Thru Hull Replacements - 4200 or 5200 to bed?

[Pete1313]

I'm replacing some thru hulls (both at and above waterline). I'm using stainless on the uppers and bronze on the lowers.

What compound should I use to bed and seal them? Since they are bronze and stainless, I"m thinking they won't need replacement for a long time....

Should I use 5200 or 4200? Something else?

Thanks!

 

[richie rich]

Both adhesive sealants are made to work below the waterline...4200 is more flexible but not really necessary for a thru-hull..but I like the 4200 UV grade if any of the sealant will be visible above the waterline as it won't yellow like the 5200....

 

[Pete1313]

Thanks Richie Rich -

I didn't know 5200 yellowed in UV...although I am in the Pac NW and I trailer my boat so UV damage is really not a problem

I was asking more along the lines of adhesive qualities as well...my understanding is that 4200 is not as "permanent" as 5200...and on something like a thru-hull, where I hope I won't have to ever replace them again, it is possible....should I go with 4200 to make that job easier on whoever has to do it (probably me)?

 

[Doc Stressor]

They are both "permanent" sealers/adhesives in that they should hold up as long as your hull. But if you ever need to replace a through hull component, you'll be very glad that you used 4200.

 

[richie rich]

Pete,
most marinas and boaters will use the 5200...both are permanent as Doc states..........the 4200 cure is softer but you can remove 5200 with just a little more effort...its not permanent in the sense that it won't come off later on...it just cures hard...even epoxy comes off with some heat or a grinding tool...I use it below the waterline on pretty much everything. Just an FYI...when exposing the hole, it would be a good time to seal the fiberglass and/or wood end grain with a little epoxy first to prevent water absorption....then when dry, finish the job with 5200 during assembly of the part.

 

[Pete1313]

Thanks guys - that answers my questions. 5200 it is then in my mind.

Re: epoxy - what kind do you use? I see so many types out there and have no idea what to use. I have no experience with epoxy or fiberglas, so I'm truly a beginner.

I've heard west-system has some good products but again, there are so many choices even within a brand, I don't know what to do......

Any help is appreciated!

Thanks,

Pete

 

[richie rich]

Pete, any of the name brand marine epoxies will work for what you're doing....the standard West, Mas, System 3, Marine Epoxy etc will work fine for this....just don't get the thickened version as you want the epoxy to penetrate into the wood core...straight or "neat" epoxy is best....read the directions carefully, mix well in a plastic cup and in small quantities, and wear gloves...brush it on with a small disposable acid brush (those litttle cheapie metal ones that come 10 in a pack) and let it sink in..add a little more if it all goes in and looks dry on the surface...I like using the slow hardener as it gives you more time before setting up and normally does not leave a surface residue called amine blush...but that really is not a problem as it washes off with just plain water and a rag.

 

[Pete1313]

Awesome-- thanks!

 

[sfc2113]

My thru hulls were put on with 5200 from prev owner and it was a %$# to get them off. The outer side of the thru hulls had to be ground off because the 5200 was pulling off the gelcoat when trying to pry them off. used 4200 on the new ones. I did not want the next owner to go through the same thing I did.

 

[82seafarer]

NO to 5200

I always use LIFE-CAULK or LIFE-SEAL for stuff. There are two kinds, one for using on fiberglass so it will not discolor or break it down chemically which is LIFE-SEAL. The other (LIFE-CAULK) is a tad stronger/gooeyer longer-lasting but not as good for fiberglass and will also stain it. I worked in a marina and they swore by 3M-5200 for stuff you did NOT care about EVER getting apart again but not for your own boat or stuff that you may need to.
I found that most of the time it BEING VERY hard to get apart is NOT something you need really. You just want stuff to seal and last a long time like hull fittings and stuff.

 

[Doc Stressor]

5200 is really for permanent things like deck caps. Even though a lot of boat manufactures and boat yards use 5200 for through hulls, it is not the best choice.

If you seal the hole with epoxy as Richie suggested, all you need is Life Caulk or 4200. It is almost impossible to replace a through hull fitting that has been sealed with 5200. You usually don't have enough room to work.

I once removed a through hull transducer that was bedded with 5200. I used the special de-polymerizer that 3MM sells specifically for removing 5200 and the job was still a bear. You need to brush it on, let it sit, and dig out as as much sealer as you can. This must be repeated many times. It's a multi-day project.

 

[JUMPNJACK]

Just my Luck!

Hi gang! Everybody has been swearing by 5200 until I have just used it to install a box full of thruhulls. Hopefully I won't ever have to remove them! You guys have me about ready to go remove them all right now before the 5200 fully cures and start over with 4200! (Not Really!) Just my Luck! 8)

 

[Pete1313]

Thanks for all the replies...I think I'm going with 4200.....or life seal....not sure which one is better...they both sound about the same.

JUMP N JACK - sorry I brought this up right after you did yours - I was reading your thread....considered going with the marelon ones, but ended up buying bronze and stainless....I'm doing 2 now and I'll do a few more this winter.....

 

[Brad1]

According to 3m, 4200 and 5200 are equivalent sealants. 5200 however has superior adhesive properties. When bonding with a mechanical fastener, use 4200. On the other hand, when you need an adhesive for bonding as well as a sealer, use 5200.

Personally, I would use 4200 for thru hulls.

 

[gradyrod]

I vote for LifeSeal

been using Life Caulk and Life seal for over 20 years now. 5200 is great, but not for any fitting you may want to someday replace or remove.

Life seal should be used with a plastic thru-hull, while life caulk can be used with a bronze thru hull. They both work great, and if you ever have to change out a thru hull it can be easily done.

Gradyrod

 

[Grog]

If it's a bronze or SS fitting use either sealant but if you're using plastic fittings DON'T use 5200.