Professional Engineers

If porosity is your problem, color the box.

Or melt the surface on an open flame.

But 3d printing is not that bad anymore, so i'm not convinced porosity will be a problem at all - of course it depends on the printer...

Will your enclosure be subjected to very high pressures?

FDM parts will not be waterproof, they are filled with tiny holes and channels.

I worked on a project that had to hold water, the client insisted on FDM because it cost less than an SLA model. We spent days "sealing" the surface, and retesting the ability to hold water. Our part was printed with 100% infill to get the best model to start with. It was also a rather thick model, I think the walls were about .25" thick and they still leaked.

I suggest not doing it.

Instead, buy an already waterproof box, then modify it for your needs. There are dozens of websites that sell waterproof project boxes in a number of shapes/sizes.

If you try to waterproof the printed parts, try:

• Soaking the FDM part in molten wax
• Using a rubberized spray coating like what is used on the underside of cars
• painting on a rubberized coating like those you can dip tool handles into
• being prepared for a leak and protecting the electronics with a wax coating, and/or sealing the electronics in something like a balloon or condom
• I've never used it, but saw a can of spray paint called Never Wet. Somehow it repels water. It might be worth looking at

Check this video, he made 3D-printed shot glasses waterproof using Varnish.

He tried resin first, but it didn't polymerize correctly, so I can't say whether it'll work or not...

My enclosure will be placed about one foot below ground, so there will certainly be some pressure, i am uncertain will this pressure cause water leakage

Thanks for the suggestion.

The requirement for the project was to protect electronics of the sensor, which is a very small area, and unavailability of any standard waterproof enclosure box at that small scale and cutting and adjusting it to the sensor would definitely mess with its IP rating. So the decision for a custom 3D printed part was made

I have tried coating my sensor with silicone, hot glue, acrylic paint. But overtime all of them have failed.

I didnt know about the rubber coating material, will surely try that.

Thanks for the suggestion, will surely look into that

At 1 ft the pressure is minimal.

A few years ago i had several parts 3d printed with ABS on an Afinia machine (i think) and the models were watertight.

However there was an issue during printing - temperature was miss-regulated on some parts. Thus "spread" was too high on some parts, and too low on others.

On parts with too low spread, cracks formed, which made the part brittle and leaky.

But on parts with correct spread and too high spread, there were no gaps and they did not leak.

Printing resolution was 0.1mm, parts' thickness was ~2mm.

If your part turns out leaky, you can always use 'rubber spray seal'. Coat inside and outside of the part. It should hold quite a while.

A friend uses them on his car, and they are really resilient.

Really appreciate your guidance.

If you are using ABS I have had some success coating the surface with acetone which melts the surface on contact and re-solidifies when the acetone dries. I'm with fredswug though, unless it has to be something very specific you might check into NEMA rated enclosures, there are all kinds of different options already out there. try www.automationdirect.com and saginaw control engineering

Yes, we actually went through a lot of standard of enclosure box and design. But we could not find something with dimensions as low as 40mm. In any case we would have had to modify the structure a bit to adjust our sensor which would definitely hamper the NEMA protocols.

Thanks for the suggestion of using acetone in sealing the surface.

Will surely try it.