waterproofing connectors

so i finished the CAD model of the connectors at the last meeting. The subconn connector needs to be wired to the pressure transducer through a small board - microcontroller or PCB? I don't remember.

Anyway I was supposed to go to the MIL and get the board's measurements, but Monday was one crisis after another(Heat Transfer!!) so I completely forgot and didn't have time anyway.

So hopefully I will read this on Monday and take measurements and post them here and CAD the casing for the connectors...

feel free to add comments. especially if you know what the board I'm supposed to measure is called. Or you need something from MIL.

I went to the MIL today and nobody was there that would know what I need to measure, or where it might be. Try again tomorrow.

Blue and I finished the CAD drawing of the waterproof enclosure for the pressure transducer. It turned out to be more complicated than we originally thought.

We met with Braddock this morning, and with a few small changes, we have a solid design.
Braddock even said he had extra materials that he could let us use. Bonus!

Blue ordered some of the parts. The rest should be stuff we can get around town or stuff that Braddock has in his shop, plus hardware.

Now we need to wait for MIL to finish the PCB, include a little more detail in the CAD so that we can pick out hardware, and then we should be ready to manufacture.

The main thing im looking at now are are orings/the channels they go in. If we cant get this right then the whole thing is a failure.

I'm telling you, you need to design the entire parts around the O-rings, select an O-ring first, and then build around it, don't try to make one fit.

I'm still not particularly wild about those custom/any shape you O-rings that you have to cut.

well, we can find an o-ring and then cut the grooves to fit it. Does that work?

Yeah that works...what Morford is referring to are Orings that are cut to fit an oblong shape...ie not a circle. Pretty much case and point, the display case made last year by Patrick Star.

Morford...Braddock is giving us a choice between 2 wall thicknesses for the steel tubing (0.045 and 0.065'') in addition to this we can alter the end cap to fit the desired O-ring.

Dana did you check with Brian about the chemistry stuff, also check if he could powder-coat as well.

You can still use a circular O-ring, I would just hope for it to be all one piece, that's what I would prefer. I'm just saying design around the O-ring, don't try to make something fit.

Do we have to use a steel tube? Something like aluminum would be preferable. Probably the thicker of the two would be better since we could have more play with machining or anything like that. Although the downside of using the thicker walled steel would probably be increased machining time, but I don't know how much that would be.

Powder-coating would work, but probably not very well for any threaded portions. Also it would be important to prevent any scratches from happening to the surface, since if I remember one of my classes (materials?) correctly, it can actually rust faster with the powder coated surface if there is a scratch. Or maybe that the damage can be worse without it being noticed as early thereby leading to massively epic failure. But its late and I'm probably rambling....

haha. The reason why we didnt choose aluminum is two things. The pressure transducer has an NPT style thread on it so finding a nut that fit the thread was difficult and the only ones available were either SS or steel. Steel is also preferable because of ease of manufacturing (welding) and it is important we have a good seal between the nut and the surface of the enclosure. For the most part these enclosures will be out of the way so chance of scratching will be minimum. The only occurrence we might scratch will be during installation.

To be specific the enclosure will be made of two parts. Main enclosure or shell will be constructed out of steel and the cap end where the waterproof connector is will be made out of aluminum.

Morford - I don't know if you looked at the CAD assembly yet. But in case you didn't, the o-rings are circular. Since circular o-rings are pretty common, we don't have to worry about it not being all one piece.

Don't worry, I'm right there with you - NO o-rings unless they are all one piece!!