I have many out of date plates that are copper mounted on magnesium.
Does anyone know a good way to separate these so they can be recycled?

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I believe most of those plates are glued on and the glue bond can be softened by heating the plate. I would try a heat gun, or putting the plate face down on a hot plate and then pry apart (wearing gloves of course. Do NOT use open flame-as the magnesium could ignite!

One place i worked the boss was taking home a lot of old mag dies mounted on wood, what he didn’t tell us was he was going to burn them in his fireplace, he nearly burned down his house, that stuff will catch fire easily and then water doesn’t put it out.

The magnesium plate makers in Nashville had a standing order with the fire department to not fight the fire. Trying to pour water on a magnesium fire will cause an explosion. You can use lacquer thinner to soften the glue used on mag plates. But please do it outside, with safety glasses and gloves, and no open flame. The copper should actually peel off.


The engraving shop I managed had a 5-gal container of a powder designed to smother a magnesium fire. We kept the lid loose, so it oculd be used at a moment’s notice. We never had to put it to use, but always worried about it.

John H

Keep in mind that the copper coating on top of the magnesium is almost microscopically thin, so if the intent is to salvage the copper for it’s value, there simply isn’t enough there to warrant the trouble.

As I recall from Vietnam, it takes an enorous amount of heat to ignite the magnesium - almost white-hot flame, so I am skeptical about tossing it into the fireplace to get it lit.

On an aircraft carrier, if a magnesium fire occured on an aircraft (generally the mag wheels) - it could not be put out and would literally start burning right through the deck. The procedure was to have a huge tub full of sand underneath on the next deck down so that when it melted through it would fall into the sand and the whole works could be quickly removed and thrown over the side (big explosion when it hit the water!)


Rick, after my bosses problem there was a man i worked with that said the same thing as you, so i took my line gauge and scraped some flakes of mag off a die, put the small pile on our cement floor and tossed a match in it, no one could believe how hot it burned, not even me, there was about a tablespoon of mag.

I guess I assumed the copper that SteveO54 was talking about was a full 16ga. copper plate mounted on the base with thermal adhesive. In that form, it would be worth recovering for scrap if the volume were high enough.

I can attest to the fact that throwing some scrap magnesium into a fireplace can start one heck of a fire. Perhaps it is the alloy of magnesium used for engraving, but it starts quite easily.

It is quite likely that the mounting base is not magnesium, but rather aluminum. It would have been less expensive to use and almost as light for the application.

John H

Quite an interesting turn on an otherwise mundane thread.

Magnesium catches fire at 880 degrees, and burns at nearly 5100 degrees, more than double the temp of melting steel. Oxygen rich alloys lower the ingition temp, and increase the burn rate.

One of the reasons I prefer to use zinc.

This mornings’ price of scrap copper: $3.7955/lb.
A U.S. cent (dated mid-1982 and prior) has a melt value of .0250342, (2.5+ cents each).
A roll of fifty cents from 1909 through mid 1982, melts at 0.0325 copper and 0.0171 zinc, and is valued today at $1.25/roll.
A 1000 copper pennies = 6.5128 lbs.
Of course it is not legal, nor profitable, yet, to melt them in the US.

You can use a hairdryer to get double sided adhesive off a mag plate, and to separate a mag plate from a base.

Can anyone help with magnesium recycling in the UK? I can’t seem to find anywhere that will recycle use magnesium plates, even the companies that make the dies do not know what can be done with them.

Any help with this will be very much appreciated.

Hi SteveO54,
As mentioned, if you can heat the dies to about 250 degrees F, they will be easier to separate. but even cold you can separate smaller dies hitting any kind of chisel or strong ink knife with a hammer right at the joint between the two metals and pry them apart. Strongly suggest you use thick gloves and eye protection.
Magnesium fines, or shavings, will ignite easily and give off toxic, corrosive fumes as well as ultraviolet light that can damage your retina. If the metal is in larger chunks it is very difficult to get hot enough to ignite. Pouring water on a mag fire creates a hydrogen explosion. Very dangerous. Smothering with silicon or sand is the preferred method of fire suppression.
In the Washington, DC area there are several scrap yards that will pay for scrap metal. It is big business and there are many yards across the country that are coming under scrutiny for buying copper illegally salvaged from abandonded houses and construction sites, etc. Suggest you google scrap yard to find a local company.
Good luck

Yes I did find a local scrapyard to take it in the end, so thanks Bruce.

The scrap metal dealers I spoke to in London were all pretty surprised to hear from a printer needing to recycle magnesium, it’s obviously not a regular request!