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"Spin Weld" PVC Pipe & Fittings?

RickDelta
RickDelta Member Posts: 403
Hello HeatingHelp.com community!

I'm pondering the best way to PVC to PVC weld a 4" x 2" reducing fitting and a 2" pipe stub (3" long) with a special .2mm stainless steel filter screen wire mesh entrapped within the socket connection.

The screen serves as a water filter resin bead containment barrier (keeps the beads in the 4" pipe side yet allow the treated water to pass to the 2" out port side)

In the conventional "primer + cement" application ..... trying to keep the primer and cement from reaching (clogging) the screen ...... is problematic! : (

Even if I try to protect the screen during priming and cementing with a removable paper disk ...... the primer is so invasive it always finds a way past any protection! The cement not so far behind in this respect as well.

I could just easily "sandwich" this screen in between a PVC union ...... but the cost per screen mounting (30 to 40 2" unions needed per unit) would become outrageous. Using the existing socket connection has no cost at all.

So now I'm thinking ..... don't chemically weld at all ..... spin weld!

I've spin welded PVC pipe ends together with perfection (see pic) .... but don't know if the tapered socket + un-tapered pipe will actually work for this method.


....... any thoughts on all this?

Thanks!











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Comments

  • Intplm.
    Intplm. Member Posts: 2,128
    @RickDelta
    The best thing to do is to keep it as simple as possible by using fittings and adapters related to each other to offer the best result possible. ie... no leaks, true plumb and level.
  • Intplm.
    Intplm. Member Posts: 2,128
    Seems trial and error will be the saying of the day as you continue with this. Give it a try?
  • RickDelta
    RickDelta Member Posts: 403
    pecmsg said:
    ...... @ $63.00 each x 40 = $2,520 I'll take a chance with the socket design!
  • pecmsg
    pecmsg Member Posts: 5,099
    RickDelta said:
    I would just install a Y strainer rather then taking a chance

    https://www.amazon.com/TOMEX-Y-Strainer-Sediment-Socket-Female/dp/B0CL5SX5TQ?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A3GTUGHQ8MD61X
    ...... @ $63.00 each x 40 = $2,520 I'll take a chance with the socket design!
    Your choice!
    RickDelta
  • hot_rod
    hot_rod Member Posts: 22,784
    That looks like an awfully fine mesh? Prone to easily plugging and no easy way to service. That is where a Y strainer is handy, easy to disassemble and clean. Or change mesh size.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    PC7060
  • Grallert
    Grallert Member Posts: 714
    Is it under any pressure? You could prime and glue only the very ends of the fitting and only insert the pipe a 1/4 to 1/2 way?
    Miss Hall's School service mechanic, greenhouse manager,teacher and dog walker
  • RickDelta
    RickDelta Member Posts: 403
    Grallert said:

    Is it under any pressure? You could prime and glue only the very ends of the fitting and only insert the pipe a 1/4 to 1/2 way?

    Its under street pressure.
  • RickDelta
    RickDelta Member Posts: 403
    hot_rod said:

    That looks like an awfully fine mesh? Prone to easily plugging and no easy way to service. That is where a Y strainer is handy, easy to disassemble and clean. Or change mesh size.

    The cost for that many Y strainers would be way to costly for this application.

    I never need access to clean this filter. After service life of the resin beads I dispose of the entire assembly.
  • DCContrarian
    DCContrarian Member Posts: 484
    I know you want us to tell you that you've come up with a brilliant idea, but ...

    Is spin welding an approved method for joining street-pressure PVC in your jurisdiction?

    If you used a 2"x4" reducing bushing instead of the reducing coupling, and the bushing was threaded on the 2" side, you could put a male threaded adapter on the 2" pipe and screw the whole thing together. The bushing plus the adapter costs less than the coupling.

    If you're at street pressure you need fittings rated for potable water, which may be hard to find in 4".
  • RickDelta
    RickDelta Member Posts: 403
    edited April 11

    I know you want us to tell you that you've come up with a brilliant idea, but ...

    Is spin welding an approved method for joining street-pressure PVC in your jurisdiction?

    If you used a 2"x4" reducing bushing instead of the reducing coupling, and the bushing was threaded on the 2" side, you could put a male threaded adapter on the 2" pipe and screw the whole thing together. The bushing plus the adapter costs less than the coupling.

    If you're at street pressure you need fittings rated for potable water, which may be hard to find in 4".

    "Is spin welding an approved method for joining street-pressure PVC in your jurisdiction?"

    They "heat weld" the blue PVC water mains here I know.
    The spin weld "butt" end methode is extremely strong. When I smash it with a hammer the pipe breaks ....... but the joint remains intact.

    Your idea of using a threaded bushing sounds perfect! I will have to see if they make such a thing.

    ..... but I do believe a threaded connection derates (weakens) its use in a pressure environment.

  • pecmsg
    pecmsg Member Posts: 5,099
    Sorry but that’s not gonna cover your a$$ when there’s damages 
  • RickDelta
    RickDelta Member Posts: 403
    pecmsg said:

    Sorry but that’s not gonna cover your a$$ when there’s damages 

    .... what damages?? : (
  • pecmsg
    pecmsg Member Posts: 5,099
    What can possibly go wrong?
  • RickDelta
    RickDelta Member Posts: 403
    RickDelta said:

    I know you want us to tell you that you've come up with a brilliant idea, but ...

    Is spin welding an approved method for joining street-pressure PVC in your jurisdiction?

    If you used a 2"x4" reducing bushing instead of the reducing coupling, and the bushing was threaded on the 2" side, you could put a male threaded adapter on the 2" pipe and screw the whole thing together. The bushing plus the adapter costs less than the coupling.

    If you're at street pressure you need fittings rated for potable water, which may be hard to find in 4".

    "Is spin welding an approved method for joining street-pressure PVC in your jurisdiction?"

    They "heat weld" the blue PVC water mains here I know.
    The spin weld "butt" end methode is extremely strong. When I smash it with a hammer the pipe breaks ....... but the joint remains intact.

    Your idea of using a threaded bushing sounds perfect! I will have to see if they make such a thing.

    ..... but I do believe a threaded connection derates (weakens) its use in a pressure environment.

    Thinking:

    ....... Prime and cement the "threads" !!

    This would eliminate the primer and cement migration towards the filter screen and restore the joints pressure rating to standard pipe working PSI.


  • hot_rod
    hot_rod Member Posts: 22,784
    I had not heard of spin weld before. Does the pipe, used in water mains around there, have a specific end to maintain alignment
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • DCContrarian
    DCContrarian Member Posts: 484
    RickDelta said:


    Your idea of using a threaded bushing sounds perfect! I will have to see if they make such a thing.

    ..... but I do believe a threaded connection derates (weakens) its use in a pressure environment.

    https://www.homedepot.com/p/DURA-4-in-x-2-in-Schedule-40-PVC-Reducer-Bushing-SPGxFPT-438-420/203225044

    Rated for potable water too.
  • pecmsg
    pecmsg Member Posts: 5,099
    Is this on Potable Water?
    RickDelta
  • RickDelta
    RickDelta Member Posts: 403
    pecmsg said:
    Is this on Potable Water?
    Yes!
  • RickDelta
    RickDelta Member Posts: 403
    edited April 12
    Your idea of using a threaded bushing sounds perfect! I will have to see if they make such a thing. ..... but I do believe a threaded connection derates (weakens) its use in a pressure environment.
    https://www.homedepot.com/p/DURA-4-in-x-2-in-Schedule-40-PVC-Reducer-Bushing-SPGxFPT-438-420/203225044 Rated for potable water too.
    That won't work!   How do you "sandwich " the screen in-between the two mating surfaces?

    Think of a 2" pvc union ...... I could simply insert the screen in between the o- ring.

    That would be ideal ...... but is cost prohibited.

    .... just like I did with incerting a fender washer in this union at the end of a circulator.




  • RickDelta
    RickDelta Member Posts: 403
    edited April 12
    hot_rod said:
    I had not heard of spin weld before. Does the pipe, used in water mains around there, have a specific end to maintain alignment
    No!   ...... it's a "butt" joint. (just as I did in my pic)
  • DCContrarian
    DCContrarian Member Posts: 484
    RickDelta said:


    That won't work!   How do you "sandwich " the screen in-between the two mating surfaces?

    There's going to be a lip at the bottom of the threading, same size as the lip on the coupling in the original post.

    If that lip isn't big enough, here's an idea for making a bigger one: get a piece of 2" PVC and a 2" threading die. Thread the end of the PVC pipe, then cut 1/4" off the end. Use a nipple wrench to screw it down into the fitting until it bottoms out. Put in the screen, then screw in the rest of the pipe.

  • Larry Weingarten
    Larry Weingarten Member Posts: 3,481
    Hi @RickDelta , The screen you're looking at is pretty fine and could have a problem with blowing out if the flow rate got too high. Is there a way to put a grid behind the fine mesh? Maybe something like 1/4" welded wire mesh, but made of stainless??? Or, will the flow rate always be low?

    Yours, Larry
    RickDelta
  • RickDelta
    RickDelta Member Posts: 403

    Hi @RickDelta , The screen you're looking at is pretty fine and could have a problem with blowing out if the flow rate got too high. Is there a way to put a grid behind the fine mesh? Maybe something like 1/4" welded wire mesh, but made of stainless??? Or, will the flow rate always be low?

    Yours, Larry

    The manufacture of the screen mesh offers several high pressure reinforcement options ..... exactly as you had suggested.


  • RickDelta
    RickDelta Member Posts: 403
    edited April 14
    I think I found the perfect solution.
    Works with either chemical or spin welding.
    High pressure safe without added reinforcement.


    Simply lay screen disk over end of the 2" PVC pipe and heat press (embed) the stainless steel screen into the pipe end (aprox. 5 sec).

    Destructive testing (hitting with a hammer) punctures the screen ....... but the embedded mesh/seal remains intact!

    The tiny micro ridge formed in the PVC end is easily removed during the edge chamfering.

    During the pipe to fitting assembly, the screen edges are further entrapped tighty against the internal end stops within the socket itself.






  • Intplm.
    Intplm. Member Posts: 2,128
    @RickDelta My thought on this is to use a wye strainer as what @pecmsg says above. Go shopping for one that fits your needs and budget and modify it as necessary.
  • RickDelta
    RickDelta Member Posts: 403
    Intplm. said:

    @RickDelta My thought on this is to use a wye strainer as what @pecmsg says above. Go shopping for one that fits your needs and budget and modify it as necessary.


    ...... "Y" strainer @ $63.00 each x 40 = $2,520 I'll take a chance with the socket design!

    The filter never needs to changed or cleaned!
    The entire system including the pressure vessels are disposed of at the resin beads expiration.

    There is a replaceable particulate filter before and after this TAC water filter assembly.

    This entrapped socket filter design essentially costs nothing except for the 86 cent stainless steel mesh filter.


    CLamb
  • DCContrarian
    DCContrarian Member Posts: 484
    RickDelta said:

    I think a found the perfect solution.
    Works with either chemical or spin welding.
    High pressure safe without added reinforcement.


    Simply lay screen disk over end of the 2" PVC pipe and heat press (embed) the stainless steel screen into the pipe end (aprox. 5 sec).

    Destructive testing (hitting with a hammer) punctures the screen ....... but the embedded mesh/seal remains intact!

    The tiny micro ridge formed in the PVC end is easily removed during the edge chamfering.

    During the pipe to fitting assembly, the screen edges are further entrapped tighty against the internal end stops within the socket itself.

    I don't see how that is any less prone to fouling from migration of the cement than just using a fitting.

    How about this amendment: use a threading die to thread the end of the 2" pipe and screw it together.

  • ChrisJ
    ChrisJ Member Posts: 16,121
    What is spin welding?  Is that another name for friction welding?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • pecmsg
    pecmsg Member Posts: 5,099
    ChrisJ said:
    What is spin welding?  Is that another name for friction welding?
    That’s what it sounds like
  • RickDelta
    RickDelta Member Posts: 403
    ChrisJ said:

    What is spin welding?  Is that another name for friction welding?

    yes! .... (I posted a pic of it above)
  • ChrisJ
    ChrisJ Member Posts: 16,121
    I saw the picture, didn't know what I was looking at. 

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • RickDelta
    RickDelta Member Posts: 403

    RickDelta said:

    I think a found the perfect solution.
    Works with either chemical or spin welding.
    High pressure safe without added reinforcement.


    Simply lay screen disk over end of the 2" PVC pipe and heat press (embed) the stainless steel screen into the pipe end (aprox. 5 sec).

    Destructive testing (hitting with a hammer) punctures the screen ....... but the embedded mesh/seal remains intact!

    The tiny micro ridge formed in the PVC end is easily removed during the edge chamfering.

    During the pipe to fitting assembly, the screen edges are further entrapped tighty against the internal end stops within the socket itself.

    I don't see how that is any less prone to fouling from migration of the cement than just using a fitting.

    How about this amendment: use a threading die to thread the end of the 2" pipe and screw it together.



    The problem with a threaded filter screen solution is the rotational shear on the ultra fine screen mesh wires. It would tend to rip at the .2 mm filter spacing size and allow the resin beads to escape the 4"containment tank.

    .... and a threaded pvc pipe it's working pressure degraded.

  • RickDelta
    RickDelta Member Posts: 403
    edited April 14
    "@DDContrian"

    "I don't see how that is any less prone to fouling from migration of the cement than just using a fitting."

    ...... by having the filter screen embedded onto the end of the pipe (as opposed to inside the socket) the filter sits backwards 90 degrees away from the primer and cement application.

    ..... also, the big white fuzzy ball applicator is to un-controllable (messy), I'll be using a more controlled application to apply primer and cement (foam stick).
  • RickDelta
    RickDelta Member Posts: 403
    edited April 13
    ChrisJ said:

    I saw the picture, didn't know what I was looking at. 

    In-between the arrows is the spin weld joint!!

    I also take a 2" schedule 80 PVC pipe and expand its diameter to 4" schedule 40 as a sewer lateral repair liner.
    It then it becomes MO-PVC (Molecularly Oriented-PVC)




  • RickDelta
    RickDelta Member Posts: 403
    ChrisJ said:

    What is spin welding?  Is that another name for friction welding?


    ...... my first "spin weld"!

    CLamb
  • ChrisJ
    ChrisJ Member Posts: 16,121
    I'm sorry for I've only heard it called friction welding 
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    RickDelta
  • hot_rod
    hot_rod Member Posts: 22,784
    Doesn't the mesh interfere with the spin weld surfaces?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • RickDelta
    RickDelta Member Posts: 403
    edited April 14
    hot_rod said:

    Doesn't the mesh interfere with the spin weld surfaces?

    No! ...... unlike the "butt" joint type ... the friction is on the outside of the pipe wall.
    .
  • DCContrarian
    DCContrarian Member Posts: 484
    RickDelta said:

    hot_rod said:

    Doesn't the mesh interfere with the spin weld surfaces?

    No! ...... unlike the "butt" joint type ... the friction is on the outside of the pipe wall.
    .
    How do you guarantee it doesn't bottom out in the fitting?