Fabricated Plastic Hinge

These guys might be able to reverse engineer one for you:

https://www.stockcap.com/

http://www.mocap.com/

http://www.americap-mfg.com/starthere.asp

JavaHead, thanks for such a quick reply. I will check it out.

60 PSI?

I'm lost here. I see no way this piece of plastic seals against 60 PSI.

Hi Lyn, well because of the internal parts and design of the tubing I have a partial permanent seal piece welded to the end of the 2x2 tubing which is the major support for the end cap. The end cap cover (seal) doesn't have to hold all the pressure on its own but provides the water tight seal. Admittedly there is a better way than we have now. Any suggestions?

There is a lot of information missing here! You say a hinge, so I assume the end cap must open at some time, and close at some other. I don't see anything pushing in on the end to hold that 240 LB of force (2x2"*60PSI). From the photo, It appears that the extrusion is not a 2" square. What shape does it have? What causes the hinge to open or close? Is this tubing made of plastic, aluminum, or...? What is the cap made of?

How and why is the end cap notched? A lot more information will likely lead to a lot more useful answer.

dkwarner, yes thanks I can see that I wasn't very clear as to what I needed. The end cap was not meant to open and close as a general rule. When it is necessary to open the end cap I would replace it with a new one and re-seal. It is 2"x2" square alumimum extrusion with a slot cut out of one side. It works as part of a water nozzle so water is passing through at no more than 50-60 psi. I used the terminology of a hinge but it is just a type of hinge cut so the plastic delrin material can bend around the square side to make a clean tight fit. There is a notch cut out to fit around the slot that is cut out on one side. Just trying to find a simple effective water tight end cap but ends up not so easy after all. Hopefully I explained it a little better this time. Thanks Hook

OK. If I understand correctly, here is my suggestion:

Putting the rim of the plastic inside the tube puts that rim under compression instead of tension, and helps to seal the water. The tapered end (blue cap) should seal a bit better. I've shown holes for pins or screws to retain the caps; if the caps are to be attached with adhesives, the holes could be omitted.

I'm virtually certain I have seen end caps like the green one, but I don't know where... 80/20 has similar end caps for their T-slot extrusions; I couldn't find ones for square tubing in a cursory search.

Thanks to everyone who has replied , what a great site to find help. All the ideas were good and has helped me think this end cap through. I will try to make some prototypes and see what works best, I do think using the insert type of end caps will work if I can find them. There are other parts internally that would conflict with inserting a cap into the extrusion but I think I have enough room to extend the length of the tubing enough so the end caps can be inserted like showned in dk picture. Appreciate all the time members take to help each other. Hook

Try http://www.exercise-equipment-parts.com/2x2-plastic-end-caps.html?gclid=CJSZg9n0u8gCFQqEfgodc00NEA

or RC2X2-1/2DBK1 on http://www.mocap.com/tube-plugs-rectangular-standard.html

Thanks dk checked out the sites and I think my problem is solved. Will order a couple of samples and then go from there. Appreciate hanging in there and sending me the the info. Hope I can return the favor. Hook

You're Welcome! Please come back and let us know your final results.

Dick

You could 3D print it if you have the file. Lots of files can be downloaded for free. We now have a 3D printer in our city library. They charge only for the material that you use up. My son has found this out recenly and used it a few times. There is also a 3D printer group that has several machines that can be used by members of the group.

StandardsGuy, also thanks for your suggestion. Never considered the 3D print option but it's definitely a good idea to pursue. I don't have the file and haven't done any type of 3D printing before but if I can't find a way to make the type of end caps that we need it's a direction I can build to. Thank you Hook

Could you hammer a wooden plug into the end?

What I see in the picture that you have tied a plastic stopper with a thread to the Aluminum square section. I would like to suggest instead of a plastic cover, fabricate Aluminum cover with lugs for bolting to the main section it will act like a flange. You will have fix lugs on the main square section by welding. This bolted joint will be stronger and being bolted it will be easier for maintainance.If required you may provide rubber gasket to avoid any leakage. More over aluminum stopper will be stronger than plastic and last longer.

I do not think any one far away from site can solve your problem. I suggest either give job to local fabricator or solve the probem in your own shop. If you can not weld a lug on the square pipe then you should drill small holes and fix small lugs with help of small bolts. I mean small angle pieces one side bolted on the pipe other to cover.