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  • Techno-Geek Questions

    My topic isn't right on point for this section but I'm thinking readers of this section have this topic closest to their interest. We'll see.

    Background: Electroless Nickel plating (and it's variations).

    I am interested in doing repair work as opposed to decorative work with EN & relative formulations. I must say I am ecstatic over my first attempts using the Caswell EN kit. After doing a few test runs on used parts, I managed to decrease the inner bore size of a couple of new ball bearings by plating a precise amount of EN that enabled "blueprint" specifications to be achieved on the crankshaft to inner race fit. After plating, I pressed the bearings on the crankshaft and then removed them. There was about a .0005" interference fit on a fair sized crank journal (this is a motorcycle in case you're wondering where the ball bearings come from) so the forces involved were substantial. After removal, there was no sign of flaking or scratching on either the EN or the crankshaft journal. I'm confident by this test that the EN is sufficiently hard and attached well enough that there should be no problems in rough service as a result of this repair method. Now I'm readying to raise the bar. So, I have a few questions regarding what I did already, and what I'm getting ready to do. Here goes:

    1) My water break was lousy. Still, using a relatively fresh plating solution and following the specifications otherwise to the letter seems to have resulted in an aggressive attachment of the EN to the substrate. Since I was plating (relatively) clean, probably high alloy steel that had been oiled at the factory immediately after fabrication, I did not see the need to pickle. Also, I was somewhat worried about protecting the unplated regions of the part from the pickling as this has already become problematic anyway. What I did was to simply use lacquer thinner and brushed and scrubbed the target surface thoroughly then rinsed with DW. But, man, there still must have been a film there because it beaded water. Recommendations for a cleaner that will pass the water break in such an applications? SP degreaser? Remember, I'm having challenges with finding material that will mask off the non-target areas as well as resist the action of the cleaning activity. Also, why were my plating results apparently so good with a failed water break test? Lucky break?

    2) I've been doing a lot of reading on EN. It would make me feel better to know what the phosphorus level of Caswell EN solutions are, i.e. high, medium or low phosphorus?

    3) Next steps are to attempt professional repair of surfaces that slide or more particularly, roll against one another. Normally a hard chrome application but I think if nickel will withstand the rigors, it is a much better process to apply for these applications than is the chrome process. One reason is the uniform size control possible. There are others. One thing I could try is to harden the nickel by baking after plating. I'm also wondering, might not it be better to try Electroless Krome instead as the cobalt should make for a harder wear finish. What about ductility of Electroless Krome? Is it more likely to flake than EN? In this application I have in mind, the reground and plated shaft will actually be the inner bearing race and the rollers will be in direct rolling contact with it. Am I making myself clear here?

    Well, I'll leave off here and see what kind of interest I've inspired in this topic.

    Best regards,
    Ed Clark

  • #2
    Ed..... I'm glad to see you're still "with this" as I was curious as to what stage you were at. I'm by no means a plating expert, but seriously intrigued by the whole process and your findings, so I've been wondering and watching myself (as I know a few other here are as well, by the number of views I see).

    Bearings,huh? Hmmmmm. This is a long shot, but do you have any test equipment around there that you can take advantage of? I'm curious as to the hardness of the coating and actual thickness after elevated hours of use in a pressurized environment. Could it be lack of wear was helped via lubrication as well? .0005 *should* be a sufficient measurement to see if it were to degrade, I must admit. Keep me posted on that,k?

    1) Did you try other solvents? Hydrochloric or possibly something in the oppsite direction but just as caustic to take the oils out of the pores? Normally I'd say mineral spirits, but bearings are usually a "higher end" alloy or at the very least heat treated. Perhaps if you were to test just the cleaning process alone on say... cast steel or cold rolled would you get the same "wetness" issues? How much of a miniscus was left on the bead of water. Was it a well rounded droplet, or did it still cling but have an angle enough to still hold tension? Again... I'm not a plater so I don't know how much surface tension applies to this substrate. Possibly heat treating enough to drive out any oils or smut would help the process? Along with you... I'm taking guesses here as I'm just as curious. I'd have to imagine a hypereutectic alloy would give you the same sort of result due to impregnation of non-alloy. The best advice I can give is to try it on various substrates and see if you get like-minded results. If it doesn't happen on any other metal but your bearings or exotic alloys... then you know it's an impregnation issue I'd assume.

    2) you'd have to get an MSDS from Caswell directly I'd think for content. Even if not listed there, I'm sure somebody at Caswell could get in touch with the manufacturer or formulator if it's that big of an issue.

    3) Again... most of that is a "platers" territory. I'd assume a bearing surface is MORE than sufficient test for what you are looking for. I'd also perhaps try coating the skirt of a piston or two to see what that achieves. Why not... the crank and connecting rods are out anyways,right? What about coating the piston rings? You don't get any better wear indicator than a piston ring O.D. as they probably take the most abuse in any engine and you'd know your results in a very short while.

    Keep us all posted. This is turning out to be a very interesting topic (at least for yours truly). High lubricity with heat resistance? That's a great thing. I bet anybody with a turbo or supercharger would be overjoyed to hear about this kind of product once you have your testing completed. ( $$$) . Just food for thought..... Thanks again for the update... Russ


    • #3
      Well, there is some interest out there in this kind of foolishness, hey? Russ, I'm going on vacation in a few days and will be parking some of my projects for a couple of weeks so "R&D" won't have much to report for awhile.

      Just a clarification: so far, I have only EN plated the part of the bearing that contacts the shaft, i.e. the "inside bore." Not any internal parts in contact with the rolling balls. You probably understood that. I'm just going by published literature what the resulting hardness of the EN plate PROBABLY is. That's why the question on phosporus content. I'm convinced, though, from what I've read in the Caswell manual and elsewhere that I better starting passing the water break test or I'm going to be sorry sooner or later. A little additional reading has also convinced me that you're probably right about trying a different formulation of degreaser.

      I'm going to order some "SP" and give that a try first because it's supposed to be so gentle. I've got some muriatic acid handy, but I don't want to fool with that stuff around bearings for fear of etching the rolling parts then seeing a premature failure. If the SP doesn't do the job, I'll go with a more caustic cleaner. Apparently from what I've read, there's a vast difference in cleaning compounds needed for different lubricants and probably a stout caustic is a good starting place for steel anyway. We'll see, but I'm going to try the SP first because of it's supposed "gentleness."

      I can get accurate measurements of my plating thickness by using a micrometer but I think the hardness will be a little evasive. I've read that it's hard to check the hardness of a plate because the measuring instrument basically just pentetrates the plating and measures the hardness of the surface underneath. I'm thinking of a Rockwell type tester. So for now, I'll just test my parts by throwing them in an engine and see how they work out.

      I definitely like your idea about plating a piston for wear resistance. Most of the pistons I replace are worn very uniformly on the skirt and nowhere else. When I get back from vacation I'm going to order some BN for that purpose. I plan to plate a rectangular patch on the thrust surfaces of the piston. Also, I plan on plating the inner bore of some valve guides as well. However, unless it self-destructs before, it should be the end of summer before a teardown and inspection reveals the results.

      What I was referring to on the "other" proposed project was this: I've got a transmission shaft (out of a motorcycle) where three of the gears ride on needle bearings that in turn ride directly on the shaft. Something passed throught tranny and left some small dings in both the shaft and gear and you can see a slight imprint of where the needle rollers dinged both. Of course, the gear now turns a little roughly on the shaft so it's no good for racing duty and has been replaced.

      Now, I've got access to a small, professional grinding machine that can take the dings out of both the inner bore of the gear and the shaft. See where I'm going with this? Next step, plate both back up to original tolerance of course. This isn't the first time I've run into this little problem. And these parts are made in Austria and the Austrian's are mighty proud of them judging by the price for new stuff I can tell you.This should be about the most severe application you could find for EN and things need to be pretty well perfect for it to work OK, but I think it will based on what I've seen so far. I was just wondering whether EKrome wouldn't probably be a bit harder and tougher than EN in this application. Guess there's one way to find out, huh?

      Well, sorry to turn this into a mega-reply but I wanted to spit this out before my vacation. Thanks for your interest and I'll definitely keep you posted as I go along.

      By the way, that danged Caswell has got me interested in about 3 or 4 new hobbies all at the same time!!! I'm all enthused about powder coating as well as some of the plating ventures I mentioned.

      Best regards,


      • #4
        in the past I've coated the piston skirts with a polymer based "non-stick" as stated before. If it's going to wear, I'd assume that's where you would see it the most and first in any engine, motorcycle or otherwise. When you get back and do your R&D report your findings. I think basically nobody here has shown an insane interest because basically we're at the technical stage of things at the moment and they might be getting lost. So... for those who have been wondering what is going on, might I elaborate.....

        Basically, Ed here has one of the new Caswell products. Technology changes from day to day and sometimes something truly awesome hits the markets for the hobbyist to play with. Now... this stuff has been around for years and used mainly in aerospace engineering and the like. It's basically a very thin plating with some really neat properties to it. It's tough. I mean tough like all get out ( think chrome). It's also slick in some instances ( think non-stick or Teflon ). So basically... it's the best of both worlds. You have a "Teflon Plating" that's supposed to be easy to apply. Think of it's uses and properties for a second here if you will. We'll make an example out of the car guys just because we can all associate with what we normally use. Now.... imagine the piston in your motor beiang able to be toughened up, all the while making it easier to spin in the motor. This makes a better piston ( like the kinds that racecars use) so it will withstand more abuse. It also makes it very slippery so that you have less drag on metal to metal contact. This all equals more horsepower and torque. Now... we'll take it one step further. Imagine you can do that all throughout the engine and other componants. The amount of friction reduced and the wear factor being lessesned.... this makes for a stronger,faster, more fuel saving motor. Imagine all that done with one tiny coating! It's amazing stuff that kinda crosses the platform of non-stick coater and chrome plater alike. It doesn't happen often in the coating world where you can have that and be successful. This opens HUGE doorways for the plater because it's a great service that you can provide to your potential customers and something neat you can perform on the hobbyist level. It also is a good thing for anodizers as they already have a grip on how to see how the process works. Lastly... it good for the powder guys because it gets you all interested in a different area of coating something and it has the properties of powdered teflon and the like. Trust me.... this is a good thing and it would do you just service to keep watching these threads like a hawk because you are ALL in on the ground floor of something spectacular here.

        I look forward to your updates, Ed. Hope you had a good vacation..... Russ