Two Part Adhesive Dispensing: System Selection, Ratios And Waste

Updated July 2026

Two part adhesive dispensing is a controlled process for metering, mixing and placing two reactive adhesive components through a cartridge or bulk-feed path. It runs from piston movement to static mixer design, post-mix bead inspection, operator protection and supplier validation. Many buyers choose two part adhesive guns by just looking at cartridge cost, unaware that it can lead to ratio failure, lost purge or rejected beads.

This buying guide is intended for factories looking to compare two-component adhesive cartridges (empty or filled), adhesive dispensing guns, static mixers, and meter-mix dispensing equipment. First, determine what samples you should request, what measurements to take, and what to include in the Request for Quote, all before you start seeing streaks or slow curing.

Quick Specs

System choices	Manual cartridge gun, pneumatic cartridge gun, automated cartridge dispense, meter-mix dispense equipment
Ebestron public cartridge range	50ml, 75ml, 100ml, 200ml, 250ml, 400ml and 1500ml; 1:1, 2:1, 4:1 and 10:1 ratios
Material path	PP, PA and PBT barrel options; chemistry fit still requires SDS review and sample validation
Best first action	Measure ratio, viscosity, shot volume, purge practice, mixer retained volume and acceptance criteria before asking for price

What Two Part Adhesive Dispensing Means In A Factory

Two component adhesive dispensing is the practice of accurately measuring and mixing two materials that cure upon contact to achieve the desired bead characteristics in the specified application area. In practice, the dispensing process combines the material’s data sheet, the storage (cartridge/tank), the path to dispensing (pistons), the dispensing tool (gun/valve), the mixing tool (static mixer), the shape of the final bead, and the inspection criteria used.

This “6-Link Chain” is critical, as no two-component adhesive is forgiving of loosely controlled dispensing processes. Even with a standard 10:1 ratio cartridge, uneven piston travel, improper purging of the initial mixed material, or the wrong static mixer for the adhesive’s viscosity, will result in a flawed bead. Likewise, even a meter-mix dispenser will fail if maintenance and calibration isn’t up-to-date or the material isn’t properly conditioned prior to use.

For a purchasing team, a better approach than “which two part epoxy gun is best” is to ask “which dispensing system architecture best controls the single biggest risk to my process: changeover time, off-ratio curing, pot life, retained waste, operator exposure, production rate, or quote predictability?”

That is why the same project appears in purchasing research as adhesive dispensing systems, epoxy dispenser, adhesive dispensing equipment, robotic adhesive dispenser, 2 part epoxy dispensing equipment, automated adhesive dispensing system or two part epoxy dispenser. Related sourcing language such as two component epoxy dispensing systems, two component 2k dispensing, dual component cartridge guns, meter mix dispense equipment and two part adhesive dispensers points to the same factory problem: the buyer must match tool architecture to chemistry, application risk and validation evidence before price comparison.

System Selection: Cartridge Gun, Pneumatic Gun, Automation Or Meter-Mix?

When considering new dispensing equipment, identify the underlying process bottleneck before consulting the product catalog. Cartridge dispensing is generally the more practical option for testing, repair, lower-volume production, or jobs with a high product mix. Meter-mix equipment begins to make sense when the constraint is high volume, the need for automation, real-time ratio monitoring, or the potential for worker exposure and high-volume bulk material economics.

This table serves as a guide to the buying decision rather than an absolute benchmark. Data available from the supply chain points the direction for these decisions but offers no universal “daily shot count” threshold that works for every adhesive, substrate, bead design, or line.

The 6-Link Ratio-Control Chain

Use the 6-Link Ratio-Control Chain to identify problems with your dispensing ratio before blaming your cartridge supplier. It connects the data-sheet ratio, cartridge chamber design, piston travel, mixer design, purge effectiveness, and bead inspection criteria.

Reports from the field indicate that the top problems in two-component adhesive dispensing include incorrect mix ratio, premature cure within the static mixer, and over-purging. Each failure manifests in similar results on the part but require a unique solution.

Static Mixer Selection: Interface, Element Count And Waste

While static mixers are designed for easy integration with a cartridge, simply matching the connection point isn’t sufficient. At the outlet, the mixer can mask an incompatible adhesive if factors such as viscosity, ratio, pressure drop, flow rate, pot life, and bead design exceed the mixer’s limitations.

Nordson’s published static mixer guidance ties choice to cartridge, material, mixed viscosity, and housing outlet types, and different sample element ranges by chemistry. Ebestron’s public tools ask for the mix ratio, viscosity, and viscosity gap, then suggest a starting element count, cautioning buyers to validate with their actual adhesive.

“18 elements or 24 elements?” is therefore not the right question.

Instead ask, “What’s the shortest mixer that ensures complete mixing at the actual flow rate, bead size, and working time we use?” A shorter mixer can reduce residual waste, but if it’s too short it can lead to streaking. A longer mixer can improve mixing, but it also increases back pressure and discards more cured material during each tip change.

Buyer check:

Obtain from suppliers an initial mixer recommendation and then validate with your actual adhesive, substrate, bead size, open time, and dispense speed. Use element-count tables to screen possibilities, not as definitive process approval.

Chemistry Fit: Barrel Material, SDS And Process Validation

Three layers compose a chemistry fit: the chemical compatibility, worker safety, and application verification. For epoxy, polyurethane, MMA, acrylic and silicone systems, PP, PA or PBT barrel materials may fit the cartridge requirement, but cartridge material is only part of the story.

When using polyurethane systems, first examine all isocyanate exposure controls prior to the approval of any dispense method. OSHA references isocyanate exposure to irritation of the skin and mucous membranes, breathing difficulty, and occupational asthma; planning for SDS review, ventilation, and PPE therefore belong in the purchase process.

For certain acrylic systems, as well as for MMA, don’t restrict the choice solely to speed of cure. Methyl methacrylate is listed by the NIOSH as a Class IB flammable liquid, which requires control over ignition sources, ventilation, SDS review, and handling procedures in the sample room before upscaling.

Food-contact and packaging applications require the same diligence. 21 CFR 175.105 specifies the limits for adhesives used in the packaging, storage, or transport of food. It can’t be generalized for all cartridges or for every instance of adhesive application after cure.

A practical problem is that a chemically compatible barrel can still fail application approval because the process ignores exposure limits, ignition controls or validation records. Where MMA is relevant, the NIOSH Pocket Guide lists a 100 ppm / 410 mg/m3 time-weighted exposure limit and a 50 F flash point; where PU is relevant, OSHA frames isocyanates as an occupational asthma and irritation risk. Ebestron can screen PP, PA and PBT cartridge options for a sample request, but the buyer still needs SDS review, plant EHS approval and a documented bead test before OEM release.

Cost Per 1,000 Good Beads

What should the true unit of cost be for purchasing two-component adhesive dispensers?

I suggest using cost per thousand accepted beads which will include the cost of cartridge/bulk material, mixer residual waste, the initial dispense, rejects, and operator labor costs.

A helpful tool from Ebestron’s website can estimate annual mixer retained waste using cost per mL for the adhesive, mixer residual volume, daily nozzle use, and number of days in operation.

Prior to obtaining any quotations, the same calculation could be developed into a purchasing spreadsheet.

Use the table as a unit checklist not as a criterion for best. Typical trial forms often have columns for 0.2mm shim checks, 3mm bead width, 25mm overlap, 60 min open-time observation, 2 hr interim cure review, 24 hour handling hold, 7 day aging screen, 80 psi back-pressure notes, 6 bar air supply, 2% reject rate band, and 5% purge loss band. Finance can then add a $/year waste line item after the plant can supply actual adhesive cost and shift counts.

When Cartridge Dispensing Stops Winning

Cartridge dispensing ceases to win when flexibility is no longer the prime value. Signs of repeated high volume work, frequent purge loss, a record of ratio complaints, a history of rejected expensive parts, or a robotic cell requiring data logging and reproducible shot control should give a warning.

Don’t try to devise a generic daily-shot cut-off. Try instead a staged evaluation process: prove the cartridge process using a clear RFQ and a sampling plan; then calculate cost per thousand good beads; and finally investigate whether the actual bottleneck is material handling, ratio monitoring, maintenance, operator exposure or line speed.

If the bottleneck is costly and reproducible, then meter-mix should enter the project.

If the bottleneck is SKU variety, field service, short pot life, small batch validation or a private-label cartridge supply channel, cartridge could still be the better solution.

A competent supplier should know when to advise against the meter-mix solution due to a lack of repeatable volume or plant maintenance readiness.

Purchasing rule: do not upgrade to meter-mix because one cartridge quote looks expensive. Use the 1,000-Good-Bead Cost Ledger first; if your actual data shows repeated ratio failures, high purge loss, 20 tips/day changeover pressure or rejected critical parts, then meter-mix deserves a trial. If Ebestron can validate the needed cartridge ratio, mixer interface and sample plan for a mixed-SKU application, cartridge dispensing remains the lower-risk path.

RFQ Checklist For Samples And Supplier Quotes

An RFQ for a two-part adhesive cartridge system should present an obvious choice.

If all the customer requires is a price, the supplier will have to make assumptions about chemistry, ratio, viscosity, dispensing gun, mixer interface, tip style, annual quantity, and the acceptance test criteria.

Failure Diagnosis Before You Change Suppliers

Poor cure, streaks, plugged mixers and piston blow-by don’t all originate from the same cause.

Replacing the supplier can resolve problems related to the cartridge molding process, pistons, or seals, but a significant portion of the defects are traced to ratio translation issues, mixer design, purging techniques, application temperatures or handling.

Frequently Asked Questions