Silvering testing continued

I tried something that should have occurred to me before now: using multiple layers of paint.  Obviously.  I get a much smoother, shinier surface with multiple coats of primer and chrome paint, 2-3 layers of each.  Now it's looking like a mirror.  It's still a very, very poor quality mirror (this brand of chrome paint will not result in a smooth chrome surface regardless of substrate smoothness) but it's reflecting more light and focusing light more sharply.  This is very encouraging.

Silvering test

I've silvered a couple of test objects.  They work as parabolic mirrors, although the main goal here was to improve my silvering technique.  The results are good enough that I think I'm ready to move on to fabricating a hand mirror.

Test objects

I printed up a couple of test objects to see how well a 3D printer could produce the substrate for a first-surface mirror.  Just a couple cm long.  Pretty good results, with some concerns.

- slump.  There's a real danger that the mirror will sag while bing printed.  Very bad given that I need soe degree of precision, especially if I'm building an array of small mirrors.  I'll need to take preventative measures in mirror design (vertical support for the curved surface from the bottom up)
- the thickness of the layers affects surface smoothness and slump

Next task: mirroring.  I've picked up some chrome paint.  Chrome paint has a pretty poor reputation for actually producing an even shiny surface so we'll se how it goes.

First you get the sugar...then you get the power...

Disappointingly, my PLA plastic has yet to arrive.  I'm wondering if it's been misdirected in shipping.  I'll need to look into it.

While waiting I had an idea: sugar.  There's precedent for 3D printing sugar objects, though my idea is a bit different.

Move the focal point of a mirror over a bed of sugar.  A point heat source can caramelize sugar; think of the way a butane torch scorches a creme brule.  Sucrose caramelizes at 160°C.  Having browned a 2D pattern, add a thin layer of sugar on top of the bed and repeat.  The layers should be thin enough that each layer fuses to the one before.  When all necessary layers are complete, the printed object can be lifted out of the bed of sugar, extra sugar being shaken off.  Might work.  One challenge: sugar darkens as it caramelizes, and a darker surface absorbs light better.  The rate the sugar is being heated would go up just when heat is no longer required.

Maybe I'm just feeling a bit bitter.

Handheld mirror: Plan A

So, here's the first proper test mirror I intend to make.  The plan:

- First surface mirror
- 3D printed PLA plastic substrate
- Off-axis mirror
- approximately 20cm x 20cm

Details inside

Every mad scientist needs a PhD

On Tuesday of this week I successfully defended my thesis.  Congrats to me.  I now have a bit more time on my hands to make mirrors.

Safe and stylish

Look what's arrived: 

My new welder's helmet.  I went with a #10 lens.  In direct outdoor sunlight I get a dim, green-tinted view of the world.  It's bright enough that I can see what I'm doing with my hands.  I wouldn't rule out the possibility of going to a darker #12, but I'm reasonably pleased.  This upcoming week is going to be extremely busy for me, but at some point I'm going to need to post my calculations of reflected light intensity to give a sense of why I thought serious protection was a necessity.

As a bonus, I'm now halfway to a fun Halloween costume: Darth Vader, of the planet Vulcan.