Honda CB750 Sandcast
The Restoration Shop => The Beginning => Topic started by: Steve Swan on February 25, 2010, 11:43:07 am
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Hi All,
What are your suggestions for cleaning old zinc plating ? I have a front and a rear wheel in decent shape, the spokes have no rust but the zinc is dirty and dull. I have a feeling removing the 40 years of scum will clean things up a bit, but i am reluctant to use a green abrasive pad, i don't want to scratch the zinc plating, just want to clean it to remove the scum and hopefully brighten the zinc a bit.
Would appreciate hearing your experience cleaning zinc plated parts.
Same for some chrome parts i have, there is 40 years of scum, no rust. I have always used Simichrome after washing with soapy water and then clean with Windex, but wondering again what you guys have used with success to clean and polish old chrome.
OK, i will fess up ! I am really excited !!!! i was very lucky to recently have the good fortune of being able to purchase #2157. It is minus the engine, exhaust, oil tank, side covers, airbox and a few other small odds and ends; otherwise complete. I am so excited !!!! I have a new rebuilt engine in unstamped cases, so i am going to put this engine in 2157 -and- have a rider !!!! It will be really great to have a sandcast i can ride and get dirty, wet or what have you!!!!
Does anyone have a set of new or good used Honda repro HM300 stamped exhaust they want to sell ? I would be very happy with a set with the paragraph and the relief in the #4 pipe.
If anyone has a spare oil tank, a David Silver Spares or Yamiya repro airbox or side covers, i would be interested in buying them from you.
Thanks in advance !
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I'm going to throw out a suggestion for comment. Soda blasting using a siphon style gun seems like it might be good for this application. Soda is the softest of all blasting media, it's basically inert, and washes off with water. Obviously you wouldn't want to use heavy pressure, but from what I've seen on other forums it should work really well and not damage the plating. I haven't tried this particular application, but I might give it a shot just to see.
Congratulations on the new sandcast!
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STEVE
Do test with a few of the dull bolts & nuts etc. Soak them in "simple green" I have had real good luck with this on the grungiest parts. The metal bands & the small screws on the carb rubbers are usually nasty, you will be suprised @ how well they will look after an overnight soak
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An update on my trial metal cleaning process.......
Blake, i will bet soda blasting would really do the job, although i am not familiar with the process, it does make good sense. I have a cabinet blaster, but little to no room, to think about investing and then storing another piece of equipment, i do know there is not alot to a siphon set up though. i literally have 10 pounds of s**t crammed in a 2 pound bag here in my humble little "shop" to do the restoration work that i do.
Cleaning parts to bring back an original plated lustre, I am a bit out of my league here. I usually just run everything through a wire wheel to prep for new zinc or cad plating, so finding a good way to bring back some of lustre of an original plated finish is unfamiliar territory for me. And i am feeling lazy with 2157, i am looking forward to doing alot of hand work, but for some reason, encumbering myself investing in another piece of equipment and storing it in my tight work quarters demotivates my motivater, if you any can understand what i this means to me.
Don, i appreciate your suggestion using Simple Green. I happen to have a gallon of the stuff i rarely have used, so i took off a few bolts and the ground cable and soaked them about 6 hours, the difference between original scum dulled appearance and after being soaked in S.G. was pleasantly surprising. I just took a stiff plastic brush to the bolts and they cleaned up better than i expected, some of them are almost actually bright. I also tried some Purple Power, it did not produce the result of Simple Green.
I wonder if out there somewhere, someone makes a somewhat stiff plastic bristle wheel ? That is, instead of a wire wheel, a plastic bristle wheel.... ?
Has anyone used the rust removal method of using an electrolytic Sodium Carbonate bath ? See - http://antique-engines.com/electrol.asp I have heard it works extremely well, old tractor and car guys use this method to remove rust. A good friend of mine has been going to try it, but never got around to it....... I have heard this method produces very good results and can be used on rusty motorcycle gas tanks, simply filling the tank with the Na2HCO3 solution and dangling a bolt off the + terminal of the battery charger without the bolt touching the inside of the tank. For removing rust on other parts, sounds like basically all on needs is a 1 gallon or a 5 gallon plastic bucket, depending on size of parts, some Arm & Hammer Washing Soda, water, electricity and a 6-10 amp battery charger. Quite a few of 2157's smaller chrome parts have the beginnings of some deeper rust. I don't feel like going to the effort nor expense of plating these parts or replacing them with new. I just do not know if this Na2HCO3 method will damage the chrome plating.......... ? But it sounds worth trying, if it can remove rust *and* not damage chrome........ !
Looking forward to hearing your thoughts !!!!
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Steve
Rust on steel including chromed steel parts can be removed safely using molasses. Won't work on cleaning corrosion from alloy though. Mixed around 1 part molasses with 2 parts water, it's one of the oldest and safest methods of removing rust. You leave it in the solution for a few weeks or a few months depending on the amount and state of the rusty part. Works a treat on fuel tanks as well and doesn't affect the paint.
Simple, no equipment required and cleans up with water. Enviromentally friendly as well KP
PS Here's a link but a Google search produces lots of stuff on this
http://www.moreg.org.au/dissolving_rust.htm
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YEP WORKS GOOD ....
& besides the molassis smells purty too!
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Steve,
No need to buy another big piece of equipment. you can have a soda blast setup for real cheap....first go to home depot and buy this for $9.00
http://www.homedepot.com/webapp/wcs/stor....25X-_-100008764
then go buy a large box of soda at walmart or Sam's or harbor freight.
OR if you really want to do it on the cheap, you can try this....
http://www.aircooledtech.com/tools-on-the-cheap/soda_blaster/
Just make sure that every thing is dry prior to blasting. put bolts in any holes. Even though soda washes away with water, it leaves a film that needs to be cleaned up
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Try vinegar.
Vinegar works quite well. The zink will brighten up to new but be aware that any zink that has weathered all the way down to bare metal will become dull in contrast. Atleast you'll know if you need to re-zink at that point.
Will also brighten up dull chrome if the chrome is not pitted/weathered under that skum. As with any acid it will eat rust in a day or so. It's mild enough not to eat through chrome though. It's prbably a weaker strength then the 3% acedic acid that the Kreem products for gas tanks come with but it's a natural and much cheaper form of acedic acid.
Chrome parts that have surface rust that I don't want to remove I use Mothers. If I don't get desired results without going too agresive on the polishing I let it sit for 24 hours and try again. The corosion is surprizingly less resistant the next day or even after two or three days in a row. In other words it's better to walk away than to go for the green pad.
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I bought a CB750 341 style rear fender from the USA for my UK K0 (I could not find a new300 style one with the UK 4-hole lamp mount) and the chrome was in really good condition but had the usual slight surface rust underneath, which I wanted to remove. I was recommended to use a product called 'Deox-C' by a friend who runs a local engineering company. I dipped the fender in it for about 48 hours, as I was assured that the chrome would not be damaged in any way. I have to say that the stuff is magic because it removed all of the rust but no base metal or Chrome. I think they also sell it in Gel form too. Don't know what it does to Zinc plating though but will try it out and report back. definitely brilliant for restoring chromed parts though.
http://www.bilthamber.com/deoxc.html