I've just received my first batch of printed parts. These will be used to create a 1:144 scale model of the SpaceX Falcon 9 rocket. One of the parts is in FUD: <a href=" http://www.shapeways.com/model/1004887/falcon-9-engine-clust er.html" target="_blank"></a> The rocket nozzles each contain a hole all the way up to the support plate. This hole is small (about 1 mm at its narrowest point) and they contain a viscous liquid that won't drain out on its own. This could be wax, or the raw (unfused) printing material. For now I'll try some of the cleaning tips I've found here, but I think I'll have to change the design to prevent this in the future. I could make sure the hole goes all the way through, but the narrowest point will remain 1 mm (otherwise my walls would become too thin). Maybe I'd be better off making this section solid? I've also had comments that this part will be difficult to paint. To improve that, I'd have to remove the nozzles from the base plate, but that would make positioning them in a neat grid tricky. I'd like to provide locator holes that the nozzles would fit in. How much clearance would I need for the parts to fit snugly?