Finished with casting drivers

After a couple of do-overs, I’ve finished casting the drivers for 622. It has not been a fast process, but at least it works, and I believe it results in a reasonably good wheel. I really should have remastered the mold before starting, as every wheel needed a little carving to account for overzealous application […]

Any wheel I want

Looking back on 2018, it would be easy to despair about the amount I didn’t accomplish on Pembroke. Two floods put a damper on things (so to speak), and many non-rail projects also ate my year. However, the singular achievement of the year came on January 1st of this new year, when I pulled the […]

Insertion cast wheels

On Wednesday, I managed to get away from the Christmas concerts for a meeting of the North Shore chapter of the local NMRA division. It was Graham Stokes’s annual “Trains and Scones” evening, and as usual he had a little table to show off progress on our current projects. I wanted to show the wheels, […]

Wanted – pressure vessel

Readers of this blog will know that it is unusual for me to admit defeat. Usually, I will doggedly pursue an idea until everyone has pretty much drifted off to cat videos, except for a few readers who check back to shake their heads and mutter such things as “he had so much promise.” However, […]

Perfidious air

The past couple of weeks have been all Christmas gifts all the time, but tonight I finally managed to get few minutes to spend on my projects. With the heavy shop out of action until we rebuild from the flood, I’m reduced to the crowded garage floor for heavy shop work. I’m still working toward […]

Closing in on wheel castings

Thanks to Brian Pate, and to Don Mitchell who suggested I call him, I’ve started vacuuming my castings when I pour them. Brian indicated that he liked to vacuum before and after pouring, but I’ve found the pre-pour treatment makes little difference. The post-pour treatment, on the other hand, dislodges all sorts of bubbles from […]

A good effort at pressure

I’m still grappling with the problem of bubbles in my castings. The accepted wisdom indicates that you want to set polyurethane castings under pressure so the bubbles become very small. I think the Smooth-on site suggests 60 psi (413 Kia). Not having anything that holds pressure, and not wanting to spend a lot of money, […]

Bubbly bolster

The wheel plan for 622 requires perfect castings. Unfortunately, every attempt so far using my test molds has resulted in large bubbles. These bubbles are not there when I pour the resin, but seem to be forming during the curing process. According to the Smooth-on website, this could be due to humidity, and I should […]

Solvent fail

I should have known I was in trouble when the Tamiya cement so reluctantly entered the syringe. But, my trusty MEK Pak has finally breathed out the last of whatever makes it work, and so, I was stuck (so to speak). So I went ahead and made that test mould with Tamiya Cement. Plainly this […]

Test masters

I was just about to glue my 3D printed wheels to the bottom of a box and rashly pour rubber over them, when my inner project manager whispered in my ear and pointed at the risk register. Wrecking the Shapeways wheels would put me back a couple of weeks and $16 in shipping alone! For […]