Hi. I’ve been lurking for several years but have decided to appear. There are many threads here concerning blocking thread crochet but I’ve never seen my method mentioned. This way of blocking creates a doily/tablecloth that drapes but holds it shape. I use this for any thread crochet that does not need to be stiffened.
Clean & completely dry your crochet. Center it on an ironing board or an ironing pad, right side down. The ironing pad allows larger items to be shaped. If there are ‘bumpy’ areas such as popcorns put it on a turkish towel.
With SPRAY SIZING (found in the soap isle beside the spray starch) spray the area of the item that is flat on the ironing board or pad. Your iron should be warm, not hot, just warm enough to make the sizing sizzle gently. I use a small iron, the kind that used to be very common, not the full size iron. This gives me more control of the item being shaped.
Beginning in the center, & using the edge of the iron, gently pull the iron towards the edge of the item. Do this all around. Keep working in this manner until you are satisfied with the shape. The object is to stretch not flatten the stitches.
If the item is larger than your ironing surface, allow the work you have already done to dry. Then center another portion on your ironing surface.
When you are finished with the item lay it (still damp) carefully on a flat surface to finish drying. That way you can work on a 2nd item.
Thread crochet shaped this way will stretch quite a lot. It will hold it’s new shape until it is washed, & reshapes just as easily.