Homemade Polymer Clay* Questions and Answers

Awhile back I posted a recipe for polymer clay. I recently viewed the post and saw all the questions that readers had asked in their comments. Rather than answer each individually, I thought I'd post a follow-up that answers the most frequently asked among them. So, here goes:

Can you add color while the clay is wet?

Yes, you can add acrylic paint or even food coloring, but for even tinting throughout, you'll want to do it while the mixture is still liquid. If you want a swirly effect, then add it to the dough. Be prepared for color-stained fingers. And also note that adding a lot of colorant will alter the recipe and affect how the clay performs.

Does the clay shrink as it dries and how much?

It does, about 15-20%.

Can you bake the clay to speed drying?

Absolutely! I usually dry my items in the oven at about 150°F. How long to keep them in depends on their thickness. Also, if you’re making flat shapes, watch them for curling. Periodically flip them over to keep that to a minimum.

Will dried items stand up to water?

Dried items are water resistant but not waterproof, so if they get a little wet it’s OK, but don’t submerge them in water or even subject them to wet environments. They’ll certainly do better if they’re sealed with polyurethane or acrylic or the like.

Can dried items be used outdoors?

I haven’t tried but wouldn’t risk it. Dried items are water resistant but not waterproof. A sealant will help but I still wouldn’t expect them to last very long, especially in wet conditions.

Can dried items be used for food?

No. While the clay does plasticize during the curing process, it won't stand up to extended exposure to moisture.

Can the clay be used to make shapes with cookie-cutters?

Absolutely! Sprinkle a bit of cornstarch on the surface and roll it out on wax paper, or even in a pasta machine. Flip your shapes over throughout the drying process to keep them flat (they tend to curl).

Can you use glue other than Elmer’s Glue-All?

I haven’t tried but any PVA (polyvinyl acetate) glue should work, with, I would expect, somewhat different but probably OK results.

Cracking?

Shouldn’t be a problem. If it is, your clay might be too dry. Be sure to keep it in an airtight container between uses and only take out what you intend to use immediately.

Stickiness?

Cook the mixture for longer or use a bit less glue. Once out of the pot stickiness is harder to fix but sometimes adding more cornstarch helps. Altitude and likely also humidity will affect how the recipe performs.

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* Not homemade Sculpey or Fimo. The polymer base of those products is polyvinyl chloride (PVC), while for this one it is polyvinyl acetate (PVA). Both PVC and PVA are polymers, and both this clay and commercial polymer clay “plasticize” during a curing process. This clay therefore has many of the characteristic properties of commercial polymer clay (elasticity, pliability, flexibility, durability), but it doesn’t have all of them (particularly insolubility).

Until next time --

Linda Purty Bird

Egghead Learns to Sew, Part VI

Today I start applying machine-sewing to the material I intend to work with, namely, felt! This involves learning about types of thread, needle sizes, and a few key machine settings.

Fabric, Thread and Needle -- Combining Heaviness, Strength and Size

Felt doesn't appear in the Fabric, Thread, Needle Chart in my Instruction Manual but I'm approximating to be somewhere in the neighborhood of jersey and tweed in terms of heaviness. I used my outfit of denim and jersey (jeans and a t-shirt) to make this determination. Felt is thicker than jersey but not as dense as denim, so... best guess.

My Chart describes thread in terms of cotton, fiber and silk. None of the thread I own states these as its components; it's all just polyester, if it even says what it is (a lot of it is inherited). Hmmm. This is the point at which I had to go beyond the Instruction Manual for information. I learned that the important thing is to match the type of thread to the type of fabric, not just in terms of color but also strength and stretchiness. Although the best source I found (Tying it All Together: All You Need to Know About Thread) didn't specifically mention felt, I gleaned from the wide range of fabrics it included in its more extensive fabric-thread-needle chart that polyester would work just fine with felt.

On to needle size. My Chart said to use a needle sized between 11 and 14. I wasn't sure what size needle was already in the machine, though I deduced from the sizes of the needles included in my little box of sewing machine accessories that it was probably an 11. But what a problem it could be if I was wrong, so I decided to take the needle out and with a magnifying glass and a lot of light, read the teeny-tiny number engraved on the rounded side of the base of the needle. To get the needle out, I followed the directions for "Changing Needle" in the Instruction Manual. Using the little screwdriver that came with the machine, I loosened the needle clamp screw. Then I gently pulled down on the needle until it was free.

I couldn't make any sense of what the teeny-tiny engraved text said for the longest time, until I realized I was looking at it upside-down. That's how tiny it was! Probably the glare from the additional light I had shining on it didn't help. 

In any case, the needle turned out to be a size 11, as I suspected. According to my Chart, it would likely work fine with felt (it recommended size 11-14). 

Pressure of Presser Foot and Length of Stitches -- Setting the Settings

For heavy fabric such as I determined felt to be, my Chart said to use heavy pressure, so I pushed the pressure regulator all the way down.

As for the stitch settings, I set the selector dial to straight stitch (versus a zigzag stitch). For this type of stitch my Chart recommended a stitch length of between 0.5 and 3. I set this dial to 3.

I turned the machine on, depressed the foot control, and clickety-clack, off I went a-sewing on felt! I planned to make a little pillow, in part to test how much stuffing I could stuff into something and still be able to sew it up on the machine. Stuff it too full and there's not enough fabric to get under the presser foot.

Considering that in any given project I'll probably be combining machine-sewing with hand-sewing, I'll probably opt for a longer stitch so that they match, setting the dial to 4 instead of 3. I did try this, not on the pillow but on a scrap of felt, and it worked fine. For decorative purposes I may also want to use a thicker thread than the multi-purpose polyester I used today, requiring further machine settings to be investigated and duly adjusted. More on that to follow.

Until then --

Linda
Purty Bird

Egghead Learns to Sew, Part V

Hooray! Today it all comes together and I sew a couple of pieces of fabric together!

I gleaned from the Instruction Manual how to do this based on its coverage of the topic  "Changing Sewing Directions," rather than by following specific steps because this was the topic that immediately followed "Drawing Up the Bobbin Thread."
Doing so turns out to have been a good thing, as the section that I would have expected to follow "Drawing Up the Bobbin Thread," namely, "To Start Sewing," which I eventually found a few sections  later, was inadequate and even nonsensical: When I later followed those instructions, the thread got all tangly and/or the machine simply did not respond. I found Step 2. to be particularly confounding.

In any case, I hope that the steps to start sewing that I gleaned from the "Changing Sewing Directions" aren't bad for the machine or otherwise ill-advised. (Please do tell me if they are!)

To Start Sewing

This is obvious, but since I haven't used them in awhile, it might be worth noting that before starting to sew I attached the foot control the sewing machine and then plugged it into a power source.

After threading the upper thread, drawing up the bobbin thread and pulling both threads toward the back of the machine, I positioned the fabric that I wanted to sew under the needle, which was raised to its highest position.

Turning the hand wheel clutch slowly toward me, I lowered the needle into the fabric. Then I lowered the presser foot.

I pressed down on the foot control and woohoo! I was sewing!

When I got nearly to the edge of the fabric I stopped. With the needle in the fabric, I lifted the presser foot and pivoted the fabric around the needle to sew down the next side of the fabric.

I had the idea that I'd make a pincushion or tiny pillow of some sort as my first sewing project so I left the last side of the fabric open (the remaining side of the fabric was folded over). Thus, when I got to the edge of the second side of the fabric I was sewing, I stopped and followed the directions in the Instruction Manual for finishing a seam.

Specifically, pushing down on the reverse lever, I sewed backwards for about two inches. Then, turning the hand wheel clutch slowly toward me, I raised the needle to its highest position, lifted the presser foot, and pulled the fabric out toward the rear of the machine. As instructed, I cut the threads using the thread cutter on the back of what I think is the needle bar, but this was awkward so next time I'll just use scissors.

Next, I have to learn about different kinds of fabric and thread, and corresponding settings on my machine.

Until then --

Linda
Purty Bird

Egghead Learns to Sew, Part 4

Today is a big day! I get to the very cusp of sewing by adding the bobbin thread to the upper thread that I threaded last time. According to the Instruction Manual, this entails four steps: removing the bobbin case and bobbin from the compartment below the needle plate, inserting the bobbin into the bobbin case, inserting the bobbin case into the shuttle race, and drawing up the bobbin thread. Whoooeeee!
The first three steps really comprise one big operation, so I cover them together, followed by the fourth step.

Removing the Bobbin Case and Bobbin, Inserting the Bobbin into the Bobbin Case, and Inserting the Bobbin Case into the Shuttle Race

One thing to note: the Instruction Manual sometimes calls the sewing machine parts relevant to a given operation by names other than the one it originally used to identify them. For instance, regarding the set of operations I'm covering here, the originally identified "bobbin door" is called the "shuttle race cover." I'm going to keep to the original names for clarity's sake but note where the Instruction Manual diverges, just so you're aware of the alternatives.

As mentioned earlier, the action in this operation occurs in the compartment below the needle plate, behind the bobbin door. It's where the bobbin lives, in a case, inside a part of the machine called the shuttle race.

The first step of the present operation is to remove the bobbin case from the shuttle race.  (Before you start make sure the needle is at its highest position.) Open the bobbin door. Find the little latch on the front of the bobbin case and pull it to release the bobbin case from the shuttle race.

Next, insert the bobbin into the bobbin case, leaving a tail of thread about about 3-3.5 inches long outside it.

Pull the end of the thread through the little notch on the inside rim of the bobbin case and  out an oval-ish opening on the side of the bobbin case, called the tension spring.

Holding the bobbin and bobbin case together, pull the latch on the front of the bobbin case again and set the bobbin case inside the shuttle race. A handy tip: The bobbin case and shuttle race are like pieces of a puzzle; they have corresponding, inverse parts. Specifically, the bobbin case has an arm attached to the front of it that fits into a notch at the top of the shuttle race. Line up the arm and the notch and place the bobbin case onto the center pin of the shuttle race. Release the latch. The completed puzzle looks like this:

You're done! Close the bobbin door!

Drawing Up the Bobbin Thread

(This step requires that you've already threaded the upper thread. Please see my previous post for instructions if you haven't. Thanks!)

It's all starting to come together! Hold the upper thread (here, in dark blue) to the left side of the needle loosely with your left hand. Turn the hand wheel slowly toward you until the needles goes down and comes up. The bobbin thread (here, in red) will be brought up looped around the upper thread.

Pull the bobbin thread out with your fingers and together with the upper thread, under the presser foot to the rear of the machine.

Add electricity and fabric, and.... Stay tuned!

Until next time --

Linda
Purty Bird

Egghead Learns to Sew, Part III

Today I thread the needle (or "upper thread," in the parlance of the Instruction Manual) of my fabulous Christmas-gift sewing machine, inching ever closer to efficiently and effectively stitching fabric and making all kinds of wonderful textile-artistic things! Yay!
Excitement is beginning to overtake the nervousness I initially felt at this prospect.

The Parts

Threading the upper thread involves a few previously labeled parts of the machine, namely, the spool pin, bobbin-winder/thread guide, thread tension knob (although indirectly), and the thread take-up lever; plus a few unnamed parts. One of the unnamed parts is located behind the the face plate cover. The others are attached to the named parts, which may explain why they're not specifically named. In any case, the Instruction Manual provides a diagram (pictured above) of the path the thread is supposed to travel through these parts on its way to the needle. While it's reasonably easy to follow, it would benefit from color photos and a bit of narrative. This is where the the current post comes in.

The Steps

Obviously, the first step is to place thread on the spool pin. (This is Step A on the diagram, in case you're following that as well.) Now you're on your way. The thread's first touch-point is the bobbin-winder tension knob and thread guide. Pass the thread under the bobbin-winder aspect of this part of the machine (the circular bit in top) and through the little horizontal hook part just below and in front of it (Step B on the diagram).

Pull the thread down to the thread tension dial. Just behind the dial itself are a couple of circular plates. The space between the plates is where the thread passes through. Attached to the tension knob/twin plates is a delicate little hooky-loopy thing. Pass the thread in-between the plates and through the delicate hooky-loop (Step C on the diagram).

Now, pull the thread up and through another hook located just above and to the left of the thread tension dial/twin plates (Step E).

Keep pulling up. Pass the thread through the thread take-up lever (Step F). It's probably easiest to do this if the lever is in its upper-most position. To get it there, turn the hand wheel clutch (the larger of the two wheels on the right side of the machine) slowly towards you.

Next, open the face cover and pull the thread down and through another hooky thing located at the very bottom of that whole inside-the face-cover section of the machine (Step G). Close the face cover.

Keep pulling down and pass the thread through a final hooky-loopy thing located at the base of the needle bar (Step H).

Now, get ready. You're about to complete the circuit of hooky-loopy things and actually thread the needle of the machine. The diagram combines this step with Step H above but I think it deserves its own Step. After all, it is the gateway Step to effectively and efficiently stitching up all kind of wonderfulness. I know you can hardly stand the anticipation anymore, so without further ado....

Find the eye of the needle. It's just above the pointy end. Pull the thread down so you have a little slack. Then pass the end of the thread through the eye and pull it toward the back of the machine.

You did it! Make yourself a cup of tea and relax for a while before moving onto the final set of precursor steps to learning to sew on a machine, namely, inserting the bobbin into the bobbin case and uniting the bobbin thread with the thread you just threaded. What?! Don't worry, I'll explain.

Until next time --

Linda

Purty Bird

Egghead Learns to Sew, Part II

In this installment of my klutzy-bookish guide to learning to sew on a machine, I explain how to wind a bobbin. For those of you who never took sewing in school, the bobbin is essentially the spool of thread that contributes the bottom stitch. While it's not really necessary to wind your own bobbin --- you can buy them pre-wound --- I thought the process of doing so would be a manageable way to introduce thread and electricity to the post-it labeled parts of my machine and thus, to dip my toe into actually using it.

I began by identifying the relevant parts: the spool pin, bobbin winder tension knob, bobbin winder spindle, bobbin-winder stop, and the stop clutch knob. The diagram above shows these parts in relation to each other, albeit from the back of the machine (which, incidentally, I found confusing; the owner's manual is my friend, but, it turns out, not the most reliable one, alas). The pictures below show what these parts actually look like.

 

It took me poking around for awhile to figure out how to extend the spool pin so it was long enough to hold a spool of thread. Once I scaled that hurdle I followed the instructions in the owner's manual and placed the bobbin on the bobbin winder spindle, pushed the spindle to the right to engage it, and released the clutch.

Next I plugged the machine in. Ack! Electricity! We're getting serious now. I paused to collect myself and then put my spool of thread on the spool pin and wound the thread twice around the bobbin winder tension knob. The owner's manual didn't explain how exactly to attach the end of the thread to the bobbin so I just wrapped it around a few times and hoped for the best.

I depressed the foot control and lo! The thread began to wind itself around the bobbin! I marveled at how evenly the the thread distributed itself. I was also impressed that the machine knew when the bobbin was full. When the bobbin winder stop stopped turning, I was done. Nothing got jammed up or tangled. Yay!

I snipped the end of the thread with a scissor, removed the bobbin from the bobbin winder spindle, and felt accomplished. And relieved.

Until next time, when I go inside the machine to insert the bobbin, and thread the upper thread into the needle --

Linda

Purty Bird