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Is PVC Primer Necessary For PVC Pipes?

Is PVC Primer Necessary For PVC Pipes_

 

Depending on who you ask, tradies and DIYers alike have strong opinions on the necessity of PVC primer.  Some swear by it and slather it liberally on their PVC pipe joints, while others claim that you can make strong, sturdy connections even without primer. So, which is it? Is it really an essential step, and can you substitute something cheaper?

While not all applications require PVC primer, using one will definitely help ensure your pipe joints are sturdy and leak-free. Major building authorities in Australia all agree that PVC primer (also known as priming fluid) should be used when joining PVC pipes with solvent cement. 

The use of a primer is required under AS/NZS 3500 Plumbing and drainage Standards whenever PVC solvent is used to join PVC-U and PVC-M pipe. 

Whether you’re doing a plumbing job that requires inspection or you’re simply doing a DIY project around the house, using a PVC primer avoids premature failure of the joint.

However, just like any industrial product, PVC primers can be tricky and ultimately unforgiving. If you don’t know how to apply PVC primer correctly, mistakes and mishaps can be irreversible, leading to frustrating clean-up or needing to replace sections of pipe. Applying PVC primer properly requires timing, technique and a bit of know-how. 

Luckily, you don’t have to spend hundreds of dollars getting a professional to join PVC pipe. This guide will tell you exactly why PVC primers are necessary to create airtight joins and, more importantly, how to use it effectively. 

What is PVC Primer?

PVC primer is a substance typically applied to the joint connections between PVC pipes.  What makes PVC primer so effective is that once applied, it sets off a chemical reaction that softens the PVC pipe, making it ready for the PVC cement. 

PVC joints are not exactly “glued” together as such – the two parts are bonded together through a change in their chemical composition. The softer the pipe is (thanks to the primer) the better the joints will be cemented. 

What’s the difference between PVC Primer and PVC Cleaner?

Since PVC primer can act as a cleaner, it is sometimes confused with PVC cleaner. However, it’s important to distinguish them. 

PVC cleaner is used to remove oil, grease, and other dirty substances from the outer layer of PVC pipes. However, it cannot do what a primer can do, which is softening the pipe and preparing it for a secure connection. If you use a PVC cleaner on the joints, you will still need to use PVC primer on them afterwards.

What’s the difference between PVC primer and PVC cement?

PVC primer can also be confused with PVC cement.  They are also two different materials, but for best results, they should be used together.  

To put it in simple terms, the priming fluid sets up the PVC cement to do its job properly.  The primer acts as a cleaner, removing grime as a PVC cleaner does, and it also softens the surface that it is applied on.

PVC pipes are joined together through a change in their chemical composition.  It is the solvent cement that does this, effectively making the two parts inseparable. The softening of the PVC surface as a result of the primer application makes this bond much stronger. 

 

What is PVC Primer made of?

PVC primer is a substance made mostly from two main chemical components: acetone and cyclohexanone. The chemicals tetrahydrofuran and methyl ethyl ketone, among others, are also added to some products, depending on the brand.

 

What kinds of PVC primer are there?

PVC primer is naturally clear in colour, but the most common variants are coloured – typically in purple or red. There are a few reasons for this: it makes it easy to tell where you’ve applied PVC primer, and it’s easier for a building inspector to tell if PVC primer has been used. In parts of the world where it’s mandated, failing to use PVC primer means your plumbing work will not pass standards.

In Australia and New Zealand, it’s part of the Plumbing and drainage Standards that priming fluid be used, and that the PVC primer is red. 

 

Is PVC Primer Necessary for PVC Pipes?

Is PVC primer truly a necessity when it comes to creating a strong PVC joint?  Or is it simply an unnecessary product purchase that benefits only the manufacturers? When you take a look at any plumbing forum, there are plenty of contributors who say they never use PVC primer and don’t see a need for it. 

PVC primer maximizes the strength and longevity of the joint connection.  A joint will still weld together without the primer, but the connection will not be as strong as the primer allows the cement itself to penetrate deeper into the material.

The truth is that it can be hard to tell whether PVC primer has an impact or not. However, failing to use PVC primer can lead to premature problems with the plumbing joint, even if that issue happens 5 or 10 years down the line. Particularly if the work isn’t done by the homeowner, the contractor responsible might not even be aware of the consequences – but taking a few minutes to use PVC primer has a genuine impact on how long the joint will last. 

Therefore it is recommended (and in some areas, it is mandated by law) to use PVC primer, especially if you have liquids passing through the pipe.

 

How do I correctly apply PVC Primer?

First of all, PVC primer and PVC cement have very intense fumes. Ensure you’re wearing a suitable mask and that the area is properly ventilated. 

To join PVC using priming fluid and solvent cement:

  1. Apply PVC primer on the fitting socket and to the end of the PVC pipe. You can use the brush that is included inside the primer can, or wipe the primer on if it doesn’t come with a brush. 
  2. Wait exactly 10 seconds (and no more or less than that!) and then immediately apply the cement directly on the primed areas of the pipes.
  3. You can now insert the pipe fittings and let it set – though of course when using solvent cement, you’ll need to work quickly!
  4. You will need to have the two ends of the pipes held together for about 30 seconds, or until the plastic hardens. It will take about another 15 minutes for the joint to completely harden where it can withstand water pressure and about 2 hours for it to fully cure. 

Note that it’s essential to work with an appropriate type of solvent cement or glue when applying PVC primer. Choosing the best PVC glue for high-pressure systems is essential for long term irrigation systems. 

Overall, allow about 3 hours when joining PVC pipes with primer/cement.

What if I have leftover primer? 

It is important to note that shelf life is based on when the product is stored on the shelf, still unused; and it is based on the manufacturing date, not the date it is used.  So for PVC primer, the typical 3-year expiration clock starts ticking the moment it is sealed and packaged in the factory.  

Again, like most products in the market today, the way PVC primer is stored, opened, and used also can contribute to how long the product will remain usable. This is, thankfully, well within your control and there are many steps you can take to ensure that the product will last as long as it can. 

Here are some tips:

  • The first consideration is where the PVC primer is stored.  It should be stored in a cool, dry place ranging from 5 to 37 degrees Celsius.  The product will experience chemical changes which will render it less effective if it is stored in places above or below that temperature range.
  • Next, since a product’s shelf life is instantly reduced the moment it is opened for the first time, and it continues to shorten every time it is opened, care must be taken to make sure it is well sealed when not in use. 
  • Since PVC primer’s solvents quickly evaporate, make sure you promptly close the can as soon as you get what you need to use for the moment. This is to also ensure that there are no difficult-to-remove spills – more on that later!
  • Lastly, after you have finished using PVC primer and are ready to store it, make sure the cap is sealed on tight to avoid further evaporation from its solvents.  However, do not overdo it to the point that the lid becomes distorted (such as applying too much pressure on the lid with pliers).  The lid can be distorted to the point that an airtight seal will become impossible.

 

How do I remove stains if PVC primer spills?

Nobody is perfect, and even the most careful of individuals can’t help spilling something here and there. More frustrating still is finding a PVC primer stain left behind by the plumber or neighbour who fixed your pipes, but was not thoughtful enough to clean it up afterwards. 

As soon as a priming fluid spill occurs or is discovered, you should deal with it as soon as possible. The longer the primer stays and is allowed to solidify, the more difficult it becomes to remove.

While the solvents in PVC primer evaporate before significant damage is done, the product is designed to melt plastic and therefore can permanently alter the surface it spills on if it’s also made from plastic.  If the PVC primer is of the coloured variety, then the dye becomes very difficult to remove, unfortunately.

The best way to prevent permanent stains or damages from spills is to protect the general area where you are doing your priming work. This should help protect your home and save you the trouble of cleaning up afterwards.

If accidents do happen, here is what you can do if you spill PVC primer:

  • You need to moisten a cotton ball or swab with either clear PVC primer or PVC cleaner and very gently pat the area, removing a small amount of the spill’s dye with each dab.  
  • Repeat the process with a new ball or swab until get as much of the stain out of the surface as possible.  If you were lucky enough to catch the spill early, you may have a chance of removing the colour entirely.
  • Alternately, you can also try using acetone, such as a nail polish remover that is acetone-based.  
  • You can also try using methyl ethyl ketone, which is also readily available.  You may remember from earlier in this article that these two solvents are the key ingredients in PVC primer, so use them just as carefully.
  • You can also try using paint thinner to tackle the stains, since it does not affect plastics.  
  • If none of the above are available, you can turn baking soda and water into a paste, then scrub the stain using the rough side of a sponge. If you catch the spill early enough, it may do the trick. 

 

What can I use instead of PVC primer?

Depending on the materials you are using, it might be better to use an alternative product. You also may be wondering what else you can use to do the job of priming fluid in a pinch. Read on to learn more about your best options.

 

PVC Primer Alternatives

Although this may go without saying, the bond created by PVC primer and cement are permanent. If that is not your goal and the structure you are building is only for temporary use, then PVC primer and PVC cement will not be needed, and in fact will be counterproductive.

Secondly, PVC primer (and cement) are only used for slip connections – the type of connections where you push the pipe together to connect.  If you are working with threaded connections, then these jobs call for a different set of adhesive aids: thread seal tape (casually referred to as Teflon tape) and thread sealant (also known as pipe dope).  

Threaded seal tape and pipe dope don’t only work with PVC pipes, – they’re effective with many different types of pipes, such as metal. When there’s a threaded connection involved, thread tape and sealant are superior solutions. 

 

Can I use acetone as a PVC primer?

Some plumbers, hoping to take a more affordable route, argue that acetone can be used as an alternative to PVC primer. Acetone is one of the main ingredients in priming fluid, after all. 

So, will acetone do the same job as the PVC primer?  Well, yes it can be moderately effective in cleaning and softening the pipe, readying it for the PVC cement.  However, for just a minor difference in price, why not make sure you achieve the best bond you possibly can?  PVC primer is a product made specifically for this task. 

 Besides, as mentioned already several times, PVC primer use is mandated in some areas, and the inspectors will look for the coloured dye that gives proof of its use. Acetone isn’t recommended by any industry body or Australian standard, and won’t pass muster if your pipework is being inspected.

 

Related Questions

Does PVC primer go bad?

Yes, like most plumbing products on the market today, PVC priming fluid (as well as solvent cement and cleaners) do have an expiration date. These dates indicate when the product will be at its most effective, and for PVC primer it is usually about 3 years. This is calculated from the date of manufacture and not from the day you open it, so it’s best not to leave it on the shelf for too long, even if the bottle is unopened. 

What to do if you spill PVC primer?

PVC primer, especially the dyed variety, can accidentally drip onto the floor or another surface and leave a stain that’s difficult to remove. Short of sanding the area, the only way these stains can be removed is if you gently apply other similarly strong solvents on it. Refer to the article above to see exact steps you can take should you accidentally spill PVC primer.

 

Disclaimer:

This article is published for general informational purposes only and does not constitute professional advice. Any action you take upon the information you find on this website is strictly at your own risk. Always ensure you have the right qualifications and certifications to carry out DIY work and never put your safety at risk. Hills Irrigation recommends consulting a professional for all electrical and plumbing work. 

 

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