Aluminium plates

I know .plates are usually photopolymer, Zn or Mg or lead or timber.
Why not aluminium? Has anyone tried it. Is it too soft?
It is a lot easier to get hold of here than any of the above and would be relatively cheap
Muddy

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That is an interesting question.

Photopolymer plates are light sensitive plastic. You expose them with a negative and then wash them out to get the relief we need for letterpress.

Zinc, Mag and Copper plates have a light sensitive coating on them. You expose the coating with a negative. The light “hardens” the coating where the image areas will be, and the coating in the non-image areas is removed. The coating forms a “resist” to keep the chemical etches, which etch down the non-image areas, from attacking the image areas.

Lead type (or more properly type or stereotype metal) is cast in molds.

Wood type is routed (or in rare cases, carved).

Now to your aluminum. Since it is relatively close in characteristics to magnesium, I suppose the most logical assumption would be that it might be possible to acid etch it. Dow Chemical (I believe), perfected and commercialized the powderless etching process for magnesium. I am guessing that there must have been a good technical reason that they did not come up with a process for aluminum. DO NOT TRY TO CHEMICALLY ETCH ALUMINUM…IT COULD BE VERY DANGEROUS!

It might be possible to laser engrave aluminum. However, aluminum is a pretty reactive metal, and before trying it, you should ABSOLUTELY, WITHOUT FAIL, find out from some really knowledgeable people whether this would be safe and successful to do.

I think you could mill aluminum with a CNC milling machine.

Unfortunately, I have still not answered the question about why aluminum has not been used as a plate material (image carrier). Hopefully others will be able to shed more light on it……I am interested too.

Hi Geoffrey
etching isn’t a problem if done by electrolysis, have done it for large letters. It is safe.From memory Al lies in the periodical table between Mg and Zn so their characteristics should be similar.
To do the small letters under 10 -12 point may be tricky and I would have to do some experimenting
Am in Australia and any photopolymer, if not bought in large quantities, has to come in from overseas, so I am looking for alternatives.
I did foiling years (8+) ago using a windmill and since that time magnesium plates have more than doubled. It would nice to be able to do plates with easily available local material
Kerry

Australian plate suppliers, like Melbourne Etching Supplies, et al, have a bewildering stock of metals, plastics and woods available (presensitised and/or uncoated).
http://mes.net.au/products/subcat-30-32.php
http://www.e-artstore.net/etching.html
With regard to Aluminium: Suppliers (and even the local hardware) have a wide range of polished or anodised facia strips in different widths, cut to length. Aluminium can be covered with a preprocessed-sandblast-photopolymer (Rayzist, ImagOn), or DIY stencil, then sand-carved, etched, or photochemically-milled.
If you want more details on Al-etching, contact me.
John (AUS).

to muddy and others:

I would not venture an opinion, except to say that the person who put magnesium plates into a fire was very lucky; can you find a friendly industrial chemist? We all know that aluminium [aluminim] is a very reactive metal. But it has certain properties which make it very useful. Aluminium on steel backing is used for offset printing in some processes. I do not have my chemistry books at my present residence, suggest you spend a little time looking at library. —- Alan.

there are small digital engravers widely available-experiment with these to see if get sufficient relief on sheet ali(what grade would be important for clarity of letter etc) then mount on backing ..try half tones too?….useful for small platten presses, visitor cards, so long as it is looked after as ali oxidises especially in damp atmospheres. Have etched ali. with caustic soda and ferric chloride , but really it only produces textural effects and not sufficient detail, very messy too and of course fumes and risk of burns from caustic soda, very volatile this way-I did it in a proper fume cabinet. has anyone recently tried to recreate the famous borders- metamorphic? -and similar by J F Earheart of artistic printing fame , or do any survive?

to johnathonjeclipse and others:

Depending on my memory, but I seem to remember that aluminium [aluminum] and caustic soda makes straight hydrogen [high schoolboy’s experimental chemistry at home]; any industrial chemists out there?

Alan.