Part Tackiness

[kumaichi]

Hi,

I anodized some parts and they have this strange kind of sticky tackiness feeling to them. I did some searching and from what I can find, bad sealer would be my most likely cause for this. If that's the case, can I just reseal them in good sealant or do I have to strip the pieces and then reanodize?

Thanks for your input,

Craig

[Fibergeek]

Good question.

I don't know. Perhaps someone else does.

[buckeyevs]

I have experienced the same thing. They look fine, but are tacky. The most recent was freshly prepared sealer LT. I hope someone helps us out.

[Fibergeek]

This is what you can do to find out if its the sealant.

Seal at least one part in boiling water only, use enough water and heat so that it doesn't stop boiling when you immerse the part. Boil for 10 minutes.
Any tackiness? If no, it probably is the sealer, did you mix according to the directions, and are you using it at the correct temperature? I could see how it could be tacky if it was mixed too strong.

I don't think you can get the sealant off without loosing dye, but if you used boiling water as described above it might take the sealant off of the surface at least and reseal the part.

If you are doing small parts, and not in large batches, so that having enough boiling water isn't a problem, you would be better off using boiling water and/or steam. Nickel acetate sealants don't have any advantage over boiling water when used on a small scale.

[buckeyevs]

I sure did mix as instructed. The temperature might not have been quite there because the parts were anodized and I was preparing the sealer longer than expected, but it wasn't far off the mark.
That was going to be my test next time I ran the system. It's good to know that boiling water is just as good in small scale parts. That said, is it better to use Nickel acetate sealants on parts with large surface areas?

[Fibergeek]

Nickel acetate sealants were intended to be used where the size of the work or the way they are racked makes boiling water impractical. Boiling water or steam sealing is actually superior and is much more chemically inert.
I'll say this again because its important; you must have enough boiling water and heat available so that the boiling doesn't stop (ideally doesn't even slow down) when you immerse the parts.

[buckeyevs]

Fibergeek,
With that said, would it be best to first or only pressure steam the parts to bring them up to temperature in order to avoid stopping the boiling which might happen when immersing the parts? I'm not sure if I have a pan large enough to provide the volume.

[Fibergeek]

You could do that.

Neilfj always steams and then boils to seal his work.

[neilfj]

I've never run into the 'stickiness' issue. Perhaps, I'm just lucky, but as Fibergeek said, I usually suspend the part over the boiling sealer for about 10-15 minutes with the cover in place over the bucket.

I started doing this for one reason. When I first began anodizing, I had problems with the dye leaching from the part during sealing, especially when I screwed up and the pores were too large. The steaming stopped the leaching and closed the pores enough to hold the dye. I then dropped it into the sealer and let it boil for another 10-15 minutes. A 2nd benefit of this method is that it heats up the piece so that when you drop it into the sealer, it doesn't dramatically drop the temp. below boiling. (Be careful when opening the lid, I've burned my hands a number of times and eventually learned my lesson and wear gloves).

I'm sure the times I use can be shortened, I don't watch it very closely during sealing. Usually I suspend the part and begin a little cleanup. When I'm finished, it just drop it into the sealer.