Metal Coating GREAT Product

[Larry Lyons]

Re: Metal Coating GREAT Product

Just a note here but; powder coat is a hard cover that is designed to look good. It is so hard that it can chip and when it does there is no protection at all. Zink Chromate on the other hand makes a chemical bond to the steel to protect it from corrision, granted it is not as "tough" as the new stuff but its design criteria is totaly different. Or am I all wrong? I may be, however I base my info on conversation with an old A&P and that was his opinion. Think about it, we are working on planes over 60 years old that have been recovered many times, repaired many times too, however all we have done in most instances is repaint the problem area and go. Will the powder coat stand up as well for as long? Larry

[astjp2]

Re: Metal Coating GREAT Product

Just a note here but; powder coat is a hard cover that is designed to look good. It is so hard that it can chip and when it does there is no protection at all. Zink Chromate on the other hand makes a chemical bond to the steel to protect it from corrision, granted it is not as "tough" as the new stuff but its design criteria is totaly different. Or am I all wrong? I may be, however I base my info on conversation with an old A&P and that was his opinion. Think about it, we are working on planes over 60 years old that have been recovered many times, repaired many times too, however all we have done in most instances is repaint the problem area and go. Will the powder coat stand up as well for as long? Larry

Zinc Chormate is not for Steel, its for aluminum. If you want to coat steel properly, you need to use red oxide primer or black alkyd primer depending on the top coat..... Tim

[Larry Lyons]

Re: Metal Coating GREAT Product

Zinc Chormate is not for Steel, its for aluminum. If you want to coat steel properly, you need to use red oxide primer or black alkyd primer depending on the top coat..... Tim

OK I stand corrected but what is the green coating on steel tubing? My T-Craft has it and the one I am helping rebuild has it. My T was last recoverd in "73".
Larry

[Larry Lyons]

Re: Metal Coating GREAT Product

Another question, my ribs are not green but natural alum. Should they be chromated this time when the go back in the wing?
Larry

[tawadc95]

Re: Metal Coating GREAT Product

I wonder about that to myself spotter vs. the added weight. Wood ribs are varnished so you would think there is a bit of weight to give towards coating alum ribs........btw,where is the crusader you are standing in front of located?

[astjp2]

Re: Metal Coating GREAT Product

Well not everybody uses the correct product... but most of the new aircraft are using a 2 part green epoxy that is real similar to Chromate....Tim

[fearofpavement]

Re: Metal Coating GREAT Product

Zinc chromate IS often used on steel. The choices for protection of aluminum are much more limited than steel and zinc chromate or zinc oxide is a good choice from a relatively small menu of coatings suitable for aluminum. With steel, the object is to simply separate the steel from the atmosphere and other sources of moisture and oxygen. Thus anything it is coated with will protect it from corrosion. And everything from wax and oil to exotic coatings will achieve that. DuPont Corlar, an epoxy primer does have a yellowish greenish tint and could be easily mistaken for zinc chromate but chances are if your steel parts have a coating that looks like zinc chromate/oxide it probably is.

[astjp2]

Re: Metal Coating GREAT Product

Well Zinc Chromate is a self etching primer that only works on Aluminum, if you are using it on steel, it wont self etch....and the Green that is used on everything from the apache helicopter to the 747 inside the airframe is epoxy. It comes in either yellow or green. Used lots of it. If I was wanting to save a few pounds, I would yellow zinc the steel tubes and that is a plating process that is not affected by any chemical. It would be about 500.00 but if you were serious about saving weight then that is the way to go. just food for though. Tim