Best techniques for waterproofing ABS plastic?

This might need a little more clarification. Plastic is pretty water proof already. Are you trying to waterproof a connection like ABS plumbing pipe? Are you trying to patch a crack? If you explain the problem you will be more likely to get an answer that solves it.

It is a 3D printed part by an additive method. The application of the part requires it to be in a solution.

I’m trying to think what sort of part you printed that isn’t already inherently waterproof.

The print heads on a 3D printer basically weld the material together. Assuming proper print head temperature and non-defective feed-stock, you aren’t stacking a whole bunch of layers of plastic; you’re welding a thin layer onto a solid block.

A proper weld doesn’t stick two pieces together; it turns two pieces into one piece. If you can crack a weld and separate the two pieces under any circumstances, you fail at welding!

This from a CNC Machinist who used to work with SLA parts on a daily basis.

Woah, hold up. Are we talking A part, as in singular, or joining multiple pieces?

In fact, there’s so many missing details that I’m almost tempted to flag this question for editing.

That previous comment makes a bit less sense now that @RandolphOcampo‘s response was flagged out of existence.

jerv,

I would agree with you about the how 3D additive printing works, however we have seen vessels made entirely of ABS plastic, when put under pressure, the fluid within begins to seep through.

We are talking about a singular part

Ah, under pressure. That changes things a bit.

How much pressure are we talking here? It would seem that it’s more pressure than household plumbing.