Cryptic crossword No 3,670

Across

1. Canal gunk? (6)
2. In the middle, mainly empty of air - then expanded outwardly (8)
3. Let go, it winds up aglow with gold curtains vanishing from sky? (8)
4. The way this is going here, what's a stand for? (6)
5. The king leads from one, nobly sitting in it? (6)
6. Primarily, controllable float? (5)
7. Result of the rubbing away from weather, perhaps? (4)
8. If unconstrained sip goes for one's head, it could lead to collapse? (6)
9. Perhaps room's least talked about feature - it's one of the big five? (8)
10. By trading order, so a soul's treated soullessly (7)
11. Originally made as something to enable replication (6)
12. Old method on the corner that's secured page? (7)
13. Men's clothing supply? (8)
14. Who am I to you, a dog? (6)
15. All in one place? One will be on your face (4)

Down

1. Starters for "Extra Virgin", having been extracted from crushed olives? (4)
2. Perhaps one of week's ends? (4)
3. Something soon out with energy? (4)
4. Looks both ways? (4)
5. Glimpse that consumes last bit of cognition? (6)
6. Principally, maybe able to be getting on, without coming at the top? (8)
7. Stump growth? (4)
8. Quite how form becomes deformed? (6)
9. Portion of Pietracupa staple? (5)
10. More sad let down? (5)
11. Has to be dodgy, extremely dodgy? (5)
12. Many points as covered by correspondent on the outside? (8)
13. In some measure, much a tête-à-tête (4)
14. That ambition reaches at first to obtain? (6)
15. Chopped tree cooks - black on the bottom coming out? (8)
16. Seen regularly, maybe? No - irregularly; rum, mad, and conclusively atypical (8)
17. Back tick? (6)