Good advice above! I wanted to add, avoid using putty, except in very thin applications. It's brittle, and can crack and break off. I'm using superglue more, especially when working with resin, I have no choice. I also use baking soda to accelerate the cure, but when the part is washed, it dissolves chunks and creates tiny holes, that's when putty is used. It's a good idea to glue in more plastic than you need, which will be removed when getting the final shape. In this case, I screwed up the cut, so had to correct. Putty will shrink over time too. Just my two cents, for what it's worth.