Can I seal still-curing 3M 5200 under a rub rail sealed with 4200?

jim_s

Petty Officer 2nd Class
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Sep 12, 2013
Messages
105
Had a gas dock try to remove my rub rail for me last season in some choppy conditions, and in preparing for Spring, removed the rub rail rivets in that area, and assessed the situation. (Water was leaking in on hard turns to that side.) Main problem seems to be that the hull/cap joint seal (this is a little FG bowrider) in that area was opened up. My plan is to 5200 the hull/cap joint section that is separated at the overlap, then put a bead of 4200 on the back side of the rub rail and re-rivet it into place. This will result in the 5200 (advertised 5-7 day cure time) sealed in under the 4200-sealed rub rail. (The 5200 joint will still have exposure to air on the inside of the boat, FWIW.) Can I do this all in one operation, or can I at least do the 5200, wait a day or two, then do the 4200, and expect the 5200 to cure adequately, or should I let the 5200 cure completely, then re-attach/seal the rub rail?

Thanks!
 

Bondo

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Apr 17, 2002
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70,465
Re: Can I seal still-curing 3M 5200 under a rub rail sealed with 4200?

Ayuh,.... Why not use resin, 'n glass, instead of 5200,..??

Or do the whole job in 4200,..??
 

jim_s

Petty Officer 2nd Class
Joined
Sep 12, 2013
Messages
105
Re: Can I seal still-curing 3M 5200 under a rub rail sealed with 4200?

Well, I must admit that I'm asking myself that same question right now. I mis-typed, BTW - I ordered 3m 4000, not 4200 - just what was available when I ordered. My thinking had been to use 5200 for bonding the joint, as this should be a permanent attachment, but at the same time, the cap and the hull are simply riveted together, with some fairly-easily-removable sealant between them - they don't appear to be actually bonded, at least not on the outside of that seam. So, A) its the original manufacturer (2000's Bayliner) that used a sealant vs a bonding adhesive, and B) if I ever, for whatever reason, needed to separate the cap and the hull, the 5200 could make that a tough task, esp w/ it being up between 2 sections of FG (ie, the overlap seam of cap and hull). So, my current thinking is also, "why just not do it all in 4000?"

I'm a noob to boats and boat repair, so don't have a great feel for the various adhesives/sealants/etc yet - would 4000 be sufficient for providing a good seal in this overlap seam? (I'd also hope to get a little bit of strength/stability out of it, as several of the rivet holes are a little bit distorted due to the original incident.)

Thanks for the help and advice!
 

Woodonglass

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Dec 29, 2009
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25,924
Re: Can I seal still-curing 3M 5200 under a rub rail sealed with 4200?

IMO you'll be fine using the 4000 all by itself. I might remove a bit of the rubber rub rail a drill a few extra screw/rivet holes if the existing ones are wobbled out, just to tighten things up a bit. Other than that I think you oughta be good to go.
 

jim_s

Petty Officer 2nd Class
Joined
Sep 12, 2013
Messages
105
Re: Can I seal still-curing 3M 5200 under a rub rail sealed with 4200?

Thanks All for the info - I think I'm going to go with you guys' recommendation, and just use the 4000 - simpler all around, and if I ever need to get it all apart again, I should be able to do so w/ the 4000 vs the 5200.

I really appreciate the help!
 
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