Thread: Bonding PVC Pipe

I duct tape all my joins.

Originally Posted by CMB

I duct tape all my joins.

Interesting, how strong are your joins? Are they able to hold some heavy duty flexi pipe weight for example?

I'll be using the 100mm to run some flexi to my TS blade guard and it needs to take some weight.

Talking about tape. I purchased some double sided carpet tape (Norton, "good" $20 stuff), used some strips for a router job, and then about a year later went to use some more on a similar job and guess what...the tape was no longer adhesive!!

It had obviously got tired of watching me beavering away over the year and decided to forget about it's primary object!!!

Originally Posted by GarethR

Interesting, how strong are your joins? Are they able to hold some heavy duty flexi pipe weight for example?

I'll be using the 100mm to run some flexi to my TS blade guard and it needs to take some weight.

Talking about tape. I purchased some double sided carpet tape (Norton, "good" $20 stuff), used some strips for a router job, and then about a year later went to use some more on a similar job and guess what...the tape was no longer adhesive!!

It had obviously got tired of watching me beavering away over the year and decided to forget about it's primary object!!!

That can happen with double sided tape. Only super expensive commercial grade will last while sitting on the shelf.

As for duct tape, it's commonly used in commercial workshops here in Vic. Personally, I haven't had any problems to date on both rigid or flexi. Also easily removed as it's not permanent. Will leave behind some adhesive residue though that is quickly cleaned off. I don't use foil or webbed tape, just good old stretchy silver/grey duct tape. I'm sure others will agree, but happy to stand corrected if need be.

The joint the OPs is referring to is non-standard (a 45º entry of a 100 mm duct in a hole cut into a 150 mm Y) with very little to zero overlap (i.e. largely unsupported at the join) and not a smooth joint, so stuff like gaffer tape is not going to work and neither is PVC glue.

What works best is something that provides some support via a build up of material around the joint which is why I suggested a hot glue gun or plastic welding with plastic rod. This method will also fill any holes resulting from an imperfect fit. If the 100 mm duct is going to be under stress with say 100 flexy hanging off it I recommend adding some gussets for extra support.

Sikaflex, run a thick bead around it, smooth out with finger, 24hrs later same again, then in a weeks time you wont budge it, support it temporary for first 48hrs then good to go. You can reinforce it with 3 aluminium tabs about 100mm long x 20mm wide bent to the required angles and pop rivet to PVC

Originally Posted by rwbuild

Sikaflex, run a thick bead around it, smooth out with finger, 24hrs later same again, then in a weeks time you wont budge it, support it temporary for first 48hrs then good to go. You can reinforce it with 3 aluminium tabs about 100mm long x 20mm wide bent to the required angles and pop rivet to PVC

Sikflex is good stuff but there are zillion different kinds - which one would you recommend?

It also tends to be expensive and the amount that would be used for this job is small so you'd want the tube to last
I heard putting sikaflex silicone in the freezer is one way to prevent an opened capped tube hardening - anyone know if that is correct.
What about the other types?

BTW for extra strength.I would use the Al as gussets rather than tabs.

Thanks Guys.

Hot glue gun seems an attractive option. I'm guessing glue sticks have a reasonable shelf life?

Bob, did you have any recommendations what glue sticks to look out for? I'm guessing something with a medium to high viscosity and ability to bond with PVC, and depending on the gap something that can fill it?

Also, will a standard craft hot glue gun do or do I need something a little more industrial?

Thanks,

Gareth

Originally Posted by BobL

Sikflex is good stuff but there are zillion different kinds - which one would you recommend?

It also tends to be expensive and the amount that would be used for this job is small so you'd want the tube to last
I heard putting sikaflex silicone in the freezer is one way to prevent an opened capped tube hardening - anyone know if that is correct.
What about the other types?

BTW for extra strength.I would use the Al as gussets rather than tabs.

Sikaflex Pro

Originally Posted by GarethR

Thanks Guys.
Hot glue gun seems an attractive option. I'm guessing glue sticks have a reasonable shelf life?

I bought an elcheapo kit that came with a box of sticks about 10 years ago that are still working

Bob, did you have any recommendations what glue sticks to look out for? I'm guessing something with a medium to high viscosity and ability to bond with PVC, and depending on the gap something that can fill it?
Also, will a standard craft hot glue gun do or do I need something a little more industrial?

Unfortunately I can't help here, I'm not a big hot glue gun users.
One of the members posted about ducts and junctions using a hot glue gun - hopefully he will pop up and chip in

Acetone, works the same way the normal glues work.

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Originally Posted by steamjunkprops

Acetone, works the same way the normal glues work.

Sorry, not sure I understand this comment?

Originally Posted by GarethR

Sorry, not sure I understand this comment?

What he's saying is that acetone works like regular PVC glues (they dissolve some of the PVC from both pieces) and when it dries it bonds the two pieces.

Unless you have practice with acetone, because it is colourless you can't always tell where it has been applied and some of it can dry before the two pieces bond so it won't make a complete seal. The way I use acetone is put the two pieces together and then squirt the acetone into the joint and turn the pieces until the bond. It can be a messy process and it's toxic stuff so it's safer and easier to use the PVC cements.

Originally Posted by BobL

It can be a messy process and it's toxic stuff so it's safer and easier to use the PVC cements.

Thanks Bob, will take the safer option.

Originally Posted by BobL

Sikflex is good stuff but there are zillion different kinds - which one would you recommend?

It also tends to be expensive and the amount that would be used for this job is small so you'd want the tube to last
I heard putting sikaflex silicone in the freezer is one way to prevent an opened capped tube hardening - anyone know if that is correct.
What about the other types?

BTW for extra strength.I would use the Al as gussets rather than tabs.

Hi BobL

I keep my opened sikaflex silicone tubes in the beer/bait fridge in the shed. One opened tube has been in there over two years and is still good. I just seal the end with a couple of layers of glad wrap. I haven't tried the freezer though - not enough room anyway with it being full of bait and ice for fishing.

Regards
Twosheds