Need ideas for a PEX octopus

GopherT

Joined Nov 23, 2012
8,009
I'm sorry, what I've been calling 5/8" is actually know as 1/2" PEX. It's actual OD is 5/8". The industry's nominal 5/8" is indeed 3/4" OD, but that is not what I'm using.
If this will be blowing in the wind, I assume it will be blowing in the sun as well. PEX has terrible UV ratings.
Read the 6th FAQ listed in this page. 1 month limit of UV exposure on some grades, the rest get 3 months. I know you will not be running water pressure or risk any damage, but I cannot imaging this thing looking nice after 3 or 4 years in the sun.

Uponor is a PEX tubing manufacturer.
http://www.uponor-usa.com/Residential-Plumbing/Contractor/FAQs.aspx

Apparently there are building codes that require all PEX to be covered after installation so it cannot be seen (or it will not see any sunlight). Also, some postings about building codes that dictate how PEX is handled before installation (when it is unpackaged, where it is stored, ...).
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
Yup, I'm aware of that issue. The plan is to paint these orbs to make them appear they are made of metal. The paint won't last long either but it may get through a few seasons. Since the PEX will not be carrying water under pressure, the implications of a crack are not so dire.

I've tried to convince the artist to use barrel hoops but those are not so easy to find outside of the Kentucky bourbon area. They're quite popular with the crafting crowd.
 

GopherT

Joined Nov 23, 2012
8,009
Yup, I'm aware of that issue. The plan is to paint these orbs to make them appear they are made of metal. The paint won't last long either but it may get through a few seasons. Since the PEX will not be carrying water under pressure, the implications of a crack are not so dire.

I've tried to convince the artist to use barrel hoops but those are not so easy to find outside of the Kentucky bourbon area. They're quite popular with the crafting crowd.
Paint with Krylon Fusion. The only paint I know of that is designed for low surface energy plastics. It really sticks and looks good for a long time. Do not prime before spraying the PEX.
 

cmartinez

Joined Jan 17, 2007
8,218
Paint with Krylon Fusion. The only paint I know of that is designed for low surface energy plastics. It really sticks and looks good for a long time. Do not prime before spraying the PEX.
Excellent tip, I too have to do paintwork every now and then. Would you mind elaborating and explain what a low surface energy plastic is?
 

GopherT

Joined Nov 23, 2012
8,009
Excellent tip, I too have to do paintwork every now and then. Would you mind elaborating and explain what a low surface energy plastic is?
Nearly all plastics are lower surface energy than wood or metals (surfaces are normally metal oxides). Best description is any plastic that you cannot fasten with superglue or solvent adhesive (like PVC or styrene). They normally feel slippery, water beads up more than normal (polypropylene, Teflon, polyethylene (HDPE, LDPE, PEX, UHMWPE)).

The other DIY option is flaming. Literally running a flame from a propane torch over the surface before you spray it. Not enough to melt it, you don't really even need to heat it. The process creates a thin, partial oxidation and polar attachment points for adhesives or paints. Not as good as a paint or glue intended for low energy surfaces but a surprising improvement vs. no surface chemistry attempt.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
Since no one is jumping forward to print my hub, I've continued to make some refinements.
1) I enlarged the tubing sleeves by 0.005" to 0.63 instead of 0.625. The commercial SharkBite fitting drawing I found used that ID, and it makes sense to ensure the PEX tubing will slide in easily and to leave a little room for adhesive.
2) I added fillets in between the arms and this should add quite a bit of strength without using much plastic.
3) The arms were shortened 0.1" and the central hole was enlarged, both to shave off some plastic. I don't think much strength was sacrificed by this.
Screen Shot 2015-03-24 at 11.36.58 AM.png Screen Shot 2015-03-24 at 11.08.41 AM.png
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
Yes, I realize 3D printing may be a blind alley for this project since it takes time and materials - more of both than I can ask of anyone. I only investigated this avenue because of Bill's generous offer to print at (I assumed from his comments) a discount, and because I wanted to learn new tricks and see what all the hoopla is about.

The quotes I've gotten at the online service shops range from ~$16 to over $100 with only a little information on what the differences (if any) might be. I live in a 3D-printing desert with only one option within 50 miles. Not that I have to be there in person, but local would be nice.

The hype of 3D printing is a bit overblown in my opinion, when a cheap hunk of plastic costs >$20. That's nothing if your work requires making prototypes but it's not cheap for DIY or craft projects.
 

mcgyvr

Joined Oct 15, 2009
5,394
The hype of 3D printing is a bit overblown in my opinion, when a cheap hunk of plastic costs >$20. That's nothing if your work requires making prototypes but it's not cheap for DIY or craft projects.
The machines are simply too slow to not be a "hype" at this point..
I'd print one for you.. but don't have the time to print all you need.. So I don't want to be the let down there..
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
Well, even just one would be hugely useful to validate the drawing. Maybe my patron would be willing to pay for the online services if we have confidence in the approach.

I hate to ask for such a big favor, but if I could get a prototype it would be very helpful. No problem to pay for the plastic and shipping. Let me know if you're game.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
Yes, and I saw it there. I'm sure the advances of 3D printing are not reaching the end, they are just beginning.
 

Wendy

Joined Mar 24, 2008
23,415
Actually, I am still planning on printing it, if the plans work as is. Been a bit bust lately, sorry bout that.
 

Thread Starter

wayneh

Joined Sep 9, 2010
17,496
No problem, Bill. mcgyvr generously stepped in to give it a go. This first prototype will tell an awful lot about what to do next. Then we'll consider #2.
 
Top