OSTC Oil Filling

[Anonymous User]

As I am planning some deep diving, I was wondering if anyone has filled the OSTC with mineral oil and what was the result?

Also, what is the best way to open the unit and fill and reseal?

[andersnasman]

Also interested, what oil would fit the best or should we use alcohol?

How deep have You (Heinrich) tested the casing, can we bring it to 150m? I have'nt had a deeper look at the buttons, but they are magnets?

[heinrichsweikamp]

Hello,

The switches are sealed with two O-Rings. In terms of a potential compass update we have decided not to use reed-switches. We filled an OSTC under vacuum with silicone-oil once but the OLED died within some months of use due to the pressure applied. We will do a new test with a preliminary sealed OLED again soon and report our results. I'm not a fan of oil filling - it will make any maintenance like battery change nearly impossible or expensive.

Regards,
Matthias

[Anonymous User]

I would have thought that white mineral oil (food or medical grade) would be suitable for filling... any thoughts?

Never opened a unit (still awaiting delivery of my first OSTC), but would it be necessary to apply a vaccum for filling?

Personally, even if I have to throw the unit away every 5 years I do not mind given the added benefits to a filled case.

[Anonymous User]

...one more thing... when Mathias says "...the OLED died within some months of use due to the pressure applied..." - was this the pressure from the vaccum filling process, or was this presre from actaul dives?

When the OSTC is filled with silicon or mineral oil, would the ambient pressure transfer to the internal components (i.e. OLED and battery) so that say at 100 meters the OLED itself is seeing 11 bar of pressure?

[sailor]

OSTCfan Wrote:
-----------------------------------------------------
> When the OSTC is filled with silicon or mineral
> oil, would the ambient pressure transfer to the
> internal components (i.e. OLED and battery) so
> that say at 100 meters the OLED itself is seeing
> 11 bar of pressure?

That is correct as the oil transmitts the outside pressure directly from the case onto all internal components.
Reiner

[Anonymous User]

How do the X1 internal components survive to 300+ meters as this is the rated depth limit of the X1?

[Anonymous User]

...I have been told OLED are completely sealed with no air voids as O2 kills them... so should not be affected by pressure (anybody know better?)...

...still unclear if Li-Poly batteries have air voids inside and would crush/collapse/fail when compressed (anybody?).

[heinrichsweikamp]

Hello,

Since I do not have seen the internals of an X1 until today I only see the informations on their webpage. Seems like they are using a gel (unsuitable with the OSTC buttons) instead of an Oil.

regards,
Matthias

[Anonymous User]

Gel or oil, the internals like the OLED and the battery would be exposed to the ambient pressure transferred to the oil... how is it that the X1 internals do not collapse under pressure?

[heinrichsweikamp]

Well, you should ask this the manufacturer. Most likely all components are pressure resistant. I do not expect any problems with the batteries, as well. If you punctuate a LiPloy battery very carefully it starts smoking immediately so I think any air inside the battery would be a bad idea.

Matthias

[Anonymous User]

I asked, but I do not get a reply to anything which remotely resembles a quest for knowledge (i.e. "Intellectual Property").

[andersnasman]

The X1 casing is aluminium and the "window" is tempered glass which makes the inside not really subjected to the outside pressure. The inside is also filled with gel. There are no pushbuttons.

The OSTC has big plastic surfaces (especially the window) which will affected from the outside pressure.

A solution is to build a stonger casing (like the X1 or Shearwater) and put the electronics from the OSTC in it. The problem with the push buttons still reside, so the easiest is maybe to add the X1 "tap" function instead of the push buttons?

[Anonymous User]

I would pay a price to upgrade my OSTC to a stronger aluminum case.

I would think magnetic type buttons like on the Vr3 and the Meg would increase reliability reducing failure point of the current buttons and would not add the complexity/cost of the tapping X1 buttons.

I'd like the OSTC to be good to 150 meters (the Meg displays although in plastic same as the current OSTC casing seem to be good to 150 meters withou oil fills... beyond you need the oil fill).

[andersnasman]

I agree on that, not being able to implement a compass is not an issue to most divers i guess...

[heinrichsweikamp]

Hello,

As promised, here's a follow-up on this topic. We did another long-time test with oil-filling in the last month. The oil-filled OSTC was pressure tested to 120m/60minutes quite a lot of times and the OLED started to degrade (pixels getting "thinner") as the last time. We concluded that the used OLED and oil are not compatible and this is not a way we will go, sorry.

regards,
Matthias

[Anonymous User]

Oil filling is the old ways of potting electronics.

There are two commercial (non home-build) rebreather and dive computers using polyurethane electronic potting systems, which are flexible and have a shore hardness of maybe 50.

The OLED seems unaffected by the material, and the "give" in the material, unlike epoxy, looks like does not "crush" the electronics components.

Any thoughts?