Protection after shaft burnished

From someone who has spent many years in the business of rotordynamics, including design, repair and maintenance...

Recommendations for probe track protection

3-M Scotch Weld DP-100: This is a two-part epoxy adhesive that is a 1:1 mix ratio
mercaptan-cured epoxy adhesive. It has high shear strength and good peel
performance. This clear coating was tested in 1996 for surface speeds up to 300 ft/sec, and 350° F, plus 4-day oil bath soak. Tests conducted using 15-mil layer of this material with good results.  [Comment by John from PA: this product still seems to be available.]

Another material from the early 1990’s is a two-part epoxy enamel named Aeroply. It also performed very well in extensive tests. This material is available from: Rowe
Bisonite, 470 Niagara Park, N. Tonawanda, NY 14120. Phone (716) 693-6130.  [Comment by John from PA: this product does not seem to be available and the company Rowe Bisonite may no longer exist.]

Standard 2-part epoxy floor paint (for example) does not hold up very well. There is
also the option for ceramic overlay, but that is hard to do because of potential high
temperatures involved, and the potential risk of shaft distortion.

 

Thanks John,  A few questions:

Taken from the instructions: 

The following cleaning methods are suggested for common surfaces:

  • Steel
  • 1. Wipe free of dust with oil-free solvent such as acetone, isopropyl or alcohol solvents.
  • 2. Sandblast or abrade using clean fine grit abrasives.
  • 3. Wipe again with solvent to remove loose particles.
  • 4. If a primer is used, it should be applied within 4 hours after surface preparation

What happens with regards 2 without upsetting slow roll values?

The probe passes through a shaft seal arrangement (Cameron Compressor) therefore seal contact maybe made on the epoxy.  Do you foreseen any problems?

How does one ensure thickness  uniformity ( even radial seal clearance).  Can the epoxy  be machined? 

 


 

 

vibramac posted:

Thanks John,  A few questions:

Taken from the instructions:  

Now that you make mention of Cameron Compressor I suggest you go back to Cameron for suggestions.  Those are typically very high speed machines, something I had not anticipated from your original problem statement.  

I assume you mean the specific instructions packaged with the 3-M Scotch Weld DP-100 product and I would not do step 2, just clean with appropriate materials to insure a clean surface, otherwise the risk is high that the slow roll values would be upset.  When I have had to use the product I simply brushed a very thin layer on the surface with a clean brush.  On gearboxes I typically was dealing with 25 to 30 mils diametrical clearance so a potential rub with a seal was not an issue.  I never encountered it, but even if it did rub in a gearbox, I suspect it would abrade off the tight area.  Gear rotors usually have very high gear induced forces on them during operation and would probably remain stable unlike what you might encounter in a metal-to-metal situation.

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