Sewing Patches & Pinkie Patch

A few folks have asked me about the differences between sewing a patch and sewing regular embroidery.  When you get down to it, the 2 processes are very similar.  I'll illustrate the differences using a patch design that was requested; Pinkie Pie.

One of the big differences is with the machine.  First, you need to use the smallest hoop possible.  The smaller the hoop, the less likely the design will tear itself apart when being sewn.  Second, you will need a special needle.  Originally, I tried using a regular chrome hardened embroidery needle, but I kept breaking them.  As mentioned below, the patch is overlapped in many places, in some cases there can be a bunch of layers.  In fact, this Pinkie Pie design has a few spots that are actually 7 layers of thread.  I switched to a titanium hardened HLx5 from Organ Needles instead of a chrome 15x1.  The HLx5 needle is basically a needle made for a commercial machine, but machined to fit in a regular home machine.  HLx5 needles are about 5 times more expensive than a regular 15x1 needle, but they break way less often.  I paid about $5 per needle in a store for mine, but you can get a pack of them here for a lot less.  By the way, don't hover over your machine or stare at the needle while it works.  I had a needle break once and fly across the room and hit me in the back while I was on the computer.  It didn't hurt or anything, but if my face was over the machine, it may not have been pretty.

Another change is that the embroidery design is sewn directly onto stabilizer, instead of being sewn onto fabric. In addition, instead of 1 sheet of stabilizer, several different sheets of different types are required.  In general, I use 4 sheets of stabilizer per design, though some require more depending on how many stitches are in the design.  For 2 of the sheets, I use a normal 1.5oz tearaway, while for the other 2 sheets I use a 2.0 oz cutaway.  I also alternate the sheets, starting with a 2 oz cutaway.  This alternation of types adds to the sheer strength of the assembly, which keeps the thread from tearing apart the stabilizer while the design is being sewn.  Once it starts to tear, you're done and need to toss that patch and try again.  Here's a pic of Pinkie's outline (the first sewing step) sewn directly onto the stabilizer.

The next big change is with the design itself.  In embroidery, the stitches tend to run in 'random' directions.  This is fine for normal embroidery, but when a bunch of stitches line up in equivalent directions, they will put extra force on the stabilizer and tear it.  This is most evident when you have a dense solid design that is all the same color, such as the body of a pony.  Each thread will be under about 1/2 a pound of tension (my estimate, not tested), and if you hit the tear point of the stabilizer (about 10 lbs by my estimation) the stabilizer will come apart like a zipper.  That means the colors must be put down in an order that will equalize the tension in all directions.  If too much is put down at once, it will come apart, like this design did at the lower left.

The next problem is that the design will not have any strength to it once taken out of the embroidery hoop.  If a design falls apart once it is sewn, it won't be worth diddly. Well, besides as stuffing in your next plushie I suppose. Solving for these 2 concerns requires some knowledge of math and physics when doing the design.  I think I can simplify it though, so you don't need to know any math, as you were told there would be no math in this debate.  I mean blog.  But I'm a computational physicist by trade, so you are going to have to deal with some of it anyway.

First and foremost, the design needs to be overlapped between colors.  In a normal embroidery design, there is almost no overlap, as the thread lower down on the Z axis is not going to be seen.  However, if not overlapped, there will be a weak spot in the design wherever the design changes colors.  It wouldn't do for Pinkie's mane to come off, though it would be hilarious.  Therefore, I overlap the colors by at least 1 stitch, though I generally go with 2 overlapping stitches or more.  In normal embroidery, the thread is just there to add color, but in a patch, it needs to be structural too.  Here's a closeup of Pinkie's mane, where it overlaps her body.  The magenta outline is for the mane, the pink is her body, and the purple is the mane outline.  The mane outline is 2.5mm in width for perspective.  Sorry that this is so hard to see.

For most of this design, the thread is running left to right.  This means the patch will be insanely strong left to right, but not vertically.  The only thing holding the pieces together vertically would be the outlines around Pinkies mane and body.  This weakness would make it so the patch could actually be pulled apart by hand.  Again, this is not conductive to Pinkie continuing to look like Pinkie.  To solve for this, I use 2 different runs of thread that are there just to hold the design together.

The first layer is a square pattern on a 45 degree angle.  Almost no thread in the design runs in this direction, so this will help hold both the horizontal and vertical stitches in shape.  This will also add strength to the stabilizer itself.  The thread doesn't have to be too close together for this to be effective.  Each square is roughly a square centimeter.  The color isn't too important as it will not show though the top thread.  I usually use a color that is prevalent in the design, in this case, the same color as Pinkie's body.

The next layer is much more important to how the design will stitch out.  It is a single layer of thread running from the top to the bottom over the entire design, with a very wide spacing.  Note that it goes under the entire design, including the mane and tail.  Not only does this add strength top to bottom, it distributes the tension from the left to right fill thread that will be laid down later.  This helps the stabilizer withstand the pull without tearing.

Now, we have a silhouette of Pinkie done out of vertical and 45 degree stitches.  Now, we can lay down the actual color stitches.  A balance must be found between the color order and strength of the design at a given point in the process.  For example, it would be better to sew Pinkie's eye first, but it can't be done that way because the eye needs to be on top of the body thread to look right.  Some trial an error may be required when doing your own designs and your own brand of stabilizer.  No matter how you do it, the design will have a point where it is weakest.   In my design of Pinkie Pie, it's easy to figure out where this point is.  It's right after Pinkie's Tail is sewn.

Why does Pinkie look cool in only 2 colors?

At this point, all the top layers of thread are pulling left to right.  The longest runs of thread are between Pinkie's rump and the hoof farthest to the left, and this is where the design would come apart first.  Starting now, the clock is ticking.  The longer it takes to finish the design, the more the stabilizer will pull apart at the edges, and it is going to do it at one of those 2 places.

The very last thing to do is outline the design.  This is done last as it will use a ton of stitches in a really small area.  This will weaken the stabilizer, in some cases to the point where it will come apart within minutes of the outline being sewn.  Besides adding color, the outline is necessary to survive the next steps in making a patch.  cutting the design out, and sealing the edges.

Cutting the design out is straight forward.  I use a hobby knife and a bamboo cutting board.  The goal is to get as close to the outline as possible without cutting the outline itself.  If the outline is cut, even a little, the design will start to unravel.  Leaving too much of the stabilizer on will leave a white ring around the finished patch.  A steady hand and patience is required for this step.  It usually takes me about 15 minutes to cut out a patch.  Having a sharp knife is absolutely necessary as well.  The sharper the knife, the less likely it will be that you cut yourself by accident.  Seriously.  I change the blade when I drop it from 1" high into the cutting board and it doesn't stick into the board.

Cut out Pinkie

Once cut out, it's time to cook your patch.  The point is to burn off any fuzz left over, and seal the edges of the patch so they last longer.  For this, I use a propane torch.  Don't try this at home, I am a trained pyro with a fire extinguisher handy.  I use a self igniting, spiral mixed propane blowtorch and regular propane.

The reason for this is because you want the flame to be as hot as possible so that the patch edges melt, not burn. Anyway, you want to be quick, and do all the edges, the back, and the front.  Total time in the blowtorch should be very short, 1/2 second or less.  If the patch gets too hot, it can melt entirely or catch on fire. Using a regular lighter won't get hot enough, and the patch will tend to start on fire before it melts.

Crispy Pinkie

After that, you're all done with the design.  Put out any latent fires, and start on the next one.