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Posted by kad | Jan 23, 2013 @ 09:17 PM | 5,315 Views
I had heard that DJI arms could be dyed with fabric dye and decided to give it a try.

The process worked well, with one small issue.

  • 3 x Genuine White DJI 450/550 arms
  • 1 x Bottle of RIT Liquid dye
  • 1 x Gallon (~3.8L) of Bottled Water
  • 1 x Stainless Steel Pot


I heated the water in the pot to 160F (~70C), turned off the heat and added the entire bottle of dye, stirred thoroughly, then added the arms.

I'm not 100% certain what the DJI arms are made of, but I followed the procedure on the RIT web site for Nylon and added 1/2 cup (~120mL) white vinegar to the pot after 5 minutes. It definitely seemed to help, the color on the arms smoothed out almost immediately. I left the arms in the pot for about an hour, moving them around occasionally.

The arms took the dye very well, coming out richly and consistently colored, as you can see from the photo below.

The one little issue? Well, the dye I used was Goldenrod Yellow, a nice bright yellow. The arms, as the picture shows, came out Orange. I consulted with a friend who does a lot of fabric dyeing before starting and was told that Iron in the water will cause Yellow dyes to come out Orange or Ocher. This is why I used bottled water, as my house water has a lot of iron, even after a softener and filter system. It looks like I should have used Distilled water as opposed to Bottled water though, as it appears there was still enough mineral content in it to change the outcome. (It was not a bad dye lot, as the stains on rags used during the process are bright yellow.) It could have been that or some property of the arms. I'll try again when I get some more arms.

Conclusion: It works, your colors may vary and, unless you're doing a lot of arms or you have a lot of arms already on hand, it's probably easier to buy the color you want from these guys: http://www.wildpilots.com/store/colo...wheel-f450-arm

Posted by kad | Nov 11, 2012 @ 06:05 PM | 5,782 Views
Problem: My mini-fume extractor (ala MAKE Magazine article) didn't have sufficient suction and ate batteries like Lays potato chips (Betch'ya can't eat just one!) and I wasn't willing to pay $50-$100 for a commercially produced unit.

Solution: Build a bigger/better one myself!

  • 2 x 2.5" 12v 1.2amp fans out of an old IBM server
  • 1 x 16v DC IBM Thinkpad power supply
  • 1 x Pelican 1150 case *
  • 2 x Toggle switch (Radio Shack) (I want to control each fan separately)
  • 1 x Panel mount DC jack. (Radio Shack)
  • 3 x LM7812 Voltage regulators
  • 1 x 1000uf Capacitor
  • 2 x 100uf Capacitor
  • 9 x 1 Ohm Resistors
  • 1 x Heat sink. (Small aluminum heat sink that had held 3 LM78xx's on something I disassembled)
  • Piece of perf board
  • Carbon filter medium

* Note: I would not normally have used such an expensive item for this project, but I got this one for free after buying it on eBay and receiving it with a cracked latch. The seller refunded my money, but did not want the case back. It also already had a 1" hole drilled in it with a waterproof connector for a battery system of some sort.

  • Soldering Iron & Solder
  • Fordam Tool (Or Dremel) with cutoff wheel
  • Drill press w/ Circle cutter and assorted drill bits
  • Hot Melt glue gun
  • Assorted hand tools (clippers, screwdrivers, etc)

Problem: My fans are 1.2amp draw, but the LM7812s are only rated for 1 amp. As the 78xx series are not precision items, just hooking them in parallel will result in the lowest voltage one taking all...Continue Reading
Posted by kad | Jul 13, 2012 @ 02:40 PM | 5,506 Views
TX: Hitec Auroa 9
RX: Hitec Optima 7

I got a great deal on this radio from www.servocity.com. They've got the best prices on Hitec radios that I've seen and they sell bare bones kits, no useless (to multirotor pilots) servos, etc. Also, you can choose which Receiver, if any, you want in the box.


I started with a $150 X525 kit off of eBay, consisting of:
  • X525 folding frame
  • cheap power dist board
  • KK FC Board
  • Hobbywing 20amp ESCs
  • no-name 1000kv motors
  • 3 blade 9x5 GWS props

This seems to be the same kit that GoodLuckBuy sells, but I didn't know about them at the time.

I ordered some Zippy Flightmax 2100mah 3s batteries from HK to complete the build.

I assembled the frame with the locking plate reversed so it does not fold. I drive an extended cab pickup truck, so I have plenty of room to transport it and don't need it to fold.

Since that time I have made the following changes:
  • Aluminum motor mounts from Small Parts CNC
  • HK Power dist board
  • Multiwii 2012 FC
  • HK Low battery alarm
  • Changed to 2 blade 9x4.7 Gemfan props (tried 10x4.5 for a bit, actually too much for a learner such as myself)
  • Self Designed (shapeways printed) LED holder brackets and a self built set of LED lights.
  • Self Designed (reprap printed) brackets that hold 1/8" square plastic rods fore and aft. Fore rod hold RX antenna, aft rod holds an orange ping-pong ball for orientation. The brackets themselves weigh about 1 gram each, I think the screws that hold them on weigh more!
  • Ultra light (
...Continue Reading
Posted by kad | Jun 24, 2012 @ 03:40 PM | 5,332 Views
Check 'em out...