Silly question: scavenging resin

[betchern0t]

Hi,
I took a punt and have pre-ordered a peachy. This will be my first foray into 3D printing. I have looked for the answer but have yet to find it which probably means that it is obvious to those in the know.

At the end of a print run you are left with three things in the bottom tank: the printed item, a layer of resin and a layer of salt water. I presume you can simply lift the object out. But how do you separately decant the remaining resin and the salt water? At $95 per litre delivered I would not want to waste resin and from my reading it suggests you start with just a layer of resin in the bottom tank.

So specifically how do you:

1) get the resin out of the tank after printing without any saltwater
2) How do you save that resin - back into the main bottle or separate to be used first?
3) Can you reuse the liquid resin left in the bottom tank when the print is completed?
4) is there a best way of removing the object?

Cheers Paul

[rylangrayston]

Hey Paul Thanks for backing us and thanks for the great questions.

Lets say your tank is a 2 litter pop bottle ( with the top cut off), it takes only 50 mL of resin to cover the surface of the salt water so.
if your resin cost 100 dollars per litter delivered, then at the end of a print you only every have about (1000mL/50mL = 20th , $100/20th = $5)
$5 dollars of resin that you don't want to waste.

Typically I think people will just leave that 5 dollars of resin in there printer until the next time they print. Its actually good to leave it there because it prevents salt water from evaporating and leaving behind lots of messy salt crystals. Care must be taken to make sure no stray UV light is hitting the resin both while printing and in between prints.
If UV light dose get to the resin you have left in your printer then you will have a rather useless 5 dollar hockey puck, which you can just remove from the printer.

lets say your planing to travel some where with your printer, in this case I still wouldn't recommend separating the resin and salt water. Instead I would grab a new 2 litter pop bottle, spray paint the outside black and then using a funnel pour both the liquids in to the black bottle. When you get to your destination pour the liquids back into the printer and give them a minuet or two too separate.

Lets say you want to change colours from blue resin too red resin, in this case I would recommend using an oral syrng with a bit of hose on it to suck up all the resin from the surface, and inject it into a bottle. Typically I dont ever put resin back into the bottle it came in, that's because im doing testing and I dont want anything to taint the results.

The stuff I wrote above hopefully gives you a feel for what you might do, its up to you tho there are probably lots of good ways, to deal with it.
I notice that you asked specific numbered questions ( which I love) so Ill answer each of them now aswell.

1) how do you get the resin out of the tank after printing without any saltwater?
pull it off the top using a syringe with a 20 cm hose on the end. tip the nose of the syringe upward when you empty it, so that the resin floats above all the salt water in the syringe, this way the resin will come out first and you can just stop squeezing the syringing before you expel the salt water.

2) How do you save that resin - back into the main bottle or separate to be used first?
I would not recommend putting resin that has been in a printer back into the bottle it came from, just incase there are contaminants like partly cured blobs of resin or salt crystals that you dont really want to put in with your brand new resin, instead store it in a second pop bottle that is painted black, and store it in a cool dark room.

3) Can you reuse the liquid resin left in the bottom tank print is completed?
YES!

4) Is there a best way of removing the object?
Simply lift it out of the tank slowly, the instructions will show you how to make a print base with a handle so that you dont have to go fishing around for your print with a pair of pliers.

[MemorianX]

If you want to separate it you could build separation funnel like this http://highschoolchemistryguide.com/...-apparatus.png
they way I would go around to building my own would be using a soda bottle cut of the bottom and attach a small diameter rubber hose to the top and putt a clamp on the hose.
Simply pour in the water/resin mixture hold the funnel over a tank for the salt water remove the clamp and use your fingers to control the pressure on the hose and thereby the speed of witch the bottle empties, once the resin just passes the pressure point you squeeze the hose to prevent further outflow move the funnel over container for spent resin and release the pressure