Tag Archives | masking

Some useful tools

I was grateful for the tip about the grids on Lynn Fraley’s blog. In the previous post, you can probably see the bubble wrap lining the smaller damp box. That had been my own solution for keeping the greenware elevated from the damp plaster, but I can see her tool will work so much better. It also reminded me that I’ve meant to share some of the tools I’ve come to depend on for some odd jobs around the studio. Since I’ve been absorbed in mold-making these last few weeks most of these are tools used either for that or for prepping the resin masters.

1) Sponge-backed sanding pads
Although they are here with mold-making tools, I really use these for everything from cleaning masters, to polishing plaster to cleaning greenware. They often aren’t sold by standard grit numbers, so I like to buy them in person by feel, and I use all kinds. Often I cut them into small strips and round the edges (a big help when they are used on soft greenware, since the corners can gouge), then strip off most of the padding from the back. I find for some tasks I need them a little more flexible than the thick layer of foam allows.

2) Miskit Liquid Latex
This is another all-purpose tool in the studio. It’s primary purpose is to mask off bisques during underglazing, but I also use it when I want to clay up a resin original. The blocking clay I use, Plastalina, is really soft and sticky, so I find that masking areas with deep grooves (like the mane or the eyes) before I place that side down in the clay makes the later clean-up much easier. Just be careful to keep it well away from the mold lines, since the seal against the master needs to be tight there.

The exposed face of the resin master tends to get clay residue as well, especially near the mold lines. To clean those places without disturbing the clay, you can paint the latex over the area (including the plastalina itself) and allow it to dry. When it is peeled off, it takes the residue with it. The small square under the Miskit bottle is a rubber cement eraser, which is useful for removing dry latex. It is quite rigid, so it can be cut into shapes to reach tight areas.

3) Clay Shaper

These tools are really popular with sculptors and can be purchased with different tips and with varying firmness. I use the smallest firm (black) wedges to apply the liquid latex. The have just enough give and dried latex peels right off of them.

4) Fingertip Swivel Knife

I found this tool, made by Fiskars, at a scrapbooking store and immediately fell in love with it. (That hobby has more cool tools!) The tiny blade is just the right size for cleaning seams, and the loop that fits around your finger braces the knife in a much more controlled fashion than an ordinary Xacto handle. Even better, the blade can be positioned at any angle to the handle, so it is perfect for getting into tight spots. It was made for cleaning out the “keyholes” in manes and tails – and Oliver’s crossed legs!

5) Schwan All-Stabilo Pencil

We used these water-soluble pencils at my family’s sign shop to mark cut lines. They were great because they gave a very visible blue line that didn’t brush off easily, but could be removed completely with water. I use them to help mark out mold lines on resin masters. I can see the lines more clearly than with a regular pencil, but I can still remove the marks (or change them) when I am done.

6) Embossing Stylus

This is another cool tool from the scrapbooking store, also made by Fiskars. One of the most time-consuming – and truly boring – tasks in making molds is sealing the mold boards. The clay needs to be sealed against the edges, as do the corners of the box. It has to be done reaching inside the box, and without bothering the soft clay around the horse. It is messy work, and it always left a messy edge around the rubber master. Now I just run the larger end of the embossing stylus along the seam, and it makes a clean seal in minutes.

Here is the stylus sealing the edge of the mold in yesterday’s picture. I love this tool!

7) Swizzle Stick Sanders

I found these at a hobby store that catered to military miniatures, and they are particularly handy for sanding hard to reach areas of hard surfaces like resin. They are more rigid than the sanding pads, and can be bend at angles when needed. They come in four different grits, with the finest pretty comparable to 600 grit sandpaper.

Most of these tools are pretty inexpensive, but it is really the time saved (and frustration avoided) that makes such a difference. Hopefully some of them will prove useful to others.

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Removing underglaze

One thing I worry about when blogging is that after three years, I often forget whether or not I have already posted about something. For every post I make, I usually have two or three that I meant to post, so it’s hard to keep track of which ones were written and which ones I only thought about writing! Maybe there is a reason I am so fond of this “flair” from Facebook: maybe I am closer to making those “new friends” than I think!

So with apologies in case I have previously passed this tip along, I wanted to include it before I got back to using Concepts and art glazes. It’s a pretty important detail, so it really deserves its own post anyway.

The post from a few days ago showed how Concepts interact with latex masking. It’s an important thing because almost all underglazes are airbrushed. It’s almost impossible to create an even tone with them any other way because they streak. Raw (that is, unfired) underglaze also looks opaque long before it really is, so the streaking isn’t visible until after the piece has gone through it’s final gloss fire. At that point, everything is permanent.

Masking is used to protect those areas that need to stay white. Because earthenware bisque is porous, it is almost impossible to completely remove color after it has been applied to the surface. The only drawback is that none of the most common forms of masking – liquid latex, wax, tape and foil – give a very precise line. They are not suited to fine detail. For that reason, the final edges are usually etched with a blade or other sharp tool.

With some underglaze colors, this works really well. Others are more resistant, or leave a more pronounced stain. For that reason, it’s often a good idea to apply a barrier between the underglaze and the bisque.

I have found the best choice for this is the Duncan Cover Coat “Arctic White” (CC 101). It fires to about the same color as white earthenware, so it doesn’t really effect the final color. It does etch off really easily, though.

There is more information about why lighter colors do not change darker colors in this older post.)

That’s why it makes a useful mask for the last few millimeters of a pattern. The larger areas of the pattern (or in the case of my current tiles, the background) are masked with liquid latex, but the area closest to the final border is thin layer of Arctic White. Unlike the rest of the underglaze, I apply it with a small brush. It’s also a little more flexible than the latex because I can decide to leave an area (ie., not etch it off) and it will fire normally. Were it latex, traditional underglaze would flake off.

A similar approach is taken with patterns that have a lot of body roaning. For situations like that, the Arctic White is airbrushed in a light coat before the other colors are added. Doing this makes the body color more fragile and prone to scuffing, but with roaned horses that is usually pretty easy to correct or at least camouflage.

Here is the Inspire tile from the previous post (the one with the bright green background). I painted the inside edge of the horse with Arctic White, then applied the liquid latex. The second tile, which isn’t pictured yet, will have the horse painted first so the outside edge was painted white and the mask was applied to the background.

I’ll explain the two different approaches (“background first” and “horse first”) in the next post.

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