Have you ever grabbed a dish towel to take a cookie sheet out of the oven? Would this work as the batting for a pot holder? Maybe you made a pot holder and wondered how much batting is really needed, and if the special insulating batting really works. I wondered the same things and set out to answer these questions and more.
To determine how well different materials insulated, I took my trusty Bar-B-Que temperature probe and iron and measured how the temperature under the potholder increased with time. I used a variety of materials; cotton batting, an old stained dish towel, a terry cloth towel from Goodwill, denim from a pair of torn blue jeans, cotton knit from my husband’s worn out undershirt, pieces from an old flannel sheet and Insul-Brite. Insul-Brite is a metallic poly sheet with a thin layer of polyester batting on both sides. It is advertised as an insulating batting for pot holders, oven mitts etc.
I put the probe under a sandwich of two pieces of cotton fabric and the various battings and put a hot iron on top. I checked the temperature after 15, 30, 45 and 60 seconds. The results of the first round of testing is in the chart below. I then sewed up a variety of pot holders and retested the time, in case the quilting made a difference. It didn’t. I then wanted to give them a more practical test, so I put my hand underneath the pot holder and hot iron on top. I timed how many seconds before I had to pull my hand away. I know that using my hand isn’t the most scientific method, but it gave some interesting results. For example, the 4 layers of tee-shirt fabric with Insul-Brite in the middle got unbearably hot much more quickly than I would have guessed based on temperature alone. I have added these results in the last column of the chart and called it “Hot Time”.
It seems that “fluffiness” is the critical factor in providing protection for your hands. The air trapped in the fabric of the batting and terry cloth provide more insulation. To prove this definitively would require more work than I am ready to commit to this project, but my conclusion is that fabric like tee-shirts and denim are more densely woven and conduct the heat to your fingers more quickly. The dish towel that I sacrificed for this study was not only ugly and stained, but threadbare. I think that a thicker towel would have performed better.
If your pot holder is mostly decorative, or you are just going to use it as a trivet for items that are only a little too warm for your table top, don’t worry about the batting, use anything you want. If it is going to get a lot of actual oven use, I would suggest going thicker. I have taken a casserole out of the oven and only then noticed that all the trivets were in use and it took me several seconds to find a place to set it down. The last thing you want is for your fingers to start burning while holding a full pan of ground beef, noodles and tomato sauce. I would recommend that you use at least 2 layers of batting material. Either towels or cotton batting or a combination of batting and Insul-Brite.
What about Insul-Brite? Well, it absolutely works. It will keep your fingers 5⁰ to 10⁰ cooler or about and extra 5 to 10 seconds of carrying time. Please be aware that the instructions say to keep a layer of batting between the Insul-Brite and the heat source. They aren’t kidding. The fuzzy stuff on either side of the foil is polyester. See in the picture how the iron left a mark after 60 seconds. The Insul-Brite wasn’t even directly touching the iron, it was between two layers of cotton fabric. The foil layer means that this is not microwave safe, so keep that in mind for projects like insulated bread warmer baskets. It also makes a soft crinkling sound when bent. Used correctly, it is a great product and I would recommend it if you were very concerned about temperature. It isn’t absolutely necessary though, so don’t let a lack of this product prevent you from sitting down at your sewing machine.
If you want this quilt to be used as a trivet for very hot items, then look to how the products hold up after 60 seconds. According to Wilson Art, a manufacturer of laminate counter tops (similar to Formica), their glue can start to soften at 200 ⁰F and you should avoid prolonged contact greater than 150 ⁰F. Corian, solid surface counter tops, say their product can withstand 300 ⁰F. But other web sites say you should keep the temp. below 212 ⁰F. Wood will char at 248 ⁰F but the finish can be affected by much lower temperatures. I have seen a table’s finish marred by the moisture and warmth of a delivery pizza box. There is no exact number, but my best guess is that you would want to keep the 1 minute temperature at or below 140 ⁰F. I know that you bring things out of the oven as hot as 450 ⁰F, but realize that the pan is starting to cool as soon as it hits the room temperature air. So, while the bottom of the pot holder is getting warmer over time, the pan or dish is getting cooler over time. If you are really concerned, then go with a triple layer, it will keep the temperature below 130 ⁰F. The triple layer items are similar to the commercial pot holder which I have used for many years and never had it burn my fingers or mark my table.
My next question was how difficult would it be to quilt a potholder with thicker and thicker batting. My Bernina didn’t have any problem with 3 layers of cotton, but the final trim was a little difficult with my rotary cutter. I used an open toed foot, a walking foot and the free motion foot and didn’t have any problem with any of them. The triple layer of terrycloth towel, shown below, just barely fit under the open toe presser foot on the Bernina Artista 165.
To get to the center of the piece with the walking foot, I had to lower the feed dogs. There was plenty of room under the free motion foot. Once in place I had no trouble sewing through all the layers of fabric with any of the feet. I checked very carefully and only found one skipped stitch. It is worth noting however that the sandwich was so thick that the free motion foot didn’t appear to move up and down, but I was still able to move the fabric back and forth. There was also plenty of space under all of the feet on my Bernina B740. The real problem was using the rotary cutter for the final trim before adding the binding. I have three rotary cutters, a Gingher, an OLFA and a Fiskars. Only the Fiskars had enough space between the edge of the blade and the center holder to be able to cut through all the layers. Cutting the layers with scissors was slow and difficult until I pulled out my great hacking 10” Gingher Dressmaker Shears.
In conclusion, almost any scrap cotton items you have lying around will work fine for a decorative pot holder or one that only gets light duty. Cotton batting and towel material work best and you can add Insul-Brite to give it a little boost. My personal choice depends on whether this is for a gift or if I am going to use it myself. If I am giving this as a gift, I would use either 2 layers of terry cloth (1st choice) or 2 layers of cotton batting, depending on what I had on hand. I wouldn’t use the Insul-Brite because some people may not like the crinkly sound. For myself, I love the idea of turning an old ugly dish towel into something new and beautiful. I use 2 layers of dish towel with a layer of Insul-Brite in the middle. I don’t mind the sound and the extra insulation protects these quilting fingers.
So, before you throw away that old dish towel, beach towel or bath towel, think about giving it new life with some left-over fabric and a little imagination.
Don’t miss next month’s newsletter, it includes a free pattern!
|No Batting, 2 pieces of cotton fabric||0.02||0.51||139||160||203||245|
|Double Layer Tee Shirt||0.055||1.397||135||148||156||175|
|Single Layer Blue Jeans||0.062||1.57||125||164||198||233|
|Single Layer Cotton Batting||0.066||1.67||126||142||161||185||14|
|Single Layer Insul-Brite||0.067||1.7||115||136||156||177|
|Single Layer Old Dish Towel||0.082||2.08||130||151||160||183|
|2 Layers Blue Jeans||0.088||2.24||107||145||158||165|
|2 Layers Cotton Batting||0.091||2.31||114||129||137||144||35|
|Single Layer Terry Cloth Towel||0.096||2.44||125||145||152||161|
|4 Flannel Sheets||0.1||2.54||115||138||150||160|
|4 Cotton Tee Shirt||0.102||2.59||116||143||152||157|
|Cotton Batting on Top Foil on Bottom||0.105||2.67||108||123||135||149||40|
|Foil on Top Cotton Batting on Bottom||0.105||2.67||109||126||140||154|
|6 Layers Tee Shirt, no outer fabric||0.112||2.84||106||133||146||157|
|2 Layers Old Dish Towel||0.12||3.12||106||131||140||148||24|
|6 Layers Tee Shirt||0.134||3.4||95||124||135||141|
|2 Blue Jeans Insul-Brite in the Middle||0.137||3.48||109||132||141||147|
|4 Flannel Sheets Insul-Brite in the Middle||0.15||3.81||100||127||135||140|
|4 Cotton Tee Shirt Insul-Brite in the Middle||0.152||3.86||98||124||132||138||25|
|2 Layers Terry Cloth Towel||0.163||4.14||93||124||134||140||40|
|8 Layers Flannel Sheet||0.183||4.65||90||120||135||141|
|2 Cotton Insul-Brite in the Middle||0.186||4.72||92||113||118||124||55|
|Triple Cotton Batting||0.188||4.78||100||119||123||129||49|
|Triple Dish Towel||0.193||4.90||86||109||125||135||35|
|2 Dish Towel Insul-Brite in the Middle||0.199||5.05||88||113||126||131||45|
|2 Terry Towel Insul-Brite in the Middle||0.25||6.35||81||101||118||128|
|Triple Terry Towel||0.274||6.96||80||101||119||128||85|
|Commercial Pot Holder||0.281||7.14||88||112||128||138||65|
All Temperatures are in degrees Fahrenheit.
Don’t miss next month’s newsletter, “What am I supposed to do with all these scraps”.