Storing luggage in BKK or getting it from A to B - even across to Laos

[Blackline]

This forum seems to know everything so here goes:

I'm a rockclimber who also enjoys a stay in Bangkok or Pattaya amongst my climbing trips. This does regularly leave me with a problem: outdoor climbing requires lots of heavy gear which I do not always want to carry around or even take on a plane. So: who has some useful experience in long term storing/sending luggage to/from Bangkok.

Specifically for storing: where can I store a big duffelbag of gear safely for a few weeks or even months in Bangkok for a reasonable price? There are commercial luggage storing facilities available but they get expensive fast. hotels will store your stuff for maybe a week in advance of your stay - I've done that - but surely not for weeks or even months.

And for sending: I would like to get the afore mentoined big ass dufferbag from Bangkok to Laos (Vientiane) or at least to Udon Thani. (I would be traveling there the long way around and do not want to take the big bag myself) Any suggestions on services to use?