Does anyone know where I can purchase the soft elastic that comes inside better hats? My daughter's Liz Clairborn sun hat headband elastic made the hat very comfortable and almost windproof and she would like me to sew it into all of her sunhats. Joannes has never had it so I may have to order it online.

I'm not sure what kind of elastic you mean. However, I can recommend clear invisible elastic -- very soft and is very suitable for swimwear. Haven't purchased it in years, but I used to be able to find it on the notions wall at JoAnn's. Found a photo of it on eBay:
http://cgi.ebay.com/NEW-1-2-inch-CLE...-/370488691941

I think the kind I used to buy was 1/4-inch wide, though. A simple zigzag through the middle of the elastic works well. With swimwear you would sew it on that way, then turn the fabric edge and enclose the elastic inside the seam.

No, the elastic I'm seeking looks woven, color beige and an inch wide. It may have some cotton in it so that it doesn't hold in the heat and make your forhead all sweaty.

Is it a lingerie elstic?

No. It was specificly designed for hatbands or possibly for waistbands. I've seen it in pricier hats but never in the cheapest ones from K-Mart or Walmart.