PVC Jointing Techniques & Materials
Types of PVC Joints?
There are 2 prodominent types of PVC joints:
- Solvent welding / Gluing
- Threaded joining connection
The subtle difference between these two PVC jointing methods is that one creates a permanent joint while the other a semi-permanent joint which can be disassembled. Both methods are relatively quick and uncomplicated providing the correct preparatory work is carried out before any joint is attempted.
Below we have listed the key elements to the joint preparation required to ensure a leak free connection, let’s take a quick look at both methods…
1. Solvent Cement/Glue Jointing System
This method, otherwise known as a Solvent Weld, is the most popular and requires a low skill capability.
PVC ‘solvent cement’ or ‘glue’ is in essence the chemical mixture that when applied to the mating surfaces of the PVC pipe, fitting or valve connections, welds them together by means of a chemical reaction creating what is technically known as an ‘homogenous bond’ i.e. the two separate surfaces are now chemically fused to become one. You can see a range of PVC cement products on our PVC metric accessories page.
2. Threaded Fittings Jointing System
This method utilises a simple threaded connection whereby interchangeable ‘male threaded fittings’ (threaded outside) are screwed into ‘female threaded fittings’ (threaded inside). This method requires no skill capability, equipment or tools.
Ensure correct checks and connection preparation will ensure the best joints. You can see a range of PVC metric threaded fittings on the Imperial threaded section of our website.
Top Tips for PVC Solvent Welding
- We highly recommend that you double check all of the actual measurements of the physical structure to be assembled against any drawings, sketches or samples before cementing anything together. If possible test your structure first with a dry-fit to ensure everything fixes together nicely and is dimension-ally correct.
- To ensure an effective joint, make sure the area is free from all dust and debris and is dry before you apply your cement.
- Prepare and clean your materials before cementing them using our MEK Cleaner, available in our accessories section. Always check the tin of solvent cement for details of the recommended curing times per system size that is being assembled and adhere to these instructions. Also ensure that the correct PPE (Personal Protective Equipment) is used during assembly.
- Always ensure any empty tins, used glue brushes and PPE are disposed of in the correct manner.
Top Tips for PVC Threaded Jointing
- First and foremost is to ensure that the thread types e.g. BS, NPT etc are the same for both the mating male and female fittings.
- Threaded fittings can be supplied in both TAPER and PARALLEL type threads. The threaded male and female fittings supplied by epco generally both have PARALLEL threads. This usually means that the connections are easy to make, feeling loose on both assembly and disassembly. The fittings generally mate 100%. If TAPER threaded fittings are used, the connections can feel tighter on assembly and the fittings generally do not mate 100%.
- Check that the threaded connection sizes are compatible.
- When creating threaded connections in a plastic system always ensure that PTFE thread seal tape is used on the threads and not jointing pastes which can attack the plastic base materials.
- A hand tight connection is generally considered sufficient to create a leak free joint. There is generally no requirement to use a spanner or wrench on a plastic threaded joint. Under no circumstances should plastic pressure pipe fittings and pvc threaded fittings be joined to metal threaded fittings.
Solvent Weld or Threaded Connection?
If you require a fixed permanent connection with no maintenance then we would recommend solvent weld. Systems joined by solvent welding are generally available in a much larger range of sizes.
If you require a semi-permanent connection which may require disassembling at some point, then we would recommend a threaded connection. Systems joined by threading are only available in a limited range of sizes.
Any questions? Get in touch!
It is important to know the difference between pvc metric and pvc imperial fittings before you begin specifying your project. For more information give us a call on 0113 2491155 to discuss your exact requirements in detail.