MDF-PVC and Delrin
John Conrad KleinbauerMDF is a material you can find in your local Home Center or Lumber Yard. It is 3/4" thick and it comes in 2' X 4' and 4" X 8 foot sheets. It looks more like a paper bag then Particle Board. It is very heavy!!! You can also buy it as shelving in 1' X 4' or 1' X 8' foot lengths. As soon as you bring it home, paint it with three thin coats of Acrylic Latex paint. I suggest a light grey color so you can see your layout lines. After you cut your parts you need to paint the cut edges. This keeps the MDF from changing size do to changes in room humidity. It also keeps it from staining from sweat or oil. MDF can be tapped and bolted together using 10-24 bolts. There are screws and other methods but those can cause splitting. A surface of MDF that is painted will stick to a second surface if bolted to it for a few days.
PVC (Grey) comes in 1/8" 1/4" and 1/2" (.6) thick sheets. You can buy it at your local plastic center as scrap. You can also buy in online. Grey PVC is cool stuff! You can cut, drill and sand it just like wood. It is cheaper than aluminum and in the right places it is just as strong. It can be tapped with 2-56 threads and smaller.
Delrin is a material that was invented in 1957. Only in the last 20 years has its use exploded. Delrin is a Dupont product. Delrin is a acetal resin but not all Acetal is as good as Delrin. Delrin was designed to be bearing material. Delrin unlike Nylon and Cutting Board Plastic (HDPE) is hard and cuts like aluminum. Nylon and HDPE distort when bolted. They swell and cause binding due to heat caused by friction. They call it the poor man's Delrin. You can buy Delrin online from McMaster-Carr. Buy it as a bar and then you only need to cut it to length. Other places sell it online but beware of getting it from an online auctions!
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