Honda CB750 Sandcast
The Restoration Shop => Chrome - Anodizing and Other Metal Finish Procedures => Topic started by: ojbiii on February 25, 2010, 11:38:01 am
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Greetings,
I am restoring a sandcast that is pretty much unmolested. It has the original un-numbered exhaust pipes. The pipes are in very good shape. The pipes have no holes or dents, but look "weathered". Here's were I need some guidance and I'm hoping someone can help. Is it a good idea to try and re-chrome my un-numbered pipes? I've cleaned them up as best I can, but they still lack the luster this bike needs. Not sure if re-plating exhaust pipes is even a viable option, but please chime in with your ideas. If re-plating is possible, does anyone know a reputable plating company?
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Hi ojbiii,
I'm in the same situation. I have a nice set of un-numbered's. But, from what I've found, most platers will not replate used pipes because the carbon contaminates their tanks.
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One thing you might try......devleop a relationship with your plater and ask if he can put your pipes in his tank immediately before the time that he has to change the chemicals......last in so to speak....he has nothing to lose. Worth a try.
Steve
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The risk is if there are any areas near rusted through, the electrolytic acid bath will finish what the products of combustion or condensation started, so it is possible to have mufflers with holes after being submerged in the electrolytic bath.
If previously chromed, a part will need to be submerged in the electrolytic bath to remove the old chrome, this is where any potential defects will become apparent.
It IS a gamble to send in what looks like a solid muffler, only to have holes become visible after the old chrome is removed, because obviously, the electrolytic acid bath removes rust as well.
I have used a plater/metal worker for the past 10 years, when unseen defects have appeared, he is able to make the repairs in his shop. I have not had him plate any CB750 mufflers. He not only can weld, he also can lead in dents, so any defect he has been able to repair for me. The only problem with these old exhaust, IF a defect does exist, will require a patch and of course this likely would be visible after repair, considering the repair would have to be made from the outside. And, likely the patch will require a radius and the size of the patch could be considerable, so i am not sure if "my" plater would be willing or able to tackle a job of this sort. Small holes or dents, he can deal with, but larger holes, you wuld have to talk to him.
Based on my experience, I would suspect, the cost of chroming a set of exhaust would be in at least the $150 - $200 range, per pipe. Almost not worth it, unless you know your mufflers have good solid steel throughout.
"My" plater has chromed 2-cycle exhaust for me, he plugs the inlet and outlet. He is a motorcyclist, so the parts i send him are not just some chunk of iron to him.
If you want his contact information, let me know.
A couple guys in the club have used him and been VERY happy with his work. His plating quality is some of the best out there. But, i will say, he is a bit slow, turn around time may take 4-6 months.....
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I met a well known VJMC memeber/restorer at the Barber festival last weekend. He suggested "Hot Tanking" used pipes to clean them. He said you have to find a radiator shop that will work with you, but you simply let the pipes soak until they are clean inside. He said the latest set he did took a couple of weeks to get clean, but after that, they are ready to be sent to a chrome shop. If anyone knows any more about this method, I'd love to hear it.
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I just took a couple days ago the gas tank off 2157 to my local radiator shop. I noticed the typical steaming huge tank of whatever the chemical bath is. The radiator man told me the gas tank inside would be clean to the bare bright steel and it will either have no leaks or it will be, in his words, "a sprinkler system." He said his bath removes rust, but will not remove paint. Looked like there was heat involved as well as chemicals, but not know if there is some sort of electrical charge to the bath as well, which i doubt there is. I really doubt this "hot tanking" process will remove chrome plating, unless the bath is electrolytic. I know for a fact, talking years back with the man who does my chrome plating, he has one tank for removing the old chrome and remving old chrome can only be done by submerging the parts in an electrolytic charged acid bath. So, the short of what i am saying - if you hot tank your exhaust at a radiator shop and likely this hot tank method uses some type of caustic chemical bath, this hot tanking will likely not remove chrome unless the hot tank bath solution is electrolytic. And, if this process does not remvove the chrome, then the mufflers will have to b submerged in the plater's electrolytic acid bath to remove the chrome -and- a 3rd time to replate with new chrome. i am thinking the steel in the mufflers would have to be pretty solid ot withstand 3 acid dips.
When i go to pick up my tank, i will ask him about the process. a breif internet search yileded this info - http://www.mmresto.com/index.php?menu_id=51
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Blake the hot tank will remove everything but the nickel & chrome. Platers remove these with acids & reverse electrolysis & trust me you do loose some metal along the way, notice how much thinner your parts are when you pick them up. Delicate / thin parts, the only way ( that i know of) to remove nickel & chrome & not loose metal is to do what i do. I use a product called B-9 nickel stripper. With a little water, heat and labor It will completely dissolve the nickel so you can bring your plater a perfectly clean part. I strip all my own chrome bolts, nuts brackest etc. & polish myself to save money on the plating. I've never stripped anything as large an a cb750 exhaust but am sure I could- check out the link
http://www.parisho.com/