PVC pipe is a versatile, durable, and cost-effective material used for a wide variety of plumbing, irrigation, and general construction projects. When working with PVC pipes, choosing the right PVC cement or glue is crucial for creating watertight seals and strong bonds between pipe fittings and joints.
The two most common options are blue and clear PVC glue. But which one is better for DIY and professional applications? This guide examines the key differences between blue and clear PVC cement to help you determine which is the best choice for your next PVC project.
Table of Contents
Here is an in-depth comparison table for blue PVC glue vs clear PVC cement:
|Blue PVC Glue
|Clear PVC Cement
|Tetrahydrofuran solvent + PVC resins + blue dye + thickeners like fumed silica
|Tetrahydrofuran solvent + PVC resins
|Thick, gel-like texture
|Thinner liquid consistency
|Slow, can take 2+ hours for full bond
|Fast, joints can be pressurized in 30 mins
|Ideal Pipe Size
|Works well for pipes 1/2″ or larger
|Best for smaller pipes under 1/2″ diameter
|Stays blue as it dries, easy to see glued joints
|Dries transparent, joints are nearly invisible
|Withstands temperature extremes, UV exposure
|More prone to environmental damage over time
|Thick texture prevents drips, color indicates coverage
|Runnier texture can drip and sag if applied improperly
|Slightly more expensive due to dye additives
|Lower cost option, good for large projects
|Oatey, Weld-On, Christy’s, Blue Monster
|Oatey, Weld-On, Christy’s
|Fills gaps on large pipes, easy application, finds leaks
|Flows into tight spaces, faster cure, subtle joints
|Long cure time, more expensive
|Not as gap filling, can’t see application
What is PVC Glue?
PVC or polyvinyl chloride is a durable, lightweight plastic material commonly used for plumbing and drainage applications. PVC pipe is joined together using solvent cements, also called PVC glue or PVC cement. When applied to the surfaces of PVC fittings and pipes, the glue melts and fuses the PVC together through a chemical reaction, creating an air and water-tight seal.
There are two main types of PVC cement – clear and blue PVC glue. Both work the same way. But they have a few differences in their formulas and applications that are important to understand when selecting one for your project.
Clear vs Blue PVC Cement
Clear and blue PVC glues have the same basic purpose – to join and seal PVC components together to form a complete piping system. But they have some key differences:
- Clear PVC cement consists of tetrahydrofuran solvent mixed with PVC resin. It has a thinner consistency than blue PVC glue.
- Blue PVC glue contains tetrahydrofuran and also includes blue die along with amorphous fumed silica thickeners. These additives give it a thicker, gel-like texture.
Setting & Curing Times
- Clear PVC cement is fast-setting, allowing joints to be pressurized more quickly after application. Cure time is about 30 minutes.
- Blue PVC glue is slower setting. Joints take longer to become pressurized, with full cure time around 2 hours.
- Clear PVC cement is better for smaller diameter PVC pipes and fittings 1⁄2” or less in size. The thin formula allows it to flow easily and penetrate tight spaces.
- Blue PVC glue is ideal for larger diameter PVC components 1⁄2” or greater. Its thicker gel consistency makes application easier on wider surface areas.
- Clear PVC cement dries transparent, making it difficult to see which joints have been glued.
- Blue PVC glue remains blue as it dries, enabling glued joints to be identified easily.
- Clear PVC cement tends to be slightly less expensive than blue PVC glue.
- Blue PVC glue usually costs a bit more due to the dye additives. But the price difference is generally minimal.
Some of the top brands for each type include:
- Clear: Oatey, Christy’s, Weld-On
- Blue: Oatey, Christy’s, Weld-On, Blue Monster
Now that we’ve compared the key differences between clear and blue PVC cement, let’s look at when each type is the better choice.
When to Use Clear PVC Cement
Here are the main applications where clear PVC glue has advantages over blue:
For Small Diameter Pipes
The thin consistency of clear PVC cement allows it to easily spread and penetrate gaps in smaller diameter pipes and fittings. This includes sizes 1⁄2” and under – common for specific plumbing applications like sink drains. The clear glue can spread thoroughly across the joint surfaces to create reliable bonds.
For Tight, Enclosed Spaces
In situations where pipes joint together in very tight, cramped spaces, the thin clear PVC cement can flow down into the gaps more easily. The thick gel-like texture of blue glue can make it harder to apply in very confined areas.
For Inconspicuous Joints
Since clear PVC glue dries transparent, it results in virtually invisible joints. This may be preferred for exposed piping where you want the joints to be subtle and not stand out. Blue PVC cement remains blue as it cures, making joints more visible.
For Faster Pressurization
If you need to pressure test PVC pipe joints shortly after cementing, clear glue provides faster set and cure times. Joints can typically be pressurized after 30 minutes. The longer set time of blue PVC cement may require waiting up to 2 hours.
For Tight Budgets
Clear PVC glue is usually a couple dollars cheaper than blue for the same quantity. So if you want to save a little on material costs for a large project, clear cement may be the more economical option.
In summary, clear PVC cement works very well for smaller diameter pipes, confined spaces, quick pressurization, invisible joints, and budget-friendly projects. Next, we’ll examine where blue PVC glue is the better choice.
When to Select Blue PVC Glue
Here are the main situations where blue PVC cement is preferable over clear:
For Large Diameter Pipes
Blue PVC glue’s thicker, gel-like texture makes it easier to fully coat the surfaces of wider diameter pipes 1⁄2” or larger. The viscosity helps prevent drips and sagging when applying to overhead or vertical joints. This provides reliable adhesion across the entire joint.
The blue tinting acts as an application guide for DIYers and professionals. It lets you visually ensure full coverage across joints and avoids missed spots that could lead to leaks. The blue color also indicates which joints have been glued vs those still needing cement.
For Extreme Environments
The additives in blue PVC glue allow it to better withstand temperature fluctuations, UV light, and chemical exposure. This makes it ideal for outdoor plumbing and water lines prone to these elements. Clear PVC cement may become brittle or fail prematurely if exposed.
For Identifying Leaks
The blue dye remains visible if any leaks occur after curing. This allows you to quickly pinpoint the origin of leaks at blue-tinted joints. Clear PVC glue makes it hard to trace leaks since it dries clear.
For PVC to CPVC Joints
For transition joints connecting PVC to CPVC pipe, blue PVC cement is recommended, as the formula is compatible with both materials. Clear PVC glue may not adhere as effectively for PVC-CPVC connections.
In summary, blue PVC glue excels for wider pipes, beginner DIYers, extreme conditions, leak identification, and joining dissimilar materials like PVC and CPVC.
Key Takeaways on Clear vs Blue PVC Cement
Deciding between clear vs blue PVC glue depends on several factors:
- Clear PVC cement – best for small pipes, tight spaces, invisible joints, faster pressurization
- Blue PVC glue – best for large pipes, beginners, extreme elements, finding leaks, PVC-CPVC
- For most general applications on standard PVC plumbing up to 1-1/4″ diameter, either clear or blue PVC cement will work well.
- Make sure the glue you select is designed for the specific types of PVC pipe in your project.
- Always follow the manufacturer’s instructions carefully when applying PVC cement.
- Allow adequate cure time before pressurizing joints – 30 minutes for clear, 2 hours for blue.
- Wear gloves and work in a well-ventilated area when using PVC glue.
Now that you know the pros and cons of clear vs blue PVC cement, you can choose the best option for your next plumbing or construction project using PVC pipe. Taking the time to select the right glue will result in strong, lasting, leak-free bonds.
How to Apply PVC Cement
To properly join PVC pipes and fittings, it’s crucial to apply PVC cement correctly. Follow these key steps when using either clear or blue PVC glue:
Prepare the PVC Components
- Cut pipes square and deburr the ends. Bevel cut pipe ends slightly to increase surface area.
- Chamfer and deburr the interior of fittings to smooth surfaces.
- Clean all parts thoroughly to remove dirt, grease, and moisture.
- Prime both joint surfaces with a PVC primer before cementing.
- Primer etches and softens the PVC to improve adhesion.
- Wait 30-60 seconds for primer to set before applying glue.
Apply PVC Cement
- Shake or stir PVC glue thoroughly before using.
- For pipes under 1-1/2” diameter, apply a medium coat of cement on the pipe end and a thin coat inside the fitting socket.
- For larger pipe diameters, apply a thin coat to both joint surfaces.
- Avoid puddling extra glue in the fitting socket.
- Work efficiently after applying cement. It begins curing quickly.
- Insert pipe fully into the fitting socket immediately after applying glue.
- Twist pipe 1/4 turn during assembly to ensure even cement distribution.
- Hold joints together firmly for at least 30 seconds.
- Remove excess cement with a rag before it begins to set.
Allow Proper Cure Time
- Support joints and avoid strain while cement cures.
- Clear PVC glue takes 30 minutes to cure. Blue PVC cement takes 2 hours to fully cure.
- Longer cure times are required in cold temperatures below 60°F.
Following these basic application steps will ensure you get leak-free, lasting bonds between PVC components. Avoid common mistakes like insufficient solvent and improper positioning when assembling joints.
PVC Cement Tips & Safety
Here are some additional pointers for handling and using PVC glue safely and effectively:
- Store glue in a cool, dry place away from sources of heat and moisture. Shelf life is 2 years unopened.
- Stir or agitate containers before each use to mix contents.
- If cement becomes too thick, carefully thin with primer rather than water.
- Apply during dry conditions only, between 40-100°F. Avoid damp or very cold conditions.
- Use proper ventilation, gloves, and eye protection when working with PVC cement.
- Avoid breathing vapors – work in a well-ventilated area.
- Dispose of used containers properly according to local regulations.
- Keep glue away from open flames or other ignition sources.
- Follow all safety directions from the manufacturer.
Using these tips along with the application steps outlined above will allow you to safely cement watertight PVC joints that last for years.
Signs of Problems With PVC Joints
Though PVC pipe systems can last for decades, failures can occur if joints are not properly glued. Here are signs of potential problems:
- Leaks: Water drips or moisture at joints indicate a breach in the seal. Glue may have been insufficient or improperly applied.
- Slippage: Loose fittings that twist or move indicate the cement did not fuse the joint completely. Pipe was likely not inserted fully into the fitting.
- Cracks: Cracked or brittle cement beads around joints can lead to leaks and failure over time. This may be due to freeze damage or chemical exposure.
- White powder: Chalky white powder around the joint could be residual PVC cement. However, it may signal early bond deterioration.
- Discoloration: Yellowing or darkened cement near seams can be an early indicator of UV damage or exposure issues.
Inspect PVC joints regularly, especially after the system has been pressurized or seasonally winterized. Make repairs immediately if any problems are found to prevent major leaks or damage.
Fixing Leaking PVC Joints
If you discover leaking PVC fittings, you can repair them by:
- Sanding down the area with emery cloth to expose fresh material.
- Cleaning and priming the joint surfaces.
- Applying fresh PVC cement adequately.
- Assembling joint correctly and holding until supported.
- Allowing for full cure time before re-pressurizing system.
For severe leaks or damage, the affected fittings may need to be cut out and replaced entirely with new PVC components.
Prevent leaks proactively by assembling joints correctly the first time. Make sure to fully insert and support pipes in fittings after applying the appropriate cement for the project.
- Clear and blue PVC glue both fuse joints effectively. Choose based on pipe size, conditions, application.
- Prepare pipes and fittings properly before cementing. Use primer and proper glue amount.
- Assemble joints fully and hold firmly for 30-60 seconds to allow bonding.
- Allow full curing before pressurizing system – 30 minutes for clear, 2 hours for blue.
- Inspect PVC cement joints periodically for signs of leaks or damage.
- Repair minor leaks by exposes fresh material and recementing with fresh glue.
Applying the right glue carefully allows you to create strong, durable PVC joints that should last indefinitely both indoors and out.
PVC Cement vs Glue – What’s the Difference?
PVC cement and PVC glue are often used interchangeably to describe solvent welding products used to bond PVC pipes and fittings. But while their names are similar, there are some subtle differences between cements and glues.
PVC cement is a fast-drying solvent welder that creates strong, permanent bonds between PVC components. It acts by dissolving the surfaces of PVC parts and fusing them together into a homogeneous material upon curing. Key features of PVC cement include:
- Made from tetrahydrofuran (THF) solvents and PVC resins
- Lower viscosity for easy application
- Dries transparent for invisible joints
- Low cost, ideal for tight spaces
PVC glue utilizes THF solvents but also contains fillers that alter its properties. It has higher viscosity and more gel-like properties. Characteristics of PVC glues:
- Contains fillers like silica to thicken formula
- Better gap filling for larger joints
- Tinted blue for visibility
- Withstands temperature extremes
- Costs slightly more than cement
While very similar chemically, the differences in viscosity, color, and additives make each product better for certain applications. Many manufacturers use the names PVC cement and PVC glue interchangeably for their solvent welding products.
Comparing Popular Brands of PVC Cement & Glue
Several top manufacturers produce both PVC cements and glues suitable for plumbing, construction, and DIY applications. Here is an overview of key products from major brands:
Oatey PVC Cements
- Clear Medium Set Cement – general purpose formula for 1⁄2” to 1-1⁄4” PVC
- Clear Quick Set Cement – fast-drying cement for small diameter PVC
- Clear All Purpose Cement – designed for large diameter piping
Oatey Hercules PVC Glues
- Blue Ribbon PVC Cement – medium set, blue tinted all-purpose glue
- Yellow Heavy Duty Cement – extra thick for large joints
- Grey Heavy Duty Cement – for schedule 80 grey PVC piping
Christy’s PVC Cements
- Red Hot Blue Glue – fast-setting blue PVC cement
- PVC Handi-Flow Cement – medium bodied, general use
- Extreme PVC Glue – high viscosity formula
Weld-On PVC Cements
- Weld-On 711 PVC Cement – versatile cement for various pipe sizes
- Weld-On 717 PVC Cement – premium thickened glue for extra gap filling
- Weld-On 705 Clear PVC Cement – low viscosity for tight fitting joints
Within each brand, the products are tailored for different specific applications, diameters, and joint types. Always select the appropriate cement for your project based on the manufacturer’s recommendations.
Frequently Asked Questions
Does PVC pipe glue ever expire?
PVC cements and glues have a shelf life of around 2 years when stored properly unopened. After opening, their effectiveness slowly decreases over time as the solvents evaporate. Most brands will remain usable for 12-18 months if resealed adequately between uses. Expired cements lose solvent properties, take longer to cure, and may not create strong pipe bonds.
Can you glue schedule 40 and schedule 80 PVC together?
Yes, schedule 40 and schedule 80 PVC can be successfully joined using the proper cement or glue products. Special schedule 80 PVC compounds are formulated for these thicker, high pressure piping systems. Make sure to use the product recommended by the manufacturer for schedule 40 and 80 connections.
What’s the difference between one-step and two-step PVC glues?
One-step PVC glues combine the primer and cement so that joints can be assembled immediately after one application. Two-step products involve applying primer first to condition and soften the surfaces, followed by application of the PVC cement. Both create strong bonds if used as directed.
Can you use PVC glue to fix leaks?
PVC leaks can be repaired by sanding the area, cleaning with primer, applying a fresh coat of glue, and properly assembling the joint. The new application of cement re-fuses and reseals the connection. Severe leaks may require replacing the damaged fittings and re-cementing.
Is PVC glue waterproof?
Yes, when fully cured, quality PVC cements and glues provide waterproof, air and fluid-tight seals between pipes, valves, and fittings. Joints glued properly remain waterproof for the life of the plumbing system. Make sure to allow full cure time before pressurizing.
Whether you call it PVC cement, PVC glue, solvent welder, or adhesive, using the right product is critical for bonding rigid PVC pipe and fittings. Match the viscosity and properties to your pipe sizes, configurations, and applications. Brands like Oatey, Christy’s and Weld-On offer quality products tested for HVAC, plumbing, water and DWV systems. Follow instructions for proper joint preparation, application, assembly, and curing times. And take safety precautions when working with PVC solvents. Choosing the optimal PVC welding chemistry along with good technique will produce secure, leak-free pipe unions that last.