A skin does not necessarily mean that the inside is completely hardened.
Product and application
Select the system so that only relevant test steps appear. If no system is specified, the test will remain general.
01
What are you observing?
02
Identify the cause
03
For reference
All test steps in this guide can be used even without the guided process.
Terms briefly explained
Hand strength
The parts should be handled carefully. The connection is not yet fully load-bearing.
Complete curing
The curing conditions and times prescribed for the product were adhered to.
Adhesive gap
Distance between the two joining surfaces, not the length of the adhesive seam.
Pot life and nozzle life
Test the processability of a mixed quantity and the processability in the mixing nozzle separately.
Soft inside, already a skin on the outside: 3 testing steps
MS polymers harden through moisture from the outside in.
1. Moisture ingress
Can sufficient moisture reach the adhesive layer?
Dry conditions and sealed joints can slow down the curing process.
Check ambient humidity and access to joints.
Improve humidity conditions within the manufacturer's specifications; do not simply add water.
2 · Layer thickness
Does the planned waiting time correspond to the actual layer thickness?
Thicker layers harden more slowly.
Measure joint thickness and check curing according to the product-specific schedule.
Do not subject the bond to stress until it has sufficiently hardened.
3 · Storage
Has the material been stored within its shelf life and according to the data sheet?
Aging, humidity, separation of components or unsuitable temperatures can alter processing and hardening.
Record batch number, expiry date and inventory history.
Check for segregation, thickening, and contamination. Do not correct conspicuous material with unauthorized additives.
If the material quality is unclear, check a fresh, correctly stored batch for comparison.
Difficult to squeeze out; 2 test steps
After opening, moisture can cause material to harden in the nozzle.
1 · Nozzle
Is the nozzle free of hardened material?
Prolonged inactivity can cause the nozzle to become blocked.
Clear or replace the nozzle according to the product specifications.
After use, seal tightly and prevent further hardening towards the container.
2 · Storage
Has the material been stored within its shelf life and according to the data sheet?
Aging, humidity, separation of components or unsuitable temperatures can alter processing and hardening.
Record batch number, expiry date and inventory history.
Check for segregation, thickening, and contamination. Do not correct conspicuous material with unauthorized additives.
If the material quality is unclear, check a fresh, correctly stored batch for comparison.
Strength is insufficient; 3 test steps
MS polymers are particularly suitable for elastic, low-modulus connections and larger bonding surfaces.
1 · Interpretation
Is an elastic system suitable for the required load-bearing capacity?
High structural strength may require a different adhesive technology.
Check the adhesive surface, load and deformation requirements.
For high structural stress, evaluate a different technology in conjunction with the application engineering.
2 · Surface
Are the actual materials clean, dry, and properly prepared?
Oil, release agents, varnishes, and weak oxide layers can impair adhesion. Changing suppliers can also alter the surface.
Determine the material and alloy or plastic mixture. Ask the supplier about any changes to release agents, plasticizers, and coatings.
Adjust the cleaning process to the material and allow the cleaning agent to evaporate completely. Check the blasting media for cleanliness and condition.
Apply adhesive promptly after pretreatment and avoid further contact or oxidation. If necessary, test wettability using suitable testing methods.
3 · Load
Is the bond only subjected to stress within its operating conditions after sufficient curing?
Premature stress, peeling forces, media, or differing thermal expansion can weaken a connection that initially appears to be good.
Compare the waiting time before loading with the product data sheet.
Capture joint geometry, temperature, chemicals and humidity in real-world use.
For peeling loads or different materials, test tougher or more flexible systems with the application engineer.
German version prepared according to the archived Permabond guide troubleshooting-ms-polymer.md. Always compare product-specific values and procedures with the corresponding technical data sheet.
