You can try buying such in BKK. I have seen gate security on DL flights to NRT, but never on BR flights (though I only fly BR to TPE).

I have no idea how the prices are though.

EDIT: It is the transit security that is most likely to catch you if you bring it in. I have no idea if it really would do so though. OTOH, TPE confiscated a tiny pair of wire cutters I accidentally had on me (even though their transit is fairly lose).