Dispensing Adhesives with Hand Pumps Reduces Cost

Threadlocking and thread sealing adhesives have become one of the most reliable and inexpensive ways to ensure that a threaded assembly will remain locked and leak proof. Applied drop-wise to fastener threads, these adhesives fill the grooves of the threads and cure to a hard thermoset plastic when fastener is assembled exposing the adhesive to metal ions in the absence of air – therefore they are also called anaerobic adhesives. Threadlockers are available in low strength formulations for easy removal, medium strength grades that can be removed using common hand tools, and high strength formulations that offer the highest holding abilities. Bolts that have previously been locked with a threadlocker can be re-used by removing the old adhesive.

Dispensing Metal Adhesives Manually

Typically anaerobic metal adhesives are made available in special purpose plastic bottles. The bottles are approximately half filled with adhesives. The unfilled space contains air that keeps the material stable and some suppliers, such as Loctite, actually developed special bottles that are slightly air-permeable, allowing air to pass through the bottle to further ensure product stability before usage.
Most users apply threadlockers directly out of their original packaging. With manual dispensing straight from the bottle, the volume of the adhesive dispensed is controlled by the operator. The bottle must be tipped so that a drop of threadlocker will be released from the bottle and placed by gravity onto the fastener.

Common challenges related to bottle dispensing include excessive dispensing of the adhesive where too much is applied, and applying the adhesive in tight locations where the bottle cannot be tipped for drop-wise application.

Hand Pumps Minimize Waste

A simple and effective solution is to use a low-cost hand pump unit that can be installed onto the bottle-top. Hand pumps are positive displacement dispensing systems, which by definition is the volumetric displacement of fluid. A positive displacement system is unaffected by external variables and is therefore very repeatable under changing conditions such as temperature and viscosity. The variables that affect positive displacement dispensing are stroke, bore, and or rotation. By pressing a trigger, the dispensing wheel is turned and an exact quantity of the product is transported
through the tube to the applicator needle. Most handpump designs include an adjusting screw to set the stroke on the trigger. With this it is possible to control the quantity of adhesive to be applied very accurately.

A leading adhesive manufacturer provides hand-pumps for use with its products. These manual systems will dispense threadlockers, thread sealants, and retaining compounds from 0.01 to 0.4 ml, and in viscosity’s up to 30,000 cPs. They work at any angle, won’t leak, and eliminate waste. In addition, they require no flushing, power, or air source. Loctite - has done comparison tests, and test show that correctly applying a hand-pump can effectively lower usage of liquid threadlocking adhesive by more than 40%.