I have been anoziding for a couple weeks with success. I have done several parts of different sizes and even multiple parts. I normally use the Titanium Wire and form a spring clip with it. However, I have to anaodize 4 plates that are 20" x 12" x 0.5" and I don't trust the titanium wire to support the part. I want a more 'absolute copnnection'. However, I have run three so far and none of them have anodized. I cannot figure out what is going wrong.
The plates are supported vertically in a cooler. I made two tank bars. Each bar has two 16 ga aluminum wires bolted to it. I bolted two 3.5 inch pieces of aluminum all thread through two holes at either end of the part. The two aluminum wires from each tank bar is also bolted to the all thread studs. Everything is tight and everything is aluminum. The two tank bars are connected together with aluminum wire (bolted). I checked continuity between the supply line and the part before I started each run and continuity is good. The connections seem OK.
I use the resistor method to control current and calculated that I need 15 amps current. Using the 720 rule I calculate I need about 2 hours and 40 minutes immersion.
With everything set up it 'appears' all is well. Normal activity in the solution. Current hums along with normal adjustments. Initial high drops off, settles in and holds fairly steady with minor, periodic adjustments necessary to keep the current level up. About two and a half hours in the current stops declining and starts to increase slightly. At 2 hrs and 45 mins I pull it out.
Part is not anodized at all. Fails continuity test (still conductive). All thread is not anodized. Aluminum nuts are not anodized. Hanging wires are anodized (no way the wires alone can develop 15 amps current).
I am wondering if the all thread or aluminum nuts are causing the problem. I think my next step will be to try it again but add extra jumpers of titanium spring clipped into the holes to make SURE the part is in the circuit. Has anybody had a problem with bolted connections. Is there any certain types of aluminum bolt or nut that might cause this.
Thanks,
Bill
The plates are supported vertically in a cooler. I made two tank bars. Each bar has two 16 ga aluminum wires bolted to it. I bolted two 3.5 inch pieces of aluminum all thread through two holes at either end of the part. The two aluminum wires from each tank bar is also bolted to the all thread studs. Everything is tight and everything is aluminum. The two tank bars are connected together with aluminum wire (bolted). I checked continuity between the supply line and the part before I started each run and continuity is good. The connections seem OK.
I use the resistor method to control current and calculated that I need 15 amps current. Using the 720 rule I calculate I need about 2 hours and 40 minutes immersion.
With everything set up it 'appears' all is well. Normal activity in the solution. Current hums along with normal adjustments. Initial high drops off, settles in and holds fairly steady with minor, periodic adjustments necessary to keep the current level up. About two and a half hours in the current stops declining and starts to increase slightly. At 2 hrs and 45 mins I pull it out.
Part is not anodized at all. Fails continuity test (still conductive). All thread is not anodized. Aluminum nuts are not anodized. Hanging wires are anodized (no way the wires alone can develop 15 amps current).
I am wondering if the all thread or aluminum nuts are causing the problem. I think my next step will be to try it again but add extra jumpers of titanium spring clipped into the holes to make SURE the part is in the circuit. Has anybody had a problem with bolted connections. Is there any certain types of aluminum bolt or nut that might cause this.
Thanks,
Bill
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