WatchUSeek Watch Forums banner
61 - 80 of 156 Posts

·
Registered
Joined
·
5,832 Posts
somewhere around 4000 psi.

6061 aluminum shouldn't have any problem with that kind of stress (safety factor of about 10).

Designing a pressure tester?
I actually wasn't too concerned with it failing (which wouldn't be that dramatic if it did). More about how much the pressure vessel would expand.

I'm out in the boonies right now but maybe when I get some free time at the office I'll build one. There's enough pipe and fittings floating around for most of it. I'll probably have to buy a pressure transducer and some flanges though.
 

·
Registered
Joined
·
5,594 Posts
This does seem like a feasible project. Instead of aluminum, I am thinking steel 6" square tube (commonly used for compression post like in my garage). Cheaper and easier to weld a pressure tank, than aluminum, and flat surfaces could accommodate observation window. So, my design would be 1/2" plate steel base 12"x12", weld 6" square tube 12" height, weld flat lid, cut large diameter hole 5" (big enough to get hand inside), weld 5" diameter pipe 2" height onto the top of the chamber, thread 2" pipe for screw on lid. (I am thinking that there should be some large pipe fittings for this purpose). Now there should be an observation window -- 1/2" Lexan secured with SS bolts and industrial adhesive. And finally the pressure nut. Oh, this is a project for sure ! My guess is that the darn thing will leak around the nut. Nice conversation piece on the bookshelf.

somewhere around 4000 psi.

6061 aluminum shouldn't have any problem with that kind of stress (safety factor of about 10).

Designing a pressure tester?
 

·
Registered
Joined
·
8,842 Posts
I actually wasn't too concerned with it failing (which wouldn't be that dramatic if it did). More about how much the pressure vessel would expand.

I'm out in the boonies right now but maybe when I get some free time at the office I'll build one. There's enough pipe and fittings floating around for most of it. I'll probably have to buy a pressure transducer and some flanges though.
4000 psi is below the yield point for aluminum, it shouldn't deform at all.

'Pressure transducer'? What is this pressure transducer you speak of?

You can buy a analog hydraulic pressure gauge (0 - 3000 psi) for as low as $10 for a 3-2-3 industrial gauge or go as high as $1000 for a .25% full scale digital gauge.
This does seem like a feasible project. Instead of aluminum, I am thinking steel 6" square tube (commonly used for compression post like in my garage). Cheaper and easier to weld a pressure tank, than aluminum, and flat surfaces could accommodate observation window. So, my design would be 1/2" plate steel base 12"x12", weld 6" square tube 12" height, weld flat lid, cut large diameter hole 5" (big enough to get hand inside), weld 5" diameter pipe 2" height onto the top of the chamber, thread 2" pipe for screw on lid. (I am thinking that there should be some large pipe fittings for this purpose). Now there should be an observation window -- 1/2" Lexan secured with SS bolts and industrial adhesive. And finally the pressure nut. Oh, this is a project for sure ! My guess is that the darn thing will leak around the nut. Nice conversation piece on the bookshelf.
The problem when you go big, the forces go big along with it....

With a chamber 6" x 6" the force on the lid will be 52,560 lbs at 100 atm. A little tiny cup 2-1/4 inches across (just barely big enough for a Submariner) the lid forces are only 5,805 lbs at 100 atm. 6000 lbs can easily be handled by a few 1/4-20 grade 8 bolts from Lowe's. 52,500 lbs will take either a lot of bolts or some very big ones...

Then there is lid bulging and the associated problems with sealing......

If you have access to a milling machine one of these can be made fairly economically:



Especially, if you forgo the window, after all what is there to see?
 
  • Like
Reactions: jamesbee

·
Registered
Joined
·
8,842 Posts
Bubbles ?
If it leaks, you won't see bubbles, you will see a rapid drop in pressure on the gauge if the seal fails catastrophically, or nothing if it is a slow leak.
 

·
Registered
Joined
·
5,594 Posts
Some how my 26-years of legal experience just doesn't help in these matters. Good thing we have experts in the field like Lysander looking out for us.
Rhino


4000 psi is below the yield point for aluminum, it shouldn't deform at all.

'Pressure transducer'? What is this pressure transducer you speak of?

You can buy a analog hydraulic pressure gauge (0 - 3000 psi) for as low as $10 for a 3-2-3 industrial gauge or go as high as $1000 for a .25% full scale digital gauge.

The problem when you go big, the forces go big along with it....

With a chamber 6" x 6" the force on the lid will be 52,560 lbs at 100 atm. A little tiny cup 2-1/4 inches across (just barely big enough for a Submariner) the lid forces are only 5,805 lbs at 100 atm. 6000 lbs can easily be handled by a few 1/4-20 grade 8 bolts from Lowe's. 52,500 lbs will take either a lot of bolts or some very big ones...

Then there is lid bulging and the associated problems with sealing......

If you have access to a milling machine one of these can be made fairly economically:



Especially, if you forgo the window, after all what is there to see?
 

·
Registered
Joined
·
5,832 Posts
4000 psi is below the yield point for aluminum, it shouldn't deform at all.

'Pressure transducer'? What is this pressure transducer you speak of?

You can buy a analog hydraulic pressure gauge (0 - 3000 psi) for as low as $10 for a 3-2-3 industrial gauge or go as high as $1000 for a .25% full scale digital gauge.
QUOTE]

I'm thinking modulus of elasticity. How much of the pressure introduced by cranking down a screw gets relieved by expansion of the vessel at roughly 1500 psi. When I'm not traveling I'll sit down and do the calcs to see if it matters. I haven't done those particular calcs since sitting for the FE test 2-1/2 decades ago. Yes, I know: use a longer screw and don't worry about it.

Last time I looked at pressure gauges for work, decent quality ones were running around $150, but they did have features not necessary for this application.

I'm also thinking about the screw assembly: To my mind that's the most likely leak point.
 

·
Registered
Joined
·
8,842 Posts
It would depend on the geometry of the vessel, a thick cylinder with hemispherical ends would have the least deformation. A low flat cup with flat ends would see the ends bow outward, how much would depend on the thickness.

I did a design study o this a few years back and came to the conclusion, if the inside is about 2.5 inches in diameter and about 3.5 inches long it will fit just about any watch and with the walls about 3/8 inch thick, the deflection will be negligible. Coincidently, that looks about the same size as the Lentz tester I pictured and the Roxers. (but, the Roxers are made from steel.)
 

·
Registered
Joined
·
1,545 Posts
It would depend on the geometry of the vessel, a thick cylinder with hemispherical ends would have the least deformation. A low flat cup with flat ends would see the ends bow outward, how much would depend on the thickness.

I did a design study o this a few years back and came to the conclusion, if the inside is about 2.5 inches in diameter and about 3.5 inches long it will fit just about any watch and with the walls about 3/8 inch thick, the deflection will be negligible. Coincidently, that looks about the same size as the Lentz tester I pictured and the Roxers. (but, the Roxers are made from steel.)
The name of the Manufacturer of the tester you posted the pictures from is "LITITZ", difficult to read on the small front picture unless you know the brand.

Follow the link, and there is a video clip showing the use of their pressure tester and why the viewport is useful to check/remove air bubbles from the internal volume before clamping the cover; hence my comment above.

Lititz Precision Products | Quality Watch Testing Equipment
 

·
Registered
Joined
·
1,545 Posts
Hey, if we all chip in -- we can get one of these -- then we have a GET TOGETHER (remember when those were the rage? can't remember last time I saw a thread about a Get Together).

We GET TOGETHER test our watches, publish results and have a great time.

Diver 125 Watch Wet Pressure Tester
My diving watches get pressure tested every time they get serviced each three or four years, I never had any leakages during héliox or air diving involving heavy work like tightening up large diameter flange piping with impact wrench or flogging spanner and hammer
 

·
Registered
Joined
·
8,842 Posts
If you don't have a window, you check for bubbles before you put the lid on.... (Also, helps if you spray a little soap on it.)

The industrial ones that can test 200 - 300 watches at a time don't have a window.....

Or, did you think there is one guy at Rolex putting one watch at a time in a pressure tester all day?
 

·
Registered
Joined
·
1,545 Posts
If you don't have a window, you check for bubbles before you put the lid on.... (Also, helps if you spray a little soap on it.)

The industrial ones that can test 200 - 300 watches at a time don't have a window.....

Or, did you think there is one guy at Rolex putting one watch at a time in a pressure tester all day?
My comment "bubbles" was a pun linked to the video clip showing the operation of the LITITZ tester.

As for what I think, don't guess......

There is a very publicized Rolex video clip showing their facilities it's hard to ignore it.
At 3'25" one can see a "wet" hydrotester with a batch of 9 tray of 10 watches being tested.

A look inside the Rolex factory - YouTube
 

·
Registered
Joined
·
114 Posts
Curious about this. The vast majority of divers out there have not undergone ISO 6425 testing, and hence do not have "proper" certification as a real diver watch. So would it be accurate to say that all divers that lack the ISO certification (regardless of its water resistance rating) aren't "real" divers, but rather are diver-styled watches with high water-resistance ratings?
short answer is no. Its possible to make and test your own watch that will pass iso6425, but decide to avoid the hassle and expense of submitting it for certification. In that case, its all a matter of trust.
 

·
Registered
Joined
·
8,842 Posts
short answer is no. Its possible to make and test your own watch that will pass iso6425, but decide to avoid the hassle and expense of submitting it for certification. In that case, its all a matter of trust.
Holy Pete!

How many time does it have to be said?

THERE IS NO SUCH THINGS AS ISO 6425 CERTIFICATION.

THERE IS NO OVERSEEING OR GOVERNING BODY FOR DIVER'S WATCHES. NO ONE SITS IN JUDGEMENT OF YOUR DIVER'S WATCH DESIGN.

The company makes 'em, the company tests 'em, the company markets 'em. Your responsibility is to trust the company or not.
 
  • Like
Reactions: jamesbee
Joined
·
945 Posts
^earlier you mentioned a few examples of brands that you would trust on that front. Is orient among those?

Someone posted their ti m-force here. I like all those iso certs it has for no good reason, & am thinking about it if I can determine whether it also has a ti back, but just curious about your opinion- I assume if you trust Seiko, you also trust orient too?
 

·
Registered
Joined
·
5,594 Posts
Lysander,

I get what you are saying (and hopefully everyone else is now well informed).
But, at the same time, let's not argue over semantics or word usage.
Orient USA web site regarding M-Force "Air Diver" description states: "Orient's own special [case] structure which has earned this watch ISO certification in three areas...." (emphasis added)

SEL03005Y0 SEL03005Y M-FORCE | Orient Automatic Watches & Reviews | Orient Watch USA

If Orient USA stated "hey, our watch was self-tested and passed 3 separate ISO tests" would the meaning or intent be significantly different to the average consumer? Or how 'bout "we here at Orient tested our watch and it passed the ISO 6425 with flying colors ...."

I agree with you that to state the watch is ISO Certified suggests that International Standards Organization may have performed the tests or reviewed the test data.

But HOLY COW (my colloquial "For Pete's Sake") anything short of a live broadcast black tie awards ceremony with a long-bearded duck hunter announcing this years ISO CERTIFICATION goes to .... is just not going satisfy the most discriminating (insert skeptical) dive watch enthusiast.

Rhino

PS: despite everything that I've read and learned on this thread, I am insisting that all my watches be ISO CERTIFIED !!! (insert sarcasm and big smiley face).



Holy Pete!

How many time does it have to be said?

THERE IS NO SUCH THINGS AS ISO 6425 CERTIFICATION.

THERE IS NO OVERSEEING OR GOVERNING BODY FOR DIVER'S WATCHES. NO ONE SITS IN JUDGEMENT OF YOUR DIVER'S WATCH DESIGN.

The company makes 'em, the company tests 'em, the company markets 'em. Your responsibility is to trust the company or not.
 
61 - 80 of 156 Posts
Top