Allum. Lithoplate adhesion question
 

I am building a 1/3 scale sopwith pup and purchased some Allum. Lithoplate from a local printer. When I purchased them the printer used a solution to clean the plates of there film. When he finished, the sheets still have a dull primer finish on them.

So I tried using some sand paper and they cleaned up to a normal allum. finish. (although they have swirl marks on them)

My Question is: do I need to clean this dull finish off of the sheets back side in order to get a good adhesion to the wood? If so is there a better way then using sand paper? I tried mother allum. polish and it does not work.

I plan to use 3m super77 spray adhesive.

Is that the best way?

Please help. In the garage right now scratching my head?

Thank you for the help!!!

Mike,

RE: Allum. Lithoplate adhesion question
 

I’d use acetone or finger nail polish remover if I were you.

RE: Allum. Lithoplate adhesion question
 

I will go try that right now.

Thank you,

RE: Allum. Lithoplate adhesion question
 

So I tried the nail polish remover. Main ingredient was acetone.

it did make it feel very clean, however did not change the finish. maybe the finish is normal but it looks like the color of a light grey primer or maybe a powder coat.

So far, paint remover, denatured alcohal, acetone, soap, silver polish, mothers allum. polish and one other polish and no change to the color or finish.

when I sand it with a few different grits it seems to come to life and I can get the allum look (ie polish) that I am used.

I guess I dont need to worry about it if the finish is truly clean, all should stick well...

RE: Allum. Lithoplate adhesion question
 

mpriestly,

Not sure if you have solved your problem yet, but this may help. Are you referring to the printing side of the plate, or the bare aluminium side? If the printer has "cleaned" the printing surface, then you are half way there. I think your problem is that lithoplates are anodised. Anodising is a hard oxide "film" over the surface of the aluminium, which is very hard. You need to remove this "film" before any polishing will be successful. Try soaking the sheet in Draino for about 45 minutes, or another producthat contains Sodium Hydroxide, like oven cleaner. This will etch away the anodised surface, leaving the aluminium intact. You will initially have a dull grey surface, but it will take a polish much better than before.

See here: http://www.secondchancegarage.com/public/665.cfm

Regards,

James.

RE: Allum. Lithoplate adhesion question
 

Hi Mike,

I used quite a lot of litho on my Glenn Torrance Hanriot, and I just scuffed up the grey side and glued the litho to 1/32 ply for the side panels. You will find that after the glue has set the panel edges can be sanded, litho and ply together. The ply gives the litho a little rigidity but if the glue is not smoothly applied, any lumps will show through the soft litho...not all bad though, it actually looks more authentic. I did anneal my litho in a 500 degree oven for about 10 minutes. This makes it very soft and it will form over nearly anything. You can even roll it over the edges of the ply, so no wood shows at all. My build thread is still on RCU, just search gtm hanriot build and the litho action is on about page 7...I think I used contact cement to adhere the litho to the ply, but I might have used thick CA.....try a couple of test pieces....

Randy

RE: Allum. Lithoplate adhesion question
 

You can glue the "dull" side of the sheet to the model as-is, it sticks fine and doesn't seem to peel. I've used contact adhesive and CA with no problems. Just polish the "outer" or visible side, with fine steel wool.

Cam

RE: Allum. Lithoplate adhesion question
 

you could always soak it in Coca Cola overnight. You will be amazed at what that stuff will "clean" Try soaking some old coins in it overnight. Next day they are like new.

Makes me wonder what it is doing to my guts too [:-]
cheers
Peter

RE: Allum. Lithoplate adhesion question
 

Randy,
very impressed with your skill in shaping the lithoplate around that complex curve on the cowl, would love to learn how to do that. Any tips?

ta
cheers
Peter

RE: Allum. Lithoplate adhesion question
 

Cam,
Have you tried to give the litho plate a "mirror" finish? I am trying to replicate the polished finish on a Ryan STM-2. I have not started yet, but have heard that it is hard to polish litho. I have read that it is anodised, and that may be why most people tend to sand it first and then polish.

James.

RE: Allum. Lithoplate adhesion question
 

I've only ever "polished" it to a dull "natural" aluminium finish as that was all I needed (like the photo above). If you want a nice shiny finish, the self-adhesive aluminium films like Flitemetal are probably easier to work with, if your surface prep is good.

Cam

RE: Allum. Lithoplate adhesion question
 

Actually the product is "foil" as it is aluminum and not a plastic film. Yes, the
Flite-Metal product will polish to a mirror finish with little effort due to its alloy
being work hardened as it is applied and massaged in the slurry of polishing
compound containing high levels of pumas.

Try Mother's and the Metal Polish available at Pep Boys in the plastic bottle
with the metallic label on it.

Remember never polish aluminum on a model until it has been completely
covered because the micro size aluminum will contaminate any uncovered
surface.

Additionally, after finishing the aluminum surface to the texture and color of
aluminum needed to replicate your documentation...wipe it down with Cape
Cod Silver Polish. This inhibits oxidation preserving the finish you've achieved
with citric acid (fruit juice), tobacco stain (cigar ash), and Uncle Bob's Hot
Section Paint.

Hope this helped your surface achieve your desired result...;)