Hi All, I thought I'd share the various hints and tips that I've learned about working with EPP foam.... First, things that don't work well: 1) Electric drills: They tend to tear rather than making clean holes. Use a soldering iron or gun for small holes. 2) Electric routers- I personally haven't used them. I remember reading that Mark Mech has used a dremel tool with success for creating servo bays. For a clean surface finish, say on a wing, use a hot wire as described below. The recent post about from Purdue about the CNC router results suggests that the finished surface there was a mess, so I would avoid that method. It sounds like they had results like #1 above. Things that do work well: 1) Serrated Kitchen Steak Knifes- These are great for rough shaping the corners of foamie fuselages. The job can be finished in just a minute or two with great resuts. Tom Nagel recently reported using an "electric knife" (two counter-moving blades) with good results. Handy for Turkey, too! 2) Sandpaper/Sanding Block- This technique works well. Start with 60 grit to rough shape the foam, then move to 80 grit, then 120 grit to finish. You'll find that after using the fine grit you will have a decent finish, especially of you are following with 3M-77 and strapping tape. To further smooth a sanded finish, Tom Nagel tried using aluminum foil over his monokote iron with some success. Again, for the most smooth finish, use a how wire. 3) Hot Wire- I use several size bows (36", 18", 4") to cut wing cores, fuselage blanks, or small detail parts. I string 0.022" SS Fishing Leader (Cabela's) between two sprung 1/4" music wire arms with great success. With EPP foam use the lowest power setting that still cuts through the foam. EPP foam of 1.9 density will require slightly more current than the 1.3 density foam, and the new 0.9 stuff uses even less current. Low current will accomplish two things 1) Less re-melt plastic that is easier to deal with and remove, and 2) Less toxic smoke from burning liquid propylene on the wire (Always use lots of ventalation! Open windows and blow several fans). Cut at a nice slow rate, and let the wire move at it's own rate, with the assist of a slight amount of weight on a lever arm. EPP foam cut this way has a glossy, re-sealed surface that is quite smooth. If others folks have handy hints, feel free to add to what I've said above. You can see more about this topic at: http://members.aol.com/Rpvi/home.html Ok, back to the shop to complete a production run of F-21 Predator wing cores..... Rick Powers RPV Industries Palo Alto, CA [EMAIL PROTECTED] RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
