DIY RLT, takes 2 & 3

LouieAtienza · 2019-02-11T02:31:30.000Z

So I thought I’d try these semi-hemispherical baking forms. I bought these a few months ago and shelved them. Then I came across an older thread here where someone tried to use them, but remarked how they couldn’t get the surface shiny, and the aluminum was pitted. Upon looking at these, and that thread, it seemed the OP didn’t realize he had to remove the anodized surface off before it can be polished effectively. I removed the later with 320 silicon carbide paper. It’s important not to start too coarse or you’ll leave scratches that will be hard to remove, and only visible when your doing the later polishing. I progressed to 500, 1000, and 2000 Mirka Abralon pad, and finish sanded with 3000 and 5000 3M Trizact pads. I build guitars so I try to get as good a surface as I can after shooting my clear coat, which I use automotive paints.

It’s also important to pre-soak these abrasives, and wet-sand. Breathing the dust from the anodized surface is not good, and it can wreck havoc on the ways or screws of a mill or lathe - so you probably don’t want to sand these near machinery. But once you get through the anodized layer, the aluminum underneath is pretty soft, and sands and polishes beautifully and easily. I used automotive polishing compounds, then metal polishing cloths to enhance the surface.

LouieAtienza · 2019-02-11T02:33:58.000Z

There is a slight haze on the surfaces that is a residue from the polishing cloth. This gets removed with dishwashing soap and hot water. Not 100% perfect, but 95% cheaper than the real deal…

Pöbel · 2019-02-11T06:18:12.000Z

very nice. But will these be precise enough to focus the emitter properly? I guess you will show us soon

LouieAtienza · 2019-02-11T18:06:01.000Z

Thanks… and with the LED on low mode, yes. The question is whether or not when I step up the juice, how much stray light doesn’t make it onto the LED and illuminates other things inside the assembly - which may or may not look good. I did a spotlight build with one I made from a steel door knob, but the door knob had a small dent. I didn’t think much of it but that dent acts like a tiny lens and illuminates the whole chip - enough that at 40ft I can read the writing on the MCPCB and almost read the s/n on the White Flat!

Barkuti · 2019-02-11T22:27:34.000Z

LouieAtienza:

… I did a spotlight build with one I made from a steel door knob, but the door knob had a small dent. I didn’t think much of it but that dent acts like a tiny lens and illuminates the whole chip - enough that at 40ft I can read the writing on the MCPCB and almost read the s/n on the White Flat!

Cool! Just ask the implied parties some subliminal advertising royalties. :-D

^:)

DavidEF · 2019-02-11T22:39:35.000Z

Looking forward to seeing your results (beam shots).

LouieAtienza · 2019-02-11T23:45:28.000Z

Thanks…. Me too!