Hi the previous owner of my bike (850 mk1 Interstate) had chromed the rear brake plate. Unfortunately through the ravages of time, this has become pock marked with little rust devils poking their way through to the surface.
I think the best thing is to return this to its original black finish, but the question is 'what is the best way to remove the chrome' so that I can paint it again, bearing in mind that I want to do this safely at home. My concern is that even if there was a paint I could use to just paint right over it, the rust would break through eventually.
Any thoughts, anyone please?
The best way is to have a plater remove it electrochemically - otherwise it's emery wheels and lots of elbow grease. Grit blasting will help but can be very aggressive.
that's what I had feared. The nearest plating works is not nearby and neither are they cheap. maybe if I could flat it down, grind out the rust with a flapper wheel and then etch prime it, I might be able to paint over the chrome?
Anyone tried this?
A good powder coating firm should be able to clean off the rust and coat the wheel in a nice controlled environment to prevent any damp/moist air getting on the 'cleaned' surfaces.
Don't know if it helps but it's another option
I have a similar problem on an AMC wheel I am having built, I believe you can remove it by reverse electrolysis if that’s the right word but haven’t investigated yet. Otherwise it’s paint or powder coat for me.
Having read how to do it .....
Perform a reverse electroplating. Chrome is affixed to metal through the process of electroplating, in which electric current is used to bind chrome to the metal at a molecular level. By reversing this process, chrome plating can be removed extremely effectively. However, doing so can be extremely dangerous. Not only does the process involve a live electric current, but also produces several toxic, carcinogenic chemicals as products of the reaction. Hexavalent chromium, for instance, is one extremely dangerous product. Thus, this process is best left to professionals - the steps below are for informative purposes only.
- Mix chromic acid and sulfuric acid in water in an approximately 100:1 ratio. For example, you may add 33 oz. (936 grams) of chromic acid crystals and .33 oz. (9.36 milliliter) of sulfuric acid fluid to distilled water to make 1 gallon (3.79 liter). Mix solution in a proper immersion tank used for electroplating, materials testing, and/or chemical treatments.
- Heat the solution. Keep the temperature of the solution from 95 to 115 degrees Fahrenheit (35 to 46 degrees Celsius) for decorative chrome. Keep temperature from 120 to 150 degrees Fahrenheit (49 to 66 degrees Celsius) for hard chrome.
- Run a negative charge from a DC power source through the chromic plating solution via wire.
- Attach the positive cathode to object intended for stripping and submerge the object into the solution. The positively charged exterior chrome metal will be pulled from the object.
- Rinse object in agitating running water, then rinse again. Have waste products professionally processed and disposed of.
more here : https://m.wikihow.com/Remove-Chrome-Plating
I May use abrasive methods!
Send it to a plating shop and have them do it - it should not be any where near the cost of plating because there is much less work and materials involved. As noted by Dan in the above post , chrome plating and it’s reverse produces some VERY unhealthy stuff.
Removing it mechanically will be very laborious and possibly damaging to the plate itself . I can’t stress this enough - let the plating shop do it .
Buy another? Are they that rare or dearer then deplating?
My local paint-man declined to take on my slightly rusty Chromed front brake plate for a make-over. Instead he suggested the following process to remove the old Chrome. Carried out in a very well ventilated open area. ie. ....outside.!!!
Disolve 1Kg of Caustic Soda (Sodium Hydroxide) in 2 Gals (9 L) of Water. Use a plastic container , liquid proof gloves and a good mask.
Connect Positive Electrode to item needing de-plating. Negative to a piece of clean Mild Steel. Dunk both Electrodes into the solution.
Connect the Electrodes to a 12V power source and watch for bubbles. Once there are bubbles the process is working. Leave the power on for just a few minutes.
Then switch off the power, remove the item and wash in clean water. Dry asap.
My recommendation would be to use a professional service on the grounds of Health & Safety
Thanks for the input.
New plates are readily available from ANIL but they are not cheap. Hmmm...........trouble is that apart from the rust, the plate is fine, since even the bush for the cam is easily replaceable.
Need to think about this.
My bike's PO removed chrome from various objects in the way Phil describes because he preferred the appearance of the underlying nickel on vintage vehicles. Passed away last year aged 95.
Gateros do reasonable priced kits which can de-plate and plate metal parts. Chrome removal is as Phil describes, but I don't think it's really necessary to remove all the chrome before painting. Hand sand it or use a sanding disc to get any loose chrome off then use some trusty Kurust or a rust curing paint of your choice. The old grey Kurust from the 1960s was best as it was acid-based, but there are many products around. Halford has bucket-loads! Another old favourite is Jenolite.
Once the rust is treated you can use a metal primer then a primer-filler to fill the pock marks. Expect to have to use a few coats of paint and buff it down in between coats. You could spray on black Hammerite gloss as a finishing coat, if that's the colour you want, or any decent solvent-based paint. Never EVER use water-based!
In my past employment I was involved with material inspections at a 'top secret' nuclear establishment. Part of the job was corrosion assessment of various metals used by our main customer. One of the more useful and common rust curing materials used on site was a dilute Phosphoric acid solution liberally applied and left for 24 hours or more after loose surface rust had been removed. The phosphoric acid neutralises the rust through the ion exchange process and applies a thin coating of phosphor to the neutralised metal. Wash off residue in clean water, no need to rub it down and, apply a good quality coating material. As long as you do the work in a nice warm location to prevent atmospheric condensing on the treated surface it should be ok.
If you intend to display it (either as a correctly re-finished museum exhibit, or as some kind of custom piece) then professional refinishing is in order.
If you "merely" want to ride it, then Jenolite/Kurust/etc., plus painting, as described in other contributions sounds ample.
Have a look at
eBay item number:
£20. Any good?
Looking up 'Commando brake plate' reveals that yours isn't he only chromed one!
I used Hammerite Gloss Black on both my front brake plate and the fork sliders. The brake plate had been previously Chrome plated and most of this was either ground off or removed with a Jenolite wash. I then added a layer of Etching Primer and used the Hammerite as the top coat. This all worked well and the finish looked good has been quite durable.
The fork sliders received a coating of a standard Primer followed by the Hammerite. These also looked good to begin with but soon began to show chip and scuff marks. The Primer clearly has not bonded with the Aluminium. I need a Plan B to sort the finish of these sliders out.
Sorry for not getting back; I have been immersed in making a new wiring loom since the insulation on the original wiring had gone brittle.
I intend to use the bike - not exhibit it. I have plenty of jenolite, hammerite and other noxious paints so I shall rub it down, jenolite it and then paint it. As long as I can get a good adhesion to the remaining chrome that's all I need.
Thanks for all of the input. Most encouraging.
Thanks and BR,
Hammerite supply a "Special Metals Primer" for non-ferrous metals, including aluminium.