Glue guns are the tool of choice for a variety of home and industry applications because they are fast and simple to use. New features have made them even more useful and ergonomic. But what do you do if your favorite glue gun in your tool arsenal malfunctions?
There are several factors to consider before attempting to fix a hot glue gun. Some glue gun problems — especially those involving an industrial model — require a trained expert. Other issues are relatively simple to fix if you have some degree of knowledge about your glue gun and how it operates.
In some cases, glue gun manufacturers may not provide spare parts. Others will void the warranty if you disassemble the machine and determine it was a factory defect.
Other gun models may not be worth fixing, making it more cost effective to buy a new one.
Read on to determine the types of repairs you can fix yourself, what sorts of parts may be available, some basic steps you can take to affect the repairs and what to do if the problem is beyond your mechanical ability.
Types of Hot Glue Guns
Hot glue guns range in price from relatively inexpensive — under $50 — to investment-worthy at over $2,000, depending on their use. Depending on the type of adhesive you use, some will operate at relatively low temperatures while others require much more elevated temperatures. There are even dual temperature guns so you can tackle a variety of projects with one gun.
Repair vs. Replace
Unless you are a devoted do-it-yourself-type repairman, it is usually easier and less costly to replace machines that cost under $200 than attempt to repair them. Even if the parts are available, the additional time, materials and hassle involved indicate you should opt for replacement.
Obviously, you want to consider repair if you use larger industrial machines at your business.
For example, the TEC 6300 Spray Glue Gun is a robust, quality pneumatic machine. If a problem develops, it would be worth trying to determine what is causing the issue first, and perhaps sending it to us to have an expert determine whether the problem can be fixed.
Troubleshooting
The first thing you need to do before you can know if the glue gun can be repaired is troubleshoot the problem.
Some common problems and their causes include:
Nozzle Leaks
A small amount of leakage from the nozzle is normal — usually just a few drops when you first plug it in and after dispensing the adhesive.
If you get a lot of leaks, it may not be a problem with the machine but with the glue sticks you use. Check the manufacturer’s manual or call an expert to find out what sort of glue sticks may be incompatible with your machine.
Excessive leakage may also be due to your nozzle wearing out, and these can be easily replaced.
Poor Flow or No Flow
If adhesive stops coming out or flows out of the gun very slowly, this could also be caused by using the incorrect type or size of glue stick. Refer to the manufacturer’s instructions on types of glue to use with your glue gun.
Another cause may be a broken gripping mechanism that is failing to move the glue stick forward as the hot adhesive dispenses from the tip.
Clogged Nozzle
If you notice poor flow and leakage from the gun’s seams, your nozzle is likely clogged. This can prevent the flow of adhesive and cause a pressure build-up, inducing back melt. Back melt will foul the interior of your gun. If this is the case and you leave the gun plugged in and heated, the glue will start to leak from various points on the gun.
NOTE: Increasing the pressure slightly may alleviate this problem — but do not increase beyond 80psi for safety reasons.
Jammed Glue Sticks
Sometimes, the appearance of a worn or dirty nozzle may be due to a jammed glue stick. Check and ensure you are using the correct type of glue stick for the gun. The glue may have jammed and charred, making the nozzle appear as if it has gone bad.
Adhesive Surges
If you are experiencing glue surges whenever you pull the trigger, it is likely a setting problem and not a part failure. You may need to adjust the flow control valve (if there is one) or the air pressure.
Typical Glue Gun Problems
Leaks
A constantly leaking glue gun can indicate that the internal parts have worn and need replacement.
Temperature Gage Problems
If your adhesive stops coming out in the correct consistency — such as being too thin or too tacky — your temperature regulator may be broken or the wires may have shorted out.
Cracked or Chipped Case
Normal use over time inevitably results in the occasional chip or crack in the case due to dropping the gun or laying it down with too much force on a hard surface.
If, however, you start to experience performance issues after a crack or chip appears, the interior mechanism may have developed a loose connection.
Electrical Failure
Batteries or the power supply often require replacement after prolonged use. If your gun stops working entirely despite being plugged in and turned on, check your battery or power supply.
Most Common Repair
Problems with hot glue gun nozzles are the most common types of repairs that users make. The nozzle’s O-rings break or the threading gets worn causing a leakage.
The repair steps for a nozzle problem are simple:
- Preheat the glue gun. If you don’t, you may strip the nozzle threads, causing a permanent leakage issue and possibly damaging the equipment irreparably.
- Once the is warm, remove the old nozzle by simply using a nozzle wrench or a pair of pliers to unscrew it.
Warning: Use safety gloves so you don’t burn your hand on a hot nozzle.
- Screw in the new nozzle. Don’t over tighten, but ensure it is snug and doesn’t move.
Glue Gun Spare Parts
The price of the gun usually determines whether a glue gun manufacturer sells spare parts. Often it is not cost effective to repair a low-cost model.
However, for many brands, you can find suitable spare parts for many types of repairs.
3M
For the larger, industrial glue guns from 3M, there is a broad selection of parts to help avoid the expense of replacing these more expensive, heavy-duty use machines.
For example, for the Polygun II Pneumatic Glue Gun, we offer several repair kits and parts.
All the repair kits include instructions on how to remove and replace the part.
Triggers often wear out eventually on industrial machines like the Polygun II Pneumatics. Since these guns cost close to $1,000, a $42.80 trigger repair kit is a bargain.
9204 PG II Regulator Repair Kit
This is a very easy repair/replacement for a critical component.
EC Glue Gun Transport Mechanism Repair Kit
The transport mechanism regulates the adhesive flow from the cartridge. Sometimes cleaning the mechanism will solve the problem, but if the problem persists after cleaning, replacing the mechanism costs much less than a new machine.
EC Glue Gun Heat Block Repair Kit
The 3M Heat Block Repair Kit for the popular EC glue gun includes all the small parts needed to replace the heat block, in addition to the heat block assembly. The kit has a valve assembly, nozzle, end clip, insulation and handle screws.
PG II LT Glue Gun Thermostat TCO Repair Kit
If the thermostat is the reason your glue gun isn’t functioning, this 3M kit makes it easy for you to repair it yourself. Whether it is a thermostat or the TCO that failed, you must replace both, as they are part of the same unit.
Disassembly Tips
If you are the type that likes to spend your spare time at your workbench and you would like to attempt more minute repair of your hot glue gun, you will need to disassemble it first. You need to take special care when disassembling and fixing the equipment.
- Turn the power off.
- Determine what screws hold it together. Some hot glue guns have special screws to keep the casing locked and together. You may need to purchase a special tool, as standard flat tip and Phillips head screwdrivers won’t work.
- Use alcohol to remove the plastic seals. Chances are if you need to repair a glue gun, you have already been using it for some time. Glue may have built up along the seals through leakage or carelessness. Use alcohol to remove the glue so the casing doesn’t crack or break when you remove the screws.
- Remove the trigger. The trigger usually comes out easily in most brands.
- Carefully add power to the heating element to let any residual glue melt. Once you do so, you can remove any retainer or other parts.
- Check the heating element and temperature connections for loose wires or broken solder.
Prevention
You can help prevent the need for industrial hot glue gun repairs by periodically performing a comprehensive check of your industrial applicators, including preventative maintenance steps. This is particularly useful if you use pneumatic guns and bulk hot melt machines.
- If you have a pneumatic glue gun, remove the hose, inspect it, and if necessary, drain and purge it according to the manufacturer’s instructions.
- Don’t leave your hot glue gun plugged in.
- Keep the chamber clean and free of any excess glue. Remove melted glue from around the nozzles after each use.
- Check all your hoses for any kinks or thinning of the hose material and ensure the hose connections are secure. Visually check for signs of adhesive char. Adhesive char forms when the adhesive properties of the glue change due to thermal and oxidative degradation. Basically, the adhesive overheats and clogs the lines and the gun machinery.
- Manually fire the gun and ensure the PUR (heated polyurethane hot melt) retracts from the nozzle of the gun.
- Check all the fittings.
- Make sure you are following manufacturer recommendations for pressure and temperature settings, and that the settings match the adhesive you use.
- Go over the safety and usage instructions with your employees and include a method of checking the match between the glue used and the glue gun settings.
Final Thoughts
Glue guns have become an important tool not just for hobbyists but for professionals across a wide range of industries. Taking care of your glue gun and adequately troubleshooting any issues helps to determine whether something other than a bad part is actually causing it to malfunction.
If you want to undertake a repair yourself, the manufacturer includes clear instructions to guide you in replacing the malfunctioning piece.