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<x-charset iso-8859-1>I can personally attest to the fact that Chuck knows plating. At the last SDT3 cruse, Chuck appeared for the first time. We all thought his car was nice but everyone was stopped by his flawless, shinny bumpers! ----- Original Message ----- From: <Chazpix@aol.com> To: <type3@vwtype3.org> Sent: Monday, October 22, 2001 2:19 PM Subject: [T3] T3 Tach conversion/plating > Thanks Per. I'll contact him and see if he's got pictures/find out how much. > On chrome plating guys and gals...Actually the condition of the parts can > range quite a bit. No matter how much dirt & grease are on the parts they > still have to be stripped in a hot caustic soda(sodium hydroxide) bath to > remove all traces of paint,dirt,grease,silicone sealer,etc.(basically > anything on the base metal) Then it's rinsed & placed in a HCl (hydrochloric > or muriatic) acid bath (pickling) to remove all traces of rust (for steel > parts). Here is when you find the true condition.(just light corrosion or > heavy pitting or holes all the way through the metal). > Then begins the real work. If there are holes,they can be welded,brazed,or > soldered,then ground smooth.(flush to the surrounding area) Back to the > stripping tanks to remove flux,soldering paste,etc.(both NaOH & HCl) > Now into the plating room for a heavy copper plate(this is the most important > part of the process) Think of copper as the "primer" in painting. Since it is > a soft metal, it is "flowed" rather easily,(trade jargon) that is to say > worked smooth with a combination of Greasewheel/Sisal polishing wheels (looks > like fine sandpaper/ broom bristles on a wheel) the combination of these and > other buffs & compounds "flow" the copper into pits/scratches/other > imperfections in the bare steel & make the surface very smooth. > Now the part is sent back to the stripping tanks once again.(to remove > polishing greases/compounds) > Back to the copper tanks(this is the point at which the corrosion protection > is maximized.(or the length of time the plating will last) The heavier the > copper plate here,the more"protection" the steel has.(remember copper does > not rust)It's buffed with a softer compound (tripoli) and softer buffing > wheels(cotton sewn/coloring) > At this point the piece will be very highly polished.(mirror reflectivity) > Again to the stripping tanks.(remove tripoli/fingerprint oils/microscopically > clean) > Again to the copper tank for a quick "strike" (in & out of the tank w/another > very thin film-for adherence) rinsed twice,and straight into a nickel plating > bath(here again,more is more expensive,but protection and lustre is > dramatically increased).Rinsed. > Now finally it goes into the chromium plating bath, where for the most part > is in there for a very short time.(chrome is VERY thin compared to the other > metals) Good electroplaters will position the anodes in the chromic acid tank > to "throw" the plating into the little nooks and crannies of the > part.(although so much can only be done with this-you may have noticed some > areas look "yellow"-these are the places where the Ni shows & Cr didn't throw) > This is known as a TRUE triple plating(Cu/Ni/Cr) Some shops will polish the > bare steel,Cu strike it, Ni plate & then chrome plate-this will rust very > quickly because there is no heavy copper plate under the nickel to protect > the steel.(and you can tell because it does not look "that shiny"!)(most mass > produced chrome parts are done this way) > Sorry for the long post all.(used to plate for a living & thought folks would > like to know why the process is so expensive and time consuming,but when done > right, plating should look beautiful and last a very long time! ) > Cheers! > Chuck Salter > '66 SB > P.S. as to running hotter with chromed tin, we tested components with various > coatings(powdercoat/paint/plating) and found no discernable difference in > engine operating temperatures with plated parts. > > ------------------------------------------------------------------- > Unsubscribe? mailto:type3-request@vwtype3.org, Subject: unsubscribe > </x-charset>