'How To' Guide for DIY Home Electroplating

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'How To' Guide for DIY Home Electroplating

Postby alan.moore » Tue Aug 29, 2017 1:36 am

Some time ago I said I would compile a ‘How Do You’ guide for DIY electroplating. Well I have finally got round to collecting the information and images needed. My intention is to post a written explanation, supported by photos together with PDF’s of the instructions for the kits supplied by retailers who sell the plating kits. There are also videos, which are best viewed after reading the written explanations.

The idea of home plating will not appeal to everyone, and it is certainly easier to send the parts off for commercial plating, but I hope this topic will be of some help to those who have considered it.
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Plating Kits

Postby alan.moore » Tue Aug 29, 2017 1:39 am

PLATING KITS
DIY plating in the main involves Nickel, Zinc, Copper and Replica Chrome plating (a Nickel based system). I have only used commercially available ‘Kits’ which contain all the chemicals, anodes and other items needed to setup a home plating system (apart from De-ionised / distilled water which you will need to source) together with comprehensive written instructions. Whilst it would be possible to gather together the required chemicals and hardware from separate sources I have not gone down this route.

I have used the following UK suppliers:
Gateros plating http://gaterosplating.co.uk/Home.php
Classic Plating http://www.classic-plating.co.uk/

Their websites will give you all the info you need regarding how much the kits cost and provide basic instructions regarding how to setup and start plating. If you are interested in starting your own plating these sites are worth a look.
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Setup

Postby alan.moore » Tue Aug 29, 2017 1:51 am

SETUP
The basic setup is the same for all the plating processes.

Plating tank
The kits come with a circular 6 litre plastic ‘tub’ to contain the 5 litres of electrolyte, which is the size of the standard kit. You can of course buy more chemicals and anodes and use a bigger container, or use a longer narrower rectangular container to plate longer things than would fit in the round tank. I use a more ‘square’ 6 litre tank as this gives you a bit more room if you hang the part across the diagonal.

plating tank setup.jpg
Plating tank setup


A few tank setup tips:

Follow the instructions for mixing the components of the electrolyte to the letter. Make sure everything you use is clean and wear rubber / nitrile gloves and a mask while mixing.

Whilst plating the electrolyte can give off some fumes and the suppliers recommend plating in a well ventilated area. I have mine setup in a small plastic greenhouse which also houses my grit blasting cabinet and I use the large extraction fan in that to remove any fumes. Just use common sense is the best advice when it comes to heath and safety and bear in mind any written warnings / advice given with the kits.

If you use copper wires to hang the anodes in the electrolyte you must make sure that the copper wire does NOT go into the solution as copper will be drawn into the solution when plating is taking place. This contaminates the solution. I settled on Titanium wire (Ebay about £1 per metre) as it is inert/does not corrode. This maybe not so important in the copper plating electrolyte but I still use titanium wire hangers in that.

The anodes may come pre drilled for connecting the wire or you may need to drill them. Attach the wire to it by twisting securely.

As the anodes are consumed they can start to release small particles into the electrolyte which make the plating finish rough. Wrapping the anodes in kitchen towel (i.e J cloth) prevents this. I fold the cloth round the anode and then hand stitch it to make a sealed pocket.

You need to have at least the same total anode surface area as the part you are plating. The 5 anodes I recently purchased were about 1 inch square and 0.5 inch thick, which gives me 4 square inches per anode and 20 square inches in total. For info a VH pushrod tube has a surface area of 22 square inches and mine plated fine.

Use stainless steel crocodile clips as zinc plated or plain steel will corrode horribly because of the nature of the electrolyte.

Regarding the –ve wire around the tank you can use stainless (as it will not corrode) but copper works OK but needs a clean if its starts going green. I join the two ends to a light spring (about 3 inches long) which keeps the wire taught.

Anode wire.jpg
Anode wire
Anode wire.jpg (33.14 KiB) Viewed 457 times


Make sure you have a good connection where the anode wire is hooked under the +ve copper wire. You can check this by connecting the power and checking for voltage between the –ve copper bus bar and the titanium wire going to the +ve anode.

The parts to be plated are hung on ‘solid’ copper wires and this wire is folded over the bus bar (copper pipe). Keep the bus bar and hanging wires clean to ensure a good electrical connection. You could use a stainless steel bus bar or chrome plate a copper bar. Clean the hanging wires before use. Copper wire stripped from old household wiring works well.

The plating works by ‘line of sight’ so you need to space the anodes evenly around the part to be plated, but make sure none touch the part. I find it best to keep them a minimum of a couple of inches away. If you cannot manage that then you need to rethink the size / shape container you are using.

Plating is always better, and more even, if the electrolyte is agitated whilst the plating takes place. I use a small aquarium air pump with the air pipe going into the solution under the part. If you get an adjustable pump you can alter how much bubbling / agitation you get.


Heating
The electrolyte needs to be warm for the plating to be effective. The instructions that come with the kits give guidance but generally it is 30 to 40 degrees C. I fill a large bowl with very hot water and then put the plating tank in it, let it warm up then replace the hot water. This is normally enough to get up to temp and keep it there for an hour in the summertime. You can always remove some water and add a bit of nearly boiling if it starts to drop. You can also use an electrical aquarium heater to maintain the temp once you have got it warm. Standing the bowl on some polystyrene and wrapping it in bubble wrap also helps. A cheap aquarium thermometer can be used to keep a check on the temp.
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Supplying electrical current

Postby alan.moore » Tue Aug 29, 2017 1:59 am

Supplying electrical current
This is by no doubt the most difficult and troublesome aspect of home plating. For the supply of ‘power’ you can use a dedicated power supply (expensive), a 12 volt battery charger (which would need at least a 5 amp output and bear in mind that some of the modern solid state ones will not output unless attached to a battery) or you can use a 12 volt battery.

I use a 12 volt car battery and attach the battery charger to it, whilst the process is taking place, to maintain the voltage. The instructions with the kits say 6 to 9 volts are best, but then go onto say a 12volt battery is OK. I have not found that using 12 volts is a problem; the important value is the amount of current you are supplying to the part through the electrolyte.

The amount of current required is dictated by the surface are of the part being plated and the type of plating being done. The requirements are set out in the individual instructions supplied with the kits but for example Replica Chrome is 0.150amps per square inch of surface area, copper plate is 0.200amps per square inch surface area and zinc plate 0.100 amps per square inch surface area..

A VH pushrod tube has a surface area of about 22 square inches, which at 0.200 per square inch (copper plate) would require 4.4 amps. A VH kickstart is about the same. A small bolt with a surface area of 1 square inch would only require 0.200 amps.

To ensure the correct current is applied you need something to control / adjust the resistance in the circuit. You also need an ammeter or multimeter set to the current function to show the value of the current being supplied. Make sure the meters are rated / capable of taking the current you will be supplying. I would suggest you will not be using more than 5 or 6 amps unless you build a large setup to plate larger items than 25 square inches.

The kits all come with a ‘hot wire’ resistor which is coiled piece of fine ‘heater’ wire (such as nickel chromium wire). The ‘positive’ supply wire is clipped to one of the coil posts and a second wire is then attached between the coil itself and the +ve supply to the anodes (via an ammeter or multimeter set to current). Depending on where the wire supplying the current is clipped to the coil the resistance of the coil is altered and more or less current is supplied. I found this type of control to be problematic. If a current of say 3 amps was required very little of the wires coils were used and the short length of resistance wire in use soon heated up and eventually, after a number of sessions, the wire would fail. And even if more coils / higher resistance were used, because the wire still heated up, the wire coil would sag and stretch.

current controller.JPG
Hot wire current controller


You can buy purpose made power supplies (a 0-30 volt 10amp unit on Ebay is about £50). I have no knowledge of how good these cheap, probably made in China, power supplies are. The Classic plating website lists a similar looking one (but only 5 amp output) at nearly £80. They say it will plate up to 40 square inches, but that would only equate to 0.125 amps per square inch, so I think if you went this route a 10 amp one would be better. You can pay a lot, lot more for one of these; just take a look on Google for regulated bench power supply. I don’t use one of these at present but I think one would provide a simple method of supplying the plating current without the need for car batteries and a separate controller.
power supply.jpg
Power supply


My setup uses a wire wound variable resister / rheostat which is rated at 100 watts. (100 watts is safe for 8 amps as Power = Amps x Voltage i.e. 100 = 8.33 x 12). You can get them with various resistance values. I have initially been using a 100 Ohm one. Mine is mounted on an aluminium panel and I have also wired in a 12 volt computer case fan which blows on it to keep things cool when a higher current is required. The rheostat is fed from the positive wire of the 12 volt battery (to the central ‘wiper arm) and the +ve output / supply to the anodes taken from one of the two brass tabs at the end of the rheostat coil.

I have a resetable 5 amp fuse in the circuit between the 12 volt car battery and the rheostat so that if I do inadvertently short anything the fuse goes and you do not get the full amperage of the battery through the circuit. I think a fuse is a worthwhile addition even if you only use the supplied wire coil resistor.

With regards to the rheostat: to explain how the Ohm (Resistance) rating relates to your control of the plating Current (Amps) you need to do a bit of maths.

Voltage (V) divided by Current (I) equals Resistance (R)

So if you have 12 Volts (battery voltage) and you need 3 Amps (plating current) then 12 divided by 3 = 4 ohms.

If you have 12 Volts and you need 0.15 Amps then 12 divided by 0.15 = 80 ohms.

I have found that the problem with my 100 ohm resistor is that, whilst it is fine up to about 2.5 amps, anything over that means the central ‘wiper’ arm is very close to the supply end of the resistance wire and even small movements of the control knob can cause the current to jump by maybe an amp as it bridges more than one coil of wire. I can get it to supply 4 amps but it needs very careful setting. The solution would be to use a rheostat with less overall resistance. A 100 watt, 50 ohm resistor would provide a lowest current value of about 0.25 amps, so still OK for small items, but should hopefully have more controllability at the upper end. I am going to try one and see. I will update with the results. Rheostats are available on EBay for about £10, but only from Hong Kong unless you want to pay eight times that amount from the UK!!

rheostst.jpg
Rheostat


Ammetre
I use a cheap solid state dual voltage/ammeter from Ebay (about £3) which gives me a readout of battery voltage and the current being supplied to the part being plated. They are easy to wire into the circuit (instructions included when you buy). The one I got is rated at 30 volts and 10 amps.

ammeter.jpg
Ammeter


You could use any type of ammeter, as long as it can take the amps you intend to use. You can also use a multimeter with the probes attached in series with the +ve supply to the anodes.

Here is my setup. I have two separate power feeds (from one 12 volt battery) so I can plate say Zinc and Replica Chrome at the same time. In this case I tend to wire two 12 volts batteries in parallel otherwise the voltage tends to drop as the plating continues as the batteries are well past their best.

My setup1.jpg
My setup
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Preparing the parts for plating

Postby alan.moore » Tue Aug 29, 2017 2:05 am

I cannot over emphasise that this is by far the most important part of the plating process. If you shortcut or skip though this part the results will be poor. The degree of polishing is more important for Replica Chrome plating because of its high reflective finish. If you are just Zinc Plating nuts and bolts etc the finish does not have to be so ‘smooth and blemish free.

Cleaning
The first stage is to clean off all traces of grease from every nook and cranny. The parts need to be ‘clinically’ clean as any oil or grease will come back to haunt you later on. I have used many cleaners in the past such as paraffin (based on oil so you need to get rid of any left on the part), ‘Gunk’ type cleaners, heated caustic soda and all sorts of detergents. Then I got a parts washer and purchased a 25 litre drum of ‘concentrate industrial parts washer fluid’ from EBay. Well, let me tell you, that stuff was seriously good. You can dilute it down to 20:1 and it still cleans great, but at full strength it gets rid of every last bit of oil and grease. It is very alkaline, so you do not want to get it on your hands as they wrinkle up in an instant, but leave a part to soak a while and give it a scrub and it comes up spotless. WARNING do not put aluminium or any other soft metal parts i.e carbs in there, it will attack them mercilessly.

Removing any original plating
If some of the original plating is still on there it needs to be removed.
Chrome plating is a very hard layer deposited on top of nickel plating. In an attempt to remove old chromium plating I have tried hydrochloric and sulphuric acid of various strengths, but even after soaking for an hour or so the chrome plating was still there. The problem is that you do not want to use too high an acid strength, or leave the part in for a very long time, as the acid will also attack the non chrome plated areas. The best way I have found to remove the remnants of the chrome / nickel layer was by abrasion.
Zinc plating is quickly and easily removed with an acid. Dilute Hydrochloric acid can be easily purchased in the form of Brick Cleaner. You can find it at about 20% strength and this does the job OK. Just keep and eye on it and remove and rinse the parts well in water when the bubbling stops. You can also drop them into a solution of Bicarbonate of Soda, before rinsing, as this will neutralise the acid quickly.

Note that any parts that have been in an acid dip and then washed off will start to rust very quickly so either dry them thoroughly or only strip them only when you are ready to start the plating process

Polishing
Once cleaned, to prepare the parts you really need to get a bench grinder based polishing kit. Mine is a 350watt grinder and I use 6 inch buffing wheels. (You can fit any size of buffing wheel but the bigger the wheel the higher the power of grinder needed). The one I have has served me well. You can pick them up on EBay, either buy the grinder and polishing kit separate or as a bundle. If you already have a decent bench grinder you just need the buffing kit.

bench polishing kit.jpg
Bench polishing kit
bench polishing kit.jpg (28.92 KiB) Viewed 457 times


Assess surface
Next stage is to assess how bad the metal surface is. If there are rust pits, gouges or scratches then these need to be removed by abrasion before you start polishing. Any surface defects left will be clearly seen in the finished plating. With minor defects, such as small rust pits, it is possible to use the Copper Plating kit to put layers of copper onto the part, which can then be rubbed down in the same way as filler is when preparing for painting. You may need a few layers of Copper, rubbing down between each layer, before the defects are filled. The Copper filler is well suited to parts that are thin where you do not want to do too much physical abrasion.

Initial preparation
You can now start to prepare the part. The process is to start with a course abrasive to get rid of the larger surface defects and then work down through finer and finer grades before starting to polish. The degree of surface defects on the part determines how course a grade of abrasive you start with. It is best to start too fine, if you then find you cannot remove the defect within a few minutes you can go up a grade or two. With practice you will soon work out what grades work best for the defects you are trying to remove.

I will use a kick-start and gearlever and to describe the process I go through. Both were rust pitted and had some traces of the original plating.
gearleverrusty.jpg
Rusty gearlever


gearleverpits.jpg
Gearlever rust pits
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Stage One

Postby alan.moore » Tue Aug 29, 2017 2:12 am

Stage one
For removal of old chrome and deep scratches / pits I start using 120 or 240 grade emery cloth, which comes on a roll and has a cloth backing, wrapped around a 6 inch Sisal stitched buffing wheel. I find it best to start with 240 and if that is removing the chrome / scratches etc OK continue. If you don’t seem to be making much progress move to 120 but take it easy. Then move back to 240. If you can get a width slightly wider than your buffing wheel this can works better.

emery roll.jpg
Abrasive cloth


I wrap a length of the cloth abrasive around a spare 6 inch close stitched sisal buffing wheel and superglue the ends together with about a 1.5 inches overlap. Wrap it tightly round the wheel, mark the overlap, remove and then glue it together about 1/4 inch tighter than the wheel circumference. Just make sure it is a really tight fit when you put it on the wheel and that the end of the overlap is pointing away from the direction of rotation. If it is loose it will quickly come off the wheel when you start grinding. If necessary use a small screwdriver to ease it into the wheel a bit at a time.

250grit on wheel.jpg
240 grit on buffing wheel


120grit 4.jpg
120 grit on buffing wheel


Start up the grinder and then run a piece of scrap rounded steel bar against the abrasive to take off the initial course cut. It is then a case of grinding away the defects on the part. Use only medium to light pressure and keep the part moving at all times, sweeping it left and right across the wheel whilst rotating it a little. Once you have gone over the whole part moving it horizontally change the angle of the part so you’re abrading at a different angle and keep going changing the angle again once you have gone over the whole part. Your goal is a uniform matt surface with none of the chrome remaining, so if you have only a few areas of chrome attack those first. The trick is light to medium pressure and keep the part moving at all times. With the narrower cloth you can pull one edge of the abrasive strip past the side of the wheel to get into corners, the wider strips will already be overlapping the wheel.

If you have deep defects you will have to decide how far you want to go with the grinding. If you grind away at one place only you end up with a depression which will stand out like a sore thumb. Remember, you can use Copper plate to fill in rust pits and medium scratches during the plating process so this is an alternative to grinding away all of the defects.

It is also possible to ‘lead solder’ fill deeper defects in the same way that ‘leading’ was done on car bodies. If you want to go this route it is best to get all the polishing of the rest of the part done before you start solder filling. I have not tried solder on a substantial part, such as a gear lever, but you need to bear in mind you would need to get the part up to temperature before the solder will flow. I have done it on a headlamp rim, applying a layer of copper plate, solder filling, levelling it, copper plating again and then Replica Chrome. It turned out fine but the layer of copper can tend to lift if you use too much heat. A low temp, mostly lead based solder is best. I have not, as yet, tried solder straight onto a steel part followed by Replica Chroming without any copper plate. I will add a post as to whether this worked for me at a later date.


Stage two

If the part has only fine defects / scratches you can try starting off with a ‘scotchbrite’ wheel on the grinder. These come in various grades but I fine that a fine grade (about 320 grit) works fine. You also use these as the next step after using the 240 grade emery cloth. They are good for getting into the corners where the abrasive on the wheel cannot easily get. Again, alter the angle of the part regularly and keep going until all the 240 grinding marks have gone. Finish off in one direction over the whole part which should show uniform ‘scratches’ on its surface.

scothbrite wheel.jpg
Scotchbrite wheel

scotchbrite finish.JPG
Scotchbrite finish
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Postby alan.moore » Tue Aug 29, 2017 2:22 am

Stage three
I then use 600 grade wet and dry abrasive paper, used wet, by hand going over the whole part, initially at 90 degrees to the direction the scotchbrite scratches were made. Keep the part wet and continue until all the scotchbrite scratches are gone.

Now is the time to check on the level of finish you have achieved. It may look pretty good to the eye at normal viewing distances (a couple of feet or so) but if you take a digital photo of the part, using your cameras close up setting, and then zoom in on your computer monitor, you are likely to see some pits and slight defects remain. Only experience will tell you whether this is an acceptable finish for you after the Replica Chrome has been applied. Let’s face it, are you really going to be examining the finish this close in real life? If you wanted a show finish you would send the parts off for a professional job. If you have had commercial chroming done this in the past just use the same procedure to look closely at the finish, I bet you will still see some defects. If you are not happy with the pits that remain its back to the 240 grade abrasive and take a bit more off. Then progress through the subsequent stages again.
For the examples I have used, if you zoom right in there are still some very minor pits, but I am more than happy with this level of finish and on these parts I did not use any layers of copper to fill them in.

The following stages only polish the surface; they will not remove any pits of defects that are still there. Before polishing you can first continue with 800 grade and then probably 1200 grade wet and dry used wet, changing the direction of application with each change of grade. I have found that going to 600 and then polishing is good enough for my needs.

Stage four-Polishing
This site will give you some idea of what is available with regard to the different types of polishing wheels (mops) and compounds:
http://www.thepolishingshop.co.uk/acatalog/Polishing_Guide.html)
http://www.thepolishingshop.co.uk/acatalog/Polishing_Mops.html

There are loads of places on the internet and EBay that sell these items separately or as kits to get you started.

A good guide to polishing can be found here on the Caswell site http://www.caswellplating.com/buffman.htm#


The different grades of polish are identified by the colour of the compound. Each colour contains a certain grade of polishing abrasive. The ‘Mops’ come in different types, hard coarse ones such as ‘Sisal’, medium ones such as close stitched denim and soft ones of unstitched cotton. The ‘mop’ screws onto a tapered arbour which fits on the shaft of the grinder. Buy mops that have a leather washer attached each side where the hole is as they are a better fit on the arbour.

The bench grinders normally rotate so that the mop wheel is moving downwards when viewed from the front of the grinder which is where you would normally be standing. If you move the part upwards, against the direction of rotation, the abrasives cutting action will be increased. If you move it down, in the direction of rotation, it will be less.
The diagram below shows the safe areas of the mop to be used in relation to the mops direction of rotation. The safe areas are those that are rotating away from the part you are buffing.

safe polishing.JPG
Safe polishing
safe polishing.JPG (27.6 KiB) Viewed 454 times


You have to be extra careful with any part that has a defined or sharp edge as it can be caught by the spinning mop and thrown out of your grasp damaging the part and / or you. You should offer the part so that any such edge will not dig in.


I start with a course polish grey compound on a’ Sisal’ mop. Spin the mop up and apply the bar of compound which you will see being transferred to the mop. Once you have an even coat you can start polishing. Again light to medium pressure, keep the part moving and keep changing the direction of attack.

The idea is to continue until the scratch marks from the previous operation (in my case 600 wet and dry) have been removed. Finish this stage so that the polishing action / marks are all in the same direction on the part.
grey sizal apply compound.jpg
Course compound sisal mop


grey sizal buff.jpg
Course compound sisal mop


Use a rag to clean off any compound then change to the next mop, in my case a close stitched denim mop used with medium polish brown compound. I have since found out that some brown is only normally used for soft metals, not steel and that green compound is the one to use on steel. I find that brown and green give a similar degree of polish. Initially polish at an angle to the previous course grade buff and continue until the course buffing marks are gone. You can then polish in various directions, again finish off in the same direction all over the part.
medium denim mop.jpg
Medium compound denim close stitched mop


This image compares the results of the course and medium compound on the kickstart. The gearlever above is the 600 grit wet and dry finish.
course to medium buff comparison.jpg
course and medium buff comparison
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Fine compound polishing

Postby alan.moore » Tue Aug 29, 2017 2:30 am

After cleaning off any medium compound the next stage is to use the unstitched cotton cloth mop with a fine finishing compound. I use a blue compound. Below is a comparison between the medium and fine buffing results.

fine loose stitched mop.jpg
Fine loose leaf mop


medium fine buff comparison.JPG
medium and fine compound comparison


You can then move onto using Solvol Autosol on an unstitched cotton mop for a final polish.

Below is the final finish compared with a commercially plated part. In this case I still have some very small pits in the finish which could be filled with copper plate if you were going for a ‘perfect’ plated finish.

Compare final buff to commercial chrome.JPG
Comparison final polish with commercial chrome
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Preparing for plating

Postby alan.moore » Tue Aug 29, 2017 2:39 am

Preparing for plating

I would suggest that now is the time to decide how you are going to suspend the part in the plating tank. It is sometimes useful when you start out to have a ‘dummy’ plating tank with nothing in it and before final cleaning decide how long the ‘hanging’ wires need to be, where you are going to attach them to the part and do a trial ‘suspend’. This means you are not messing about trying to sort this out with a nice clean part and a ‘live’ plating tank. Apparently the best plating takes place if the part is just below the surface of the electrolyte, so take this into account when determining the length of the hanging wires. I have the top of my parts about 1 to 1.5 inches below the surface.

Now is also a good time to work out the surface area of the part (or parts if you are plating a few smaller items) and calculate how much current you need for plating as discussed earlier.

Regarding where you wrap the hanging wires; bear in mind that where they touch the part you are unlikely to get a mark or shadow in the plating, so use bolt holes or wrap the wire around an area where it will not be readily seen. I use copper wire to hang the parts as it is easily bent to ensure good electrical contact with the part. With items longer than about three inches it is best to use wire at both ends as this evens out the flow of electrical current through the part. Most parts will be hung horizontally anyway, to fit the plating tank, so suspending from each end is the best way. Avoid trying to hang just from the middle anything longer than say three inches. Also, if your hanging wire only has a small single point contact with the part you can get a high current flow at that point which results in grainy uneven plating, so make sure your copper wire is a snug fit around the part.

Final cleaning
From this point onwards you must not touch the part with your hands as the grease from your skin will contaminate the part so wear a pair of clean nitrile gloves. The part should already have been cleaned of all grease in the pre buffing cleaning stage but make sure there is nothing lurking in any holes, bolt holes, splines etc or inside tubes such as pushrod tubes.
The next stage is to clean the part so that all traces of the polishing compounds are removed. If anything remains on the part the plating will not adhere to the part and it is likely to peel off. As set out earlier on in the post I use a concentrated parts washer alkaline cleaner for initial cleaning and this works great for this final cleaning. I find that washing up liquid tends to make the beading worse, I think it contains something which makes the water bead and run off so your plates and glasses dry streak free.

The way to make sure you have removed all grease and polish is to do a ‘water break’ test. This involves putting the part under running water, I use the kitchen sink tap but you could use a bottle of water. If there is still grease on the part the water will ‘bead up’ and form globules which will run off the part.What you are looking for is a uniform unbroken film of water all over the part with no beading. The video below shows what you are looking for.



Once the part passes the water break test it is very susceptible to flash rusting so only do this final clean when you are ready to plate the part. Give it a final rinse under the tap and then rinse again in a container of deionised water. I use a 5 litre container which allows you to leave the part in there while you sort out your hanging wires. Make sure your hanging wires are clean before attaching them to the cleaned part. I pull them through a piece of scotchbrite pad then through a rag with some of the cleaning fluid on it. Again use gloves to do this.

Acid Etch
The part now needs to be acid etched so that the plating adheres to the surface. I use ‘Dry Acid’ crystals that you mix with water to make the etching solution, you get some with the kits and you can buy them from the plating supplies companies mentioned earlier or on EBay. The instructions that come with them tell you how to mix them. You can also use 15 to 20% Hydrochloric acid solution such as brick cleaner. You can etch at ambient temperature so no need to heat. Hang the part in your container of acid and let it etch, about 5 minutes for Replica Chrome and Copper and 2 minutes for Zinc (or according to the instructions that came with your kit)

Rinse
Next rinse the part in a 5 litre container of deionised water. I just ‘swish’ it around for a few minutes.

Plating
Before you starting to plate your precious Ariel parts I would suggest getting in some practice using something like various lengths of fully prepared and cleaned 15 and 22 mm diameter copper water pipe. This will let you calibrate whatever you are using to control the plating current. The current flow depends on the surface area of the part (which you measure / calculate) the type of electrolyte (Replica Chrome, Copper, Zinc) and the electrolyte temperature. By doing some test pieces you can determine approximately where your current controller needs to be ‘adjusted’ for various surface areas for each type of electrolyte.

As described earlier, you will have already have set up your plating tank, got the electrolyte to the correct temperature and calculated the amount of current you need to supply. I have read that it is good practice for the part to go into the electrolyte ‘Live’, which means that it is already hanging from the negative bus bar and that you have already adjusted the current controller to about 25% below that required (there will be no current flow and no ammeter reading until you immerse the part). The idea is that you get better initial adhesion of the plating this way, as opposed to putting the part in and then connecting the current supply. Fully immerse the part as quickly as you can to prevent a high current flow through the first part that touches the electrolyte. This is where the pre-determination of the length of the hanging wires comes into play.

Now set the current controller so that your calculated current is flowing. You may see some fine bubbles forming around the hanging wires where they enter the solution and maybe some on the part. If it is bubbling rapidly you have too much current flowing so check your settings. Now is the time to introduce the pipe from the aquarium pump so that the bubbles rise up around the part. This agitation of the electrolyte gives a better plated finish.

Do not start pulling the part out to see if plating is taking place, if you do the plating may peel. After about 5 minutes you can lift the bus bar a little and look to check that plating is forming on the hanging wires and you may be able to see some of the part through the electrolyte. I sometimes very quickly lift the part out after about 15 mins just to check I am getting a good smooth quality of plating and that the coverage is even. However, the plating instructions recommend you do not do this. I normally plate for 30 to 40 minutes and get good results with Replica Chrome, Copper and Zinc in this time period. You can leave the part in for longer to get a thicker plate but I have found that after 50 mins you run the risk of the plating getting a bit rough in some areas. Good quality, consistent, results are really a matter of practice, experience and getting to know what works best with your setup.

When the plating time is up switch off the current supply, remove the part and give it a good rinse in a dedicated 5 litre ‘post plating’ container of deionised water.

With Replica Chrome hang the part up and let it dry. You can then give it a good polish with a very slight abrasive metal polish such as Solvol Autosol. I have found that the plating is very hard (as you would expect) and does not scratch easily. It has a very slightly brown / nickel coloured tinge when compared side by side with commercial chrome but, as it is based on Nickel anodes and salts this is not surprising. The only way to get a real chrome finish is to use commercial chrome plate, not something which can be done in the garage. The finished gear and kickstart lever are shown below.

Finished items.jpg
Finished plated parts


My experience is that Replica Chrome is very robust if applied properly. An example being a kickstart I plated on my Triumph 6T restoration. After fitting it I found it would not clear the exhaust pipe requiring heating to red heat and then bending in two places to re-profile it. Expecting that it would then need re-plating I went ahead and did it. Imagine my surprise when the plating did not crack or peel and, having polished away some surface blackening, the plating was fine. Now I am not saying you will get away with such treatment but it does suggest the process can produce robust results.

With the Copper plating Kit I use you need to apply a flash coating of Replica Chrome before Copper plating as the Copper plate will not adhere to plain steel. Don’t ask my why but that’s what the instructions say. So a couple of minutes in the Replica Chrome, a good rinse, a couple of mins acid etch, rinse and then into the Copper tank. With Copper the plating is dull but polishes to a mirror finish. You can plate the Copper a bit longer if you are using it as filler, to fill pits or scratches, because if it comes out with a rough finish most of it will be subsequently ground / polished away. If using it as filler then after plating it is just a matter of rubbing it down with wet and dry until the pits and surface defects have all gone. Make sure you do not rub through the Replica Chrome layer below, as soon as you see it appearing then stop, fully clean the part, water break test, acid etch, rinse and then back into the Copper plate tank to build up more Copper. If you do polish through to the steel you can try a flash Replica Chrome plate before putting on more Copper. When you are happy with the finish, fully clean, water break test and then Replica Chrome plate.

With Zinc plating after a final rinse it is a good idea to ‘passivate’ the Zinc plate which gives it some corrosion protection. The Zinc plating kits come with the required chemicals for a clear/bluish tinged finish (like you get on commercially Zinc plate parts) and a yellow/gold finish like you get on some electrical components like ammeter cases and some Smiths speedo cases. The yellow can be a bit hit and miss and it works better if you clear passivate it first and dry it using a hot air gun. The Zinc plate can also be polished to a high shine almost like chrome, but this finish may not last long.

So now you know what is involved if you want to have a go at plating your own parts. In my experience the Replica Chrome process is the hardest to get acceptable results as the final finish is usually on parts that stand out on the bike and draw the eye, therefore the polishing process needs to be of a high quality. Zinc plating is more forgiving as it is usually used on such items as fasteners and spacers.
1939 VH Redhunter;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
http://cloggymoore.wix.com/triumph-pre-unit-6t

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alan.moore
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Videos

Postby alan.moore » Tue Aug 29, 2017 2:51 am

Here are the videos I have made in which I have tried to convey the basics of the written information.





1939 VH Redhunter;1951 Triumph 6T Thunderbird;1970 BSA B175 Bantam;1986 Yamaha SRX600 single
http://cloggymoore.wix.com/triumph-pre-unit-6t


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