Cutting Panels

[Guest]

Hi AllHas anyone figured out how to cut reasonable panels from plexiglass or other materials?? I've been battling this one for a while. For the larger, less intricate panels, hardboard is useable, but for more intricate ones like FCU's, I havent figured out a reasonable way to cut these yet.Suggestions welcome, for any materialsDave T

[Guest]

Gooday Dave...........The only way to cut acrylic or any plastic is to build a CNC machine. Now after picking yourself up off the floor, this is not quite as hard as it sounds. It only requires 3 stepper motors, a program to drive them (like Kellycam) and some time to build the moving table for the whole project !!This is not for the faint hearted, but the benefits in sim-building are enormous. Try this site for more info.http://213.10.73.60/majosoft/index.htmlRegards ........Brian

[Guest MikePowell]

Hi Dave,If you are using aluminum, a large foot operated shear is a great choice. As you are asking the question, I suspect that like me you do not have access to one. Hand shears work but distort the metal. The solution that has worked best for me is a 10" radial arm saw with a carbide blade dedicated to metal cutting. Ear and eye protection are a must, but the cut edge is wonderful.The approach to cutting holes depends on the size. For holes greater than about 3/4" a fly cutter held in a drill press works well. Cutting part way from one side, them finishing from the other, limits the burrs. For smaller holes, drill bits work up to about a half inch. From 1/2" to 3/4", I generally use a file.Square and rectangular holes often start as round holes, and get finished by hand with a file. There are punches that will work (made by Greenlee) but they are rather expensive. Unless you are making a great many of the same size, the cost just may not be worth it. Punches also are a bit difficult to keep lined up. You can keep them centered, but it's hard to keep the edges of the square punches all trued up.One of the most critical steps is doing a proper layout. Grade school rulers and pencils just don't do it. A metal rule with decimal markings to .01" is a great friend. Use it to set a marking gauge with a scribe point rather than a pencil point. There is a lacquer-like material called marking or layout fluid that machinists use. The layout is done by scribing through the dried fluid. It makes very fine, but easy to see lines. A workable substitution is a wide permanet marker. The water based markers won't work, must be the smelly permanent ones.Cutting plexi is a bit more challenging. Sawing and drilling generally work well but with the added complication that you can't let it get hot. Once it starts to melt, it grabs the tool and something breaks (drill bits, plastic and/or fingers). So far the same carbide saw blade has worked well, because the cuts are made quickly. When drilling, I drill only part way, then clean the tailings from the hole. I also use a cutting fluid to help cool the bit and plastic. I use a very high tech drilling fluid: one part dish detergent to three parts water. Sanding generates intense, very localized heating. With plastic, this means the sand paper clogs almost instantly. Get around this by wet sanding. Files clog as well, unfortunately. You can make rough straight cuts by scoring and breaking the plastic at the score.It's possible to use high speed routers on plexi. That's the basis of fabricating plastic signs by those who don't own laser engravers. There is some information on working with plastics on the Cyro Plastics site www.cyro.com .My choice tool would be a small CNC machine. There are a number of hobby sites showing home made units. Somehow I don't think I'm going to find the parts under the Christmas tree, though. If I were making an intricate panel like an FMC/CDU/etc., I'd opt for sheet aluminum. It's much more forgiving than plastic, given the tools on hand.Mikewww.mikesflightdeck.cominfo for simpit builders