How to sew PUL fabric (for waterproof layers)

This week on the Learn to Machine Sew series, I’ll be focusing one of the very few specialty fabrics that I use: PUL.

PUL (which I always pronounce “pull” even though it’s actually pronounced as the acronym that it is: “P-U-L”) stands for Polyurethane Laminate. In normal English, it’s a fabric that is laminated on the back (the wrong side). There are other types of laminated fabrics, such as oilcloth, but the main differences are that:

• PUL is a regular fabric that has been laminated afterwards, as opposed to a man-made vinyl which is created already with a lamination.
• The plastified side of PUL is the wrong side, NOT the front of the fabric, so that it can be hidden
• PUL’s lamination is soft and breathable, making it a great candidate for wearable items.

Like I said, pretty much any fabric can be laminated, even stretchy ones because of the elasticity of the lamination. You can most commonly find polyester interlock PUL, which has a good stretch to it. Less frequently you can find woven cotton PUL or even other fancy fabrics, such as Minky. There is also something called “sandwich PUL,” which is one layer of PUL between two layers of non-laminated fabric, which is useful if you want to completely hide the PUL fabric, though I’ve honestly never used it myself.

The lamination can be either 1 or 2 mil. In theory, 2 mil is more heavy duty and 1 mil drapes better, but I quite honestly don’t notice much difference (the fabric base makes more of a difference, in my opinion) and they are both equally waterproof.

I’ve never seen PUL in a brick and mortar fabric shop, though I’m sure some do carry it. However if you google it, search diaper-making websites or look on Etsy, you’ll find it pretty easily on the internet.

When would you use PUL? It’s pliability and breathable quality make it perfect for any sort of waterproof item that gets worn on the body, such as cloth diapers, menstrual pads, training pants or nursing pads, because, unlike other laminated fabrics, PUL actually allows some air to get through and let the skin breath. PUL is also frequently used to sew wet bags and portable diaper changing mats even though they aren’t worn items, because of its softness and easy foldability.

PUL is a very special fabric and you need to take many things into consideration when preparing and sewing it. Continue reading for some essential PUL rules! (Oh, and these rules apply, perhaps to differing degrees, to other laminated fabrics, too.)

Rule #1: Limit pin and needle holes in PUL!

When you stick a pin or needle in most fabrics and then remove it, it generally won’t leave a noticeable hole. The fabric self-heals. The lamination of PUL prevents the fabric from healing from pin or needle punctures. So, not only will it leave a mark in the fabric, but that tiny hole, especially if multiplied by a lot, can lead to leaking. Which defeats the purpose of using PUL in the first place.

This means:

• Be careful when sewing PUL so as to avoid having to rip out stitches, which will leave  gazillions of little leaky holes, which would be very unfortunate
• DO NOT USE PINS! Instead, use some sort of clip, such as clothespins*, hairpins, binder clips* or– if you’re particularly fancy– “Wonder” clips* (these are special clips made especially for holding fabric in place). If you want to use pins, be very careful to position them inside the seam allowance so that the holes won’t create problems. Another option is to temporarily baste PUL fabric to other fabrics with a washable glue stick*.

See? It’s pretty easy to hold fabric together with your clips instead of pins!

Rule #2: Use the right type of sewing needle.

Use the type of needle that you would normally use for the type of fabric the PUL is made of. So if you’re sewing woven cotton PUL, use a needle for woven cotton. If you’re sewing interlock PUL, use a needle for knits. Some people say to use a smaller needle to leave smaller holes, while others use a larger needle to puncture the lamination more easily. I just use an average sized needle, but see what works best for you.

Rule #3: Use polyester thread.

Cotton thread absorbs, polyester thread doesn’t. If you sew a cloth diaper with cotton thread, a small amount of liquid will get absorbed by the thread and go through to the other side, dampening it. You don’t want that, so just use polyester thread to avoid it happening.

Rule #4: Don’t prewash.

Prewashing fabric is annoying, uses energy and water, and makes you have to wait to be able to start your sewing project, but it’s necessary to remove any stiffening materials from the fabric and to preshrink it before cutting into it. Wouldn’t that stink if you “forgot” to prewash your fabric, spent hours (days, weeks…) sewing the most amazing garment you’ve ever sewn, you wore it once, washed it… and then discovered that it shrank in the wash and you’ll never be able to use it again?

Well, guess what? PUL doesn’t shrink! Yah! So unless you inherited some very dusty PUL from someone or you accidentally spilled a bag of flour on it, there’s no need to wash it before cutting into it.

Rule #5: Iron with care.

In theory you shouldn’t iron PUL, but you know what? I do. Just make sure that you use a low temperature (or medium at the highest), no steam and a protective ironing cloth*. (I like the sheer types so that you can better see the fabric below. You can’t really tell, but in the picture above there’s one on top of the PUL fabric.) Iron the non-laminated side just a little bit at a time, and you’ll be fine.

PUL doesn’t generally get extremely wrinkled, but a good quick pressing can make a difference, as you can see in the picture above. I actually only iron PUL when it’s super wrinkled, but do as you want.

Rule #6: For use with foods… or not?

Ok, this isn’t really a rule, but a consideration. Some people use PUL for making reusable bags or wraps for food and snacks, but consider the fact that it hasn’t been definitely shown whether or not the lamination contains harmful chemicals that can leach into food. I quite honestly don’t trust any sort of plastic very much as far as food is concerned, so I don’t use it that way, but feel free to make your own decision on this point.

You may say, “You’re worried about chemicals leaching into food, but not about chemicals being in contact with your skin?” Well, PUL’s lamination never comes into direct contact with anyone’s skin because the lamination gets hidden inside the sewn article. So no worries there. But if you would prefer a 100% worry-free waterproof barrier for cloth diapers or pads, you can always use felted wool. But I’ll talk about that another time.

Rule #7: When you want the lamination on the outside, just sew it upside down.

In some cases, like with wet bags or those snack wraps I just mentioned, you actually do want the lamination to show, so that damp objects inside will stay damp inside and not leak to the outside. Or if making a portable changing mat, the surface can just be wiped clean with a damp cloth and get reused without having to wash it a million times. In these cases, you need to sew it considering the laminated side as the right side, not the back. When doing this, you can only use solid colored fabric. This is because both the front and back looks the same, as opposed to fabric with a printed design, which looks pretty bad on the back side. If you look at the second picture of this post, you’ll see what I mean.

Rule #8: Cut two layers of PUL right sides facing.

The laminated side of PUL can be quite slippery, so if you double up your fabric when cutting it out, it can slip all over the place. Instead, put the two layers right sides (non-laminated sides) facing to minimize slipping.

Rule #9: Use a longer-than-usual stitch length.

There are two reasons for this. First of all, to leave fewer needle holes. Second of all to make the PUL easier to sew. More about that in Rule #10.

Rule #10: Sew PUL with tape, tissue paper, a teflon foot, a walking foot or chapstick.

The lamination makes PUL slippery when cutting it, but it actually makes it sticky when sewing. This doesn’t seem like it makes much sense, but that’s how it is and it can make you swear and kick furniture out of frustration. The plasticky surface sticks to the presser foot when it is facing up. It’s not generally a problem when facing down, because the machine’s feed dogs move the fabric along. Look at the following pictures:

When sewing one layer of PUL, it may not move along perfectly and it may bunch a bit (as seen above to the left), but it won’t be the end of the world, even if the lamination is facing upwards. And if sewing two layers of PUL, wrong sides (laminated sides) facing (as seen above to the right), things go pretty smoothly.

But once you put two layers together with a laminated side facing up, things get totally crazy, as you can see above. The lamination gets stuck to the underside of the presser foot, keeping it from sliding under it properly. However, the bottom layer is getting fed through by the feed dogs. This creates awful bunching and pulls the top layer far beyond the edge of the bottom layer, making the fabric curl up. You also end up with a tiny stitch length, which looks bad and leaves more holes in the fabric. You definitely don’t want any of this to happen.

But guess what? There are various tricks to get around this problem. Some people find that some of the tricks work great, while others will find that they don’t work at all, so try them out on some scraps of PUL and see what works best for you. And when all else fails, try to rearrange your fabric so that the laminated side is not facing up. Let’s get started.

Trick #1: Stick some tape under a regular presser foot.

The idea is that applying either transparent tape or masking tape to the bottom of a presser foot keeps the lamination from sticking to it, and therefore allows it to slide better underneath. Just cover the bottom of of the regular zig zag or straight stitch foot and poke a hole in the tape with scissors or something else sharp where the needle needs to go through.

Some people swear by this trick, but I haven’t been able to get perfect results like this. Sure, it’s better than nothing, but still isn’t enough for me. But hey, it’s free, so try it!

Trick #2: Use a teflon/non-stick/ultra glide foot.

These are different names for the same all-plastic presser foot. The idea is the same as with the tape trick: the lamination won’t stick to the non-metal surface of the teflon foot*.

Most people just LOVE this foot and it works perfectly for them. A nice thing is that it’s usually a pretty inexpensive foot, too. I’m not sure if my teflon foot is just a piece of junk, but it doesn’t work for me, as you can see above. If you want to try this foot out, I suggest bringing your machine and some PUL scraps to an authorized seller and asking if you can try out the teflon foot before purchasing it. Make sure that the foot you purchase is compatible with your sewing machine model!!

Trick #3: Use a roller foot.

The roller foot* is just what it sounds like: a foot with little metal cylinders that roll, helping the fabric move along. This foot worked for me just as badly as the the teflon foot, but if you have it, or if you’re trying out machine feet at an authorized seller, you may as well give it a try!

Trick #4: Apply a thin layer of transparent lip balm to the area you will be sewing over.

I found this trick here, just this one time. The woman who wrote it says that it works a charm, but I didn’t get perfect results with it. But, just like the tape trick, it doesn’t cost anything, so you may as well give it a try!

Ok, enough of what tricks didn’t work for me (but do work for others and may work for you). Now for my favorite tricks which work perfectly for me!

Favorite Trick #1: The walking foot!

Remember how I talked about the walking foot last week? The extra feed dogs that help feed the top layer of fabric under the presser foot work wonderfully for moving the sticky laminated side of PUL!

This is my absolute favorite solution for sewing PUL, and it’s rare that I get any bunching or sliding when I use my walking foot. If you don’t know how to use this special foot, I highly suggest you read about it here. It’s not at all scary, I promise!

Favorite Trick #2: Tissue paper!

Cut strips of tissue paper, place it over the fabric, and sew right over it. The paper lets the PUL slide right under the presser foot as if it were any other fabric!

You can actually do this trick with any lightweight paper (such as receipts or parchment paper), however I prefer tissue paper because I can see through it, so I can line up the edge of the fabric with the correct seam allowance guide on the sewing machine. I always save the tissue paper that comes with new shoes and use it for sewing.

After sewing, gently pull the paper on one side of the stitching to the side (don’t pull it straight up, because that puts stress on the stitching and can pull it up). It will tear just like any perforated paper. Once the paper has been torn along the stitching, the other side of paper will pull right out. Again, pull it to the side away from the stitching to avoid little bits from getting stuck under the stitches.

See? Absolutely perfect! And if you have a particularly difficult situation, you can even use tissue paper along with any other of the tricks mentioned above to help the PUL fabric along.

Now practice sewing PUL scraps so that you’ll be ready for the tutorial later on this week using this special fabric!

Did you like this lesson on how to sew PUL fabric? Take a look at the other lessons in this beginner’s sewing course!

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