ppo2 meter houssing

**jmurba** · 12th June 2006, 21:20

Hi all,

I've built oxymeter circuits for 5 years now to control my kiss syle dolphin.

I've nearly never had problem with electronics, playing with lcds and pic micros is a "piece of cake" compared with building a descent houssing !!!

I don't know if I am damned but i've never managed to built a watertight houssing !!!!

I'am now thinking of drowning my circuits in epoxy resin.

as anybody tried that down threre ?

regards

jean mi

Joseph Grech · 12th June 2006, 21:27

Hi I have done this several times with sucess. I normally use araldite transparent epox resin the slow setting one. All you have to do is to keep heat on the surface ( I switch on a lampshade very very near the resin ) to get a result without any microbubbles and it will be crystal clear.

Joseph

**jmurba** · 12th June 2006, 21:38

Dear Joseph,

thanks a lot for reassurring me, it is just greate, given the small price of a pic 16F876 a lcd and a oupl of cheap components; I came to the conclusion I'de rather drown all the circuit in resin, I though of doing it in 2 separate stages, first of all moulding a houssing drilling it to install a lumberg connector, second stage wirering the circuit and and filling the houssing with epoxy resin.
am I on the right track ?

regards

jean mi

Quote: (Originally Posted by Joseph Grech)

Hi I have done this several times with sucess. I normally use araldite transparent epox resin the slow setting one. All you have to do is to keep heat on the surface ( I switch on a lampshade very very near the resin ) to get a result without any microbubbles and it will be crystal clear.

Joseph

rdmmdr · 13th June 2006, 00:53

if you have a vacume chamber to pull out the air added durring mixing, before you poor it helps.
rick

Scuba_Vixen · 13th June 2006, 04:02

Quote: (Originally Posted by jmurba)

Hi all,

I've built oxymeter circuits for 5 years now to control my kiss syle dolphin.

I've nearly never had problem with electronics, playing with lcds and pic micros is a "piece of cake" compared with building a descent houssing !!!

I don't know if I am damned but i've never managed to built a watertight houssing !!!!

I'am now thinking of drowning my circuits in epoxy resin.

as anybody tried that down threre ?

regards

jean mi

I like encapsulating the circuit as a module, makes it pretty bomb proof if the housing leaks, but gives you the option to re-use the housing if you decide to make a different circuit.

Here's a pic of my remote digital readout handset that's run from my HUD controller.

The encapsulated controller module has it's own housing.

Darlene

**jmurba** · 13th June 2006, 07:21

Quote: (Originally Posted by rdmmdr)

if you have a vacume chamber to pull out the air added durring mixing, before you poor it helps.
rick

Hello,

I have one, (vacum chamber)

to be honest I and my best friend totaly failed in moulding éoxy houssings using RTV resin moulds (rtv resin is a sort of silicon resin).
In 2 years of hard work we managed to get rig of the bubbles (not all of course) but nearly never managed to get accurates o ring groves.
Due to resin loss of volume during the polymerisation we had to face sligths deformations of the o ring grove .
most of the time the houssings looked perfect, and were watertigth at the begining of the tests, but soon after the first dives we faced electronics drownings......grrrrrr!!!!!

this is why we think of drowning everything (execpt the batteries) in resin !!!!

As for the bubble problem what one have to know is that when one try to get rid of the bubble using a vacum chamber one increase the number of bubbles in the resin because of offgassing !!! so resin have to be offgassed long enough to éliminate both mixing bubbles and offgassing bubbles.

all of this require experience......we paid to know that.

on the other hand, the metal machines houssing are not perfect and machining a grove in a square piece of metal is not a piece of cake.

machining a grove in a tube is easy, not on a square houssing, ..

a good friend of mine ha machined a beautiful metal houssing.....and he drown it !!!!

regards

jean mi

**jmurba** · 13th June 2006, 07:24

nice job Darlene

Here's a pic of my remote digital readout handset that's run from my HUD controller.

jaap · 13th June 2006, 11:51

Quote: (Originally Posted by jmurba)

Hello,

I have one, (vacum chamber)

to be honest I and my best friend totaly failed in moulding éoxy houssings using RTV resin moulds (rtv resin is a sort of silicon resin).
In 2 years of hard work we managed to get rig of the bubbles (not all of course) but nearly never managed to get accurates o ring groves.
Due to resin loss of volume during the polymerisation we had to face sligths deformations of the o ring grove .
most of the time the houssings looked perfect, and were watertigth at the begining of the tests, but soon after the first dives we faced electronics drownings......grrrrrr!!!!!

this is why we think of drowning everything (execpt the batteries) in resin !!!!

As for the bubble problem what one have to know is that when one try to get rid of the bubble using a vacum chamber one increase the number of bubbles in the resin because of offgassing !!! so resin have to be offgassed long enough to éliminate both mixing bubbles and offgassing bubbles.

all of this require experience......we paid to know that.

on the other hand, the metal machines houssing are not perfect and machining a grove in a square piece of metal is not a piece of cake.

machining a grove in a tube is easy, not on a square houssing, ..

a good friend of mine ha machined a beautiful metal houssing.....and he drown it !!!!

regards

jean mi

Salut!

Yes offgassing the resin is good, I play around with casting samples in epoxy at work (For XAS-anaysis). But it can be tricky, very much so if you need it to seal against an o-ring. But why would the epoxy have to be part of the outer sealing?

Have you tried to simply coat your electronics with say clear nailpolish? Its a quick and dirty solution that has saved some of my electronics from floods in brackish water.

**jmurba** · 13th June 2006, 15:38

Quote: (Originally Posted by jaap)

Salut!
hello,
But why would the epoxy have to be part of the outer sealing?
Sorry i don't understand, maybye my poor english ???
Have you tried to simply coat your electronics with say clear nailpolish?
yes but it was not enough to face a slated water soup
Its a quick and dirty solution that has saved some of my electronics from floods in brackish water.

you are rigth it would maybye have saved a couple of circuit but on the other hand i would not have dared to dive again a drown circuit.

regards

jean mi

jaap · 13th June 2006, 18:00

Quote: (Originally Posted by jmurba)

you are rigth it would maybye have saved a couple of circuit but on the other hand i would not have dared to dive again a drown circuit.

regards

jean mi

OK

I was confused. So you tried to mold the entire housing out of epoxy?

Another thing, were did you find those threaded PVC-cross unions (croix PVC fileté) you have as sensor holders?

http://www.therebreathersite.nl/imag...ortesensor.jpg

I have been looking around on the internet and in many stores dealing with things like that in the Cannes area.

12th June 2006, 21:20	#1 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	ppo2 meter houssing Hi all, I've built oxymeter circuits for 5 years now to control my kiss syle dolphin. I've nearly never had problem with electronics, playing with lcds and pic micros is a "piece of cake" compared with building a descent houssing !!! I don't know if I am damned but i've never managed to built a watertight houssing !!!! I'am now thinking of drowning my circuits in epoxy resin. as anybody tried that down threre ? regards jean mi
(Offline)

12th June 2006, 21:27	#2 (permalink)
Joseph Grech Joseph Grech Current Rebreather/s: Azimuth Other Rebreather/s: Azimuth Join Date: Mar 2005 Location: Malta Posts: 104	Re: ppo2 meter houssing Hi I have done this several times with sucess. I normally use araldite transparent epox resin the slow setting one. All you have to do is to keep heat on the surface ( I switch on a lampshade very very near the resin ) to get a result without any microbubbles and it will be crystal clear. Joseph
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12th June 2006, 21:38	#3 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: ppo2 meter houssing Dear Joseph, thanks a lot for reassurring me, it is just greate, given the small price of a pic 16F876 a lcd and a oupl of cheap components; I came to the conclusion I'de rather drown all the circuit in resin, I though of doing it in 2 separate stages, first of all moulding a houssing drilling it to install a lumberg connector, second stage wirering the circuit and and filling the houssing with epoxy resin. am I on the right track ? regards jean mi Quote: (Originally Posted by Joseph Grech) Hi I have done this several times with sucess. I normally use araldite transparent epox resin the slow setting one. All you have to do is to keep heat on the surface ( I switch on a lampshade very very near the resin ) to get a result without any microbubbles and it will be crystal clear. Joseph
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13th June 2006, 00:53	#4 (permalink)
rdmmdr designer of death Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2006 Location: kerman,california Posts: 372	Re: ppo2 meter houssing if you have a vacume chamber to pull out the air added durring mixing, before you poor it helps. rick
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13th June 2006, 04:02	#5 (permalink)
Scuba_Vixen e/mCCR Dolphin Pilot Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: May 2005 Location: St. Croix USVI Posts: 557	Re: ppo2 meter houssing Quote: (Originally Posted by jmurba) Hi all, I've built oxymeter circuits for 5 years now to control my kiss syle dolphin. I've nearly never had problem with electronics, playing with lcds and pic micros is a "piece of cake" compared with building a descent houssing !!! I don't know if I am damned but i've never managed to built a watertight houssing !!!! I'am now thinking of drowning my circuits in epoxy resin. as anybody tried that down threre ? regards jean mi I like encapsulating the circuit as a module, makes it pretty bomb proof if the housing leaks, but gives you the option to re-use the housing if you decide to make a different circuit. Here's a pic of my remote digital readout handset that's run from my HUD controller. The encapsulated controller module has it's own housing. Darlene
(Offline)

13th June 2006, 07:21	#6 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: ppo2 meter houssing Quote: (Originally Posted by rdmmdr) if you have a vacume chamber to pull out the air added durring mixing, before you poor it helps. rick Hello, I have one, (vacum chamber) to be honest I and my best friend totaly failed in moulding éoxy houssings using RTV resin moulds (rtv resin is a sort of silicon resin). In 2 years of hard work we managed to get rig of the bubbles (not all of course) but nearly never managed to get accurates o ring groves. Due to resin loss of volume during the polymerisation we had to face sligths deformations of the o ring grove . most of the time the houssings looked perfect, and were watertigth at the begining of the tests, but soon after the first dives we faced electronics drownings......grrrrrr!!!!! this is why we think of drowning everything (execpt the batteries) in resin !!!! As for the bubble problem what one have to know is that when one try to get rid of the bubble using a vacum chamber one increase the number of bubbles in the resin because of offgassing !!! so resin have to be offgassed long enough to éliminate both mixing bubbles and offgassing bubbles. all of this require experience......we paid to know that. on the other hand, the metal machines houssing are not perfect and machining a grove in a square piece of metal is not a piece of cake. machining a grove in a tube is easy, not on a square houssing, .. a good friend of mine ha machined a beautiful metal houssing.....and he drown it !!!! regards jean mi
(Offline)

13th June 2006, 07:24	#7 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: ppo2 meter houssing nice job Darlene Here's a pic of my remote digital readout handset that's run from my HUD controller.
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13th June 2006, 11:51	#8 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 473	Re: ppo2 meter houssing Quote: (Originally Posted by jmurba) Hello, I have one, (vacum chamber) to be honest I and my best friend totaly failed in moulding éoxy houssings using RTV resin moulds (rtv resin is a sort of silicon resin). In 2 years of hard work we managed to get rig of the bubbles (not all of course) but nearly never managed to get accurates o ring groves. Due to resin loss of volume during the polymerisation we had to face sligths deformations of the o ring grove . most of the time the houssings looked perfect, and were watertigth at the begining of the tests, but soon after the first dives we faced electronics drownings......grrrrrr!!!!! this is why we think of drowning everything (execpt the batteries) in resin !!!! As for the bubble problem what one have to know is that when one try to get rid of the bubble using a vacum chamber one increase the number of bubbles in the resin because of offgassing !!! so resin have to be offgassed long enough to éliminate both mixing bubbles and offgassing bubbles. all of this require experience......we paid to know that. on the other hand, the metal machines houssing are not perfect and machining a grove in a square piece of metal is not a piece of cake. machining a grove in a tube is easy, not on a square houssing, .. a good friend of mine ha machined a beautiful metal houssing.....and he drown it !!!! regards jean mi Salut! Yes offgassing the resin is good, I play around with casting samples in epoxy at work (For XAS-anaysis). But it can be tricky, very much so if you need it to seal against an o-ring. But why would the epoxy have to be part of the outer sealing? Have you tried to simply coat your electronics with say clear nailpolish? Its a quick and dirty solution that has saved some of my electronics from floods in brackish water.
(Offline)

13th June 2006, 15:38	#9 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: ppo2 meter houssing Quote: (Originally Posted by jaap) Salut! hello, But why would the epoxy have to be part of the outer sealing? Sorry i don't understand, maybye my poor english ??? Have you tried to simply coat your electronics with say clear nailpolish? yes but it was not enough to face a slated water soup Its a quick and dirty solution that has saved some of my electronics from floods in brackish water. you are rigth it would maybye have saved a couple of circuit but on the other hand i would not have dared to dive again a drown circuit. regards jean mi
(Offline)

13th June 2006, 18:00	#10 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 473	Re: ppo2 meter houssing Quote: (Originally Posted by jmurba) you are rigth it would maybye have saved a couple of circuit but on the other hand i would not have dared to dive again a drown circuit. regards jean mi OK I was confused. So you tried to mold the entire housing out of epoxy? Another thing, were did you find those threaded PVC-cross unions (croix PVC fileté) you have as sensor holders? http://www.therebreathersite.nl/imag...ortesensor.jpg I have been looking around on the internet and in many stores dealing with things like that in the Cannes area.
(Offline)

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