EPOXY TIPS, Q&A, NEWS

QUESTION:  What is the proper curing temperature profile?   ANSWER:   In most cases, cable assembly manufacturers are curing by placing their room-temperature product into pre-heated curing ovens---quite a thermal shock.  Based on our observations, it seems that...

QUESTION: Is fabricating fiber optic cable assemblies a manual or automated process?   ANSWER:   Fabricating fiber optic cable assemblies is still in large part a manual process, requiring knowledge and skill. When something in the process goes awry,...

QUESTION:  Which epoxy is the best for my application?   ANSWER:   Fiber Optic Center offers several epoxies for single mode and multimode products. Refer to the “Chart of Epoxies for Single Fiber, Single Mode and Multimode Terminations” to review epoxy...

QUESTION: Should we check for crystallization? Do we need to adjust our inspection process?   ANSWER: Yes, here at Fiber Optic Center, we strongly encourage all our customers to actively look for crystallization in epoxy, since it’s a common occurrence. To avoid...

QUESTION:  Why aren’t packages of less than 2.5 or 2 grams available?   ANSWER: Some epoxy manufacturers offer 2.5-gram packages as their smallest quantity; one manufacturer offers a 2-gram package. When packaging the material, the manufacturers are mandated to...

QUESTION: How can I select the right epoxy for a new application? ANSWER: I’m happy to help you determine the epoxy that will work best for your application. Just send an email to me at KBarker@focenter.com and include answers to these questions: Can you tell me...

QUESTION:  Do you have epoxy information in the form of a matrix?   ANSWER:   FOC does have a Single Fiber, Single Mode and Multimode terminations matrix that can be found in the BLOG ARTICLE:  Does epoxy cause core cracking? Tips to identify and prevent this...

QUESTION:  Why do we need to consider the Tg when selecting an epoxy?    ANSWER:   One reason to consider the Tg is in selecting an epoxy that is appropriate for an application.  For an application requiring a flexible epoxy, a low Tg, something below 0°C is...

QUESTION: Our epoxy is past expiration – can it still be used?   ANSWER: Fiber Optic Center recommends that you test the material before using it in your production process. Cure it to see if it sets as expected. However, it’s difficult to determine if it has,...

QUESTION:  How precise are the epoxy packaging weights?   ANSWER: The fiber optic world is driven by precision. If you purchase a 4-gram package, you can rely on getting 4 grams of epoxy. This is a data point to consider as you determine which package size best...

QUESTION: Does Fiber Optic Center accept returns of crystallized epoxies? ANSWER: It’s important to remember that there’s nothing wrong with the material. Since crystallized epoxy is not defective, we do not accept returns. Of course, if you encounter a different...

QUESTION:  Would premixed, frozen epoxy work better for my process?   ANSWER: Our customers who use premixed, frozen epoxy report two major benefits: (1) No need to worry about improper mixing due to operator error. Epoxy that is overmixed, undermixed, or has...

QUESTION:   We have issues with crystallized epoxy: has the epoxy had “gone bad”?   ANSWER: This question has come up so often, I have written article to educate our customers about crystallization in epoxies including information on: How this happens. Why the...

QUESTION: I found crystals in our epoxy. Does this mean it has gone bad?     ANSWER: Crystallization in epoxies can look like salt granules in the otherwise clear liquid. Or the epoxy may look foggy, milky, or grainy. Or it may have solidified. Rest assured,...

QUESTION:  How do you safely dispose of epoxy?   ANSWER: Once it cures and hardens, epoxy can be thrown away in regular waste. Think of it this way: You must allow a gallon of house paint to dry and harden before throwing it out. Liquid epoxy can be hazardous,...

QUESTION: Why is bond line thickness important?   ANSWER: Proper bond line thickness ensures you’ll achieve the adhesive properties AND performance specified in the epoxy’s datasheet. If there is inadequate bond line thickness, the risks include low strength...

QUESTION:  Since cleanliness counts, how can I improve my epoxy work surface?     ANSWER: The pot life on epoxy starts the moment the two parts are mixed. This means you need to plan your work, and have everything you need at your fingertips. Here’s a...

QUESTION:  Which package size of epoxy is right for my process?   ANSWER:        I often encourage my customers to consider purchasing 4-gram packages of epoxy – if this size supports their process. Briefly, here’s why I recommend the 4-gram package: Higher...

QUESTION: Why does crystallization happen?   ANSWER: Simply put, the liquid resin is fighting to return to its natural state, which is a solid form. Crystallization in epoxies is so common that major manufacturers have written datasheets on the subject. According...

QUESTION: What is the recommended minimum bond line thickness?   ANSWER: A general guideline for minimum bond line thickness is between 25 to 150 microns (1 to 6 mils) – as a starting point. I recommend you choose a certain level to start, then make a few thicker...

QUESTION: Our technicians might be overmixing epoxy. What advice can you give us?   ANSWER: If you mix too vigorously, you can trap air in the material and introduce bubbles. In the production process, it’s important to dispense a drop of epoxy – not a bubble. So...

QUESTION:  How can we minimize epoxy material waste and reduce costs?   ANSWER: Recommendations to adjust your epoxy process, which can minimize material waste and reduce costs Here are two ideas to alter your epoxy-related production process. These process...

QUESTION: If the epoxy has filler or glass beads, will that interfere with the strength of the bond – and create the need for a thicker bond line?   ANSWER: If an epoxy has a filler or glass beads, the manufacturer has included the filler for a reason. The filler...

QUESTION: What happens if you overmix epoxy?   ANSWER: The possibility of overmixing is more likely. The goal is to thoroughly blend Part A and Part B with minimal bubbles. (In the production process, you don’t want to dispense a bubble instead of drop of epoxy.)...

QUESTION: Is a static mixer the recommendation for fiber optic epoxies?   ANSWER: Almost all epoxies used in fiber optics are two part and have dissimilar mix ratios.  This, coupled with the relatively small amount of material being applied, means a static mixer...

QUESTION: We are a fiber optic cable assembly manufacturer.  For epoxy bi-packs, what are the typical package sizes?   ANSWER: For fiber optic cable assembly manufacturers, bi-packs of 2.5-gram and 4-gram are typical package sizes for epoxy. While these packages...

QUESTION:   When working with epoxies, are there different types of skin irritations or allergies?   ANSWER: The two types of Contact Dermatitis are Irritant and Allergic:   Irritant Contact Dermatitis is an inflammatory reaction that occurs after damage to...

QUESTION: How do you ensure proper bond line thickness?   ANSWER: Plan to test your bond line thickness – and other epoxy processes – to ensure they are optimal for your application. Remember this rule of thumb: “The application dictates.” When developing a new...

QUESTION:  Which epoxies cause allergic reactions and which do not?     ANSWER: Almost all epoxies used in the fiber optic industry are two-part epoxy systems consisting of a resin and a hardener or activator.  All the chemicals in these two-part epoxies can...

QUESTION: How can I identify crystallization in epoxies?   ANSWER: If you put a glass of water in the freezer for a few minutes, you’ll see ice crystals begin to form as the water changes to ice (its solid state). Similarly, crystals often form in epoxies....

QUESTION: What happens if you undermix epoxy?     ANSWER: In fiber optic cable assembly applications, most epoxy package sizes are quite small – just a few grams – so undermixing is typically not an issue. While mixing the resin and hardener (Part A and Part...

QUESTION: When you’re setting up your process and determining how much epoxy to dispense into a ferrule, how can you be sure you have the proper fill inside the ferrule?   ANSWER: Here’s a simple tip: Use a scrap piece of 900-micron cable as a dipstick (just as...

QUESTION: Does FOC has some epoxy curing tips for when issues occur?   ANSWER: Tips regarding epoxy curing issues: To validate your epoxy curing process, we recommend following the Telcordia GR-326 adhesive testing standard (section 4.4.4.2). Avoid placing curing...

QUESTION: What happens if you have too much epoxy inside the ferrule holder?   ANSWER: Too much epoxy inside the ferrule holder can lead to other issues—for example, the inserted fibers will displace the injected epoxy so that it flows out the rear of the ferrule...

QUESTION: What size syringe needle should I use for injecting epoxy into connectors?   ANSWER: Most common connectors are machined to accept buffer tubes of 0.9mm (900um, or 0.036”) diameter.   Thus,  it is recommended to use similar diameter...

QUESTION:   Is there a way to avoid wasted epoxy?     ANSWER: Given that 2.5 grams is the smallest size that is practicably achievable, FOC recommends saving any extra epoxy in a secondary dispensing container (like a syringe), frozen -40°C.  -40°C...

QUESTION: How do you get a two-part epoxy to achieve its maximum cured bonding properties?   ANSWER: For a two-part epoxy to achieve its maximum cured bonding properties, the two parts must be sufficiently mixed, and cured at the proper temperature and time. ...

QUESTION: Are the choice of epoxies critically important and if so, why?     ANSWER: The choice of epoxies is critically important. Most Telco/Data and OSP connectors are assembled with two part epoxies that provide high tensile strength, excellent bonding...

QUESTION:   Is homemade pre-mixed and frozen epoxy real?   ANSWER: Homemade pre-mixed and frozen epoxy is the equivalent to making your own pre-mixed and frozen epoxy, which may take some trial and error, but can ultimately save time and solve the epoxy waste...

QUESTION: How and when should you purchase epoxy  material in premixed and frozen syringes?   ANSWER: To further reduce your handling and increase your process control, you can purchase the material in premixed and frozen syringes.  In this case, the material...

QUESTION:   Can you use expired epoxy? ANSWER: Epoxy does have a shelf life and the physical properties will change over time. Epoxy manufacturers recommend you do not use epoxy that has reached its expiration date. If unusual circumstances require you to use expired...

QUESTION:  Does FOC have any experience or recommendations in using microwaves to cure fiber optic epoxies?   ANSWER: FOC does not have any experience using microwaves to cure epoxies.  Certain microwave machines, much more sophisticated than the familiar...

QUESTION:  I need a really strong bond.  What is the absolute strongest adhesive you have?       ANSWER:  Modern adhesives are pretty amazing, and people do seem to want to rely on them more and more.  But it is important to know that epoxies are NOT primary...

QUESTION:   Looking for tips on epoxy work surfaces.  Do you have any information on that?     ANSWER:   When working with epoxy, neatness really counts.  Since the pot life on epoxy starts the moment the two parts are mixed, plan your work so that you have...

QUESTION:   What’s the easiest way to load a syringe with a 2.5g pack of epoxy?     ANSWER:  We think the best way to load a syringe with a mixed pack of epoxy is to have BOTH HANDS available to do the job.  This means you want the clean syringes ready to go...

QUESTION:  I have a question about the AB9112 Epoxy, what is the proper storage method? In the datasheet, under section 7:Handling and Storage, it doesn’t really specify the proper storage of the epoxy. We had a couple epoxy packs that went grainy before it’s due...

QUESTION: We are getting epoxy 353nd from you in a package of 2gr. Is it the minimum package?  We are concerned about wasting material because we are using 353nd only for MTP assembly.  Do you have any suggestions to reduce waste?   ANSWER:  It is not possible to...

QUESTION:  I am noticing a large epoxy ring with visual inspection. Can you help me understand what I am looking at?   ANSWER:  Occasionally we receive visual inspection pictures from multimode connectors that shows an evident rough epoxy ring around the fiber....

QUESTION: My epoxy is ‘behaving irregularly’, curing differently, has a different color, etc. Can you help?   ANSWER: It is possible for a batch of epoxy to be faulty, but it is very rare.  Most likely you are experiencing some variation in the epoxy that is...

QUESTION: My epoxy is past expiration. Can I use it?   ANSWER: Once the epoxy is past expiration, FOC does not recommend using it without testing the material. You can cure it and if it sets as expected, it can be used.  However, the hard part will be determining...

QUESTION: What info is needed to determine the correct epoxy for an application?   ANSWER: Here is a list of questions we will need answered: Can you tell me something about your application? What substrates are to be bonded? What is the main purpose of the...

QUESTION: Why does my epoxy have crystals in it?   ANSWER: Crystallization of liquid epoxy is a known phenomenon that frequently surprises users who are not very familiar with epoxies.  Crystallization may look like crystals, snowflakes, cloudiness, fog,...