Cavitation - any tips or tricks?

[aabausti]

Getting some slight cavitation. Where should I start? Sealant is hard and flakes off when I touch it… can I clean everything up with a wire brush?

 

[tdonoughue]

Wire brush will make a mess of your gelcoat on the fiberglass and rub that off--don't do that. But you have the right idea.

First, I would pull the pumps. Much better access that way. Use a putty knife or screwdriver to remove as much of the old sealant as you can. Replace it with 4200 from 3M. Make it as smooth as possible. Make sure you fill the bolt recesses on the grate as well.

Next, inspect your impellers while they are out. I can see some nicks in one of the blades, but they don't look too bad. I got good improvement even from taking a file and smoothing out any nicks or dings at the leading edge. But take the opportunity to inspect them and see if there are more nicks, bends and gashes than we can see here.

Then, much of your metal there looks pitted. Check your anodes. You should have some on the side of the pump (do a little search here for anodes; you will find pics, etc.). There also are some on the ride plate for your year, if memory serves.

 

[aabausti]

Wire brush will make a mess of your gelcoat on the fiberglass and rub that off--don't do that. But you have the right idea.

First, I would pull the pumps. Much better access that way. Use a putty knife or screwdriver to remove as much of the old sealant as you can. Replace it with 4200 from 3M. Make it as smooth as possible. Make sure you fill the bolt recesses on the grate as well.

Next, inspect your impellers while they are out. I can see some nicks in one of the blades, but they don't look too bad. I got good improvement even from taking a file and smoothing out any nicks or dings at the leading edge. But take the opportunity to inspect them and see if there are more nicks, bends and gashes than we can see here.

Then, much of your metal there looks pitted. Check your anodes. You should have some on the side of the pump (do a little search here for anodes; you will find pics, etc.). There also are some on the ride plate for your year, if memory serves.

 

[aabausti]

Thank you so much! Plan on pulling everything out tomorrow and following your instructions. Should I clean up the shaft with some sanding/scotch brite? Or not necessary?

 

[tdonoughue]

Probably not necessary. That looks like pitting from galvanic corrosion (which should be prevented by the sacrificial anodes). If it were on the exterior somewhere I might say to clean it up, but just for cosmetics. The shaft, no one will ever see... the concern is to stop the corrosion so that the pitting doesn't continue and weaken the metal or knock it out of balance.

 

[aabausti]

Probably not necessary. That looks like pitting from galvanic corrosion (which should be prevented by the sacrificial anodes). If it were on the exterior somewhere I might say to clean it up, but just for cosmetics. The shaft, no one will ever see... the concern is to stop the corrosion so that the pitting doesn't continue and weaken the metal or knock it out of balance.

Here’s where am at so far, still cleaning up a bit but just got everything put back together.

 

[tdonoughue]

Ah, very much better.

 

[84rzv500r]

also i have used devcon epoxy to repair cavitation pitting on the impeller housing and chips and erosion on the stator veins...