Weldon

[Gina McReeferson]

How secure is the bond between PVC and acrylic with weldon? Should a bulkhead fitting be used if the joint is to be permanent? Is it as strong as an acrylic to acrylic mating, or is it not to be trusted? The joint in question will be that of a 2" PVC pipe passing through 1/4" thick acrylic, some vibration may be present as a pump will be hooked up to the pipe, but no other forces will be applied to the joint. What are your thoughts?

-Dave

 

[mloebl]

How secure is the bond between PVC and acrylic with weldon? Should a bulkhead fitting be used if the joint is to be permanent? Is it as strong as an acrylic to acrylic mating, or is it not to be trusted? The joint in question will be that of a 2" PVC pipe passing through 1/4" thick acrylic, some vibration may be present as a pump will be hooked up to the pipe, but no other forces will be applied to the joint. What are your thoughts?

-Dave

I've been reading about it since I wish to do this as well, and apparently Weld-On 40 is supposed to do this. I got a custom made Kalk reactor with PVC bonded to acrylic, and it's a solid bond on it, just not sure if it's Weld-On 40 or not.

-Mike

 

[JohnK]

I may be wrong, but If I understand correctly, a PVC to acrylic joint could never be as strong as acrylic to acrylic. It would basically be glued, but not welded. (ie seperate materials stuck together vs same materials melted together so they become one)

To connect a pipe to an acrylic tank/sump I would absolutely use a bulkhead. It would be very easy to drill the hole, the bulkhead would be cheap, and you wouldn't have to worry about it.

 

[Gina McReeferson]

This is purely for asthetic reasons, I may just cut down a bulkhead fitting a bit to give it a more flush look. If the threaded end went on the inside this would not be an issue, but it has to on the outside and gives a messy look to the whole thing.

Anybody else have any thoughts on this?

 

[Casino]

I wouldnt trust it. It will leak in time. Try to get a small diameter acrylic tube or something. PVC and acryliC dont bond well.

 

[JohnK]

I'm really vauge on this, but IIRC you can get bulkheads sold for hot tubs that are much shorter than the ones usually used in the hobby. Sounds like they might be what your looking for?

I think Marvin might know the scoop, try PMing him and asking about this???

 

[muddskipper]

I use weldon 16 to bond pvc to acrylic ... HOWEVER when going through acrylic I use half a slip joint on BOTH sides and use a clamp and generous amounts of weldon to tightly seal the joints .. the weldon will seal the slips and pvc together and melt into the acrylic to form and bond into the pvc.. however.. as stated the weldon although making a tight bond with the pvc will seperate with enough pressure on it.. It does however take a good bit of pressure.. I tested this therory a couple months ago and wasnt dissappointed but would not trust it in med to high pressure or anywhere that should it seperate your going to be in trouble... in sump or in tank would be fine..

 

[muddskipper]

Also using this method on my DIY calcium reactor .. 3 weeks and no leaks .. Its holding very well and this is with a mag7 pushing the flow through the chamber.. I did however put several pieces of acrylic together to make almost a 1/2in thickness where the pvc went through and made sure it was a very tight fit then coated with weldon16 and pushed them through and added alittle more around the outside.. I use a heat gun with low heat to help set the weldon and use my finger to push the weldon down as it bubbles up, this insures it being bubble free and has a tight seal around the bases..
probally overkill but its better then a leak or worse..

 

[Liam]

as previously stated weldon will not work well for pvc.
You would be better off using an epoxy

splurging on extra amounts of weldon wont do you any good either.Weldon works via a chemical reaction that is specific to its contact with acrylic.Yes the extra weldon will set up but won't be of much use for the long haul.

 

[Gina McReeferson]

Some free time this afternoon Liam?

What type of epoxy would you recommend? I went with the bulkhead fittings on the larger orifices, but there are still a couple spots where acrylic tubing will need to be mated to PVC fittings... Standard run of the mill epoxy sufficient?

 

[Liam]

Some free time this afternoon Liam?

What type of epoxy would you recommend? I went with the bulkhead fittings on the larger orifices, but there are still a couple spots where acrylic tubing will need to be mated to PVC fittings... Standard run of the mill epoxy sufficient?

whats free time???

there are so many epoxies out there these days,i would take a moment to read the labels before you buy,all should work well but some would be better choices than others.

 

[mloebl]

So are you essentially saying this stuff won't work:

http://www.ellsworth.com/display/productdetail.html?productid=805&Tab=Products

-Mike

 

[Liam]

So are you essentially saying this stuff won't work:

http://www.ellsworth.com/display/productdetail.html?productid=805&Tab=Products

-Mike

it will work but is not the best adhesive for the job.Especially if you are trying to make a water/pressure tight seal when bonding small surface areas.

I have tried weldon to glue acryilic to pcv and it just did'nt seem to really hold,especially with schedule 80.

 

[mloebl]

it will work but is not the best adhesive for the job.Especially if you are trying to make a water/pressure tight seal when bonding small surface areas.

Gotcha, thank you! I am looking to use it to form an area while minor leakage is ok in a skimmer as it will be in the base, so as long as it's not gushing, a small leak would be fine. Rather than trying to does some fancy cut work to combine to create a connection from the injector tube to the riser area of a skimmer, I wanted to use some PVC elbows for the bends. Since it's inside the base of the skimmer and will never be seen again, it doesn't have to be visually appealing.

-Mike

 

[Liam]

Gotcha, thank you! I am looking to use it to form an area while minor leakage is ok in a skimmer as it will be in the base, so as long as it's not gushing, a small leak would be fine. Rather than trying to does some fancy cut work to combine to create a connection from the injector tube to the riser area of a skimmer, I wanted to use some PVC elbows for the bends. Since it's inside the base of the skimmer and will never be seen again, it doesn't have to be visually appealing.

-Mike

hopefully you will find it won't even leak.
In most cases when this type of joint is being made someone is glueing a pcv fitting that is going to be connected and disconnected many times and over time the joint fails.

I speak from wet experience

 

[Liam]

FWIW i tried pcv cement in the past and that did not work at all on the acrylic.

 

[Gina McReeferson]

Gotcha, thank you! I am looking to use it to form an area while minor leakage is ok in a skimmer as it will be in the base, so as long as it's not gushing, a small leak would be fine. Rather than trying to does some fancy cut work to combine to create a connection from the injector tube to the riser area of a skimmer, I wanted to use some PVC elbows for the bends. Since it's inside the base of the skimmer and will never be seen again, it doesn't have to be visually appealing.

-Mike

The PVC elbows will give you a smoother transition than would the angle cut acrylic anyway IME. The way it is fashioned in the link you have in your thread would be a bit less efficient and would no doubt lead to some larger bubbles being thrown in the mix. You don't want any sharp corners or ledges for bubbles to accumulate and possibly join creating larger bubbles. I am sure that design works just fine, but it seems this area could be improved upon.

In this situation I would use some acrylic rod, drill some holes around the perimiter of the joint, then insert the pins using weldon. This way, regardless of the glue between the PVC and acrylic holding or not they cannot come apart. A "captive" joint.

-Dave

 

[mloebl]

In this situation I would use some acrylic rod, drill some holes around the perimiter of the joint, then insert the pins using weldon. This way, regardless of the glue between the PVC and acrylic holding or not they cannot come apart. A "captive" joint.

-Dave

EXCELLANT idea! Thanks!!

-Mike