Lithoplate

[Piers Acland]

Is lithoplate just sheet aluminium?  If so, what sort of thickness or thicknesses does it come in?

 

Many thanks

 

Piers

[Cuban8]

I used to work as an engineer on small office offset litho machines back in the 80s and it makes me shudder to think about the hundreds of sheets of test plates that I disposed of and would be quite valuable now if only I'd had the foresight to lay away a few hundred!

They were aluminium but with a quite hard temper - thickness about 15 thou or so, but I suppose they come in different thicknesses to suit different applications. I'm no expert in using litho for modelling having only made up a few simple panels etc but I guess you could use thin sheet ali that's advertised on Ebay. I sure others will confirm or correct me.

Edited March 30, 2021 by Cuban8

[Don Fry]

It behaves just like case hardened aluminum, and it softens at the same blacken the smeared soap temperature when you need to beat it. So it’s going to be pretty pure. It used to come in all sorts of thicknesses, but do litho plate machines still exist.

[Nigel Dell]

Litho machines are in most high volume commercial printers, magazines and newspapers used high speed web offset litho with magazine covers generally printed on sheet fed litho, the plates are not pure aluminium but a zinc / Ali mix IIRC, the manner of how they are attached to the cylinder on the various presses they need to be pretty tough and hard wearing, also with the speeds of web presses 60,000 + copies per hour (for one copy per revolution) the main problem is splitting due I am pretty sure when things are not perfect on the machine and the plate work hardens, a set of plates generally I found lasted around 250-300,000 impressions.

the bigger the plate generally the thicker and higher cost, usually the machine manufacturer would recommend the specs on these and if I recall 30thou? or thereabouts was the general sizing for the bigger machines. (I can check this as I have a set of plates in my workshop that were for the A2 leaflet/poster I produced for the Vulcan Display team on the final air show year for XH558.

The dull grey on the face of the plate is the exposed light sensitive coating that the plates are produced with and wears through eventually with high use so get that off and it polishes up a treat.

The ideal plates for our use are the small offset plates unfortunately most of the shops at this end of the market have gone digital so the thinner plates will not be so plentiful in supply so if you find a good source make the most of it.

 

[Piers Acland]

Thanks all,

Very interesting and informative.

Piers

 

[Cuban8]

On 30/03/2021 at 11:43, Don Fry said:

It behaves just like case hardened aluminum, and it softens at the same blacken the smeared soap temperature when you need to beat it. So it’s going to be pretty pure. It used to come in all sorts of thicknesses, but do litho plate machines still exist.

I don't know for sure but the old small  litho (offset as we used to refer to it) process must   be pretty much finished now except perhaps for very long runs where I guess it would be cheaper. Out of curiosity I searched to see if any of the old kit I worked on (Gestetner 211, 311, 209 etc) is still around. They are about and are still worth quite a few quid.

[kc]

The aluminium used for some drinks cans could make a reasonable substitute for small panels on models, once you cut the can apart.

[Don Fry]

Am I missing something. I no longer use litho plate, local print shops don’t use the process, and I have run out. 
It was fine, free. But like most free things needed preparation.

Nowadays I use new aluminum sheet. It’s not that expensive in relation to how much I need, it’s ready to go, and .3 and .5 mm is as thin as thin litho plate.

[Nigel Dell]

20 hours ago, Don Fry said:

Am I missing something. I no longer use litho plate, local print shops don’t use the process, and I have run out. 
It was fine, free. But like most free things needed preparation.

Nowadays I use new aluminum sheet. It’s not that expensive in relation to how much I need, it’s ready to go, and .3 and .5 mm is as thin as thin litho plate.

Don, you asked if litho machine still exist, they very much do in the larger format and will do for the foreseeable future, small offset (print shops) are a fairly small section of the overall print capacity in this country (I am sure there will be those that might not agree), in fact about 5 years ago we had an over capacity, not sure how that stands now, print shops have mostly gone digital due to it being much quicker and cost effective and with of course the advancement in quality and technology.

[Don Fry]

No, I am grateful for the input of knowledge on the current state of the lithographic plate industry, and its variety. 

But back in the day we used litho plate because it was easy to obtain, cheap, what’s not to like. And needed preparation before use. 
Today, for not much we can buy new aluminum sheet, ready to use.
My point “Why mourn litho plate”.

[Nigel Dell]

On 02/04/2021 at 10:13, Don Fry said:

No, I am grateful for the input of knowledge on the current state of the lithographic plate industry, and its variety. 

But back in the day we used litho plate because it was easy to obtain, cheap, what’s not to like. And needed preparation before use. 
Today, for not much we can buy new aluminum sheet, ready to use.
My point “Why mourn litho plate”.

Sorry Don I missed your point, I totally agree with you, I prefer to choose the grade of aluminium to use.

[Phil McCavity]

On 02/04/2021 at 10:13, Don Fry said:

My point “Why mourn litho plate”.

Because it's tougher, thinner, has less resistance to collapse when forming a curve and less liable to tear when forming blisters, it's cheaper, easier to cut and requires the same prep to work and fix to a model as Aluminium sheet, it can also be used in situations not suitable for Aluminium such as head shims in IC engines. I've contacted a few local print shops who sell it by the Kilo, that quantity would last a single scale modeller a lifetime, several club members years or bring an eBay seller a tidy profit if they don't mind waiting for the return. ?

Unless I have a specific need for Alu sheet I'll choose litho over it.

Edited April 4, 2021 by Phil McCavity
Added another advantage

[Don Fry]

Err, look at the aluminum sheet industry, I think you will find stuff as thin as any litho plate. And litho comes work hardened. Soften before use. 
and as you say, a kilo lasts a life time. So we are not saving enough to buy that servo we drool over. I must be near death because I ran out of my boxful of litho plate years ago, and have never noticed the difference, since. Perhaps my dads old hammers and funny shaped bits of iron have magic qualities.

Now if I had a cheap source of thin litho, I would use it. Nice material, but just another aluminum. 

Dont know about engine shims. Never had cause to replace one. 
 

[Phil McCavity]

Err, aluminium needs annealing before working just like Litho, yes you can buy Alu sheet as thin but the properties of the equivalent thickness litho suit our purposes better. A kilo of litho plate is cheaper than a kilo of Alu sheet and I have no idea what the hammers comparison is about. If you really do desire litho plate then club together with others in your group to give you an affordable source.

[Eric Robson]

I used Fosters cans to sheet the top of the fuselage from the rear of the cockpit forward. I like a daily can of Fosters  so the aluminium comes free.  The gun troughs are aluminium foil from baking containers. The cowl is not aluminium.

Edited April 4, 2021 by Eric Robson

[Don Fry]

1 hour ago, Phil McCavity said:

Err, aluminium needs annealing before working just like Litho, yes you can buy Alu sheet as thin but the properties of the equivalent thickness litho suit our purposes better. A kilo of litho plate is cheaper than a kilo of Alu sheet and I have no idea what the hammers comparison is about. If you really do desire litho plate then club together with others in your group to give you an affordable source.

We will agree to differ. May your propeller remain unbroken.

[Charles Smitheman]

I have found a print shop that still uses the system. Yesterday I aquired enough sheets for my use. They are about 0.15 mm thick. There are two sizes about 20" by  15" and 10" by 15".

The shop is Coombe Stationers and Printers in Coombe Lane in Wimbledon. The owner is a gentleman called Asit.

He is quite happy for anyone to call him to collect some sheets. (And for me to post the details here)

I paid 50p for the smaller and £1 for the larger sheets.

 

I have been unable to source alu that thin or with that hardness elsewhere.

 

020 8947 8000 ask for Asit.

 

 

 

[Don Fry]

Try Google, search “0.1 mm aluminum sheet” or what ever thickness you want. There are alloys of aluminum as hard as you want. Consult the tables of properties. 

You won’t beat Asit for price, as long as the sheet size suits.

[Piers Acland]

Thanks everyone,

I will give Asit a call.

Piers

[Wilco Wingco]

Can you solder Litho plate or do you need some of these special aluminium rods?. 

 

[Engine Doctor]

You could possibly solder it with care but it's so thin and even a small kitchen blowlamp will melt it in the blink of an eye. Don't know whether the low 5emp stuff will work with an iron ? The demonstrators at shows often solder up a hole in a ali beer can so I guess it must be possible.

[Gordon Whitehead 1]

Aluminium can be soldered using a normal soldering iron of sufficient power, multicore lead solder and fluxite paste as follows:

 

1.  First you thoroughly clean the two surfaces to be soldered using wet and dry paper.

 

2.  Next you spread a thin layer of fluxite on both surfaces and abrade again with the wet-and-dry, ensuring that when you remove the wet-and-dry paper there is a layer of fluxite remaining to exclude oxygen from the air which would quickly re-oxidise the aluminium surface.

 

3.  Then you tin your soldering iron tip, after which you tin both surfaces to be soldered with multicore solder and the hot iron.

 

4. Next, bring the tinned alloy surfaces together and apply the iron to flow the tinning between them so that a joint is made.

 

I have not used this method on lithoplate, but have regularly used the method when making up packs of A123 cells sourced from cheap ebay-bought Dewalt 18V drill packs.  A123s have aluminium alloy cases.  The interconnections between cells used either copper wire, copper or brass strip, or even the existing connection tag material which solders readily. 

 

I have used A123 packs assembled this way in prop and edf-powered flight packs at over 60A; fuel pump packs; and even my 18V electric garden strimmer has a 5S A123 pack I made up for it when the short-lived NiMH pack gave up the ghost.

 

As litho plate is an aluminium alloy, it's probably worth trying the above method.