I always use one layer of Insul-Brite and one layer of 100% cotton batting. I also use cotton thread, since it is more fire retardant than polyester. The pot holders work great, wash up well, and last forever.

I made pot holders for Christmas gifts I cut 2 blocks right sides together and sewed around them leaving opening to turn. After I turned and pressed I put this on top of an old mattress pad and cut around it. I then rolled the mattress pad like a jelly roll and stuck in the opening and spread it out inside. (Make sure you match the end of the fabric with the pad so it will fit properly. I then hand stitch the opening shut. Top stitch around the pot holder about an inch form the edge. By cutting the mattress pad after it is sewed there is less bulk in the seam and easier to turn. They last for a long time.
Jothesewer

Insulbrite is relatively inexpensive and I'm inclined to think better safe than sorry. I use it sandwiched between two layers of 100 percent cotton batting given to me by the artist who does my long arm quilting. I love using the hotpads myself! froggyintexas

When I make oven mitts I use one layer of insulbrite and one layer of fleece on each side so it doesn't matter which side of the mitt is used. I use a sandwich of fleece-isulbrite (with the protective side up)-fleece for the hot pads so there is adequate protection for the table/countertop.

Sande, the shiny side goes towards the heat to reflect it back and away from your hand or table.

That said, I never use the stuff. Hate it. It's more trouble than it's worth, is a waste of money, and was simply 'invented' by the Warm Company to create a need. Very successful they were at it too, judging by how many people here thinks it's indispensible for hot pads and potholders. It's all pure hype.

You do all realize that InsulBright itself is polyester, don't you? And that polyester melts under extreme heat? So what's the point?

The problem with Insulbrite is that it can't be used in the microwave. And since I tend to put potholders in there, I made a little tag for the ones I gift/sell to make sure the recipient knows not to put it in a microwave. It seems that just batting is safer. Besides, I don't think Insulbrite works better than two layers of batt.

I used 3 layers of high loft poly batting in mine. They lasted many years, till the fabric wore out.

I find that it really helps keep the heat from a hot pan from transferring to my hand. My DH like french fries baked in the oven and when trying to hold the pan to push the fries onto the plates it gets very hot - the insulbrite is very helpful.

Which is why the manufacturers recommend using a cotton batting.......... The point is that it's not quite just polyester.
It's used for a myriad of other things. I don't think people are so naive that they succumb to 'pure hype' - rather they make an informed choice. Bit rude to intimate that people who like this product are 'suckers'.
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I also use the same things, even old denim. Makes great potholders. If it is thick enough it works. Several layers and it doesn't cost extra!