Durability- thickness vs density

[sswee]

I have some parts to do that no color is wanted but best durablity that can be achieved with LCD process. All the posts I have read deal with dyeing properties. Logic tells me I need a thick coating with reasonably heavy density. I am using a 1:3 elecrtolyte. I am curious about what CD would be best, and any other info on growing a coating with good durability.

[M_D]

LCD can do great looking clear anodize. As you increase the amps per square foot and/or anodize longer for a thicker final coating, there is a tendency for the coating to take on a tinted cast. LCD minimizes this, and as long as the anodize time is not pushed toward the upper limit you should be able to get a nice clear. For the toughest layer, you may want to use higher current density, or at least the upper end of LCD, which is considered here to be 6 amps per square foot.

A thick layer, which to a degree can imply toughness, and a good “clear” appearance, are somewhat opposing. I believe you will have to find a balance that bests suits your needs, as the toughest anodized layer will not have the best clarity, and the clearest layers will not be the toughest. Still, a properly done layer that has good clarity will be pretty tough compared to most types of coatings if done properly. When aiming for a thick layer you need to have your ducks in a row, as extended anodize time and or high current density can lead to dissolution, which will result in a soft crumbling layer and defeat the purpose.

Also, a cooler electrolyte temperature will help avoid the tinted cast found when running extended anodize times and or higher current density.

[Fibergeek]

Cooler electrolyte temperature will also promote smaller pores; which increases the coating density at the expense of dyeing characteristics, which is something you have to trade off (no dyeing).

Cooler electrolyte also retards dissolution, you'll want all the help you can get to reduce the dissolution rate if you're going for a thicker coating, real good agitation will also be telling. I suggest you try 60 deg. F. or so, and try for a 1 mil thickness. See if the clarity is still OK for you.