hope this has been useful to some of you.
You can either make the finished piece solid or hollow, so this is great for making helmets, weapons, armour or other props and costume pieces. Note that you don't have to use clay - you could make the original out of wood or another material if you wished. Just make sure that the material you use does not absorb water.
From the very beginning, assuming your are starting from scratch:
Step1: If you're making a helmet or armour piece, you probably don't want to make it out of solid clay due to the cost and weight. So start with an 'armature' which is something roughly the right shape. This could just be lots of cardboard or foam/packing material taped together. I started with a cheap polystyrene head:
Since these heads are a bit smaller than a real persons head (hold it up next to your head and look in the mirror), I padded it out a bit with cardboard:
It's also worth covering the entire thing in kitchen foil which makes getting your clay off afterwards much easier if you wish to do so. If you are using a water based clay it will also stop the cardboard getting damp and going too soft:
So, that's your armature ready for the clay.
Step 2: Now you need to choose a suitable clay. It is important that we can make a mould from the piece once it's sculpted, so picking the wrong clay is something you only do once. It's important to use a clay that is 'chemical free', so it contains no sulphur which is found in products like Plasticine. As you may be spending some time sculpting the piece you also probably want a clay that is not air drying, so you can spend weeks or months getting it perfect and it won't harden during the process.
The two major brands of clay that fit the bill are Chavant clays (but not all of them), or Klean Klay - which is widely available in the US and I think they sell it in Walmart, or check out my Sig for a UK/EU supplier.
If the piece you are using is much larger, then you may wish to use a much cheaper clay such as WED clay. WED was specifically designed for the film industry, and although it's mostly water based it contains silicone so it will dry much slower. If you keep the sculpture in a plastic bag when you're not working on it then it will last for months. Although WED is not considered reusable like Klean Klay which can be used time and time again.
Step 3: Make the piece. It's not easy to teach sculpting, so you'll just have to try it. Mainly you need to cover the armature with clay, then stick more on and take some off until it's the right shape for the finished piece:
Covering the head with clay:
And shaping the piece - I used cheap sculpting tools from my local art shop, generally your local clay stockist will sell sculpting tools too:
Hooray, after about 4 days the sculpt is as good as I can get it... although I could have spent 4 months if I wished as I was using Klean Klay.
Step 4: Make a mould. You only get one chance to make the mould, because when you pull it off the clay it will ruin the original sculpt, so make sure you do it right.
My helmet is quite a round shape, so I knew that I could make a one piece mould and it would pull off the clay ok. However, for some helmets or props you will need to at least put a split in the mould at the back to help you get the mould off, or make a two part mould. This was true for my Iron Man legs, so I divided the piece up into two halves, and put a split into each. The easiest way to do this is to stick a line of playing cards (or plastic sheets / copper shims etc) into the clay where you want to divide it.
Here's what I did for the leg, because it was quite a complex shape. However, for simple items, you can continue as shown here.
You will now need to choose a moulding material. If you are planning to make the final piece rigid, then you'll need to make a flexible mould. There are various materials available, including Silicone RTV, Polyurethane rubber, or standard latex. Latex will shrink and deform easily so it's generally not preferred by professionals, but it's much cheaper than Silicone RTV. I personally use Latex along with layers of dish cloths to help build up the mould thickness quickly and also stop it shrinking. I'd suggest that if you are new to this method of prop building, then using Latex will save you a lot of $$$ until you are sure of what you are doing.
***Remember we used a 'chemical free clay'...? Well, this is important as the Sulphur and other chemicals in some clays will ruin the mould material and you'll just end up with a sticky lump***
Firstly I painted about 10 coats of latex onto the clay all over, leaving maybe 1-2 hours before coats, so it will take a few days:
Next was a layer of dish cloths:
Then more latex, and I also made some latex 'lumps' from the inside of bottle tops which will help locate the flexible mould in the support jacket detailed below:
You can continue with latex and cloth until the mould is thick enough - more recently I have started doing at least two cloth layers without 10 latex coats in between.
Step 5: Make a support jacket. Once you've let the latex dry through completely (a couple of days), you will need to make a rigid mother mould or support jacket. This will hold the flexible mould the same shape once the clay has ben removed from the inside. For this piece I made a two part support jacket, but you may need more parts depending on the complexity of the mould. If you already put dividers in the mould (like I did with the leg) then your support jacket can also be divided along those lines. Since my Latex mould has no dividers, I have to make them now:
I used a line of clay to divide the piece into two:
Then I used plaster bandage to cover one half of the piece:
Next, you'll need to remove the line of clay and apply something to the edge of the plaster bandage you've already put on to stop the rest of the bandage sticking to it. I've found that paper masking tape or duct tape will work for this, or you could try a petroleum jelly - but make sure you don't get too much on the latex. Then cover the other half with plaster bandage:
Step 6: Once the plaster has set and dried (a couple of days), you can remove the two halves:
...and remove the latex mould from the clay:
Next you need to put the latex mould back in the support jacket and spend a few minutes making sure it all lines up - this is where the latex 'lumps' are useful, to make sure the latex goes back in the right place inside the support jacket:
Step 7: Choose what you will make the final piece from. There are various choices for casting materials, but prefer the ones that are non-toxic. In the US there is a product called Aqua Resin which is used a lot by artists and prop builders. In the UK/EU you can try Jesmonite which is what I use personally.
Both Aqua Resin and Jesmonite are water based, non-toxic and non-flammable, so you can use them indoors. They are supplied as a liquid and a powder that are mixed 1 part liquid to 3 parts powder. They will start to set within about 15 minutes, set solid within an hour, and achieve full strength after 24-48 hours. Both product ranges also have a Thixotrope gel available to make them thicker so you can make a 'gel coat' - the first coat that you paint into the mould.
I use Jesmonite with standard glass fibre fabric products - chopped strand mat and surface tissue. Sometimes these can be itchy to your skin, so wear gloves.
Step 8: Make the piece. The basic aim now is to coat the inside of the mould with one or two coats of 'gel coat' and leave it to solidify. Then use one or two layers surface tissue with more resin, followed by one or two coats of chopped strand mat, depending on how strong it has to be.
I don't actually have a picture of this process for the helmet, but here's one of a shoulder bell which has just had the surface tissue applied - you can see that some of the tissue is overhanging the edges, but this can be trimmed later:
If you are making a helmet, you may not wish to use glass fibre products at all. Glass fibre dust and loose fibres are very bad for your respiratory system (lungs), so you should make sure that you seal the inside of the piece very well with resin if you are making a helmet, so there are no loose bits falling off it. For my helmet I used more blue kitchen cloths layered up with Jesmonite resin so that there was no glass fibre at all, so this is something to try.
Step 9: Remove the mould again to revel the piece. If the mould is hard to pull off then wait 24-48 hours before doing so, otherwise the resin will not have set properly and the piece may crack or break. Once you are sure the resin is ready you can remove the support jacket and peel the latex off to reveal the hollow item which is the same shape as your clay sculpt:
At this point you will probably find that your clay sculpt wasn't quite as smooth as you thought it was, so you will need to do some work on sanding and filling the imperfections.
***WARNING: always wear a suitable face mask when sanding items reinforced with glass fibre products. As I said before, loose glass fibres and glass fibre dust is very bad for you.***
Here's the piece after sanding and priming (still not perfect):
That's the end of the tutorial - Hope this has been useful to some of you.
