Super tweed

[guitarmike2107]

Apparently if you laser engrave anodised aluminium it leaves the engraved part white. so it wont fade but wont be silver. steve has it faded in the sun or just faded with time?

[Steve Conner]

Some misunderstanding here I think.

My nameplates that I bought from Weber have not faded. I don't know what the black coating they use is, but I don't think it's anodised. The bits etched away by the laser aren't white, they're shiny aluminium.

The nameplates on old tweed Fenders are aluminium with a brown background.

Amp Guide » Fender*Deluxe (Narrow Panel)

I assumed that they were anodised, started out black, and turned golden brown with age, like the faceplates on AC30s do. But now you mention it, I guess they could have been screenprinted with brown paint from the start. I might have got confused by the reissue Hot Rod amps, which had black nameplates very similar to the ones I got from Weber.

I had to buy a batch of them, 8 for $40, so I've used them on everything I've built since.

I've attached some high resolution pics, taken by daylight with manual white balance.

[J M Fahey]

Both the Laser engraved and old Fender are anodized, but engraved by a different process.
In the long (50 years +) run both may fade the same way.
Anodizing creates a very porous surface on aluminum, then it's submerged in a vat full of ink until saturated (which could wash away) and then those pores are sealed by submerging the plate in boiling water.
A transparent aluminum oxide appears which seals the pores.
The difference between "ink" and "Paint" is that the first is a *dye* dissolved in a liquid, be it water, alcohol or grease, a microscope will not show suspended particles, while Paint is a base transparent "varnish" which by itself already covers the painted product, having finely ground particles of pigment in suspension, not dissolved.
A paint is much thicker and stronger than an ink.
Inks often fade under exposure to UV rays (Sun), because they are organic molecules that decompose; pigment are far simpler metallic oxides and similar strong compounds.
Black ink fades into brown; black pigment is often ground coal or black iron ferrite which does not fade at all.
Laser engraved plates are first anodized black (or any other color); then a strong laser beam is focused into a hair thin ray, burning ink and leaving the silver aluminum background visible.
Old Fender plates and front panels used the very strong and durable "Photochemical" process, the same is still used in electric motor plates, fridge engines, cars, serial number and guarantee plates and the like, where you want an "indelible" text, resistant to time, chemicals, heat, etc.
They did cover the aluminum with a photosensitive emulsion (somewhat similar to the silkscreen one), expose it to UV light through a Litho film mask, and then proceed to anodize the plate.
Some parts would take black (or other color), some would not, creating colored text over silver background or vice versa.
Personally, since I silkscreen my own panels and PCBs, I can imitate the look by sandblasting bare aluminum to create a satin silver background (easier to read in bad lighting) and silkscreening over it.
Epoxy paint is *very* strong , I think modern Fenders use that, today faster and cheaper than old photochemical process.
I'd *love* to buy a laser head and adapt it to my partner's CNC machine to be able to home laser engrave.
He is using the CNC to make beautiful Mic preamps, he makes all holes *and* engraves beautiful script lettering on anodized aluminum front plates.

[guitarmike2107]

That’s some interesting stuff, I haven’t tried engraving anodised aluminium but every reference I have read on it indicates the engraved part is more white than silver. A normal lower wattage engraving machine doesn’t have the power to cut aluminium.

I have an engraving machine so I will have to try some samples, I think Steves looks like it is powder coated or something as it seems to have a texture and thickness in the first photo?

8 for $40 is a bargain!