Aloha!
OK, so we are starting our tunnels, drawing from the recent GR issues on the subject and the "how to" video on the GR website, specifically the one for the portals.
Our tunnels will be built over hollow tile blocks. We split the hollow tile in half, and we wanted to use foam fillers between what would've been the ends and middle of the full block.
Here are my thoughts and questions:
I'd like to make the whole thing as "fire and forget" as possible, as, once capped, we are covering the lot in lava rock, which all hands agree is far more attractive than hollow tile!
Thanks as always!
Eric
That, my friend, is a hard question. When I had my blocks in place for my tunnel I started trying to seal it all up. As some of the gaps between blocks were larger than others I went a different route. I covered the "tunnel blocks" with 4 layers of 15 pound roofing felt. I then mortared in the stones for the portals. I'll leave it to others to provide a better answer to your question. Glad to hear you are still maing progress.
Tom Trigg
Thanks,
Below is a picutre of the problem at hand:
The tunnels are too short to hide the "broken cinder block look," especially since some of those areas will be exposed as we start to cover it and build vertically. Eric
The tunnels are too short to hide the "broken cinder block look," especially since some of those areas will be exposed as we start to cover it and build vertically.
Update...my father-in-law has a glue he thinks will work. In the worst case, we are out some free foam, a couple squirts of glue, and a pair of beverages.
The weekend saw some progress.
I glued in some foam inserts:
Then I shot some expanding foam into the gaps: Unfortunately, the expanding foam has not cured as advertised after 24 hours. I am not sure if its our humidity or if I applied it too thickly. I hope it will be hard enough for me to paint with some washes and then cap the half-hollow tiles to protect the foam from the elements. At a minimum, this is a low threat way to learn the ins and outs of working with foam. If the project goes really south, I can yank it out, forget about the whole idea, and proceed, since the tunnel interior will be more or less out of direct sight anyway.
Then I shot some expanding foam into the gaps:
Unfortunately, the expanding foam has not cured as advertised after 24 hours. I am not sure if its our humidity or if I applied it too thickly. I hope it will be hard enough for me to paint with some washes and then cap the half-hollow tiles to protect the foam from the elements. At a minimum, this is a low threat way to learn the ins and outs of working with foam. If the project goes really south, I can yank it out, forget about the whole idea, and proceed, since the tunnel interior will be more or less out of direct sight anyway.
Unfortunately, the expanding foam has not cured as advertised after 24 hours. I am not sure if its our humidity or if I applied it too thickly. I hope it will be hard enough for me to paint with some washes and then cap the half-hollow tiles to protect the foam from the elements.
At a minimum, this is a low threat way to learn the ins and outs of working with foam. If the project goes really south, I can yank it out, forget about the whole idea, and proceed, since the tunnel interior will be more or less out of direct sight anyway.
Do what ever is needed to keep some decoration inside the tunnel. There are a good number of us, and I put myself at the head of the list, who no longer allow camera cars on the right of way due to an unsightly tunnel interior. If I had it to do over again I would send camera cars through the tunnel prior to putting the roof on, just to check the condition of the inside. At some point you will probably want pix of the train coming out of the tunnel and the camera WILL capture the inside of the tunnel.
Good advice. Thanks. The expanding foam is still curing in places, with consistency of a well toasted marshmallow.
The plan to carefully mix a base coat to match the cinder blocks crashed as soon as the paint came open and my three year old, his siblings, and the neighbor kid grabbed brushes. The effort devolved into a mad dash to keep most of the paint on the foam. It ended up on the rails and roadbed a yard in either direction and on each painter, the youngets of whom needed an immediate bath. At least the foam did get a coat of "faded warship grey!"
Given my work environment and the crew's enthusiastic desire lend to, I have decided to simply coat the future tunnel interior with a brown latex roughly the color of the lava rock. In the end, their participation is more valuable to the long term success of this project than the tunnel interior. Still, I think I am going to use this technique (foam and washes) for smaller items like the portals as we move forward.
May I suggest a method of hiding the 90 degree corners of the roof and walls. After your paint has cured, take some small pieces of crushed rock and attach them where the roof and wall meet with a small dab of liquid nails. Adding some large particles of crushed rock dust to the final coat of paint will add texture to the tunnel interior.
As messy as it may have been for all their assistance, they have some fantastic memories of building "their" railroad.
Tom,
A belated "Thank you!" for the tip above! We finally had the time to glue some rocks down, though at the base, and it went a long way to transitioning from the vertical walls into the roadbed / garden bed. Of course, three sets of little hands glued themselves to the future tunnel, rocks, ties, tracks, etc., but, as you said, small price to pay for the memories!
Absent professional obligations...or another home improvement project...we should be through this phase of our mountain building shortly. I'll post pictures and updates as warranted on my construction blog"Progress on the Triple P" as they are warranted.
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