Making lenses from acrylic rod

[nickelplate759]

I got some Plastruct 1/16" acrylic rod for headlight lenses (about 10" in N scale, a little oversize for steam but workable - and it's the smallest size they make).

I need to cut it to length in such a way that it makes a serviceable headlight lens.  that means that it must be a square cut, but also the surface needs to be smooth.  I'm guessing that means I'll need to smooth the lens after cutting.   Anyone have techniques to share?

[wvgca]

sandpaper to get it close, rubbing compound to finish it ..
double sided tape or stickum on a skewer to hold it ..

[craigolio1]

Heat to pollish the end? Or a drop of gloss clear coat?

[peteski]

The 4-way nail buffer is perfect for this.  Use all 4 grits and you end up with a polished surface.  You can further shine it simply by rubbing it aganst a flannel shirt (which is what I often wear in my workshop.  If that is not shiny enough (I'm sure it will be), you can dab some clear gloss lacquer of your choice (including Future) on the polished end.



As for reducing the diameter, I chuck the rod in my Dremel and using a jeweler's file I file turn down the diameter (at slow speed). But I modified my Dremel's speed control, so it is capable of very slow speed. Too high of a speed will melt the rod.

[nickelplate759]

The 4-way nail buffer is perfect for this.  Use all 4 grits and you end up with a polished surface.  You can further shine it simply by rubbing it aganst a flannel shirt (which is what I often wear in my workshop.  If that is not shiny enough (I'm sure it will be), you can dab some clear gloss lacquer of your choice (including Future) on the polished end.



As for reducing the diameter, I chuck the rod in my Dremel and using a jeweler's file I file turn down the diameter (at slow speed). But I modified my Dremel's speed control, so it is capable of very slow speed. Too high of a speed will melt the rod.

Perfect!  I just happen to have one of those in my tool drawer, and hadn't thought of it.  That and a NWSL True-Sander (to get it square) was all I needed.

I did try also using heat to smooth it, but to get it warm enough to smooth over also made it swell up just a bit.

[Dave V]

Cool story, bruh, but can you make an acrylic rod from lenses?

[PaulCoats]

I do a lot of work with acrylic. 

To get a good square cut, roll the rod under an Xacto blade as you would to cut dowels.  Grip with needle nose pliers on
each side of the line and snap.  If you don't have a good end, try again.  If it is close, you can fix it.

On a good hard, flat surface (I use a piece of 1/2" tempered glass) place a piece of 800 grit silicon carbide paper grit side
up.  Hold the piece of rod with needle noses vertically, and just a few swipes will do it.  Repeat with 1200 paper.

Now here's a trick... turn the paper over, and rub it on the back of the carbide paper.  There is enough abrasive dust in
the paper to give a good polish.

Glue the rod in place with just a very tiny bit of Pacer Formula 560 Canopy Glue wiped inside the hole with a toothpick.  Press
in the rod, and wipe the inside of your new lens with a damp cotton swab.  This glue will dry clear. 

For HO you can do a flare with a flame... practice, just a quick pass through a lighter flame.  You may have to try more than once
to get it right.  A flare will be too large for N diesels, but just right for HO.  It is easier to do this before cutting it off to length.

You can use the same acrylic rod, heated in a flame, just one quick pass, to shape into a "light pipe" such as used on the Kato
HO C44-9W wor ditch lights.  You may have to do this more than once to get it right, but  you get a lot of rods per pkg.

You can join a "2 mm LED" to the end of such a light pipe with a short piece of heat shrink tubing.