New Product Announcement: Concrete Tunnel Portals

[ednadolski]

Here is a recent, experimental version of the Tunnel 9 portal in HO scale.  This is cast in anchor bolt cement using forms made with stripwood.

As you can see, it broke over the arch when I  removed the forms, tho I epoxied it back together.  Also, too much of the cap stayed in the forms as well. Next time I'll add in a short length of steel rod to act as "rebar" for the weak areas, and see if there is a better release agent I can use that won't stain.   BTW, the forms are single-use only, tho I suppose one could use it for an RTV master.

Too bad the natural color is too dark, it does need to be painted.

This is about 1" thick.  Being real cement, you wouldn't want too many of these on a portable layout

[GaryHinshaw]

Whoa - that has great potential Ed.  What did you use for a release agent?  Is the natural color of the cement nearly white?

-gfh

[tehachapifan]

I think that came out fantastic (cracks, color, imperfections and everything)!

I would install that portal on my layout in a heartbeat.

Russ

[ednadolski]

LOL, my release agent was a framing hammer....

It's just the natural medium gray cement color, which of course under indoor lighting looks way darker than any proto pic.   For grins I did try tinting a mix with some white paint, but the effect was minimal, and I was starting to wonder about weakening the mix too much.  It's kinda too bad because the natural color has variations that might be tricky to try to capture in a paint job.

Ed

[Zox]

Concrete does tend to get lighter as it cures. I'd say look at it again in a month and see if it's any different.