DIY 3D Printed CCR parts - Replacement purge cover for Hollis BOV 2nd stage

[The Chairman]

In any case i never post my designs until after i use them for a bit. I will likely share it after a few dives for testing.

I even share links to my Cad designs on OnShape, in case others want to modify what I've created.

 

[davehicks]

I even share links to my Cad designs on OnShape, in case others want to modify what I've created.

I have a number of designs on Thingiverse.

I've been designing with Fusion360. I looked at OnShape after i started with Fusion. Have you used both? I have had a few quirks with Fusion lately that made me wonder if i should try OnShape.

 

[mlavigne]

Nice project.
The benefit of onshape is nothing to install and most of the resources are on the remote server. This means anyone with any class of computer (even a chrome book would probably be fine) can check out your files, make modifications, etc.

the free-tier is non-commercial only and makes all your projects open-sourced, so dont use it for anything you want to sell (unless you get the paid version, of course)- i think Fusion has a similar non-commercial license. Anyways, this is perfect for projects you intend to share anyways.

We have considered switching from solidworks to onshape (paid tier) at work- less capable, but lower cost and does 98% of what we need.

 

[davehicks]

Nice project.
The benefit of onshape is nothing to install and most of the resources are on the remote server. This means anyone with any class of computer (even a chrome book would probably be fine) can check out your files, make modifications, etc.

the free-tier is non-commercial only and makes all your projects open-sourced, so dont use it for anything you want to sell (unless you get the paid version, of course)- i think Fusion has a similar non-commercial license. Anyways, this is perfect for projects you intend to share anyways.

We have considered switching from solidworks to onshape (paid tier) at work- less capable, but lower cost and does 98% of what we need.

Interesting, I didn't know about the Onshape public posting of all projects. I like Fusion pretty well now. I initially started with FreeCad, but pretty quickly moved off it as it's really antiquated and primitive by comparison.

 

[The Chairman]

All CADs have their limits. OnShape is more than robust enough for me, since I had never touched CAD before. I got up one Sunday, opened their tutorial, and designed a battery holder for 12 18650s to fit my cannister dive lights. I've refined it a bunch since then, but was pretty happy with my first efforts. I can't compare it to Fusion 360, because I never really figured it out. Then I tried OnShape, and have been learning ever since.

 

[OTF]

This is awesome! Great job!

Let us know how it dived, and maybe do a long-term update some time in the future. Curious to see how the TPU holds up over time.

 

[davehicks]

This is awesome! Great job!

Let us know how it dived, and maybe do a long-term update some time in the future. Curious to see how the TPU holds up over time.

Yes, I will update after my next dives later this week.

As for TPU in the water, I made optical cable connectors with TPU that have seen hundreds of dives from me and others using them. They seem to be holding up well with no issues so far. (the black bits are all TPU rubber)

 

[davehicks]

I was able to dive tonight with my DIY franken-reg on the Hollis BOV. All went just fine and the regulator performed normally. It purged well above and below the water, and breathed about as well as it ever does. Its not a great regulator and i leave it tuned pretty rough.

The original failure resulted in not being able to get a positive or negative seal on the loop. That is fixed now and it functions about as well as it ever did.

I think i can call this a success, and will keep diving this for a good long while!

 

[emoreira]

I've printed flexible 2nd stage purge covers with flexible filament (TPU). I've found that, even though the functionality is the same as the original covers, it feels hard. perhaps I'm designing too stiff.
I've done a new design with ABS and a spring loaded button, which behaves and feels a lot better. I've sold many of those replacements in the local market.
Take a look here : No more flex covers !!!
I've improved the design and there is now no need for a stainless steel screw and nut.
The spring is one used in BCD releif valves from a scrapped BCD.

 

[Timmyjane]

I dive with a fair variety of similar parts on vintage open circuit gear... I've done TPU purge covers on SP 109's, printed ABS faceplates, even printed molds for poured silicone main diaphragms with printed ABS friction plates. You're not nuts, just making good application of ingenuity! I would recommend a gradual build up in the dive testing, but I expect that was already the plan.

Respectfully,

James

I sent you a message on Thingiverse but see you’re here. Makes sense you would be.. Are the files in a Thingiverse current for the TPU diaphram cover? You liking them? I have 2 109s that are in need. Might be a good reason to get a new direct drive printer.