bonding polypropylene

[davil]

need to fasten a fitting to a polypropylene tank.
Most adhesives will fail
google it and few choices available.
suggestions?
thanks

[Pete7]

How much strength is needed and what are the consequences if it fails. Is the tank sufficiently thick you might try welding another piece onto it and then bolt to that?

P

[slug]

Originally Posted by davil

need to fasten a fitting to a polypropylene tank.
Most adhesives will fail
google it and few choices available.
suggestions?
thanks

Google “ flame treatment polypropylene “

https://epoxycraft.com/top-tips-best...treat-plastic/

This is the classic way

Also I believe there are specialized primer adhesives

[davil]

Originally Posted by slug

Google “ flame treatment polypropylene “

https://epoxycraft.com/top-tips-best...treat-plastic/

This is the classic way

Also I believe there are specialized primer adhesives

=======================================
thanks might try
the only place I found https://www.masterbond.com/tds/x21med
the wall s about 1/4 and not thick enough to thread a 1/2 pvc pipe fitting,need first to glue any material to bring it to at least 1/2 thick wall,and cannot get my hand inside to just use a nut inside to tighten and seal

[davil]

Originally Posted by Pete7

How much strength is needed and what are the consequences if it fails. Is the tank sufficiently thick you might try welding another piece onto it and then bolt to that?

P

thanks
that was my thought, to apply a piece of wood, plastic, to increase the wall thickness , is going to have a 1/2" pipe fitting to then run a hose out of it

[sail sfbay]

Originally Posted by davil

Need to fasten a fitting to a polypropylene tank...............

Depends on the fitting material. If metal to polypropylene check this YouTube out>

https://www.youtube.com/watch?v=vuehpdiICjI

[hpeer]

If you find something that works please post it.

I and a lot of other Porta-Boat owners have a rip in a highly flexible bend. None of us have yet come up with a good solution.

Beyond that you might consider making a metal tank seal if you have the room. But it would be complicated and rather large.

[Steve Bean]

davil: could you use a stiff wire bent to shape, to hold a nut and washer inside the tank? Or even a tiny pair of vise-grip pliers on the wire?

[davil]

Originally Posted by Steve Bean

davil: could you use a stiff wire bent to shape, to hold a nut and washer inside the tank? Or even a tiny pair of vise-grip pliers on the wire?

=================================================
there is a thought
will try

[davil]

Originally Posted by hpeer

If you find something that works please post it.

I and a lot of other Porta-Boat owners have a rip in a highly flexible bend. None of us have yet come up with a good solution.

Beyond that you might consider making a metal tank seal if you have the room. But it would be complicated and rather large.

===============================
I will,the only seems reputable outfit is the one in England,see my earlier link,the problem is the cost,with the heat gun etc almost $100.

[davil]

Originally Posted by Pete7

How much strength is needed and what are the consequences if it fails. Is the tank sufficiently thick you might try welding another piece onto it and then bolt to that?

P

===============================================
at the risk to start WW3, the item in question is the urine container of the Naturehead, the last time I mentioned to have the container plumbed via a small hand pump to a thru-hull I provoked the ire and condemnation of the composting toilet users/ community
The thing is last year cruising found that while at anchor is not problem underway carrying the container to empty overboard was an epic job, trying no to spell the precious liquid and making a mess when the boat is bouncing around, not an easy job.

[FPNC]

I use to 'spin weld' poly fittings into roto-molded poly tanks using a wood working router to spin the fitting that is held in a mandrel. Takes about .8 seconds. The individual fittings are available from tank manufacturers like Moeller. You have to be creative in coming up with a mandrel to match your particular fitting. I use to spin in 3/4" and 1 1/2" female thread fittings very easily.

[Dsanduril]

If you can't spin weld then PermaBond makes a primer that is supposed to raise the surface energy enough that super glues (cyanoacrylate) will work.

https://www.permabond.com/wp-content...04/POP_TDS.pdf

Pretty sure Loctite makes a competitor but I've had good luck with the PermaBond on PE. Have not tried it on PP (pun intended).

[davil]

Originally Posted by Dsanduril

If you can't spin weld then PermaBond makes a primer that is supposed to raise the surface energy enough that super glues (cyanoacrylate) will work.

https://www.permabond.com/wp-content...04/POP_TDS.pdf

Pretty sure Loctite makes a competitor but I've had good luck with the PermaBond on PE. Have not tried it on PP (pun intended).

=============================================
checked out Amazon and they have a Permabond Primer for $36
or
by Aron Alpha Industrial Krazy Glue for $ 26
Aron Alpha PP Primer For Use With Instant Adhesives To Bond Polyolefine Plastics, 100ml (3.38 oz)
4.1 out of 5 stars 3 ratings
or 3M products
by 3M
3M Scotch-Weld Instant Adhesive Primer AC77, and AC79
3M products on the $ 30 range.

looks like all of them will do a good? job at priming.

Question:
I will guess you prime the area and then use any of the superglues (cyanoacrylate)?

[davil]

update


used water and milk containers as surfaces to bond
tried with preheating them vs non preheating

preheating seems better,


used the primer on all areas



overall superglue to wood seems better

superglue bonding poly to poly seems ok too


5200 on poly to poly failed


5200 wood to poly seems to work



drilled thru wood and poly no problem.


Need to decide between using wood with superglue or 5200 to bond to surface,then will just work a hole for a plastic fitting from inside container and tighten from outside using the wooden flange and sealant.


because once in place there is not really any movement or force used the fitting should be kept in place