Process heat nozzles come in all sizes and shapes, as hot-air delivery requirements (i.e. direction and coverage area) vary by application. With dozens of nozzles to choose from for your heat sources, we’re here to help with the selection process. Featured below are five of the most common nozzle types, and possible use cases for each.
Note: This post is a general guide. Ensure you get the nozzle best suited for your unique applications by speaking with an IHS representative.
1. Wide-Slot Nozzles
Wide-slot nozzles are ideal when heat needs to be applied across a broad area. Several examples include:
Shrinking a plastic wrap around an object moving down the process line, where prolonged heat exposure is necessary to achieve the proper material tightening.
Coating a piece of fabric, as heat needs to be applied uniformly across the width of the material.
Deflashing taller objects—a standard round nozzle may not be able to properly apply heat to the top and/or bottom of the object.
2-3. Tubular and Angled Nozzles
Tubular nozzles are round tubes that extend the reach of the heater, making it possible to direct hot air into areas that are not large enough for the full air heater. Angled nozzles are simply bent tubular nozzles (typically bent at 90 degrees), which allow hot air delivery in areas where a straight nozzle won’t fit.
Both tubular and angled nozzles can also be used as extenders when a different nozzle is affixed to the end opposite the heater.
4. Sieve Nozzles
Sieve nozzles utilize small holes to effectively disperse hot air over a surface or object, instead of having a concentrated hot-air source. The sieve spreads air across an area, which may be necessary for certain pasteurizing, shrinking or curing applications.
This type of nozzle is often combined with a reflector nozzle (detailed below).
5. Reflector Nozzles
Reflector nozzles apply uniform heat to multiple sides of an object simultaneously by encasing the object on three or four sides. These nozzles are ideal for shrinking, curing, drying and pasteurizing applications.
Nozzle Best Practices
When selecting a nozzle for your process heat application, keep the following best practices in mind:
Nozzle size impacts heat output: The size of the nozzle’s opening has a direct impact on hot-air output—the smaller the nozzle opening, the hotter the air stream.
Avoid airflow restriction: In applications that call for high heat output and air speeds, certain nozzles can restrict airflow, resulting in heat build up. This build up may overheat the heating element and cause it to break.
Air temperature is hottest at the heat source: The further away from the heat source, the cooler the air will be. So while the heater may be set to a specific temperature, take the temperature at the end of the nozzle to ensure it meets the requirements for your application.
For more information on the ideal Leister nozzle for your application, contact one of our Leister representatives at info@ihshotair.com.
IHS’ Eric Pardo was featured as a contributing author in the May issue of Process Heating Magazine.
In the article, Eric talks about some things you need to know before starting to shop for a convection dryer. Having this information readily available will help to streamline your search and ensure you get the best heat source for your needs.
The above 4-minute how-to video walks you step-by-step through the process of setting up and operating the Leister VARIMAT V2. Specifically, you will see how to:
Unpack the machine.
Configure speed, heat and air volume.
Weld with the VARIMAT V2.
Shut down the machine.
This is highly recommended viewing for those operators just learning how to use the VARIMAT V2 to weld thermoplastic material seams.
The TRIAC Drive is a highly effective, semi-automatic welder that is ideally suited for joining thermoplastic material seams in confined spaces, on vertical surfaces and parapet walls, and around skylights and curves (pretty much anywhere large welders—like the VARIMAT V2—cannot).
In this post, we’ll look at five tips you can use to troubleshoot and resolve common issues.
Before reading this post, be sure to read our previous TRIAC Drive post—How to Assemble and Operate the TRIAC Drive—to ensure your welder is configured accurately and the operator is using proper technique.
What should I do if my TRIAC Drive is creating a weak seam weld?
The first thing to check is that the heat, air volume and speed are properly set for the material and environment. If each checks out and the problem persists, make sure the heat gun (i.e. TRIAC S or TRIAC PID) is properly aligned with the TRIAC Drive.
When properly positioned, the end of heat gun’s protective tube should be exactly 10 mm below the holder (labeled 6 in the picture to the right). If the nozzle is misaligned with the carrier wheels and pressure roller, you’ll experience poor heat exposure to the top and/or bottom thermoplastic sheet, and consequently poor weld results.
Why does thermoplastic material keep getting bunched up in my TRIAC Drive?
If the nozzle edge is crooked in relation to the drive roller, your thermoplastic material will either twist or bunch in the machine.
To adjust, put on heat-protective gloves and loosen the nozzle clamp screw with a screwdriver. Next, twist the nozzle until it properly aligns with the drive roller, and then retighten the clamp screw.
Why won’t my TRIAC Drive stay flat against the surface?
When welding with the TRIAC Drive, the optimal position stance is on the side of the tool (as seen right). From this angle you can more easily move along the seam at a consistent pace while retaining full view of the seam to make sure it is being welded properly.
If you stand behind the tool, you’ll have a tendency to tilt the hot-air welder slightly off the surface as you move to keep pace, which will negatively impact the weld.
Bonus Tip: When welding, hold the TRIAC Drive by its drive motor (as show in the image above), and not by the heat gun. The heat gun is on a shock and needs to rise and fall with the material surface to ensure adequate heat exposure. Holding the drive motor will also help to ensure the welder remains flat against the surface.
How do I stop air pockets from forming under my thermoplastic material?
When hot-air welding any material that is not adhered to a surface—especially vertical surfaces—there is the possibility that air will blow too far under the material creating air pockets.
To avoid air pockets, use a straight two-by-four or a metal bar to create an air dam. This will stop the air from blowing under the fabric, and keep air contained near the seam.
Why doesn’t my TRIAC Drive effectively weld uneven surfaces?
When welding over uneven surfaces, use the single-wheel support carrier (as shown right). This carrier affords you the ability to tilt the TRIAC Drive, and align the nozzle and pressure roller with surface-angle changes.
The two-wheel support carrier creates a tri-pod effect, which is ideal for flat surfaces, but limits your ability to tilt the welder.
If the above tips don’t resolve your TRIAC Drive issues, contact one of our Leister representatives at info@ihshotair.com or 800-635-0384.
While the seam is inherently the weakest part of any geomembrane liner, if properly welded, it can remain airtight throughout the life of the material. For this reason, seam welding is one of the most important aspects of installing a liner in a landfill, mine, tunnel or water reservoir.
To create a strong seam weld, you’ll need the right welder. In this post, we’ll look at two variables that will affect your choice, evaluate two common types of welders, and offer a guide for selecting the proper Leister welder for your needs.
Geomembrane Seam Welding Variables
A number of variables that can affect seam weld quality, including: ambient temperature, moisture, and heat setting in relation to speed and air volume. Most of these variables can be identified and corrected by conducting a test weld.
However, there are two variables you’ll need to define to select the proper welder for your needs—material type and material thickness.
Material Type: Different types of geomembrane liners (i.e. HDPE, LDPE and PVC) have different tolerances to heat. Make sure the welder you select can reach the temperatures needed to effectively weld the material.
Material Thickness: The material’s thickness will also dictate how much heat the material needs to be exposed to in order to create an effective weld. Leister welders are available with different length wedges or nozzles to offer the appropriate dwell time (or heat exposure).
Common Welder Types
A basic understanding of the most common types of geomembrane welders can help you qualify the right tool for your job. In general, there are two main types:
Wedge Welder: Two liner sheets are pressed against and pulled over a heated metal wedge that melts the sheets, which are then pressed together to form a strong bond. This type of welder tends to be quieter than a hot-air welder, and doesn’t produce as many fumes.
Hot-Air Welder: Two liner sheets are exposed to heated air that liquefies their surfaces, which are then pressed together to form a strong bond. Hot-air welders are generally more efficient than wedge welders, especially over long, straight seams, because the air stream preheats the material (as shown right).
Leister Geomembrane Welders
Leister offers both wedge and hot-air (or combi-wedge) welders. Use the following as a general guide to identify the Leister geomembrane welder that is best suited for your needs:
Parapets are wall-like barriers surrounding the edge of a flat roof, as seen on many commercial buildings. These half-walls serve many purposes, including:
Fire Protection—Stop flames from climbing up the side of a building and catching the roofing membrane on fire.
Fall Protection—A guardrail around the roof’s edge to help prevent falls.
Wind-Uplift Resistance—Balances wind pressure to prevent the roofing system from pulling away from its surface.
Aesthetics—Hides roof surfaces from view.
Unfortunately, these architectural features can prove challenging for contractors charged with seam welding a single-ply, thermoplastic membrane along the parapet’s vertical surface. Unlike flat, horizontal surfaces, there are no automatic welding machines—like the VARIMAT V2 or UNIROOF E—that can effectively weld these seams at high speeds.
Traditionally, vertical seams are welded using a hot-air hand tool. While effective and better for hard-to-reach areas, it is time-consuming work. A viable alternative is to use a semi-automatic hand welder—like the TRIAC Drive.
Following are best practices to remember when welding single-ply seams on vertical parapet surfaces, or any vertical surface for that matter.
Semi-Automatic Hand Welders
Most semi-automatic welders are lightweight and easy to hold against a vertical surface. These welders are self-propelled, so the operator’s job is to simply guide it along the seam edge and ensure it lays flat against the surface.
When using a semi-automatic hand welder on a vertical surface, keep the following best practices in mind:
Always perform a test weld. Perform a test weld to make sure your heat, air volume and speed settings are correct for the material and environmental conditions (i.e. ambient temperature, moisture, humidity and direct sunlight). If possible, perform this test weld on a vertical surface to ensure you also have the proper welding technique.
Do not push or pull the machine. Do not push or pull the plastic welder. This can affect weld quality by either applying too much heat to the material—over liquefying and damaging it—or too little—not liquefying the material enough to form a strong bond. Let the welder propel itself, and simply guide it along the seam.
Press the machine firmly against the surface. Press the welder firmly against the vertical surface to ensure it moves steadily along the seam and that even pressure is being applied throughout. To do this, always hold the tool with both hands—one on the heat source handle, and the other on the guide handle.
Use a guide aide. For vertical seams that travel parallel to the roof’s surface, look for a semi-automatic welder with a guide aid. These accessories roll along the roof surface, helping to keep your welder at a consistent height, and inline with the seam.
What are some other recommendations you have for welding vertical seams with a semi-automatic welder? Please share in the comments below.
The tools of any trade can pose safety risks if improperly used or maintained. Leister plastic welding equipment for the roofing, flooring, fabrication, billboard and banner, and civil engineering industries is no exception.
To keep operators of Leister hot-air hand tools and automatic walk welders safe, it is the responsibility of employers, supervisors and peers, to make sure proper precautions are routinely taken.
Following are 8 tips you can use to help keep Leister equipment operators safe:
Plastic Welding Safety Tips
1. Review Safety Instructions—Every operator should read Leister’s safety instructions, located within the product’s operating manual. If you have any questions, or would like further clarification on any item listed, contact one of our authorized service representatives.
2. ReviewM.S.D. Sheets—Plastics Magazine recommends reading the material safety data (M.S.D.) sheets of the plastic your welding. Among other things, these sheets are required to detail the plastic’s hazardous ingredients, fire and explosion hazard information, preventative actions, and first-aid recommendations. Request these sheets from the plastic manufacturer.
3. Train Employees—Train all personnel on how to properly use the Leister welder(s) they will be operating. Specifically, demonstrate how to turn the welder on, run it, shut it down, clean it after use, and what to do in the case of a malfunction or emergency—for example, if a drive motor shuts down while welding or if plastic material catches fire.
4. Store Properly Between Uses—After completing a weld, an operator may set down the hot-air tool, or leave the walk welder to prep for the next weld. Because the machine will still be hot and likely blowing hot air, make sure to do the following:
Hot-Air Hand Tools—Set the tool on a flat surface where it won’t roll, or in a stand with the nozzle pointed away from the surface. Also keep the hot-air stream and nozzle away from flammable materials and body parts to avoid the risk of fire and burns.
Automatic Walk Welder—Secure the welding nozzle in the up, locked position, and move it away from heavy traffic areas and flammable materials.
5. Clean Work Areas—Remove any clutter from the work area to ensure a full range of movement. This helps the operator avoid knocking over or spilling anything that may damage the plastic material, catch fire, or require an immediate cleanup. Hastily setting down the tool to clean messes can lead to improper storage between use.
6. Clean Plastic Surfaces—Remove any contaminants that may be on the plastic being welded, including grease, oils, dirt and moisture. These contaminants may be fire risks or cause the plastic not to weld at all, possibly leading the operator to turn up the heat to unsafe levels to attain a weld.
7. Properly Maintain the Tool—Scrape away melted plastic after each use, and clean air filters of dust and contaminants to ensure the tool receives the proper air supply. Both of these issues can lead to heat backup and overheating. In addition, make sure to replace any frayed or sliced electrical cords to avoid accidental shock.
8. Wear Proper Attire and Equipment—Make sure all operators are wearing the proper protective equipment (PPE) to limit exposure to heated air and surfaces, as well as any airborne plastic or debris. PPE should include long sleeve shirts, pants, gloves and protective eyewear. In addition, depending on the plastic being welded and ventilation, a respirator may be necessary.
What more should companies do to protect their employees operating hot-air hand tools and automatic walk welders? Please share your thoughts in the comments below.
Shrink wrap is commonly used across a variety of industries to package and protect items—from food to pallets to boats. According to U.S. Packaging and Wrapping, the most common reasons to shrink wrap are that it:
Protects items from moisture, dust and other contaminants.
Bundles items in units of two or more, or keeps extra parts attached to the main unit.
Preserves freshness.
Prevents tampering.
Adds an additional surface on which to adhere a label or attach a theft prevention device.
Because it’s typically made of polymer and PVC films, shrink wrap requires heat to work. As the material is heated, its molecules realign, causing it to constrict or shrink. (For a more detailed overview, read this Wikipedia post.)
Two common devices for applying necessary heat are hot-air hand tools or industrial process heaters. In this post, we’ll look at what you need to consider and know before purchasing your shrink wrapping heat source.
Hot-Air Hand Tools
Hot-air hand tools are effective shrink-wrapping tools for larger items (i.e. boats or pallets), or smaller items where a process line is not available. When purchasing a hot-air hand tool, keep the following attributes in mind:
Ergonomic Design—The heat gun should be easy to hold with the trigger pressed, and allow for strain-free movement of your arm and wrist. If a user’s arm or hand gets tired and continually needs rest, it can prolong the time necessary to complete the project.
Proper Heat Output—Different plastics and film thicknesses require different levels of heat for proper shrinking. Reference the shrink wrap’s packaging to identify the recommended heat for activation, and then look for a heat gun that satisfies this requirement.
Lightweight—Look for a lightweight heat gun to avoid unnecessary muscle strain and allow for greater ease of movement.
Digital Display—While not essential, a digital display can show the heat gun's exact air temperature so you know that it is properly configured for the job at hand.
Industrial Process Heaters
Selecting the proper industrial heater for a shrink-wrap process-line tunnel is a little more complex as there are additional variables that need to be considered. Prepare answers to the following questions, and then work with a reputable heat-source distributor to ensure you get the right tool for your needs.
What hot-air temperature is needed? Reference your shrink-wrap packaging to determine how hot the air temperature must be to effectively shrink the material.
What is the speed and length of your process line? Know the speed in which your process line moves and the length of your heat tunnel. This will impact the heat output required of a heater and determine if multiple heaters may be necessary.
What level of control do you need? Consider whether your heat tunnel will be required to shrink different types and thicknesses of material. If so, your heater(s) will may require an integrated or remote control interface.
What air source is available? To avoid overheating and frequent breakdowns, your heater(s) will need a consistent air source that is clean (dust and contaminant free) and temperate (not pre-heated). Filters and external air blowers may be necessary to satisfy these requirements.
What is the run time? Whether the heater(s) will run periodically throughout the day or continuously will help to determine its necessary heat output. For example, running a heater at its highest temperature setting for long stretches will cause the heating element to burn out quickly, leading to avoidable, and possibly costly, repairs.
Always consult your hot-air tool distributor before purchasing a heat source to ensure the selection you make offers the greatest opportunity to maximize efficiency and productivity.
If you have any questions, or would like to speak with one of IHS’ expert representatives, please contact 216-373-146 or email info@ihshotair.com.
The BITUMAT B2 eBook is a complete resource guide designed to help you maximize the life and performance of your BITUMAT B2 bitumen roof welder.
The BITUMAT B2 ebook makes a great training tool for new hires or those new to the machine, and can help the most seasoned professionals learn new tricks that will keep the machine in peak operating condition. For example:
“With an aerosol can of silicone, spray any part of the machine that may be exposed to splattering bitumen.... This silicone will serve as a buffer between the melted bitumen and the machine’s surface, making it easier to clean.”
(Please Note: Links will not work when clicked in the SlideShare player.)
File size is 15MB, will take several minutes to download.
Sections include:
Product Details — Machine features, specifications, and performance and technical data.
Operating Instructions — Details on how to prepare the BITUMAT B2 for operation, effectively weld bitumen seams, and properly shut down the machine.
Resources — How-to instructions for basic maintenance and part replacement, and troubleshooting tips to correct poor welding performance.
Parts List — Detailed part diagrams of the BITUMAT B2 and its ELECTRON hot-air blower, with order numbers for quick reference.
Accessories — A list of machine accessories available for individual purchase.
Related Leister Products — Other Leister automatic welding machines for the roofing industry.
Service and Support — IHS service and support center contact information.
File size is 15MB, will take several minutes to download.
Modified bitumen (APP or SBS) combines asphalt and polymers to create strong, durable roofing systems. However, as with any other roofing system, the roof quality will only be as good as its seam welds.
In this post, we’ll detail:
How to identify quality bitumen seam weld.
Two tips to repeatedly create strong welds using the Leister BITUMAT B2.
What a Bitumen Seam Weld Should Look Like
One sign of a strong bitumen weld is that a bead of melted material appears as the two sheets are pressed together, as you can see in the video below:
To see the other sign, weld two pieces together. As soon as the bitumen surface temperature over the recently welded seam is the same as the rest of the bitumen sheet, rip the two sheets apart. A quality weld should reveal the scrim of one of the bitumen pieces (as shown right).
Obviously, you can’t perform this last quality check on your finished seam, so before beginning your final weld, perform a test.
Always Run a Test Weld
One way to ensure a strong seam weld is to perform a test weld before starting any project. There are a variety of factors that can affect weld quality, including machine settings (i.e. temperature, air volume and speed) and environmental factors (i.e. ambient temperature, moisture, direct sunlight).
To perform a test weld:
Cut two 10-foot strips of bitumen sheeting and overlap the edges.
Weld them together using your pre-heated BITUMAT B2.
Using a hook blade, cut three-to-five, 2-inch-wide strips perpendicular to the welded seam (as shown right). These strips should come from the beginning, middle and end of your seam.
Wait for the surface temperature to cool (as detailed above), and then rip each strip apart to see if the scrim is revealed.
Keep Your Machine Clean
The other way to ensure a quality seam weld, and to keep your BITUMAT B2 in proper working order, is to keep your machine clean. Welding bitumen is a messy job and will likely result in melted bitumen splattering on the BITUMAT B2 and coating the nozzle. A build up of this material can damage the tool and affect welding performance.
Before powering on the machine, spray silicone on any BITUMAT B2 part in range of splattering bitumen, including the machine’s undercarriage, drive wheel, hot-air blower (do not spray the flat end of the nozzle), and black panel. The silicone acts as buffer between the bitumen and machine surface, making the mess easier to clean away. (NOTE: Do not spray silicone on a hot or activated machine. Aerosol silicone spray is very flammable.)
After each use, clean any bitumen off of the machine, paying special attention to the:
Nozzle—While the nozzle is still hot, use a stainless steel wire brush to scrape away the melted bitumen so that all air holes are clear of obstruction. A blocked nozzle can restrict airflow and cause heat to back up and overheat the heating element or machine.
Drive Roller—Use silicone and a rag to wipe away any melted bitumen on the drive roller. A build up of bitumen can cause the drive roller to lay unevenly against the surface, leading to inconsistent seam pressure.
If you notice your BITUMAT B2 not reaching the proper temperature, or producing poor welds, it may be a sign of a more serious problem. Contact our Leister service center at 800-635-0384 or info@ihshotair.com.
——
Information is intended as a guide only, and should be used by individuals familiar with the Leister BITUMAT B2 features, functionality and electrical components. IHS is not responsible for injury or equipment damage that may result from operator negligence.
Prior to setting up, operating or performing maintenance on your Leister product, be sure to read through all safety warnings and cautions contained within the product-operating manual. If you have any questions, need assistance or would like a product demo, contact the IHS service center at 800-635-0384.
Sieve nozzles utilize small holes to effectively disperse hot air over a surface or object, instead of having a concentrated hot-air source. The sieve spreads air across an area, which may be necessary for certain pasteurizing, shrinking or curing applications. 
Reflector nozzles apply uniform heat to multiple sides of an object simultaneously by encasing the object on three or four sides. These nozzles are ideal for shrinking, curing, drying and pasteurizing applications.
IHS’ Eric Pardo was featured as a contributing author in the May issue of 
The first thing to check is that the heat, air volume and speed are properly set for the material and environment. If each checks out and the problem persists, make sure the heat gun (i.e. 
When welding with the TRIAC Drive, the optimal position stance is on the side of the tool (as seen right). From this angle you can more easily move along the seam at a consistent pace while retaining full view of the seam to make sure it is being welded properly.
When welding over uneven surfaces, use the single-wheel support carrier (as shown right). This carrier affords you the ability to tilt the TRIAC Drive, and align the nozzle and pressure roller with surface-angle changes.
While the seam is inherently the weakest part of any geomembrane liner, if properly welded, it can remain airtight throughout the life of the material. For this reason, seam welding is one of the most important aspects of installing a liner in a landfill, mine, tunnel or water reservoir.
Wedge Welder: Two liner sheets are pressed against and pulled over a heated metal wedge that melts the sheets, which are then pressed together to form a strong bond. This type of welder tends to be quieter than a hot-air welder, and doesn’t produce as many fumes.
Hot-Air Welder: Two liner sheets are exposed to heated air that liquefies their surfaces, which are then pressed together to form a strong bond. Hot-air welders are generally more efficient than wedge welders, especially over long, straight seams, because the air stream preheats the material (as shown right).
Parapets are wall-like barriers surrounding the edge of a flat roof, as seen on many commercial buildings. These half-walls serve many purposes, including:
The tools of any trade can pose safety risks if improperly used or maintained. 
Shrink wrap is commonly used across a variety of industries to package and protect items—from food to pallets to boats. According to 
The BITUMAT B2 eBook is a complete resource guide designed to help you maximize the life and performance of your 
Modified bitumen (APP or SBS) combines asphalt and polymers to create strong, durable roofing systems. However, as with any other roofing system, the roof quality will only be as good as its seam welds. 
To see the other sign, weld two pieces together. As soon as the bitumen surface temperature over the recently welded seam is the same as the rest of the bitumen sheet, rip the two sheets apart. A quality weld should reveal the scrim of one of the bitumen pieces (as shown right).