Archive for February, 2017

Painted!

Posted in Design, General, Halloween, Horror, Masks, sculpting, Uncategorized with tags , , , , , , on February 25, 2017 by Jim St Ruth

So the finished mask came out well, though it was a little rough in places. My basic process is down now, and I know I just need to be a little more cautious when I’m filling the mould with foam. The mask was baked for 4.5 hrs in the end, and I left it to cool well before removing it.

Some pics of the airbrushing and a little stippling, though please note that this isn’t actually affixed to my face, and that there isn’t any makeup on my skin; so it hasn’t been blended in, and the opening around my eyes and mouth are clearly lose.

Advertisements

Oven Temperatures for Foam Latex

Posted in Uncategorized on February 23, 2017 by Jim St Ruth

So, my mask didn’t cure on the outside of the mould. I left it in the oven for five hours in total, and only the very limits of the mask inside the plaster and the foam that splooged out of the mould had cured.

Today I’m doing my next run, but I wondered if the foam latex inside the mould was even getting up to temperature. The oven that I’m using is our kitchen; an old Tricity Bendix that’s about thirty years old. It’s not a fan oven… and this over is never used to cook food in. We only use the hob above. Never use an oven that you’re going to cook in, as the released chemicals mean the oven is no longer food safe!

I decided to run a test.

A glass ramikin dish containing about 2cm-worth of olive oil. This is then covered over with a single layer of aluminium foil; not so much that the heat can’t get in.

I set my oven to 130C and left the oil in for twenty minutes to let it warm up.

The resulting temperature of the oil in my oven was 79C, just 6C off the 85C limit that I’ve read foam latex shouldn’t be baked over.

Now, I think the important two things are that it’s an old oven, so the thermostat might be unreliable, especially at low temperatures. Also, it’s not a fan oven, so the heat isn’t being circulated beyond simple heat convection. The parts of the foam latex that cured on my last run were both on or near the exposed areas, and they were also near the top of the oven.  The total height of my life cast and mould is ~ 35cm; that’s pretty big.

If you think about cooking several things in an oven on different shelves in a non-fan oven, you know that there’s a big difference between the cooking times for the different shelves.

So… I’m going to try baking at an oven temp of 110C today.

Tip: Do an oil test in your oven, like the one I’ve done. See what temperature the oil gets to at 71C on the thermostat. It might not be anywhere near the required temperatures for baking foam latex. 75C on my oven gave an oil temperature of 62C. That’s very low and, whilst I’ve read about people baking foam latex at this level of temperature, the baking times can exceed even 6 hours.

Cracked Mould… and Repair

Posted in Design, Fantasy, General, Halloween, Horror, Masks, sculpting, Uncategorized with tags , , , on February 18, 2017 by Jim St Ruth

Things went far better than my nightmares predicted!

Yet when I tried to pry the mould from the sculpt and its underlying life cast, the damned thing split into four pieces; three large pieces and one sliver along one of the main splits, right between the three pry points that I’d put into my flashing.

The solution was easy, and it’s worked really well:

  • I repositioned all of the four pieces together, which thankfully slotted together with mostly only hairline cracks visible on the inside of the mould. There were some larger chunks missing, creating some small, ragged-edged holes… Also, I realised that one of the nostril cavities had broken off.
  • Using Modroc bandages, I patched across the seam lines, then ran a ring of bandage around the whole of circumference of the mould’s outside, to add further strength. I then let this dry for a good half hour.
  • Mixing small batches of dense plaster, I then filled in the holes and the hairline cracks, only doing an inch or two’s work at a time. Moistening the surrounding plaster first, I applied the new mix, dipping my index finger in some clean water, and using this finger to remove excess plaster. Keeping that finger clean is important:
    • I didn’t want to spread the excess plaster.
    • The mould’s existing plaster soaks up water like a sponge, and this dense plaster is only in small patches, so it dries out  very quickly. A wet finger keeps it damp just long enough to smooth it out and remove any excess.
  • To restore lost wrinkles I used a pen-shaped sculpting tool with a firm, rubberised tip. Repeatedly dipping this in water as I worked on each small section, I was able to ‘sketch in’ in the wrinkles. It’s worth noting that usually I’d have to be aware that I’d be trying to created the inverse of wrinkles; as this is the mould, I’d need to texture in raised lines that would turn into the groves on the final mask. However, the ‘sketching’ I did was only shallow, and it matched the surrounding texture. I was very lucky here; the fine detail I was recreating was already faint lines and groves around where I was patching.
  • I then mixed a small batch of plaster and applied it in a relatively thin layer, around 3-4mm thick, on the whole of the outside of the mould. This covered the Modroc gauze completely, preventing me from snagging it in the future, and giving a little more strength to the patched seams.
  • Once this was dried, I found the broken nostril piece, and used a *tiny amount of superglue to stick it back on. Be careful if you need to do this; you don’t want glue seeping out of the join and into the mould itself. This can retard curing with liquid latex, at least, and leave thin spots in your creations… With foam latex, I’m not sure, but I didn’t want to take the risk. I then smoothed over the hairline joins with plaster, and used plaster to smooth over some ragged parts of the nostril, to reduce the risk of tearing when it comes to taking foam latex from the mould.

So here are pics of the outside and the inside of the mould.

casterinner1castouter1

This is now being left to dry for another day or two before I try and do my second ever run with foam latex… but this time, I’m confident I can reuse the mould for multiple runs, that the mould isn’t going to have to spend an hour in the over getting up to temperature to allow the foam latex to actually bake, and to be damned careful when I’m opening up the mould.

I was too eager. I’ll be more patient in the future. This *is a learning experience, and it’s fun… so don’t panic if this happens to you. Take a step back. Consider your plan of action. Make sure you have everything you need ready for use before you start… and maybe a glass of wine waiting for when you’re finished!

New Sculpt

Posted in Design, Fantasy, General, Horror, Masks, sculpting, Uncategorized with tags , , , on February 17, 2017 by Jim St Ruth
My new sculpt, which is now ready to be cast. The wider strip around the top and back, with the weird-looking bumps, is flashing, which will give me some room to trim down, so an area that can suffer damage both for the mould I’ll create and the final mask. The weird bumpy bits are pry points to cram a chisel into, to get the clay and the life cast out of the mother mould once it’s dry.
 
I’m now getting a little nervous, because this next step (moulding) has been my screw-up point before. *This time, I’ll not make it overly bulky. I won’t use a release agent either, because with Monster Clay that just seems to make the plaster for the mould drip off, allowing air bubbles to form.
 
I think that the thing is that, after seven months of working with Plaster of Paris, I just don’t like it as a material. Its sets too quickly, and my anxiety makes me panic, hence one of the reasons for the screw-ups.
 
So: planning, taking it slowly, don’t make the mould too massive, apply two layers of Plaster of Paris so I can work with it as it’s still a fluid, and apply modroc bandages between the two layers to add strength to my small-mass mould.
smaller1
I’m now working with foam latex, rather than liquid latex… so my last mask failed because my mould was so huge that the latex didn’t cure in the oven. The bake time is 2-3 hours, and I realised that a lot of that time was spent just getting the plaster mould up to temperate… Hence the planned smaller-mass mould this time.
My fingers are so over-crossed that I think I might need surgery.