Some of the older sewing machines have a presser foot PRESSURE adjustment - on many machines it's the knob on top of the machine above the needle bar - I found that on my Singer 237 (a 1960s "economy" model - tan) that I could sew on a lot of thicknesses when I reduced the pressure. Before I reduced the pressure, the top layers would move forward as I tried to sew.

Anyway - it's another adjustment to consider.

It also helped to lengthen the stitch.

And to use a heavier needle - like a 90/14 or 100/16 when I was using denim.

I have used old thick terry towels for the middle of potholders.

The suggestion to test the combination under a hot iron is an excellent one.

I have been making potholders for over 50 years. When I began there was no Insulbrite. I have mostly used worn washcloths, old mattress pads, bath towels, etc. No problems so far...so I guess I will continue to make do...use it up.....wear it out.

I always use two layers of insulbrite in my pot holders and mitts. I also make the mitts quite a bit longer to protectt my arms as well.

30 years ago, I cheated. I went to the commissary and bought a stack of cheap potholders that were on sale for like .89 cents a piece. The front and back were silver material which we now know as insulbright. Brought them home and make a front and back piece (pieced them) and added binding. Extremely easy and I'm STILL using those potholders. I've never been burned when using them and I can't throw them out because they just won't wear out!

I always add a layer of batting when I use Insul-Bright as that is what the manufacturer suggests. I feel that it gives the recipient extra protection and it makes for a beautiful project. Insul-Bright says that the extra layer of batting absorbs the moisture that forms from the heat which could, just possibly, cause the heat to be more intense. Have never encountered this, but I'd rather be safe than sorry.

My mother used to crochet potholders using cotton crochet thread. She would sew two together using scraps of cotton fabric (3 or 4 layers) for the "stuffing". They were fine and we never felt the heat through them. What I am saying is that you don't need insulbrite. Just use a few layers of cotton fabric. Or try towels like the chefs on tv do.

I use insulbrite, a layer of cotton batting and use Teflec as one of my outside fabrics. Works really well.

I just asked that today at the LQS. They said it made no difference ... Hope they were correct.

I have used the silver material that covers ironing boards in my potholders. It is thin and easy to sew with layers.

I place one batting square between 2 squares of the silver material. The shiny, heatproof side of the silver fabric squares face out toward the top and bottom fabrics of the potholder. ..this way both sides are heatproof.

I agree...