Good Oldie Moldie

A New Rubber Mold for the Electroliers.

The Electrolier/Line Pole Project is back on track with a new mold after the last mold failed.

This time I went with a more durable silicone rubber:

Smooth-On Mold Star. It only cost a couple bucks more but its supposed to produce a stronger mold. So we'll see.

So to recap, four useable lamps done when we last left off, and now 8 lamps to go.

Yes Sir! 8 to go!

Dandy

Oh No! The Rubber Broke!

Apparently, Rubber molds have a shelf life.

Half way through the casting of the street lamps needed for Grand Ave, the rubber mold decides to completely fail.

Now it could be I didn't use enough release agent. But the mold also cracked (Maybe the sun got to it? UV rays are so destructive!). So I'm sure its at the end of its shelf life.

So the next time I make a mold, I have got to make all the casting right away.

Yes sir- Right away!

Dandy

Well Whatdaya Know ~ All Rubber Are Not Alike

Quality Rubber - That's The  Secret Ingredient For A Successful Mold.

      What with the Backesto Bits already to go, its time to make a mold of them all. But when I went to go fetch the left over rubber compound from the Streetlamp Project, I found it has a short shelf life and had hardened.

Anxious to move forward with this project, I stopped by the craft store to pick up some of their casting rubber~ Amazing Mold Rubber. And after some time and effort, well... I found it ain't so amazing. I'm sure its fine for most crafts, but not for precision casting. In a nutshell, it shrinks!

Recycling the box from the streetlamp project, it turned out to be just the right size for this project.

There it is! In all its pink glory. Or so I thought.

The shelf life of the resin is much better. It cast just fine and faithfully with no shrinkage. But when I compared the castings with the originals, there was about 10% shrinkage with the "Amazing" rubber.

So, I'll pay the small extra for the much better quality of the Oomoo rubber compound. Lesson learned.

Yes sir! Lesson learned!

Dandy

It's De-Bubbly

The second casting utilizing EasyCast resin came out bubble free!

Since EasyCast casting resin takes forever to set, I took the time to remove every bubble before sandwiching the mold together.

And it worked! Not a bubble to be found anywhere.

Some resin dripped onto the end of the brass tube and solidified. I tried snapping it off, but its on there good and strong! I've been wondering how strongly the resin was holding on to the armature inside. Especially since it pops out of the rubber mold so easily. I guess that that mold release works really well because that resin has a hella grip on that brass! So I'm going to have to mill that resin drop off.

Next is trimming the flashing off the castings and then send them to the paint shop for painting. Finally some usable castings. Yes sir! Some usable castings!

Dandy

Light Cast

Looking for an easier way to cast these lamps.

Carving the lamp globes beforehand is tedious, time consuming, boring, wasteful, not fun, dull, waste of energy and time, not my favorite thing, noisy, dusty, etc...

And the shape of the globe is cast into the rubber mold, so why not cast it along with the rest of the pole? Seems like a no brainer to me.

I noticed that the last casting was glowing around the bottom of the globes. So I suspect that the Smooth-Cast casting resin is translucent. So I'm gonna do another cast, but this time fill the entire mold with the casting resin and forego the carved globes (after all the trouble I went through to get the correct size clear acrylic tubes!). And see how much light is emitted through the casting resin.

Wow! It glows just as brightly as clear acrylic tubing! Whew! So much easier than carving those globes. Yes sir! So much easier!

Dandy

Moment of Truth

Pouring the Resin Around the Lighting and Overhead Support Armature. And Hopefully End Up With A Reasonable Looking Streetlamp!

Here it is! From a virtual model and crazy idea to something I can actually hold in my hand! The freakin' thing actually turned out right.

Here is how it went:

Last post I had just finished building the support armature.

First the rubber mold needs a couple coats of mold release and allowed to dry. Then the armature is placed into the rubber mold into its precise position. That means bending and wiggling as needed to get it just right. (Note: I took this photo before I added the lamp globes).

Now its ready for the resin pour. I used Smooth-Cast resin from Smooth-on from the kit as described in this post. Just like the silicon rubber used for the mold, its mixing equal parts of resin and catalyst.

The top part of the mold (left) was poured first and allowed to set a bit while the resin was poured carefully around the armature in the bottom half of the mold (right). I'm not too concerned about using too much resin as I want to be sure it gets everywhere.

The resin in the top half has set enough (2 or 3 minutes) where I can flip the mold over. The two mold parts are keyed so that they almost lock together for perfect registration. I clicked the top parts of the molds together and then squished them together from top to bottom so that the excess resin is forced out the bottom (where the puddle is). 

The resin only takes about an hour to set fully. The thicker parts set first and the thinner parts take a little longer (the thicker part has more heat from the catalyst than the thinner sections would and so sets first). I knew it was ready to handle when the thin parts of the puddle had solidified.

The mold release allowed the mold to be pulled apart with no problem. And this is my first look at the lamp. And it looks like it worked!

The lamp peeled out of the mold with no problem. Most of the flash snapped right off. The rest required a little filing to get looking just right. Now the question is: Will it light?

It works! It actually works! I think this project is going to work out as intended! I mean some questions remain. How will it hold up to long term use as a linepole? How will the resin casting hold up with a brass armature inside of it over the long term? How long are those bulbs going to light for (I can't change burnt out ones!)? How is paint going to take to it? What am I going to use for power supply? 

But as it stands now, this crazy project is actually working out. I don't why I'm so surprised. But I am just giddy that this worked out. And its just a streetlamp. Not an Electroliner or something fancy like that. Just a streetlamp. But there it is all the same. A one of a kind model streetlamp.

Well then, one down and 11 to go. Yes sir! 1 down and 11 to go!

Dandy

Armature Nite

Building the Skeletal Framework for the Streetlamp that will Act as a Conduit for Wiring and Support the LEDs AND Trolley Overhead! Crazy Project I Know...

Built of brass, this armature performs three functions. 1. Support the LEDs so that the streetlamp will light up. 2. The brass tube is a conduit for the positive wires and the brass itself is the ground. 3. The loop at the top of this assembly is a tie off for the trolley span wires. Then this armature will be placed in a rubber mold and resin will be poured around it creating an ornate streetlamp! That's the plan anyway. Yes sir- that's the plan!

The basis for the armature is a 3/32" brass tube. A brass rod that has been drilled to accept a brass wire loop soldered on, is inserted into the tube just above where the holes for the wires are drilled.

The negative lead of the LED is bent and soldered to the brass. The positive lead is trimmed short and a thin wire is soldered on and then threaded down the tube which will protrude under the layout where the resister and electrical hookups reside. 

Okay! Now this next part turned out to be way too much work and is actually unnecessary! But I'll post it anyway for your edification and entertainment.

The resin will cover the bulbs so I milled lamp globes out of acrylic tube to fill in the space in the rubber mold.

The acrylic tube fits over the LED perfectly. An Acrylic rod is inserted in the top of the tube to fill in above the LED where the fancy curves of the lamp globe will be carved in.

 Using my Dremel Tool as a lathe. I have a chuck the fits snug inside the acrylic tube and the teeth bite in holding the lamp globe firmly.

Then spinning the acrylic a small file shaves it into shape.

Before and after.

Wholly Katz! Its lit! It works! This thing is actually working so far! This project might actually pan out after all.

Alright! Well! This is how the armature fits in the mold. Next week I'll pour the resin and we'll see if we get a respectable looking streetlamp. Yes sir! We'll see if we get a respectable looking streetlamp out of all this!

Dandy

Bubba Don't Forget Your Rubber

Making a Two Part Rubber Mold for the Streetlamp/Line Pole Project.

Even though this is a rather crazy project, the making of this rubber mold is pretty straight forward. I watched tons of YouTube videos on how to pour rubber molds until I was confident I knew exactly what I needed do. This video in particular comes closest to what I need to do, except that I'll be sandwiching a brass conduit and a couple of LEDs in the mold along with the casting resin (I told you this is a crazy project!).

I'm a beginner when it comes to casting, so I need everything, rubber, sealer, mold release, and casting resin. The guys on the Railroad Line Forums recommended using Oomoo Silicone Rubber from Smooth-On. Smooth-on offers a starter kit that has everything I need to make a mold and castings, so I went with that.

Last week I built this two-part mold box for the two-part mold (bottom part shown). Since the streetlamp master is suspended in the box I was tempted to fill the box with rubber just like that...

...but the rubber crept up the sides of the master and completely covered it in some parts. That's unacceptable for casting. I tried trimming it back when it set, but that didn't turn out too well so...

Take Two!

This time I'm going to do it the right way like all the instructions said to.

That means filling the bottom of the half of the mold box with clay, carefully working it up around all the details of the lamp right up to the half-way line. Packing the clay tightly against the master so there aren't any voids that will be filled with rubber. Some strips of clay protruding up will create a keying effect so that the two halves of the mold will snap together with some precision. 

The top of the mold box is attached and the whole thing is sprayed with sealer. After two coats and drying time, spray on mold release (clean the sprayers afterwards, mine clogged. Now I have to brush it all on!) and let dry. Now were ready for rubber!

To determine exactly how much rubber I need, I had filled the mold box with sand...

... and then poured that sand into the mixing cup. I marked its level with a Sharpie. Remove the sand, pour the liquid silicone Part 1 half way to the mark, and then part 2 the rest of the way. Mix well.

Oomoo is easy. Mix equal parts of A and B and mix it really well. A woman in one of the YouTubes suggested warming up the bottles a little first so that the compound is even thinner.

And then fill up the mold box and let set. So far so good!

Flipped the whole thing over and dug out the clay revealing the master and the first half of the mold. Success! Attached the second half of the mold box and then added the coats of sealer and release. Now were ready for the second pour.

Success! It turned out beautifully. The rubber captured the strata layers inherent from the 3D printing process perfectly!

Next week comes the crazy part: filling the two halves of the mold with resin and then placing the brass armature with LEDs into it and then sandwiching the whole thing together! That's the plan anyway. I told you this was a crazy project. Yes sir! Crazy!

Dandy