Hi what would be the best glue to use to glue plastic tubing to small plastic pots that would be full of water. I was going to use silicone sealant but it says not to use in permanently damp conditions. The joint would in water all the time. This is to make a watering system for a greenhouse.
I think Ed Sirrett mentioned a couple of adhesives the other day (another thread has me asking where to get one of them) - FT101 and CT1 - both sound like they'd work great, but it might depend on what type of plastic it is.
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has videos of CT1 showing it sealing joints in running water !
Do you know what type of plastic you are trying to glue? Are the tubing and pot made of the same material? Do you really need to glue at all? PVC, ABS, Nylon - in its many forms -, Polycarbonate; Polythene; Polystyrene; Silicone rubber; PET... the list goes on and on.
Some, like PVC, have oily plasticizer chemicals in, and are a nightmare to stick, without purpose made adhesives. In most cases you need to be sticking like to like, with like. Plastic plumbing kit would have all of these things matched of course...
[One basic way we used to test plastic, was the 'burn and sniff'. This won't be able to help with detailed analysis, but, if two pieces of plastic are similar, they will behave the same and smell the same when you try to light them. Cut a small piece and hold it briefly in a flame; waft cautiously, a little of the fumes towards you and note the smell - don't go inhaling! Some will light and burn with a black smoky flame; some will burn with a clear blue flame and drip; some will not burn; some will only burn while in the flame, and go out as soon as you pull out; some will burn with melting; some (nitrocellulose!) may go up like a rocket; so the emphasis is on the SMALL test piece: a millimetre cube is usually quite enough. If your two items to be stuck are of plastic that behaves in similar ways, the chances of you successfully sticking them together will be greatly increased.]
Easiest way to make sure you have a watertight system would be to use standard plastic plumbing pipe, glue (or better still 'speedifit') fittings, that are really quite cheap online from eg Screwfix.
Another way would be to use bungs/corks, and 'home brew' kit type plastic tube, and no glue at all. Easiest way to make neat holes in plastic of numerous kinds (I do a lot with plastic bottles), is to use various nails, bits of different sized metal tube, etc, heated up on the gas ring, and just push through - gives a clean hole that is less likely to split than if you try to cut or drill.
In fact, thinking on this: why not use whole plastic bottles, upside down, with a hole through the cap for your tube - make a hole in the bottom for filling.
(Incidentally, another handy use for old plastic bottles I've recently hit upon, is to tidy away my ethernet cables - I have some 20metre ones - in a way that minimises tangling: Get a 2 or 3 litre 'coke' bottle; melt a hole in the bottom with a piece of copper plumbing pipe - or you can use a hot nail and wiggle it around till the hole is big enough - just big enough to thread your ethernet plug through; feed cable right through the bottle, and slide it down nearly to the router or whatever; when not using the cable, you can then feed it all into the bottle from the cap end and it usually spirals in fairly neatly, with a shake or two, ready to be quickly pulled out when next needed.)
You might also, not bother to make any holes at all and simply put home brew taps in your flexible tube so that you can fill it with water and simply peg the top end under water in your pots so that it just siphons out at whatever rate you let it via the tap.
On the other hand, the real lazy way, would be just to get big plastic bottles and make pin holes in the bottom: then you can just stand them among your plants and regulate how fast they empty by tightening or loosening the top.
Umm why would you want to glue the tube to the plantpots? It's a bizarre way to set up watering. The normal way of doing this is to use a "common rail" tube running along the greenhouse bench with "T" pieces at regular intervals. Fron each "T" you take another length of tube at the end of which is a drip controller (a small valve, operated by adjusting a thumbscrew to set the drip rate) which you hang into the top of the pot.
Then you can move the pots if necessary, adjust the water flow individually and have a neat system that doesn't need mucking about with.
This illustrates the system used with growbags, it's similar for use with pots:
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's a link to the tube, valves, reservoirs and materials. The costs are so low that it would probably cost you more to create a homebrew version:
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here's an American site that explains the principles:
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