I am making a sash, and I have satiny material, can I use Iron on letters on this kind of material?
No. To get the iron on to stick you need the iron to be on the hotest setting. Wool/Cotton. This would burn and or leave scorch marks on the satin. Try using Arlenes Fabric Glue available at JoAnn's Fabrics, on a test scrap of satin.
This will depend on the composition of your fabric. Satin is a weave, not a fiber, and it is the fiber content that is important here. Natural fibers such as cotton, linen, wool, and silk can all take a higher temperature than man-made fibers such as acetate, nylon, and polyester. If your letters already have fusible glue on the back, you will need to look at the instructions to see what temperature you need to use to melt and fuse them to something. If your sash says 'cool iron', then you may not be successful with some pre-made letters. If you have a polyester or acetate fabric (common for non-silk satins), then your letters need to be fused with a low melt-point fusible web. You can make the letters out of whatever fabric you like. Lay the sash out carefully, place the letters, cover with a pressing cloth, and fuse. Press each iron sized area for 15-20 seconds. Keep the iron still. LIFT the iron off the fabric to move it to a new area. The pressing cloth helps to protect the fabric from the heat of the iron (which will be on there a lot longer than is usual for ironing a garment), and your iron from the fusible glue. If you are concerned that the glue may get on the ironing board, cover that too before laying out the sash and the letters.
