Accelerometer Adhesives for Permanent Installation

[MachineryWatch]

Does anyone on this forum know of any accelerometer manufacturers that have tested Belzona 1111 for installation of mounting pucks used for installation of accelerometers. Or, perhaps any other source for this kind of information. I want to make sure the high frequency performance of the sensor is not significantly degraded.

Thanks for your input!

Skip Hartman

http://www.machinerywatch.com

 

[GregLocock]

No, but a test is easy to do. Drill and tap the right sized hole in a test item (we used a 5kg steel bar), and screw an accelerometer into that. Alongside glue a mounting plate for the same type of accelerometer. Bash the test item with a hammer and look at the results.

Cheers

Greg Locock


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[MachineryWatch]

Thanks Greg. I may have to do that. It will be a couple of months before I can do this for a couple of reasons, so I am still hoping to hear from someone who has a source for info or experience with it. I have a question into the accelerometer manufacturer and waiting for a response from them. Unfortunately, in my experience the manufacturers usually simply endorse the adhesive that they happen to sell as a mounting accessory.

Skip

http://www.machinerywatch.com

 

[TugboatEng]

Belzona 1111? Is you're time not valuable?

All kidding aside, I prefer acrylic adhesives for these types of mounting applications. They come in convenient dispensing cartridges with mixing tips. The time from install to 75% strength is usually around 30 minutes. They're fast enough that I have held items by hand until sufficiently cured. The acrylic adhesives are most tolerant of "in the field" surface prep. Acrylic adhesives bond better to plastics than other types. I specifically use 3M DP100NS or DP805. There are other brands have parallel product lines.

The Belzona 1111 comes out for more complicated installations where I need time for shaping or clamping.

 

[Tmoose]

If you need to track frequencies over 1000 Hz or so, excessive adhesive thickness can start to mess with the frequency response.
That may end up being another vote for a "space age plastic" product.

And grinding the mounting surface flat for the "puck" so the adhesive film can be uniform, and THIN.

B+K used claiming good results using bees wax mounting, at least with dainty little accelerometers . I pictured the hysteresis or pumping or whatever bumped the dynamic stiffness, along the same lines as recommendations for a bit of grease for better "coupling" with stud mounted applications.

https://www.endevco.com/contentStore/mktgContent/endevco/dlm_uploads/2019/02/TP312.pdf

https://vibrationresearch.com/blog/accelerometer-mounting-tip-sheet/

https://wilcoxon.com/blog/sensor-mounting-methods/

https://www.metrolog.net/files/using_doublesided_tape_for_accelerometer_mounting_en_metrolog.pdf

Some mighty experienced folks here.

https://www.machineryanalysis.org/post/what-adhesives-are-best-for-attaching-accelerometers-9615736

 

[MachineryWatch]

Hi Tugboat and Tmoose,

Great input. Here's the thing. The application is monitoring steel mill roll stand gearboxes with 250 mVolt/G industrial accelerometers. Not a great application for bee's wax, but I have used this method with more dainty sized accelerometers in temporary mounting applications when doing experimental measurements where heat, grime and sensor weight were not a factor.

Also, it is not my time that is a factor, the customer is mounting the sensors. The customer wants to use it because they use it for lots of things in their facilities and have found it to do a better job than the other adhesives they have used. They do not like redoing the same job when an adhesive fails. Of course, they know nothing about how adhesive relates to sensor performance.

Like you, I advise remove paint to bare metal, clean away all oil/grease or paint residue. Use a cleaner that does not leave a film of any kind on the surface, then use as thin a film as possible. I preach this constantly with mixed results. They have some pretty nasty places to get to for mounting the sensors, so I am trying to determine if their choice of adhesive will still provide good vibration results when used properly.

Thanks for the links. I will definitely check those out.

Skip

http://www.machinerywatch.com

 

[MachineryWatch]

Tmoose,

Great discussion going on in that last link at the bottom of your post. Infact I am not certain, but I think the gentleman with the longest most detailed post about shipboard applications is maybe working on a program I used to be involved with at it's inception, which he says was in 1988. I was all shipboard applications back then.

It was a very helpful link. Thanks.

Skip

http://www.machinerywatch.com

 

[YungPlantEng]

Used this on a cooling tower and the pucks would fall off all the time. Granted they were exposed to a pretty rough atmosphere.

 

[MachineryWatch]

YungPlantEng,

Thanks for sharing your experience. I appreciate your input.

A Belzona engineer got back with me today following my request for help from them. He said that Belzona had no knowledge of testing done to verify that it would pass high frequencies adequately. He knew Belzona had done no such testing and was not aware of any accelerometer manufactures having done any testing with Belzona 1111 to "qualify" it for the kind of thing we use it for. I described the application, the weight of the sensors all the materials involved and the range of temperatures. The Belzona engineer felt like the Belzona 1111 should provide a long-lasting secure bond but recommended going to Belzona 1511 for applications exceeding 176F.

I also got a response for an opinion from the sensor manufacturer. They confirmed that they had not done testing on Belzona 1111 in their test facilities. However, the sensor manufacturer did not discourage using it for mounting their accelerometers.

I suspect my biggest challenge remains what it always is: getting the guys to remove paint to the bare metal, make sure that the surface of both the mounting puck and the newly cleaned surface are both film and oil free, and finally using a THIN layer of the adhesive. Then of course allowing adequate cure time for the specific adhesive before tightening an accelerometer down. I suspect that many of the times when a mounting puck falls off in a relatively short duration of time after installation the installer had prepped the machine surface correctly but neglected to clean the surface of the mounting puck to remove any cutting oil residue. Any easy thing to overlook.

Skip

http://www.machinerywatch.com

 

[GregLocock]

Is there any reason you can't drill and tap?

Cheers

Greg Locock


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[MachineryWatch]

Of course that would be my preference. I started running into resistance in the plants to me doing this as a service provider over 20 years ago. In these cases the customer is installing the sensors themselves and simply refuse to do that anymore.

http://www.machinerywatch.com

 

[IRstuff]

Product qualification testing in my world usually frowns on putting extraneous holes in the first articles.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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