Thread: It
is highly recommended that you use 100% polyester thread when sewing
diapers. Thread that contains cotton can wick moisture to the outside of
the diaper and cause clothes to get wet. I recommend Guttermann thread.
It is very strong and comes in many great colors. It is available in
any fabric store.
I have also tried Sulky brand but wasn't impressed because it kept
breaking and I would have to re-thread my machine multiple times.
Needles:
If you will be sewing PUL as a layer in your diaper it is highly
recommended that you use ball point needles. These dull needles will
allow the PUL to "heal" better as it heats up during the first wash
and/or dryer cycle. It is not necessary to use ball point needles if you
are not sewing with PUL.
Elastic: There are three major types of cloth diapering elastic: Polybraid,
Clear Elastic, and Fold Over Elastic. Polybraid is regular white elastic
that you can get in local fabric stores. Two sizes of polybraid elastic
are commonly used in cloth diapers: 1/4 inch and 3/8 inch wide. There
are benefits to either and it is split evenly between mamas that prefer
1/4 inch and 3/8 inch. Large rolls of polybraid elastic (144 yards) can
be purchased through fabric coops.
Clear elastic comes in both 1/4 inch and 3/8 inch widths as well and is clear so it works well if you will be sewing something with elastic exposed (like a single layered diaper cover for example). Clear elastic should never just be tacked down and used in a casing as it is not strong enough. It must always be sewn directly to your application.
Fold Over Elastic works as elastic and a binding in one. Cloth diapering FOE, is 1 inch thick and as the name implies, you fold it over the cut edge of your fabric that you want to finish and then sew it on. This elastic can be used to finish both diapers and covers.
Clear elastic comes in both 1/4 inch and 3/8 inch widths as well and is clear so it works well if you will be sewing something with elastic exposed (like a single layered diaper cover for example). Clear elastic should never just be tacked down and used in a casing as it is not strong enough. It must always be sewn directly to your application.
Fold Over Elastic works as elastic and a binding in one. Cloth diapering FOE, is 1 inch thick and as the name implies, you fold it over the cut edge of your fabric that you want to finish and then sew it on. This elastic can be used to finish both diapers and covers.
Closures:
Pins: These are used to close flats, prefolds, and fitted diapers. Dritz brand pins are the best. You can purchase pins from Babies R Us, Walmart, and other stores that carry baby items, but they won't stay very sharp for long and you might get frustrated with them.
Snappi: These are used to close flates, prefolds and fitted diapers.
"Velcro" (Hook and Loop): Cheap velcro brand hook and loop can be found by the yard in fabric stores but beware. It will not hold up well to multiple washings and will reduce the life of your cloth diapers. Commerical quality velcro is called "Aplix" or "Touch Tape". Aplix is softer and has a fabric type of feel with open loops. Touchtape is a "napped" loop and has a more nylon/plastic type of feel to it. Aplix and Touch Tape work equally well for cloth diapering applications, and the brand that you pick is mostly a matter of personal preference and cost. The "hook" is the rough part of the velcro and the "loop" is the soft part. Most diapers used 3x more loop that hook.
You can purchase either 1 inch or 1.5 inch hook and loop for diapering. Either works well, but you should use the same width of hook and loop together in most cases.
Snaps: Some mamas prefer snaps over velcro because as the child gets older it is harder for them to remove snap diapers on their own. If you are making your own diapers, placing high quality plastic snaps (polyresin) like you see on Work at Home Mom (WAHM) diapers is an expensive venture. You have to buy the snap press and die sets for the snaps. These cost $70+. Diapers usually use size 20 snaps.