''drop the block of steel on it, or hit it hard with a large hammer.''

I had a go at it, hammer blows no good -it springs back (almost injuring myself in the process )

The ultimate test: myself standing on it ( now I'm no feather weight at 100kg!) no matter how much I bounced on it, didn't give way. It did get a bit bent though!

I'm really impressed - will surely use it on this build!