Anodizing Problems With 6061-T6 Aluminum · Mar 5, 16:18
It seemed easy enough…
We purchased the full LCD anodizing kit from Caswell after hearing good things about their kits. We chose them since they sold a complete package and didn’t want to try to get all the pieces together from scratch. It seemed like a good idea at the time. After waiting three weeks for the power supply, it arrived (a nice unit, btw). We were disappointed it took so long to ship without updates but can certainly understand backorder issues.
Following instructions, we purchased nearly $50 worth of battery acid from the local Kragen auto parts store and began filling up the provided 5 gallon buckets with distilled water (the kit provided a filter). This all seemed pretty straight-forward. What the kit did not provide was a thermometer. In retrospect, this might have made a nice addition to the kit. After all, temperature is very important to anodizing.
While we awaited the arrival of the Caswell SPC-9250 power supply (specs below), we borrowed a cheap unit and started anodizing. With this setup and the yellow dye provided, the first batch went OK. The color turned up OK. We didn’t monitor temperatures that closely nor did we operate the power supply with full success. This led to parts that we thought could have been better, but they certainly weren’t horrible.
SPC-9250 specs from the Caswell Plating website:
25 Amp Constant Current Rectifier
Perfect for larger anodizing jobs. Will anodize parts up to 5 sq ft @ 4.5 ASF.
Features: * Output Voltage: 1-15 VDC Adjustable or 12 VDC Fixed * Output Current: 1-25A * Ripple And Noise: 5mV r.m.s. * Line Regulation: 50mV (+/- 10% Variation) * Load Regulation: 50mV (0-100% Load) * Power Source: 120VAC/60Hz, 6.3 amps * Meter: Digital LED (+/-1% +2counts) * Dimensions: 8.6” x 4.3” x 7.6” * Weight: 5.8 lb * Contents: Power Supply, Power Cord, Users Manual (PDF – 164kb)
Note: the key to using this (which they don’t describe in the instruction sheet) is to turn the voltage knob all the way UP and the current knob all the way DOWN. After turning on the unit, you start the turn the current knob UP until the desired current is reached.
Then, there were issues with the fish tank cartridge heaters. One of three blew up while in the bucket. It literally went “pop”, sounding like a blown fuse. It unfortunately spilled its contents into the dye bucket. One by one, they all either overheated (short-circuited?), or just somehow “died”. Makes us wonder if using cheap immersion heaters is the way to go.
Dangerous!
This picture shows the heating cartridge a few seconds after we took it out of the dye bucket. It was glowing red!
The Focuser knobs website sells what look like better heating units (more robust) and with a temperature knob up top. For $80, it seems to be a pretty good deal compared to the hundreds you’d spend via the catalogs.
On to the anodizing problems….
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