Author Topic: Nikasil vs Chrome cylinders  (Read 762 times)

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Offline Cut4fun .

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Re: Nikasil vs Chrome cylinders
« Reply #10 on: March 01, 2018, 07:16:24 pm »
Info from @Grandedog

Nikasil is only about .010 - .012 thick. Chrome is harder and also more difficult to do correctly. Chrome doesn't bond as well as nikasil. If you look at cross sections of cylinders under an electron microscope, chrome has a very defined line where it bonds to the aluminum. A cross section of nikasil blurs the line and, shows the nikasil actually impregnating the aluminum cylinder. This is one of the main reasons why chrome will flake and nikasil won't. Chrome cylinders are more likely to fail with port mods because you expose the edge of the chrome.
Regards
Gregg
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Offline HUSKY KEV

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Re: Nikasil vs Chrome cylinders
« Reply #11 on: May 09, 2019, 06:09:34 pm »
i know this is a late reply but i just replaced a top end on a 254sg. i used an aftermarket rocwood kit. the finish seems very good
https://www.ebay.co.uk/itm/Cylinder-Pot-And-Piston-Assembly-Fits-Husqvarna-154-154XP-254-254XP-Chainsaw/312463623838?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
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Offline Al Smith

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Re: Nikasil vs Chrome cylinders
« Reply #12 on: May 10, 2019, 06:05:35 am »
I don't know how it's done on aluminum alloy .However over steel the process was dubbed "triple  chromed " .First a thin layer of copper followed by a thin layer of nickle then the chrome .Chrome being very hard would tend to crack if it were not for the softer metals under it . The process of using hard high silicon content nickle came along later in the evolution of plated cylinders .
If you look back historically at automobiles you can see the demise of chrome .For example the late 70'e Olds Cutlasses etc in about 6-8 years the bumpers would rust right off of them because of using the less robust chrome caused by curtailing the use of hard chrome because it was in short supply  .You don't see many chrome bumpers these days .
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Offline Al Smith

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Re: Nikasil vs Chrome cylinders
« Reply #13 on: May 10, 2019, 06:27:29 am »
More on the subject .A few years back Kevin and I did a little horse trading .I ended up with a pristene McCulloch 805 .Unknown to both of us the chrome had delaminated in the engine .McCulloch it seems had some quality control problems towards the last years in business and bad chrome was one of them .It wasn't a big deal because I landed an early model Mac 850 on the cheap  and just stuffed the complete engine  under the 805 shrouding with the best parts of two model designs and ended up with a very powerful 80 cc sized saw . If it means any thing I've never had hard nickle plating fail and I've wrenched on a lot of saws of many makes and models .
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Offline Al Smith

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Re: Nikasil vs Chrome cylinders
« Reply #14 on: May 10, 2019, 06:39:19 am »
Another example .Maybe 10-12 years ago I landed a McCulloch model 125c  from flea bay from Oregon .It seems the chrome had failed on it it also but it had a lot of hours on it .My fix which is on this site was to make a cast iron cylinder liner and it worked very well although it took a long time to do it .If it were not the fact the saw was relatively rare I'd have never taken the pains to do that .However it proves ,mechanically speaking nothing is impossible although it might not be practical .
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