Monday, December 18, 2006

An Update...

Site Prep:
Last Wedensday I went out to the FAR site to help pour the big test stand. 5 People poured 145,000 lbs of concrete in about 6 hours. It looks like it all went well. Many thnaks to my wife who came out and helped finish the concrete. Jerry Irvine took lots of pictures if I get a picture of her with the trowel in hand I'll post it. This project would not be possible without her support.

Valves:
I ordered some more three piece valves from McMastercarr I'm going to make up the following valves and test them: Drill Motor Drive, Industrial Servo Drive, and BaneBot motor drive. I will LN2 test these and the KZCO valve this weekend! I have the week after Christmas off so I have high hopes of getting lots done.

Tanks:
I was told that the florescent light tubes are Polycarbonate, not PET, so I ordered some 3"x36" PETG tubes from Uline packaging. They assured me that the tubes are PETG, alas they look just like the florescent tube covers just bigger. If anyone has a bullet proof way to identify PET please let me know. PET Soda bottles shrink when heated, these tubes do not seem to do so.
In any case I'm making new spherical tank end caps for the 3" tubes. Its amazing how much
aluminum chips can come from a 3" long 3" diameter block of aluminum....

Testing..
My last tank leaked at the fittings. So I spent Most of the day Sunday making NPTF pipe threads on the lathe and testing them to see if they are pressure tight. Today my new hand pumped hydrostatic tester arrived from McMaster Carr. (Thanks Xcor for the tip)
I hooked it up bled most of the air out of my fitting and tested my fitting to 3000 PSI the good news it held... The bad news in my hurry to test my handy work I did not bleed the air out of the hose and it did not dawn on me that the hydro tester has no bleed valve, so now its sitting at 2700 PSI and I'm afraid to crack the fittings. I'll let it sit for a day and hopefully it will bleed down. When I was working on my instrument pilots license, any time I had a spare moment to think me my flight instructor would ask what are you working on now....the proper answer at all times was the next thing. Making sure that you know what the next thing you are going to do no matter the outcome is good advice for all aspects of life.

3 comments:

John Carmack said...

We use the same hydrotester -- I certainly wouldn't bother with all the grease gun / honey proposals. We added a manual bleed valve T'd off the pump outlet.

John Carmack

Paul Breed said...

I put the test connection in a bucket of water and opened the fitting.
I'll add a bleed valve before I use it again.

Paul

jason g said...

Hello Paul (Sr.)
Paul (Jr.) showed me your site. Those bottles shrink because PET is not the same as PETG, which has added glycol for physical properties.

I used to be in recycling club so I can answer your question about nondestructively identifying PET if you can't find a recycling icon on it:
- PET sinks in water, which distinguishes it from PP, LDPE, and HDPE. PVC also sinks.
- Clear PVC doesn't pass polarized light like PET does. Look through a polarizing filter at the backlit plastic. If it turns black it is PVC.
-If you can cut a piece off, clear PVC turns white when creased or bent, clear PET does not.

With a combo of test 1 and either 2 or 3 you can negatively identify PET from all other major plastics.

-Jason G.