Please Help.Stripping chrome off old parts.
- Thread starter ben2go
- Start date
WNTITAL
Been Around the Block
I just had the same issue you are facing. In order to remove the old pitted chrome the only way that is safe and won't damage the part is to take it to a chrome shop and have them strip it. I had to have the wheels strip and it cost me about $40. He also did a couple of small parts for me as well that I was getting PC so that was well worth it. Good luck!
we blast them, it really depends on what kind of shape it is in... jsut did my sled pipe not to long ago... took 3 hours to blast it, and them metal was full of divits... obviously powder does not fill that crap in but i was able to get a good coating on it... i am going to do my full bandit header and then reg powder the conector pipe and muffler... but yes we high temp powder headers... just do not chemical strip the chrome, as we do not do chrome work so we do not have a chrome strip tank.
but it worked great as a base and then coated the heat shield
also coated the header pipe on my old street fighter build
but it worked great as a base and then coated the heat shield
also coated the header pipe on my old street fighter build
OK... there's two chemical ways to do it.
First up is muriatic acid. It's messy and nasty as hell. Obviously, use gloves and even an apron if you have one. You will not be a happy camper if you get this stuff on you. It burns like fuck and causes permanent scarring with even a little contact. The fumes will eat and/or rust metal so keep this well ventilated and well away from anything else. If you have a mask, wear it. You can buy muriatic acid by the gallon from pool supply stores, Home Depot, and the like. Before you begin clean what you can off of the part you're stripping and get your acid bath ready. You can dilute the acid if you'd like (2 parts water per one part acid). This means the reaction takes longer but it also tends to get a better finish as you have a bit more control. If possible, keep the acid bath warm. Between 80°F and 100°F is good, but there will be more fumes; be warned.
After everything is prepped, carefully lower the part into the acid. Every couple of hours, turn the part and stir the acid. This process can take more than a day depending on the thickness of the chrome and strength of the acid. What you're looking for is a dull black finish. When you get to this state, carefully remove the part and place it into another bath of water and let it sit for a minute or two. Take it immediately from that bath and place it into another bath of baking soda and water and let it sit for another minute (stir the soda water gently). Time is of the essence at this point, so act quickly. You have about ten minutes to decide whether or not you're done soaking in acid. If the dull black stuff wipes clean with a microfiber cloth you should be able to see either steel, copper, or nickel underneath the black (I've used a buffing wheel for this step as well. Using a compound with a very mild cutting action heavy coloring action. Something like brown tripoli is ideal). If the black stuff isn't coming off, the part goes back in the acid for a couple of hours. If the black is wiped or buffed clean, the part needs to go immediately into a 400°F oven for at least four hours (six is better). You can skip this step for non-structural metals, but if you can do it, do it. This heating will combat hydrogen embrittlement which occurs when metals soak in acids for a long time. Embrittlement significantly reduces the structural integrity of metals, so this really is a definite must for most bike parts. After the baking, let the part cool to room temp and buff it up. The rest of the black stuff should come off. Any remaining nickel or copper is usually thin enough to be polished out with a cutting compound but can also be removed using the method described below:
The second method is electrolysis. This is the same method used to get the chrome onto the part, so you'll be doing the same just in reverse. This can get messy as well and often requires more acids to get it "perfect" but you can still get it pretty close without too harsh of chemicals. For this method, you're going to need a big bath of water, some copper wire or piping, something that has been nickel plated (a lot of automotive parts are nickel plated), and some washing soda (not the same thing as baking soda!). You'll also want a power supply capable of low voltage and high current. 6v is ideal, but don't go over 12v. Higher amps is better, but make sure you can get at least one amp out of your power supply.
First up, ready your bath (use a plastic container or something that won't conduct electricity) . Add enough water into the bath to cover the part and then add one tablespoon of washing soda into the water for every gallon of water added. Stir until the soda dissolves. Next suspend the nickel coated part from a bare wire and immerse it into the bath. Connect the negative lead to the wires holding the nickel part. Next, immerse the part you're dechroming into the bath with a bit of bare wire. Connect this wire to the positive lead on the power supply and turn it on. Within a few seconds you should be able to see small bubbles coming up from both parts. This whole thing usually takes quite a few hours and you may wish to turn the chrome part several times during this process.
If you can get it it, substitute sulfuric acid for the washing soda in order to "unplate" the chrome and then change baths and use boric acid to "unplate" the nickel. Acids will work much better than the washing soda for these metals. It will be both faster and provide a better finish if these options are available.
There will come a point where all of the and nickel chrome has been removed and you will encounter a layer of copper. Not all chrome plating uses copper, but most will and so I include this section. Clean up your bath again and switch over to vinegar for your solution. Hook up the copper pipe on the negative side of things and your (now stripped of chrome and nickel) part onto the positive. Let it sit for a few more hours. When the steel or iron start becoming visible through the copper, turn off the power and buff the rest of the copper off of the part.
First up is muriatic acid. It's messy and nasty as hell. Obviously, use gloves and even an apron if you have one. You will not be a happy camper if you get this stuff on you. It burns like fuck and causes permanent scarring with even a little contact. The fumes will eat and/or rust metal so keep this well ventilated and well away from anything else. If you have a mask, wear it. You can buy muriatic acid by the gallon from pool supply stores, Home Depot, and the like. Before you begin clean what you can off of the part you're stripping and get your acid bath ready. You can dilute the acid if you'd like (2 parts water per one part acid). This means the reaction takes longer but it also tends to get a better finish as you have a bit more control. If possible, keep the acid bath warm. Between 80°F and 100°F is good, but there will be more fumes; be warned.
After everything is prepped, carefully lower the part into the acid. Every couple of hours, turn the part and stir the acid. This process can take more than a day depending on the thickness of the chrome and strength of the acid. What you're looking for is a dull black finish. When you get to this state, carefully remove the part and place it into another bath of water and let it sit for a minute or two. Take it immediately from that bath and place it into another bath of baking soda and water and let it sit for another minute (stir the soda water gently). Time is of the essence at this point, so act quickly. You have about ten minutes to decide whether or not you're done soaking in acid. If the dull black stuff wipes clean with a microfiber cloth you should be able to see either steel, copper, or nickel underneath the black (I've used a buffing wheel for this step as well. Using a compound with a very mild cutting action heavy coloring action. Something like brown tripoli is ideal). If the black stuff isn't coming off, the part goes back in the acid for a couple of hours. If the black is wiped or buffed clean, the part needs to go immediately into a 400°F oven for at least four hours (six is better). You can skip this step for non-structural metals, but if you can do it, do it. This heating will combat hydrogen embrittlement which occurs when metals soak in acids for a long time. Embrittlement significantly reduces the structural integrity of metals, so this really is a definite must for most bike parts. After the baking, let the part cool to room temp and buff it up. The rest of the black stuff should come off. Any remaining nickel or copper is usually thin enough to be polished out with a cutting compound but can also be removed using the method described below:
The second method is electrolysis. This is the same method used to get the chrome onto the part, so you'll be doing the same just in reverse. This can get messy as well and often requires more acids to get it "perfect" but you can still get it pretty close without too harsh of chemicals. For this method, you're going to need a big bath of water, some copper wire or piping, something that has been nickel plated (a lot of automotive parts are nickel plated), and some washing soda (not the same thing as baking soda!). You'll also want a power supply capable of low voltage and high current. 6v is ideal, but don't go over 12v. Higher amps is better, but make sure you can get at least one amp out of your power supply.
First up, ready your bath (use a plastic container or something that won't conduct electricity) . Add enough water into the bath to cover the part and then add one tablespoon of washing soda into the water for every gallon of water added. Stir until the soda dissolves. Next suspend the nickel coated part from a bare wire and immerse it into the bath. Connect the negative lead to the wires holding the nickel part. Next, immerse the part you're dechroming into the bath with a bit of bare wire. Connect this wire to the positive lead on the power supply and turn it on. Within a few seconds you should be able to see small bubbles coming up from both parts. This whole thing usually takes quite a few hours and you may wish to turn the chrome part several times during this process.
If you can get it it, substitute sulfuric acid for the washing soda in order to "unplate" the chrome and then change baths and use boric acid to "unplate" the nickel. Acids will work much better than the washing soda for these metals. It will be both faster and provide a better finish if these options are available.
There will come a point where all of the and nickel chrome has been removed and you will encounter a layer of copper. Not all chrome plating uses copper, but most will and so I include this section. Clean up your bath again and switch over to vinegar for your solution. Hook up the copper pipe on the negative side of things and your (now stripped of chrome and nickel) part onto the positive. Let it sit for a few more hours. When the steel or iron start becoming visible through the copper, turn off the power and buff the rest of the copper off of the part.
