Masking electroless nickel for hardcoating

A. OK this should be non-commercial but I cannot say the product without saying where it comes from - sorry.

T5145 lacquer fron Turco

We have had a lot of success with this product.

Try application by dip 3 - 4 coats.

To stop it going where you don't want it paint a mixture of zinc oxide ⇦this on eBay or Amazon [affil links] and glycerine.

Allow to cure and cut back with a new razor sharp scalpel.

pumice ⇦this on eBay or Amazon [affil links] the areas to be treated to get a good water break free surface (hope you don't have to do thousands).

The best bit is the removal - thick coats are peelable.

Try a sample it should work well.

A. The best that I found was Super XP 2000 from Pyramid Plastics in Hope, AR. This requires a low temp "bake" to cross-link it. Use the recommended temp or it is slow to cure(low)or it is tough as alligator skin (high). They were working on an acrylic latex that had to be cross linked at a higher temp, but it eliminated the solvents.

Remove by soaking in boiling water for a few minutes and peel it off.(Makes it pliable) Don't use it of rough surfaces like sand castings or you will never get it all off, even with solvents.

A. Depending upon the configuration of your part and the area to mask,(I.D/O.D) , heat- shrink tubing(polyolefin) has worked for me in the past.

A. Try Henco blue spray mask. I use it on electroless nickel, black oxide.

A. In the process of phasing out my wax tanks, I came across product called Microstop from Tolber Corporation as stop-off lacquer. It worked for me.

A. I have also had good luck with the Super XP 2000. On critical jobs we have found that putting numerous very thin coats with ample drying time in between coats helps. If possible try bead blasting the surface you want masked with a very fine glass bead. This will roughen the surface very slightly for some mechanical bond.

A. If the threads getting worn are your main problem here, my suggestion would be to use a STI tap, Alodine/anodize (have your coater mask the threads), and then install the appropriate size helicoil insert AFTER anodizing. An insert would give you much better thread life, plus could be replaced should the need arise.

Plating/anodizing threads typically is not a good idea, especially aluminum ones.

Hi Ralph. The semi-conductor machinery industry employs parts that are partially anodized and partially electroless nickel, so it's widely done, and I've seen such parts. But lacking hands-on experience with it, I'll let someone else suggest the most practical masking sequence and process sequence to get there :-)

Regards,

A. Hi,
I've seen one of those too. Aluminum spools for gold wires.
First, the inside measurement of the spools were machined to size, the outside to be machined later. Electroless nickel plate the whole spool ... then machine to size the outside of the spool leaving the inside electroless nickel plated.
Mechanical seal the inside of the spool leaving the outside bare aluminum to be anodized.
End product is an aluminum spool electroless nickel plated on the inside and color anodized on the outside.

A. Ted is correct, this is quite common on components used in the semiconductor industry, Typically, the part will be anodized with the area to be nickel plated masked. After anodizing, the masked area will be selective Ni plated.

A. First mask area to be electroless nickel plated with [peelable maskant material with high temperature resistance]. Anodize the part, strip the maskant in acetone ⇦this on eBay or Amazon [affil links] Warning! highly Flammable! , than apply [peelable maskant material with high temperature resistance] over anodized surface and plate electroless nickel.
Be sure to chemfilm the whole part prior to any masking.
This works every time

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Ed. note: Thanks for the instructions, Vijay. Readers, we no longer post recommendations of specific brands & sources (why?)

A. Jennifer, it may help to solve this issue if you post a pic of the "paint streaks".

That being said, I believe you have this process backwards. Generally anodizing is performed before conversion chem films (i.e. Alodine) are applied. This may be part of your problem. Additionally, the electroless nickel solution is a high temperature application (180-200 °F) that could be in appropriate for the masking used.

To strip the anodic coating usually a highly caustic mixture is used and mid- or high-phos EN does not do well in highly alkaline environments.

Im sorry I don't have a better answer then that, but those are the things going through my head with the limited amount of supplied info. Any additional pics, pretreatment processes, operating parameters of each step, and masking used help in this troubleshooting process.

A. I'm going to add to Isaac's statement here. In most cases, the chem-film process is generally done prior to anodizing, and it serves as an excellent adhesion base for the "Green" paint masking. And also, if the print allows/requires chem film on areas without anodizing, you don't have to mess with trying to chem film on anodized part.

As Isaac mentioned, a picture would be really helpful here.

A. I'm not aware of an instance where nickel has been deposited on a anodized surface. Yes, nickel is often plated over non-conductive plastics, but that process was developed many years ago, and it was not simple.

It would be a development project of unknown complexity.

Why you cannot use masking and selective plating/anodizing, I don't understand.

A. Thanks Jeffrey! I don't think Joshua is opposed to conventional methods; we appended his inquiry to this discussion, and he probably wasn't quite aware of how the issue is conventionally handled.

Regards,

A. Not sure if it would work but as far as I know nickel plating on plastic is done by filling the pores* with palladium and then using those spots (of palladium) to begin the plating process.

If you don't seal the anodizing layer maybe you could fill the pores* with palladium and plate from there?

To be clear - I'm just theorycrafting -- have no idea if it would work.

Think it's a very interesting topic! please come back if you find a solution!

*I'm not 100% on the english term for micro holes in an anodizing layer.

Also this is my first post, hopefully I didn't violate any rule.

  Thanks Eric, and welcome.
We like to think that by the time people use the site a while and fully understand how it actually works, they will feel no pressure of "rules" other than common sense -- but if you get a different vibe, let us know and we'll try to fix it :-)

Regards,