Most foil strain gages are installed using an adhesive system. These adhesive systems are purchased separately from the strain gage itself. However, it is possible to order some Micro-Measurements strain gages with a B-staged epoxy adhesive already applied to the strain gage backing. B-staged adhesives are a variety of adhesive that when initially applied are dry to the touch but can be re-liquefied and fully cured through exposure to heat and pressure. Pretty cool, right? In today’s blog, we discuss the types & applications of adhesive-backed strain gauges.

How important is the strain gauge adhesive?

When measuring strain, errors are dependent on the quality of the strain gauge’s installation. Why is this? Because in order for strain to be properly transferred to the strain gage, there must be an intimate connection between the strain gage and the measurement object. Therefore, the role of adhesive in strain gage installation is paramount to accurate and reliable data acquisition.

What are the advantages of an adhesive-backed strain gage?

Using an adhesive-backed strain gage in your strain gauge installation has the following advantages:

• Convenience. When using an adhesive-backed strain gage, you do not have to purchase, mix, apply, and store a separate adhesive for gauge bonding.

• Reliability: With a pre-set amount of adhesive, you can ensure a tight bond and thus accurate measurement.

• Ease of Use: With dry adhesive already attached to the strain gauge, you no longer need to deal with messy adhesive application. 

What are the disadvantages of an adhesive-backed strain gage?

There are a few minor disadvantages to using adhesive-backed strain gages, including:

• Short Shelf Life: With the adhesive already applied, these strain gages have a shelf life of about six months under lab conditions.

• Use of Adhesive Tape: The engineer will need to use tape to hold the gage in place during cure.

How do I apply an adhesive-backed strain gage?

So, you’ve purchased your adhesive-backed Advanced Sensors Technology strain gages from Micro-Measurements. Now, how do you install them? First, it’s important to note that gages with B-staged adhesives are shipped in special non-contaminating flat trays. To install the gages after normal strain gage installation surface preparation, you simply remove the gage from the tray, align it at the prepared bonding location, and hold it temporarily in place with a small piece of MJG-2 tape. Then, apply normal bonding pressure and oven-cure. No additional adhesive needed!

What is the operating temperature of adhesive-backed strain gages?

For strain gauges with pre-applied B-staged epoxy, the operating temperature range is -452°F to +350°F (-269°C to +175°C)

We hope this overview on adhesive-backed strain gages is a helpful resource. StrainBlog is a blog written by engineers for engineers, and we’re always happy to help with your strain gage sensors and strain gage installation projects. Here’s how to find us:

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Yuval Hernik

StrainBlog Editor in Chief