Got tired of one of my structures so figured on doing a quick, cheap experiment using quikcrete to cast all the corregated beer cans (you can see the original structure first photo). Intent was to cast 4 sides and then attach to a frame using silicone and use vinylle patching cement as touch up. Concrete corrugations would then be spray painted a suitable corrugation color.
For the casting release, used used motor oil.
Lessons learned.
use Portland without aggregataes
use a metal mesh to hold it together better (reinforcement)
wait longer than 2 days to strike the mold as it was still green and broke off
Show your mistakes so others can learn. No one seems to show their mistakes, thus, I figure I’m the only one who does them
Maybe a bit more reading first! [;)] There was an excellent article in GR a few years ago (maybe 4?) by Richard Weatherby on building structures with cast walls. He used Precision Products panels for the molds and vinyl concrete patcher reinforced with hardware cloth, if I remember correctly.
Could I suggest chopped strand glass fibre as an additive? This will still give you a smooth finish and strengthen your thin wall castings (no pun intened!). As a release agent I would recommend Silicone oils (I have seen old silicone brake fluid used with success).
I think its fine to try and reinvent the wheel as long as your not an architect or brain surgeon. Richard’s article was in the June 2000 GR. He used anchoring cement and not the vinyl patcher I mentioned above.
As far as mistakes go I’ve documented the one I’ve had with my railway so far on my web site. One thing I do to minimize those mistakes if I’m thinking of doing something that is outside my normal areas of work is to do alot of reasearch on the subject. Someone somewhere has probably tried it. If that reseach shows that it’s something I feel comfortable doing I’ll do it. If I don’t feel comfortable I’ll either have someone else do it or have someone teach me how to do the project.
Much like Jack, before tackling a project that is out of my expertise, I read. I may spend several weeks reading what others have done, thereby learning from their successes and mistakes. Taking their suggestions has saved me many heartaches.
no experiment is really a failure; rather it’s a learning experience. Here’s what I did with the structure that failed; I modeled an abandoned, falling apart industry with it
I mussed up one of my tipple castings a while back and used it as a planter (the bottom was too thin in the squish moold and had holes; perfect for a planter)