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Meccano restoration

For many Meccano enthusiasts, the joy of model building is reduced by the look of their parts.  In the past, you could buy some new ones, but that's not an option today!  Most of the Meccano parts that are for sale, and certainly all of the reasonably priced parts, are in poor condition.  But all is not lost!  You can restore old Meccano to make your models look great.  Be warned, however, that restoring your Meccano will almost certainly devalue it.  And if you have any very rare parts you should probably avoid restoring them at all. 

But it is your Meccano, after all.  So if you like, just go ahead.  There are many people with many different methods of Meccano restoration.  I'm going to describe how I do it, which may not be the best way but it works for me.  To see the final result, click on "Home" above.  All of the parts in that blocksetting crane have been restored using this method.

Preparing the parts

The first stage is to strip off the old paint.  This will depend upon what paint you already have on the parts, but you can work this out as you go along.  Modern blue and yellow parts will need to be stripped using paint stripper, and zinc has to be treated differently too.  We're starting with the easy ones: all the red and green parts and all the blue and gold ones.  This method also works for some yellow and blue parts too... 

The paint in question is very easy to strip, and the easiest way is with Sodium Hydroxide, commonly known as Caustic Soda, which used to be known as 'lye' (and still is in the US, I gather).  It's normally sold as drain cleaner.  Try to buy plain sodium hydroxide – you can get special drain cleaners with extra chemicals in them, and fancy names, but they tend to be more expensive and I've not found them to be as good.  The straight stuff is cheap and works well.

Find a plastic or tin tray, fill with parts and pour in some HOT water.  Straight from the kettle. I've found that the stripper works much faster in hot water, and the temperature is much more important than the strength of the solution.  You can get away with using a very small amount of sodium hydroxide if you are prepared to work with hot solution.

It's at this point that I should probably warn you that all these chemicals are pretty nasty. Sodium hydroxide solution is caustic and will make your hands sore fairly quickly.  But we're not on a site subject to American law here so I don't have to assume you're completely dumb I hope. Be careful, use heavy rubber gloves, make sure that kids are well out of the way and that your shed can be locked securely when all this stuff is in use.  Anyone trying to do this in the kitchen is almost certain to be a single bloke, so you just carry on and do it how you like... 

I've found that wide paint roller trays are 330mm wide.  The sharp mathematicians amongst you will have figured that this is just a fraction under 13 inches – ideal for most Meccano parts! The sloping tray allows you to remove and inspect parts easily, and slide them back into the solution until they're done.  So, with your parts in the tray as per the photo (those red girders have been painted by the previous owner in the past), pour in almost boiling water to cover them and put in a little caustic soda.  A tablespoon should be enough, at this temperature.

Whoosh! See, the water is turning red already.  Ordinary parts strip in about a minute or two at this temperature, whereas it can take hours when the solution is cold.  However, you can safely leave your parts in here as long as you like – several days if need be.  I'll mention during this page where you can stop and where you can't – which is helpful when you're doing several batches, but might not be able to get back to work on them until next weekend.

You don't need to use a new batch of caustic soda each time. I have now moved on to using a portable barbeque in the garage with a large steel tray of the solution. This way I can re-heat the same solution, just topping up with water as required. Extreme safety precautions should be taken when heating tanks of caustic soda, of course! I have spilt a small splash of boiling concentrated caustic soda on my hands (although strangely in completely different circumstances!) and even though I was able to put my hand under a cold tap within less than a couple of seconds, I lost the skin on two fingers for a couple of weeks. It doesn't bear thinking about what it would be like to get this stuff on your face.

Once the paint has come off, rinse the parts in water.  You'll see when you do this whether any parts haven't stripped completely.  Put those back in the tray for next time, or give them a little more time.  Rinsing the parts stops the solution in the next stage from getting full of paint residue, and helps you see how good the parts are.  You shouldn't stop at this stage, otherwise the parts will start to rust.  Not the end of the world though, as we're about to fix that...

Zinc, yellow/blue, and other paints that are still on...

If you're stripping zinc parts, you can't use caustic soda.  The easiest way I've found is to use hydrochloric acid (I'm told you can also use sulphuric acid).  Hydrochloric acid is easy to get hold of – in a DIY store it's with the cement and is called "Spirits of Salt", or in a pool shop it's called "pool acid".  Both will be strong (about 33% solution) hydrochloric acid if you read the label.  Five or ten seconds in this will strip zinc instantly, along with its corrosion and other nasties.  You will need good gloves though! Immediately remove it and rinse well in clean water.  All normal precautions here, but doubly so...  on the other hand it is very quick!

Some parts, particularly post-1980 ones and lots of yellow flexible plates, won't be stripped with the caustic soda.  You can always try, but some just won't budge.  Similarly with some paints that have been used by previous restorations.  You'll need to use paint stripper, and rinse with whatever it suggests on the tin (water or meths), then you can carry on with the next stage.

Rust removal

Now we have a lot of bits of metal, with varying amounts of rust on them.  Apart from removing any rust we do have, we have to prevent rust in the future.  One way is to use a primer, but I prefer not to.  More about that later.  Also, we are preparing the surface for painting, so you can start here if you have brand spanking new parts from Nikko.  If you try to paint directly on new parts, you'll find the paint comes off very easily.

You'll have to look around in your local DIY store for the next product.  The one I've found is shown in the picture, called "Tergo rust remover and metal conditioner", which you probably won't be able to find outside New Zealand.  The most important component you're looking for is phosphoric acid.  This product also contains some other stuff, which it doesn't tell you about.  The phosphoric acid is the most important part, though.

You'll notice we're in another paint roller tray.  Of course, they'll fit perfectly! Check the instructions on whatever you buy – this product mentions that you can wipe the product on directly, but also states that you can dilute and soak the parts.  I use about a 10% solution (1 part rust remover to 9 parts water), roughly.  It's not too exact.  As it evaporates I top up with water, and when it stops doing its thing I chuck a bit more rust remover in.  A tray of this solution will do dozens of batches of parts.

This is one of the stages where you cannot leave the parts! You will need to leave the parts in for at least 10-20 minutes, and probably up to about an hour.  If you use warm water, you can do it quicker. You'll see tiny white bubbles creating a slight foam on the surface as the solution does its stuff. But if you leave parts in here overnight they'll get pitted and will be permanently damaged.  Of course, you still had your gloves on from taking the parts out of the caustic soda, didn't you?

With your gloves still on, transfer the parts from the roller tray of rust removal solution into a new plastic box with an inch or so of water in the bottom.  If you leave the parts exposed to the air when they have been in the rust remover, they'll go a horrible black.  The tiny amount of rust remover you transferred with the parts makes this new tub into an extremely dilute solution of the rust remover.  You can therefore safely leave these parts now for as long as you like.  If you leave them more than a day or so, they get more difficult to clean up.  If this happens, dunk them back in the rust remover for a minute, and back into the water.

Final cleaning

Now we clean each part in turn.  The solution we have them in is extremely dilute phosphoric acid, which isn't too dangerous but makes your hands stink for hours.  I now change to a pair of disposable latex gloves, which you can buy in boxes of 50 or 100 at a time.  Heavier gloves make handling the parts too tricky.

Take out each part, and scrub both sides with grade 0000 (very fine) steel wool, that has been dunked in the tray the parts came from.  I do this on a lump of hardwood, which works for me.  Radio on, comfortable chair, it's quite a therapeutic exercise.  This scrubbing will remove the residue that the rust remover left (and any rust), and will gently score the surface ready for painting. 

You'll be amazed how good the parts look at this point.  But they still have dilute rust remover on them, so you can't leave them out in the air for long.  As you do each part, drop them into another bucket with a couple of inches of clean water in it.  They will stay safe in here for an hour or more without gaining new rust.

Rinsing and drying

The next stage is one that many people haven't mastered.  It just needs care.  The objective is to get the parts clean and dry, without letting them get rusty. 

These parts are now absolutely bare steel, etched ready to paint. If you let them dry out, they will be covered in a light dusting of rust immediately.  This 'flash rusting' happens at the junction of the steel, the water, and the air.  As a drop of water dries off, it leaves a 'tide mark' of rust behind it.  So we have to remove the water! And we also have to remove all traces of the steel wool, which has probably left behind tiny flecks of steel that is particularly prone to rusting.

So the first thing is to rinse the parts well.  Several times.  I just use a hose in this latest bucket.  Empty the water out, and refill with clean water from the hose.  Repeat three or four times, swilling the parts around.  Now all the junk will be gone.  All we have to do is get rid of the water.

Yet another bucket is ready and waiting for us.  Did I tell you how many buckets we'd need at the beginning? No, sorry about that.  This is another of these large plastic boxes that I've found essential for this restoration procedure.  This box is absolutely clean and dry. Now I do a final rinse in methylated spirits.  Pour an inch or so of meths into this clean box, and transfer the parts from the clean water to the meths (shaking off excess water).  Swill the parts around, and then transfer the parts out of the meths into an oven tray with a paper towel in the bottom.  Shake off the excess meths, you don't want the place swimming in it! The parts are now wet with meths, rather than with water.  You can now carefully pour the meths back from the bucket into the bottle again, and use the meths like this again and again.  If you make sure you don't transfer too much water into the meths bucket, it'll last longer.

Now I put the tray of parts into a cool oven (not a hot one otherwise the meths will catch fire!) Perhaps 40-50 degrees C.  Drying the parts quickly helps avoid any tarnishing.  After five or ten minutes the parts should be dry and clean.  You can transfer these into a box ready for painting.  If you're very picky use a new disposable glove for this stage, which will mean that the parts are absolutely clean.  If the parts have rusted, you didn't rinse them well enough.

You are now at another stopping point.  I get lots and lots of parts up to this stage, and provided you keep them in a warm dry place (i.e.  a heated house, not outside in the garage), they will stay clean and perfect for months.  You can then select the appropriate parts for each batch of painting, and make the most efficient use of the painting process. Click here to jump to the next page, painting the parts.
Click here for a page on plating brass and nickel parts.