Thursday, January 18, 2018

How to Stop Hot Melt Adhesive Stringing

Whether you’re using hot melt for packaging, automotive, print materials, or any other adhesive application, details matter. At best, inefficient use of adhesive can result in waste – at worst, it can cause issues with your system that add to costly downtime.

One of the most common issues encountered with hot melt systems is adhesive stringing. We’ve put together the following guide to help you understand what stringing is, how it happens, and how you can prevent it.

What is Hot Melt Stringing?

Hot melt stringing occurs when some of the adhesive material is left behind on the nozzle and pulled into a string, either automatically down the production line or manually when a handgun is pulled away from the applied surface. The string of adhesive that is left behind is sometimes called “angel hair”.

Hot melt stringing can affect any hot melt application, but it can be problematic for some in particular:

  • In food packaging applications, hot melt stringing can lead to pieces of adhesive breaking off and contaminating food products.
  • In pharmaceutical applications, hot melt stringing can break off inside packaging for medications, which could be mistakenly consumed.
  • In automotive applications, precision adhesive application on visible parts is an important part of ensuring a clean appearance for an automobile.
  • In Case and Carton closing applications , hot melt can appear on the product or case the product is put in.

What Causes Hot Melt Stringing, and How Can I Fix It?

There are various causes of stringing hot melt adhesive, including:

Application Temperature: When adhesive temperature is not high enough, the adhesive can become too viscous and thick, leading to stringing.

Solution: Consult your hot melt Material Data Sheet (MDS) to find the correct temperature settings. Standard hot melt adhesive is typically designed to be set at a temperature of 350° across all zones; however, your MDS may recommend a different temperature based on your adhesive & your application.

Late Shut Off: This is most commonly seen in older AO/SC module configurations, which can shut off slower than newer AO/AC configurations.

Solution: A support specialist at Keystone Industries is happy to help you determine if the age or configuration of your gun is a factor in your hot melt stringing issues.

Distance from Surface: If the distance between the nozzle and the surface is too great, this can allow air to cool the adhesive after it is applied, leading to stringing.

Solution: Try decreasing the distance between the nozzle and the application surface.

Nozzle Issues: The nozzle’s orifice diameter can contribute to stringing because of its effect on adhesive velocity.

Solution: Try replacing your nozzle. Keystone can help you determine what size could be a better fit for you.

Other potential causes: Over the years, we have seen a variety of different parts and issues contribute to hot melt stringing, including debris build up in hoses and other parts, solenoid issues prohibiting the proper cycling of the hot melt gun, and more.

Keystone is Here to Help

If you’re experiencing hot melt stringing, Keystone Industries can help you troubleshoot and get to the bottom of the issue. Simply call us at 770-586-5990 or contact us today.

Friday, December 29, 2017

Hot Melt Machine Rebuilds vs. Exchanges

When hot melt adhesive is part of your production operation, minimizing downtime is critical to the success of your business. Each minute of downtime means production setbacks, loss of employee productivity, and other issues, each of which can greatly impact your bottom line.

Inevitably, your hot melt machines will eventually experience issues that put you at the risk of downtime. Most of the time, getting your machine back into working condition will be more cost effective than buying a new system. But for many businesses, skilled local hot melt repair service technicians are in short supply, so the best option is to choose to a rebuild or exchange program for your hot melt system.

Which option is right for your operation? Let’s review the differences between rebuild and exchange to determine the best match.

What is A Hot Melt Machine Rebuild?

Our hot melt rebuild machine program allows you to pull your existing hot melt unit off the line and send it to Keystone, where it is rebuilt to like new condition and sent back to you for use. Before opting for a rebuild, ask yourself the following questions:

  • Do I have a backup unit to replace the hot melt system being rebuilt?
  • If no backup is available, can the production line run without the system while it is being rebuilt?
  • Does my current unit have all the features needed for my operation for the foreseeable future?

If you answered yes to the above questions, a rebuild is likely a great choice for you. If the final question regarding features is difficult for you to answer, speak to a customer support representative from Keystone – we’ll be able to help you determine whether upgrading to a new system will be a better choice for you in the long term.

View Our Melter Rebuild Options >>

What is A Hot Melt Machine Exchange?

Like the hot melt machine rebuild program, a hot melt machine exchange involves you sending your hot melt unit to Keystone, where we rebuild the system to like new condition. The difference with the exchange program is that Keystone sends you a rebuilt system, and you only send your system after receiving the Keystone system and install it on your production lineto replace the unit you are returning to Keystone. The exchange program is a great choice if the following are true:

  • You do not have a backup machine to run while waiting for your machine to be rebuilt.
  • Your production line cannot run without the machine that needs rebuilt.
  • The unit you currently use has the features needed for your operation through the foreseeable future.

Avoid Downtime with Regular Maintenance and Plenty of Spares

Each dollar you spend in maintenance and planning can save you exponentially in prevented downtime. Here are some tips to help keep your hot melt systems up and running, even when issues occur:

  • Keep multiple spares of commonly replaced parts for your system. Not sure which parts you’ll need to replace most frequently? Our customer service team can help you identify the most commonly needed parts for your hot melt system.
  • If budget allows, keep a spare hot melt system to swap out when you experience issues. This will allow you to run your operation with minimal issues while you get your machine rebuilt.
  • Complete regular cleaning and maintenance of your system. Check out our resources for helpful maintenance videos.

Have questions about your hot melt system? Contact us or call us at (770) 586-5990 to get quality replacement parts for your hot melt system at a fraction of OEM prices!

Monday, September 18, 2017

Types of Precision Nozzles for Nordson

For applying the right amount of glue in the right pattern every time, nozzle type and design mean everything. You can save time, money and glue by choosing the Nordson-compatible Keystone Industries precision nozzle that is best suited to your application. Take a moment to learn how to determine the correct nozzle type for your materials and process by understanding the different terms and nozzle specifications.

You don’t need to be an expert in industrial hot melt glue nozzles. That’s what we’re here for.

We’ll show you the difference between the various styles of nozzles so you can be confident you’re ordering the right nozzles for your business and adhesive application. Keystone Industries’ Nordson-compatible nozzles are built for precision and consistency and to offer greater control and durability than other nozzles you’ll find on the market, including many OEM nozzles.

Six Factors in Choosing Your Nozzle

Consider the following technical details when choosing your hot melt glue nozzle:

  • Pattern: Does your application call for dispensing glue in a bead, slot or spray pattern for adequate coverage and to ensure you get the glue exactly where it’s needed?
  • Number of orifices: Choose the nozzle with the correct number of orifices, ranging from one orifice for a single bead or spray to multiple orifices for multiple beads at the same time.
  • Style of gun: The style of gun relates to the control and positioning you need for your application. Your gun style will allow for certain types and styles of Nordson-style nozzles.
  • Nozzle angle position: The angle of the nozzle is in relation to the gun body. You can choose inline straight, multi orifice or 90° angles depending on the position & the amount of adhesive you require for your gluing.
  • Orifice diameter: Nordson nozzles range in diameter from .008” (small) for reduced adhesive flow and precision gluing to .040” (large) for greater flow and faster coverage.
  • Engagement: This is the length of the orifice channel, or the distance from the nozzle seat to the tip of the nozzle. Select a longer engagement if you want reduced adhesive flow but greater velocity.

When you consider all of these important points before ordering your nozzle, you’re giving yourself greater control over the volume, pattern and placement of your hot melt adhesive. This control means you’ll put the right amount of glue exactly where you need it for consistent and repeatable gluing for your manufacturing, packaging or installation applications. Choose the Keystone Industries precision nozzle for your Nordson hot melt equipment that improves the quality of your gluing process and ensures more reliable long-term adhesive bonds.

Need Help Choosing?

If you understand the six factors necessary for choosing the right industrial adhesive nozzle, you can browse our catalog and place your order today. If you’re not sure which nozzle suits your application best, we invite you to contact our experienced team here at Keystone Industries. Simply fill out our online contact form with all of your questions or give us a call and we’ll point you in the right direction.

We have hundreds of different nozzle styles, including 90-degree, domed, needle, pencil, single guards and spray. Tell us about your industrial gluing application — including information on your materials, throughput speeds, adhesive strength requirements and other process details — so we can help you select the perfect Keystone Industries precision nozzle for your Nordson adhesive equipment that saves you time, effort and money.

Friday, September 8, 2017

Which Nozzle Is Best for My Application?

Choosing the right hot melt glue gun nozzle goes a long way toward guaranteeing a clean and secure job. Your hot melt adhesive nozzle needs to be adapted to your industry, the materials you’re joining and the geometry and nature of your contact surfaces. Whether you’re seeking hot melt glue nozzles for carton sealing or another specific application, we’ve got you covered. Our team here at Keystone Industries can help you determine which nozzle is best for your application.

Depending on your industry and the type of gluing you’re doing, you can choose from:

  • Button nozzle: Single orifice brass nozzle that fits on Nordson H20 & Slautterback E100 Heads
  • Domed nozzle: Customizable multi-orifice brass nozzle suitable for case sealing
  • Domed circular nozzle: Used for sealing soda bottle base caps (circular pattern)
  • Extended dome nozzle: 1” long length to get adhesive deep into parts, suitable for automatic applications
  • Domed offset nozzle: These nozzles are available as single offset nozzles, which have one orifice at an angle offset from 0°, or dual offset nozzles, which have one orifice at 0° and another orifice offset at an angle for custom dispensing applications.
  • Domed SS nozzle: Stainless steel multi-orifice nozzle suitable for corrosive environments or high wear/contact
  • Handgun nozzle: Available in various lengths and orifice sizes for manual handgun operations
  • Needle SS nozzle: Commonly used to apply adhesive along a cardboard box seam and case closing
  • Pencil nozzle: Single orifice brass nozzle suitable for a variety of carton sealing applications
  • Short Pencil Nozzle: Single Orifice brass nozzle that give options for different flow rates of adhesive suitable for carton sealing applications.
  • Single guard nozzles: Button nozzle with integrated guard to protect the tip from box contact
  • Single SS nozzle (no guard): Durable stainless steel variant of button nozzle.
  • Spray nozzle: Dispenses adhesives in a swirl or spray pattern, for products such as diapers & certain product assembly applications
  • 90-degree nozzle: Popular nozzle for dispensing adhesive at a 90° angle for case and carton sealing

Understanding Terminology

When choosing your nozzles, it’s important to understand the different terminology used in the industry to make sure you’re choosing the right nozzles for your application. Consider terms such as:

  • Carton sealing: This popular use for a hot melt glue gun nozzle consists of gluing carton lids and tops, usually with a single line of glue (sufficient for low-weight cartons and products such as cereal boxes). Many customers choose pencil nozzles or 90-degree nozzles for carton sealing.
  • Case closing: Cases are made from thicker cardboard and often require more glue (thicker lines or multiple lines) for adequate sealing before shipping — heavier products will require more glue than lighter ones for adequate sealing. Optimal hot glue nozzles for case sealing include needle SS nozzles, right-angle 90° nozzles, and multi-orifice domed nozzles are popular choices.
  • Adhesive optimization: Too little glue can result in cartons and cases that open during transport, but too much glue costs you money. Optimizing your adhesive is important for the quality and reliability of your packaging as well as your profitability.

You’ll Find What You Need at Keystone Industries

If you know which tip for hot melt glue gun you’d like or require assistance choosing, check out our variety of nozzles. Compare the different types and select the model best adapted to your hot melt glue application. You can also contact Keystone Industries by calling 800-235-8090 for more information or to receive assistance with choosing. We’ll provide a free quote and ship your nozzles to you quickly, so you can get the benefits of the perfect hot melt glue nozzle for the gluing you do.

Thursday, August 17, 2017

Air pressure for Nordson ProBlue Melters

Pressure Gauges

If your pump is shifting erratically and/or the glue output is not up to par, check the following in order to reach maximum adhesive output:

  • Verify the factory's air is clean and dry.
  • Verify the air supply is capable of providing a maximum of 6.2 Bar (90 psi) of non-lubricated air.
  • Read the specifications on your specific adhesive and what is recommended.
It is suggested that an isolation valve be installed in the factory air supply line immediately before the melter.

Minimum operating air pressure is 0.7 bar (10 psi).  Operating at pressures lower than the minimum may cause the pump to malfunction.

Still having issues, please call us.

Angela Wagley

Friday, August 11, 2017

Maintenance on Nordson Glue Melters

It doesn't matter whether you have a newfangled glue melter or and old dinosaur of a glue melter, proactive maintenance is key to long life and reduction in breakdowns.

Do you change the oil in your car within OEM recommendations?  You know what will eventually happen if you consistently provide poor maintenance to your automobile.....you have an expensive engine repair bill.

A glue melter is no different.

Periodically flushing the tank, changing the tank filter and inline filters is key to lengthening the life of a glue melter and also will reduce the amount of times the unit is unexpectedly down.  

Other ways to reduce clogging of nozzles is to verify the adhesive is stored in a clean protected environment, the glue tank is kept full and the temperature settings are within the recommended temperatures of the adhesive specifications.

Some facilities use auto-feeders for the adhesive to reduce the amount of contaminants entering the glue tank.  In addition, these provide a safer environment for the workers.

All of these steps are quick and easy to incorporate.

If your unit has too much build up of char, we can provide rebuild services to delay the purchase of an expensive new unit.

Have questions or need assistance.... please call Keystone Industries.


Angela Wagley

Tuesday, April 11, 2017

Sources of Adhesive Failures

Sources of Adhesive Failures | Keystone Industries

Industrial adhesives are normally reliable and dependable for consistent bonding. When used correctly, industrial adhesives can save money, time and effort.

Problems can and will arise when adhesives are used improperly which will cause complete chaos on the most sophisticated packaging line.

Areas to investigate to determine the root cause of the adhesive problem:


Impurities in either the dry adhesive, the substrate or the melted adhesive can cause loss of adhesion. Verify adhesive storage containers and substrate materials are covered properly to reduce the entrance of foreign materials. Some examples of foreign materials are box dust, milled food products, and any type of oils or impurities. Keep lids on glue melters closed to reduce the introduction of foreign materials into the glue tank. Any foreign material in the glue melter can char and plug the pump, hoses, filters, and applicator heads.

Adhesive Type

When speaking with your adhesive vendor, provide a sample of the substrate(s) to which the adhesive will be applied. There are many varieties of adhesive and the adhesive must be specific to your particular substrate(s) in order to bond properly. Certain adhesives are not compatible with certain substrates and will have no bond strength.

Mixed Adhesive

It is not ideal to mix any adhesives. If changing adhesives, always flush your glue melter completely to remove the old adhesive before using your new adhesive. Mixing adhesive chemicals can cause bonding issues and some types adhesive when mixed together can destroy your melter system.

Set Temperatures

Read your adhesive specifications and use the recommended set temperatures. Heating an adhesive too high will cause char issues, cause degradation of the adhesive and thus, cause bonding issues. Heating too low may cause bond issues.


Bonding issues can occur in cold environments or where fans or HVAC vents are blowing directly on the glue applicators. Check your set up and verify any type of fans are moved to face away from your glue applicators. Moisture is another factor that may adversely affect the adhesive bonding. Check the adhesive specifications and know your adhesive.

Amount of Adhesive

Are you using the proper amount of adhesive on the substrate? This is a question to pose to the adhesive vendor in the beginning. There are different choices for how to apply the adhesive to gain the bond strength needed. You can use a stitch, dot, spray, slot or continuous bead pattern. If you don’t need full coverage and are looking to save money on adhesive, consider a stitch or dot pattern. Testing in advance is key to long term success. Call Keystone for recommendations on patterns.

Length of Cure Time

Discuss cure time with your adhesive vendor to determine the setup of your packaging line. Pressure bar time should be discussed at this time to determine how long pressure should be applied to the substrate for bonding purposes. The adhesive needs to have enough time to bite properly.

Most adhesive and glue melter issues are not due to the adhesive or melters, but are due to how the adhesive and melters are being used/misused. Many dollars can be saved by being proactive in the setup stages in choosing the correct adhesive, using the adhesive properly and maintaining a clean glue melter.

Keystone Answers Your Hot Melt Questions

Need guidance with your glue melter setup and adhesive issues? Contact a Keystone representative or call us at 800-238-8090 to get help today.