I thought those baking temperatures were supposed to be considerably higher then 300 degrees F. The ASTM guidelines say something like 400 degrees F for up to 24 hours, depending on the tensile strength and rockwell hardness of the steel.
It's not an issue with weaker steels like those used in bumpers and a lot of the other things they may be used to chroming, so it might not occur to the average chroming shop to do it. If they aren't familiar with the process, or don't have the facilities, head elsewhere.
Scott Minneman San Francisco, CA
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of joebz@optonline.net Sent: Wednesday, December 28, 2005 11:06 AM To: usgeigers Cc: classicrendezvous@bikelist.org Subject: Re: [CR]RE: FrameSaver vs. Hydrogen Embrittlement
A few things need to get sorted out. The acid in the chroming process can do two seperate bad things- the first is not to get rinsed our or neutralized in which case it corrodes the tube. The second is hydrogen embrittlement.
The acid in the tubes is a matter of thorough rinsing, which can be compicated by access. Larger vent holes are probably a good idea. I suppose that using a mild neutralizing solution (baking soda) wouldn't hurt either. So make sure the tubes are rinsed and dry before using Framesaver.
Hydrogen embrittlement results fromm diffusion of hydrogen atoms into the metal while in the plating solution. This leads to cracking by mechanisms that are still probably meing argued about today. While there are claims that some platers and plating processes do not create hydrogen embrittlement, it is an ongoing problem, particularly for high strength aerospace fasteners. There is no doubt that the process matters, because the embrittlement problem is very erratic. The tried and true solution is subjecting the plated article to a baking cycle so the hydrogen diffuses back out. There are arguments about how long etc. but a 12-24 hour cycle at 300 degrees F is probably enough. Also the hydrogen diffuses out no matter what, based on the time and temperature, so a year at room temperature is OK also. Framesaver is not going to affect the diffusion process.
I think the biggest example of possible hydrogen embrittlement of chromed frames was Schwinn Paramounts. Many of the chromed frames seemed to crack. I have seen cracked Fuji Newests, but not Fuji Finests (both of which are chromed under the paint).
Joe Bender-Zanoni
Great Notch, NJ
>
\r?\n>
\r?\n> -----Original Message-----
\r?\n> From: usgeigers <geiggle@sbcglobal.net>
\r?\n> To: oroboyz@aol.com
\r?\n> Sent: Tue, 27 Dec 2005 10:21:34 -0800
\r?\n> Subject: FrameSaver vs Hydrogen Embrittlement
\r?\n>
\r?\n> Seasons Greetings,
\r?\n>
\r?\n> Let me introduce myself. I've had my Cinelli going on 35 yrs. Finally
\r?\n> decided to give it what it so richly deserves, the full spa
\r?\n> treatment:
\r?\n> First I had the frame and forks trued (just to be sure) at Shaw's bike
\r?\n> shop in Santa Clara, good guys there; they said it was out by 2mm from
\r?\n> bb to top of seat tube which is NOT uncommon (must of been that spill
\r?\n> I took back in 73'). Then off to Superior Chrome in San Jose, I asked
\r?\n> for front fork, back fork and the usual three lug treatment but they
\r?\n> dipped the entire frame instead. Hydrogen Embrittlement? Yes, I'm
\r?\n> concerned. Thanks for your earlier replies, by the way, guys. It's
\r?\n> headed for powder coat, yes, powder coat, I feel it's a stronger
\r?\n> product, however if there are concerns I'munaware of please, let me
\r?\n> know. After that, home for period correct decals then back for clear
\r?\n> coat then home for reassembly. I can't wait!!
\r?\n> FrameSaver seems an obvious preventative measure. I'm wondering tho if
\r?\n> it will aid in decreasing any embrittlement potential. I spoke with my
\r?\n> friend who is the plater at Space Systems Loral in Palo Alto (an aero
\r?\n> space
\r?\n> company) he said, the bigger concern with H/E is if any platting
\r?\n> fluids seep into the tubes and stays there. Well, both forks have
\r?\n> those 1mm breather holes in them so I hope the FS will displace any
\r?\n> residual fluidsthat may have been left behind. Mark at Superior Chrome
\r?\n> has done many bike frames and has never heard of any problems with
\r?\n> embrittlement on bike frames nor had any returns or complaints, that's
\r?\n> encouraging news. Anyway, all said it will be on my mind when I'm
\r?\n> doing 60 mph down a steep one, otherwise I'm cool. Dale, thanks for
\r?\n> the heads-up, I'm new at CR.
\r?\n>
\r?\n> Kurt Geiger
\r?\n> Cupertino, CA