Hammer doesn't cope well with brushes that have complicated vertices, or are very small (usually because they are off-grid). I think the rope idea is a great solution, but if you wanted to turn your brushwork in to a model without having to recreate it in a program like Blender, you could simply convert your existing brushwork to a model using
Propper. It takes a little bit of setting up and learning, but once you get it working, it's amazing what it does for your workflow and budget (you have a limited number of brush sides per map, so it's a good idea to use models for things that use a lot of brushes).
Propper models don't need separate textures, they use the ones in the TF2 VPKs, so after converting, you'll only need the .vtx, .mdl, .vvd and .phy files that it produces, which are a few kilobytes each.
Note: Propper was updated recently. Previously, we needed to install Half-Life 2, Source SDK 2009 Base, and extract all the TF2 assets. Now, it works with the stock TF2 installation without needing anything else. So it's just a case of plonking it in a folder and adding it to Hammer's compile options. In your case, it might be a good idea to scale your brushwork up so that you have a comfortable grid size to work on. When you compile the prop, you can set it to scale down. If you do scale it up, make sure Texture Lock and Scaling Texture Lock are enabled on the toolbar so the textures scale with it.