thick coatings

[mh]

i was curious as to whether anyone has successfully grown a coating up to 2 to 3 mil thick using the type II LCD method

i have read a few posts by fibergeek saying that he has been able to do it but every time i try i end up having dissolution problems. im wondering whether i am missing somthing

is th 720 rule still used for a coating this thick?
even at 12 ASF, it has reached 1 mil after 60 mins and any time after that i have chalky residue on the piece
i do not need to dye the pieces. the are being used for enginnering machinery.

any suggestions or expierience on the matter would be very helpful as all the anodizing shops here in australia seem to want to keep all the secrets to themselves

[sswee]

I've done a few pieces to that extent but I don't have much demand for that kind of thickness. The primary needs to acheive that kind of thickness are low tank temp, extreme agitation and a higher CD.

The 720 rule still applies and it can be done with a 3:1 ratio.
A 12 ASF CD should work. I've done it at 8 ASF.
What material grade are you using?
What acid ratio or % are you using?
What tank temp do you run at?
SS

[mh]

running 3 to 1

6xxx series alloy

68 to 70 degrees tank temp

if 720 applies then does that mean for a 3 mil coating at 12 ASF then tank time will be 180 mins.

by extreme agitation do mean mean like wildly boiling water??

[sswee]

Originally Posted by mh

running 3 to 1
Good
6xxx series alloy
Best
68 to 70 degrees tank temp
58 to 60 degrees
if 720 applies then does that mean for a 3 mil coating at 12 ASF then tank time will be 180 mins.
Yes, running at 8ASF, I've had runs up to 240 and 270 minutes
by extreme agitation do mean mean like wildly boiling water??
Close but but by the time I got to that stage of anodizing, I had started to use a pump to circulate the electrolyte. It has a fast flow in the tank without the misting problems of aeration.

Here you can see my setups. I started using a pump on the 20 gal.
http://forum.caswellplating.com/phot...ry.php/cat/510

For your use of the parts, you'll have the most success by getting the tank temp down and improving circulation. By doing this, the pore size of the coating will be smaller and give a more durable coating. The parts will have a gold to golden brown hue to them and you should be able to use a 1.5 to 2 mil coating for the same end results.
SS

[mh]

your 60 gallon tank is the best setup i have seen yet. brilliant.

can i ask what size power supply u use for it as i am using a 20 gallon tank with a 30 volt, 20 amp power supply and the other day i was doing a piece of cast that was 103 square inches and my voltage rose right up to 24volts at one point.

will i need a higher voltage range when i upgrade to the bigger tank?

also, can u regulate the flow coming out of ur pump as to change the agitation levels. if so how?

hope u dont mind but i am going to copy ur setup right down to the colour of ur hose clamps!!!!!!!!

[sswee]

I am also using a 30V20A PS. Your voltage requirements are in direct relation to the CD you choose to run. A 12 ASF is on the edge of being too much for a 30A supply. That is the reason I still use 8 to 10 ASF. Running the lower tank temps will increase the voltage demand a couple of volts. The motorcycle fork tubes (6061/7075) were approx. 279" SA each. I had to run them one at a time because the set amperage was 15.5A for an 8 ASF. They all peaked at 23 to 24 volts. Part was due to a 60 degree tank temp and part due to SA calculation being off just a little.

The tank is setup with a 3/4" bulk head connector in the center bottom of the end. I have a 3/4" PVC ball valve plumbed into it and then to the pump intake. This allows me to isolate the tank for adjustments or problems. The other two 3/4" bulk head connectors are center of the tank height and adapted to 1/2" ID also with PVC ball valves. The volume or flow can be adjusted with the two 1/2" ball valves. To get the best flow pressure for the pump I have, I calculated the pumps output area of 1/2" and jetted the tank output to match closely. To clarify, 1/2" has a .196" area, I have 3 output tubes each capped and a 1/4" hole drilled center. Three 1/4" holes have a combined area of .147". This decreases volume slightly but gives me a little more pressure. I hope I didn't mottle it up to much. Even with all the calculations I did, I still spent a couple of days running the tank with plain water and parts on string to adjust everything and trying to fine tune.

Any questions on the setup, I'll be happy to answer.
SS

[mh]

so all the agitation is directed from one end of your tank. in the pics of your 20 gallon tank it looks like u have run a length of pve with holes drilled in it much the same as the system i am using now with an air pump.

did u find the fluid shooting out the pvc setup gave u a more uniform agitation from all points of the tank?

r u able to disconnect ur chiller, by the looks of ur connections u can unplug and reroute straight from pump back to tank...great idea!!! do u always run with chiller or only on large runs??

[sswee]

On the 60 gal. it is all from one end. So far so good. The 20 gal had from each side a row of smaller holes totaling an area the same as the 1/2" pump output. It worked great. The one drawback to the smaller holes was any trash circulating was more likely to stop them up.

Watching floating ashes off a cigarette to see flow in the tank, both tanks flow good with very few slow places in the tank.

Yes I can pull the chiller and I set the unions so I could bypass the chiller straight back to the tank. With the weather as warm as it has been, I've been running it all the time. I'll have to wait until the weather changes to see if it is needed then. Since I run my tank colder than most, I most likely will still run it. The one thing I see that would have been better, is to have ball valves on both ends of the hoses.
SS

[rick201]

Hi sswee,
When you say you run your tank colder than most what sort of temp do you try to achieve and what advantage do you find from running colder is it just to make thicker coatings?
I wonder if you ran the 1mil in a colder than normal tank would the anodise become harder?
Any info would be good.
Best regards to you and like your tank setup by the way
Rick

[sswee]

Most run 68 to 72 degrees. I run mine at 58 to 62 degrees. I learned the majority on anodizing from Fibergeek before he passed on. When I first started, it was primarily to anodize golf putter heads that my brother makes. I needed a coating with the best durability. He recommended dropping the tank temp and go to a higher CD. The reasoning is the colder temp staves off dissolution and a higher CD grows the coating at a faster rate also decreasing dissolution. The end result is a coating with small pores. You just can't take it to far if you want to dye and get good coloring.

The putters are anodized to 1 mil at 8 ASF with a tank temp of 60 degrees. The only problem mentioned has been dings caused by impact with other clubs in the bag. There hasn't been any wear or color problems to date.
Steve