Thermo-couple attachment

We use uV Dymax glue for thermocouple attach sometimes, but don't like the remainder [anal] and loosing attach, sometimes.

Roger Saunders, President Saunders Technology, Inc; said: PRO: � These products are easier to use than high temperature solder. � Accelerator and UV activated products set quickly, to speed installation. � High temperature, two part epoxies will withstand reflow temperatures for many cycles. � Both products can attach thermocouples to unsolderable surfaces such as plastic or ceramic components or FR4 board. CON: (Accelerator or UV activated adhesives) � Their low temperature rating makes them prone to popping off during reflow, where peak temperatures are around 210�C. � Their relatively poor thermal conduction makes it essential that the thermocouple junction be held securely against the surface to be measured while the adhesive is activated. � They are usually easy to remove by "popping " them off with a knife. However, they do leave a film-like residue that is noticeable on FR4 and dark components, and can be difficult to remove. The most effective solvents, like acetone, also dissolve plastics, and can therefore damage circuit boards. CON: (Epoxies) � High temperature epoxy requires an oven cure of several hours. This is inconvenient, especially for quick trouble shooting. � It also requires careful fixturing to insure that the thermocouple junction stays in contact with the surface to be measured, throughout the oven cure cycle. � It is difficult to remove this material cleanly, without damaging the board or component. � Quick curing epoxies like "5 minute" epoxy are rated in the range of 130�C, so they often pop off during reflow.

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