you could pour a thin layer of m&p to glue it. I would scratch the surfaces spray all surfaces liberally with alcohol and stick together with a thin layer of m&p.
I tried soap welding as described in Grace's ebook and had very good results with this soap. I soap welded it last month and have used it daily for the past week or so and it remains intact. The post where I talk about it and give a link to the ebook is here. It was DeeAnna who reminded me of the method, which I had read about but never tried before.