Saturday, May 9, 2009
Chrome Plating & Hydrogen Embrittlement Relief
Many of you may already know this about chrome plating (though I didn't until recently) but a friend just showed me his old chromed harley springer and how rust is bubbling up through the chrome, hairline chrome cracks are weeping white powder, and some areas are becoming very fragile and almost crumbling. According to a couple people I've spoken with, freshly chromed parts, if baked at 350 degrees for 45 minutes within a 24 hour period of the chroming process can still be rid of hydrogen. This is important information to know as I do not believe many chrome platers ever bake the parts afterwards for hydogen removal! Please read the following articles as it appears the time between the chrome bath and the jump to oven spans between 1 to 24 hours!:
http://www.finishing.com/1600-1799/1747.shtml
http://www.duro-chrome.com/docs/article.pdf
I don't know how to scan stuff with my new computer, but in and early ROTH sissy rail story he's speaks of using 5/8's cold roll, as it bends easier when it is hot and is not brittle. Make surethat the chrome plater "heat treats" the bar after the copper coat to relieve "brittleness". My steel yard has always set me to the "hot Rolled" section for rail stock, cause it bends better, but will rust faster than "cold rolled". Here we have been using 1/2 or 9/16 but have had flexing (back n forth) concerns on the taller rails. Next rail is gonna be like
ReplyDeletea tall 5footer with stacks. Keep you posted on any breakace or chrome concerns. Please all others visiting this site, let us known, don't what 2 have rigthous ole ladies falling of the back of our scooters. K.K.
Gentleman, It's true! Spokes are really prone to breakage if not relieved in the oven. When we do white cad for restorations it to needs relieved. Coldf roll molecules are tighter than hot roll that's why it bends easier. Stainless is cool but it work hardens. ahy thing that you chrome that is a high stress item, forks, frame, spokes, etc. relieve it. 350 at 1 hour will do it. air cleaners, oil tanks, etc. Not stressed to speak of. Gussets and bracing if you think it needs it cause it probally does. Mig on cold metal is the worse for fracture zones, Tig and gas welding pre-heat and relieve stress. Aluminum is the worst because it's low in the work cycle area. that's why it has to be thicker. hope some of this helps. Could go on for days.
ReplyDeleteRoth always mentioned getting forks baked after chroming to fight hydrogen embrittlement. Does anybody do it? How many chrome shops have ovens? Just Google the subject. looks to be a lot out there on the subject.
ReplyDeleteOnce when I had some parts cad plated, the shop baked some small parts like springs and anything that flexed. Another time after picking stuff up, I put it in the oven and it turned slightly golden. Plater just bright dipped it after so it was no problem. Oven smelled weird after, Don't do it, I'll probably die from cad poisoning.
I've done some checking around recently and what I've found is basically the hard chrome or production line chrome shops that take orders for big businesses have treatment ovens whereas the cosmetic chrome shops for motorcycle and car chrome don't bake their parts. I've only searched a handful of places but its looking pretty bleak that I'll find a chromer who has an oven and since time is of the essence between dip and bake and you don't want to turn your oven at home into a toxic furnace. I'm sure theres got to be someone still doing but who?
ReplyDeleteYou might check Barry Avenue Plating in Santa Monica CA. They baked some of my cad parts years ago.
ReplyDeleteI'm sure they can answer any concerns you have. They offer all kinds of plating services. Aerospace grade and military spec.
Google them for website
hi i was searching some information relating to Chrome Plating and found your blog.
ReplyDeleteI found it really interesting and informative.
Goog post!!!!