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how to prep bare aluminum

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painterjrm

New Member
I am applying some IJ35C to some bare aluminum panels to retrofit a backlit cabinet. How should it be prepped to insure long exterior life? The 3M tech bulletin says the film can be applied to metal, but does not say how to prep. Wax and grease remover? Isopropyl alcohol?
 
HIGHSPEEDGRAPHIX

HIGHSPEEDGRAPHIX

Rog
Just clean it good with alcohol. Sticks well to Mill finish Alum. I like to spray with a little windex or soapy water (zep bottle with two drops) and use a window squgee to remove the water after i wipe with paper towel, gets any lint or dust missed you dont get those uggly dust specs, tac cloth work too.
 
2B

2B

Active Member
painterjrm said:
I am applying some IJ35C to some bare aluminum panels to retrofit a backlit cabinet. How should it be prepped to insure long exterior life? The 3M tech bulletin says the film can be applied to metal, but does not say how to prep. Wax and grease remover? Isopropyl alcohol?
Click to expand...

If it is mill finish then yes it does need to be cleaned GOOD

Usually a couple of cleanings will do,
first is done with RAPID PREP then a mix of Isopropyl alcohol and keep doing this till the lint free paper towel is clean and shows no dis colorization

 
Techman

Techman

New Member
mill finish aluminum will always tarnish. Always has always will.
It will eventually cause the vinyl to fail.
It is usually anodized to prevent short term changes.

When cleaning it with whatever concoction all that black is tarnish. You can scrub it down to clean all you want but it will tarnish again. Clean it today and next week it will show black again.
 
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painterjrm

New Member
Thanks. I understand the black residue is "aluminum oxide", yes? Is it better to seal the surface with primer and/or paint before applying film?
 
TXFB.INS

TXFB.INS

New Member
why are you using mill finish?

Since you are dealing with a cabinet sign why not use a grade of aluminum that has a baked enamel surface for the longest life span. Typically we only use mill finish when it is thick.

we have mill finish .125 that has had vinyl on it for YEARS and no issues (knock on wood)
 
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painterjrm

New Member
It is a 42" x 13' cabinet with cutout letters. I had the letters cut via waterjet, and legs bent around the edges to retrofit the cabinet. Material is .125".

Here's another question: my plan is to apply the film, cut out letters, then affix trans white acrylic to back. The vinyl will want to pull away from the letter cutouts... shall I seal the edges of the letters with liquid overlaminate to prevent curling? Perhaps airbrush some liquid overlam on the bare aluminum around the letters first, then apply film?
 
Mosh

Mosh

New Member
I like to spray with a little windex
Click to expand...

Windex is the worst thing to put vinyl on with. it has amonia in it. Even the
"normal" windex has some not just the windex with amonia...
 
skyhigh

skyhigh

New Member
Every speed limit sign (caution, curve, route# ect) you see on the highways is vinyl on mill finish.

Clean with xylene...rinse...dry....wipe with alcohol.....apply vinyl.
 
Techman

Techman

New Member
Every speed limit sign (caution, curve, route# ect) you see on the highways is vinyl on mill finish.
Clean with xylene...rinse...dry....wipe with alcohol.....apply vinyl.
Click to expand...

Every highway sign is not standard mill aluminum. Well the legal ones anyway...

It is usually a high grade alloy of at least DOT 5052-H38 or of several others in that grade level. It is a high density metal heavier than regular mill aluminum.
Do not use strange home made weasel **** concoctions because it could promote a negative reaction. Use the correct cleaners. Many have a coating on them as an added protection.

It is much harder than mill aluminum. Is also used for aircraft skin and rivets etc.
It is a specific alloy made to resist corrosion and is treated in several ways to prevent curling, warping, vandal bending etc.

Street signs are not supposed to be made with novelty grade mill metals and must meet a guideline, I do not remember the standards but there is one out there..

Some may wish to check the specs to make sure the local officials allow cheap low grade novelty metal for a street sign.


Most..Extruded sign cabinets are made from alloys suitable for making Extruded parts. They are not made from regular mill aluminum either. There may be a few incidental parts but the frames are mostly an alloy..
 
Pat Whatley

Pat Whatley

New Member
What Techman said. Don't use the mill finish if you can at all help it. I covered six 4' x 8' mill finish panels with prints a couple of years ago. Cleaned them with denatured alcohol and Rapid Prep first, mounted the panels and they were stuck like they'd been printed on there. Two months later I get a call that the graphics are coming off. Sure enough they'd started to peel from the corners and you could see the film on the back of the prints. I blamed it on the summer sun and poor cleaning on my part. Redid them, literally scrubbed them with a brush and soapy water and alcohol and got them squeaky clean. Mounted the new prints....two months later they were rolling off.

White enameled aluminum isn't much more and worth every penny.
 
Techman

Techman

New Member
found this to share


Mill finish is the natural finish that aluminum extrusions have as they emerge from the extruder die. It's basically bare aluminum. Mill finish will oxidize with a light white powder (aluminum oxide) as it is exposed to air and moisture. It can oxidize a lot under very moist or salty conditions.

Anodized rail is pre-oxidized in a controlled environment, which creates a very thin but very hard natural barrier to corrosion. If the anodizing is kept intact, it can resist a fair amount of moisture and even salt in the air - this is why anodized parts are always suggested for corrosive environments.
 
skyhigh

skyhigh

New Member
skyhigh said:
Every speed limit sign (caution, curve, route# ect) you see on the highways is vinyl on (replace with) STARTS OUT AS mill finish.

Clean with xylene...rinse...dry....wipe with alcohol.....apply vinyl.
Click to expand...

My correction for Tech....
Anodized or painted is what should be used, but...... If I had a piece of mill finish and wanted to apply vinyl, then I would clean with an acid wash (and feel comfortable the job would not "peel off" like Pat experienced). Street signs, as tech said, are a different grade of material (but that really doesn't make much difference when the conversation is about adhesion.....Not Strength)


Seems everyone is resurrecting old threads these days.
 
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