What do I do when a quilter brings me a quilt to machine long arm that has flared borders?
First, you will probably need to use a fluffy batting, like a poly so that you can get some “hills and valleys” into the quilting area that needs to be taken up. Usually 3.5 or 4 oz is ok but increase batting thickness with the degree of the flare.
Second the style of quilting should be either large meandering or wavy lines 1 and ½ inches apart radiating outwards on the border (we call it bars on the border). Either one of these two styles of quilting can and will take up the slack in the flared borders and distribute it into the “hills and valleys” correcting the situation without taking the borders off and re- cutting.