Some newbie questions...

[kiwijetpilot]

Thanks for all the info.

Two things... do you happen to know if using LDPE (low density polyethylene) tanks will cause a problem?

Second, I had read about using RO or distilled water, but I expect to be using a lot of it in the rinse stages, and I can't see how I can economically produce enough RO water to do the job - and I would then have to pump it to the rinse baths, right?

Where is this issue on a scale of 1-10?

I find it interesting talking to people who have worked in the field for years. They keep telling me I need to check the pH of the solutions every day, particularly the dyes and Nickel Acetate sealer. They also say that you should only use PVC or polypropylene tanks, not just any old plastic. And then there is heating the solutions... how critical is all this stuff? I am assuming it is more for big commercial plants.

Thanks for helping me get going!

[sswee]

I haven't seen anything negative on using LDPE (low density polyethylene) tanks. The tank I am using now is a 66qt clear plastic storage bin with lid. Its been running for a few months now with no visable problems.

The degree of necessity for using distilled or RO water will depend on the quality of water in your area. Here the water is medium on minerals and very high in chlorine, Ph, etc. It adversely effects all steps, but primarily the dye step more than any that I can tell. Rain water is an alternative. Splotchy finishes can be a result of using harsh water. With all the prep time involved to get a great looking part, it would be a waste to gamble on using poor quality water. I rate this fairly high on importance. There are other filtration options for higher output needs.

I don't see Ph levels as a critical problem. I have seen posts about certain colors being more ph sensitive than the rest. Maybe someone else can input more knowledge on this.

The heating of the chemicals does have a direct effect on how well they work. This I consider to be necessary to achieve good consistant results. I use a combination of ways to heat the chemicals. Hot plates, crock pots work. You just need to pay attention to the container used in reguards to the chemical being heated. Eventually I'll get the ceramic heaters from Caswell so I can use more plastic containers.

Hope this helps. SS

[kiwijetpilot]

It does... thanks very much.

[kiwijetpilot]

OK here's another question- does it matter how thick lead cathodes are? I am planning on running two cathodes down the long sides of my tank. However, the lead sheet I can obtain locally is thin (1mm) sheet. Will that do the job? My gut says yes... but...

Also has anyone successfully adapted a MiG welder as a power source? I have 20A supply on the way (same as the Caswell one but 240V), but am thinking ahead a bit to possible bigger tanks.

Finally - and I realise this is close to heresy - but does anyone know how anodise compares to electrophoretic coatings?

[Fibergeek]

Electrically, no.

1mm = 0.039" lead sheet that thin might be kind of flimsy and makes for handling problems in your tank.

All DC arc welding processes use high currents at low voltages. To keep these power supplies cheap they are usually unregulated. This means that how much voltage they provide depends on how much current is drawn from them. You will measure 20V or so with no load, put a 20A or 30A load on them and the voltage drops to 5 or 6 volts or so. This is OK for welding, but when anodizing, you won't have enough voltage to support the anodizing current you want. Ohm's Law again. This same mistake is commonly made in attempts to use battery chargers (also unregulated power supplies) even big ones. Neither a welder or battery charger will provide the necessary current control for anodizing by itself, which is another problem.

Electrophoretic coatings are kind of a cross between electroplating and powder coating, and are not comparable to anodizing.

[sswee]

The thinner lead sheets will work. What you are needing is suface area. Thickness would not matter unless it was enough to add more SA.

The mig is possible although controling the current is problematic. Fibergeek can give more detail on this. Also some work arounds on PS's tend to be more costly in the long run than the direct route.

I am not familiar with electrophoretic coatings. Maybe someone else has some input on this.

SS

[kiwijetpilot]

Thanks folks.

I won't bother with the welder, apart from anything else I want to use it for welding! I just wondered if it was quick adaptation of an existing power supply.

In any case I am now looking at a juicy power supply that includes various options for controlling and monitoring via computer. I hope to get my process standardised and repeatable. Apart from anything else, it will allow me to program the system to warn me when PAR is reached, and save me having to watch it.

Cheers from the sunny hot place!