You know the problem: If the basin receives 9 ingots-worth of molten metal it will cast a block. If it receives less than 9 ingots of metal it will just sit there partially filled. Breaking the basin will empty it, making it usable again, but will waste the metal.

Without using other mods a simple way to recover the metal is to stick a seared faucet on the basin, and put a casting table under it. This will allow you to drain the liquid metal off and use it for casting.

Its also possible to route the liquid back into the smeltery if it is tall enough: You can arrange to have a casting channel under the faucet, leading into another smeltery drain.

Further to the above:

I haven't properly tested this but as far as I can tell the smeltery channel forms a kind of limited fluid pipe system. Update: but its incredibly unreliable due to an odd fluid routing algorithm, and using fluiducts is far easier.

The faucet behaves like a "wooden pipe" to pull fluid from a container and transfer it to a destination underneath, but only when clicked or pulsed. The smeltery itself behaves like a passive storage tank except for the ability to hold multiple fluids simultaneously.

I would strongly advise NOT trying to connect channel blocks directly to other pipe types.

"The smeltery itself behaves like a passive storage tank except for the ability to hold multiple fluids simultaneously."

What do you mean by this? Smeltery can hold many different liquids and in large (or infinite amounts) inside at the same time.. you just click on the liquid you want to use inside the controller block..

It would be much easier to use other mods, for example TE3 fluiducts or Ender IO liquid pipes, they connect instead of the faucet right on the drain block and you can easily transport fluids in and out of smeltery and, if you wish, store it in seperate tanks. Then you can just pour back in liquid you need to use..

I found that apart from being able to smelt villagers into emeralds and horses into glue, you can also turn endermen into liquid ender and they drop pearls on death, very useful..

another thing is that you can pour liquid ender over obsidian blocks you placed in basins to get endstone..

Pouring molten tin over gravel gets you Brownstone blocks..

(another way to get glue is to use sawmill to get glue balls from rubber wood and place it in smeltery to make glue blocks)

sry for straying a bit off topic, but I thought someone might find this info useful when using tinkers..

I tried, some time ago, managing liquids the way you described, but it always seemed kinda wonky and unreliable.. using most pipes would work, but ones I described work best (ender IO even goes both ways so is probably the best choice)

Its fair to have a more general discussion of TC. I just thought I'd mention it because I didn't really "get" the fluid transport thing initially and had some snafus where I'd got an incomplete amount of fluid somewhere and had trouble removing it. In my opinion you are most likely to hit the basin problem in early game before you have more advanced machines/pipes available. Later you should have enough materials that it won't matter.

By "passive tank" what I mean is that the smeltery drain appears to act like a "tank valve", in that fluids will flow in from a pipe or channel, and to get fluids out you need a pipe with a pump function.

I'm inclined to agree that it is wonky, I experimented with the obsidian recipe and ended up with an odd discrepancy of a few mB of lava left over and a few mB water short. It doesn't matter as there are far easier ways to make obsidian.

The villager thing is interesting as I'm playing Monster single player currently and have absolutely no emeralds. My plans call for at least three.

actually you can have pipes very early in game, TE3 fluiducts only cost you 2 tin and 1 copper ingot.. and you just place a lever next to it, send redstone signal (or place a pneumatic servo inside of it, which is also cheap to make) and it will have the suction ability.. First thing I did on some other server is that I build a smeltery and made it automated with few of those pipes, tanks and few drains..

I then connected itemducts (also cheap) to a few basins to auto extract blocks from them and place them in a chest so it was fully automated.. add a hopper to controller to input mats (or use pipes also)
only flaw is when theres some fluid left in basins or some in fluiducts, but you can solve this by wrenching them to reverse the suction to take liquids out of basins back into the smeltery drain..

You don't need to take liquids out, just fill it with everything you want and when you need a specific liquid drained, enter the smeltery controller GUI and click on the liquid you need so it will be the one used..

for villager smelting, it's best to place an auto spawner from mfr above the smeltery (use conveyor belts to redirect them if needed) and let it spawn tones of villagers right into the smeltery (u need 4 villagers for 1 emerald and you need at least 9 to make an emerald block since it can't output only 1 emerald)
also worth mentioning is that you need some other metal to be smelted inside of it so that it can melt villagers or any other mob.. you need just a little amount to be inside already..

you could also smelt other mobs or even yourself to get blood from which you can make coagulated blood balls (act somewhat like slime balls or can make blood channels from them)
or use blood to get pig iron.. (think you need liquid iron, emeralds and blood for this)

here's our old umbrella villager eater smeltery that I made on a previous map:
http://s2.postimg.org/ho7gaeni1/Screen_Shot_2014_04_17_at_22_36_44.png

True, I was forgetting about the opaque version which is seriously easy to craft compared to needing hardened glass. I really prefer clear ducts.

To make the auto spawner you need two emeralds. On the server I could just withdraw some. On SSP I'm leaning towards cheat mode spawning in some stuff but that kind of defeats the object of playing survival not creative. Then again I'm getting bored.

Incidentally if you put one emerald on the casting table I think you're able to make an "emerald cast", that would allow you to draw off one emerald at a time. Having said that the liquid quantities may be wrong.

Oh BTW I'm only playing SSP because I can't get on the server without crashing it, I've placed incompatible pipes and I can't remove them. I've PM'd Broonie but I've had no reply, and since the fix is probably going to involve reverting my base or waiting for a map reset I'm probably not getting back on.