Casting Fail

These Lamps Are Way Too Hard To Build To Have Failures Like This!

I can't tell you how disappointing it is to open the mold after 3 days of curing to find it to be a complete fail. It takes a better part of a day to build the armature and to pour the casting resin around it. It's too time consuming and costly to have this happen!

I'm not sure where I went wrong, I didn't do anything different. The only thing I can guess is that the resin ran when sandwiching the two parts of the mold together, creating these bubbles. Surface tension of the resin and no escape routes for the trapped air didn't allow the resin to fill in the voids. This clear resin takes much longer to set than the Smooth-Cast resin does, so its much more liquidy when to two halves of the mold are sandwiched together.

I'm amazed at how delicate some of these structures are. The resin stayed in the corners and edges creating this skeletal look. Unfortunately, I can't think of a way to save this lamp. The resin would have to be pried from the armature, which would damage it. Maybe- I could fill the voids with resin and put it back in the mold? Maybe?

So put it in the past and carry on. Since then I casted this perfect casting. This time I was sure to "paint" the sticky resin onto every surface of the armature before closing the mold so that it would be less likely to run away. And it seems to have worked! So- 3 useable lamps down, 9 to go! Sheesh!
Live and learn? Yes sir! Live and learn!

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

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