Aluminum AnodizingI'm happy to say that the 150 Aluminum VIUD's are finally off to anodizing! The polishing of the bodies went well with no unforeseen issues. The preparation of the plugs took a little longer than expected. Originally I was looking into buying or making a broaching set for squaring the rounded inside corners of the plug. However, I decided to simply file the corners by grinding a small square file to be the exact width of the hole and making a simple handle to hold the file. Filing the Aluminum plugs took some time but was relatively easy and we'll see if the same holds for the Titanium plugs. I wasn't going to polish the plugs but the filing created a sharp edge which was good to get rounded with a quick buffing.
Next step was cleaning everything. The buffing process caked a considerable amount of debris in all the nooks and crannies of the parts so I soaked everything for a day in Mineral Spirits and then brushed/wiped each part and left it to dry.
For this production run I'm doing four basic colors for the Aluminum VIUDs:
- Black (already done)
A Little More Impact Testing....I did another run of impact testing with a new set of USB circuit boards and a modified epoxy filling technique to ensure everything works as expected and there are no premature failures. Fortunately, the VIUDs fared better than my new stone target which broke clean in half while testing the Titanium VIUD at speeds above 200 km/hr.
|Another Broken Stone Target|
The Aluminum VIUD managed to survive up to impact speeds of 230 km/hr on the stone target which seems to be the typical failure point for the modified epoxy technique. The Titanium VIUD broke a new record by surviving impact speeds up to 250 km/hr on the stone target which is rather incredible when you think about it let alone experience the violent event itself.
Cap MagnetsI've always been trying to figure the best way to secure the magnets in the cap. Initially I tried superglue which works reasonably well but is a little messy and tends to fail at low to moderate impacts.
I then tried denting the metal around the magnet on the inside using metal point punch. This works pretty well in Aluminum but in the much harder Titanium it is very difficult to hit the punch hard enough to secure the magnet but not so hard as to crack or break the magnet. This method also tends to fail at moderate impacts.
On the last set of impact tests I tried another method: covering the magnet with a small amount of epoxy (the same stuff I use to fill the base). I didn't think this would work very well as you can only fit about 0.05" (1.3 mm) of epoxy above the magnet and still leave room for the USB connector. Fortunately I was completely wrong and the epoxy didn't start cracking until very high impacts, far surpassing the other two methods I tried.