When I first read this I thought "okay.......... But, when I think about it.. though I have never done this it does sound interesting in reference to paperpiecing stars and all their intersecting points I run into. I too have a wooden leathercraft hammer, and think I will also go raid my husbands shop and check out his rubber mallet and try them both. I do not use steam for paperpiecing it quite often will make the ink run so the hammer might help when there are many intersecting points.
Thanks for posting.