Need advice quick! Trouble bedding struts!

[cool beans]

Such a frustrating experience. I needed to replace to my struts (long story) and I have the dry fit basically perfect. The alignment is spot on, the shafts sit on the bottom of the cutlass bearing and the shafts spin with one finger on the propeller. I used two bolts to hold a strut in place while the epoxy cured and drilled the remaining thru bolts so they should theoretically act like alignment dowels. I then dropped the strut and applied a thin (via squeegee) layer of 5200. But when I reinstalled the struts, they moved. Since the 5200 is thick enough, it like that thin film is letting the struts float as I torque the bolts down. Enough that you could feel and see binding in the bearing and it is driving me nuts! I'm on my second attempt tomorrow. I played with the bolt tightening sequence for 2 hours tonight and decided to drop it and clean everything up. I'd love some advice as to what I might be doing wrong or how to do it better. If I don't hear from anyone, I'm probably going to try old school hardware bonding and bed the struts in thin epoxy, let it kick, and just goop sealant on the bolts

Please share your knowledge

 

[Ski in NC]

Sounds like you did not get a good contact squeeze on the epoxy. Must have been a partial contact patch, then when you dropped it and put the 5200 in, then torqued, things flexed. If the epoxy covered the whole footprint there would have been no flex.

Last time I did it I smeared peanut butter epoxy on the hull and taped trash bag to the strut top, snugged a couple of bolts and saw I did not get good squeeze. Dropped it again and added more peanut butter. Got good squeeze and then all was well.

Epoxy is not going to squeeze after cure when you torque the bolts. Had to be a gap in there.

 

[cool beans]

Sounds like you did not get a good contact squeeze on the epoxy. Must have been a partial contact patch, then when you dropped it and put the 5200 in, then torqued, things flexed. If the epoxy covered the whole footprint there would have been no flex.

Last time I did it I smeared peanut butter epoxy on the hull and taped trash bag to the strut top, snugged a couple of bolts and saw I did not get good squeeze. Dropped it again and added more peanut butter. Got good squeeze and then all was well.

Epoxy is not going to squeeze after cure when you torque the bolts. Had to be a gap in there.

Is this something I can tap-test and tear a hollow thud? When I tore out the first strut, some 5200 took the cast pad and a layer of the original hull (even after heat ) so I know there was no gap in round one of the the starboard strut. I will dry torque the struts tomorrow and check if they move. Thanks

 

[Ski in NC]

Could have been the 5200 was slick and when you torqued the bolts, strut pad slid on the hull, cocking the bolts in the holes. May need to get struts in aligned position with all six bolts in, but not torqued, then torque them after the 5200 cures.

The only 5200 I used was just around the bolt holes to seal. Otherwise the epoxy was the bedding.

The trash bag kept the strut from getting badly stuck.

 

[Art]

On a completely different application [not marine at all]:

I found that in cementitious water based, small aggregate filled, constant friction process that IMO 5200 never really hardens.

 

[STB]

Did you thicken the epoxy? If so, to what consistency?

I think you want it thin enough to be able to "use a bigger glob for a better job" and then be able to squeeze it out. But, you also need it thick enough that the squeeze out is the only thing causing it to move vs gravity.

 

[cool beans]

Could have been the 5200 was slick and when you torqued the bolts, strut pad slid on the hull, cocking the bolts in the holes. May need to get struts in aligned position with all six bolts in, but not torqued, then torque them after the 5200 cures.

The only 5200 I used was just around the bolt holes to seal. Otherwise the epoxy was the bedding.

The trash bag kept the strut from getting badly stuck.

Interesting! So you did it the way I'm thinking I should have done it to begin with :lol: Appreciate the advice!

Did you thicken the epoxy? If so, to what consistency?

Ketchup consistency