Bedding material for new deck hatch installation ?

[MickeyB]

I’m getting ready to install new hatches In 21’ SE center console deck and am trying to decide best bedding material to use.

seems to be a few choices to consider

3M 4200 or 5200

marine silicone

life caulk ( this was my choice but specs say not for use on plastic - ok for aluminum leaning post bedding I suppose )

other options?

any feedback / recommendations appreciated.

 

[pelagic2530]

I’m getting ready to install new hatches In 21’ SE center console deck and am trying to decide best bedding material to use.

seems to be a few choices to consider

3M 4200 or 5200

marine silicone

life caulk ( this was my choice but specs say not for use on plastic - ok for aluminum leaning post bedding I suppose )

other options?

any feedback / recommendations appreciated.

Your best bet is likely 3M 4200 or LifeSeal. You can go around and around for hours/days about the benefits of either. 3M4000UV is another option, but it seems to have mixed reviews and few benefits over the other two.

Your main differences in sealants are between Polysulfides (LifeCalk), Polyurethanes (5200, 4200), "specialty products" (Lifeseal), and silicones.

Polysulfides are not a good choice for plastics, although to be honest I've used them on deck hardware such as pie plates and hatches and haven't had any problems.

Polyurethanes are better served for plastics. 5200 is going to be pretty much permanent and make removal of the fitting almost impossible. As most plastic deck fittings break and/or degrade over time, most will have to be removed at some point. For this reason, 4200 is your better bet. It has the same sealant properties as 5200, with an adhesion limiter added to make it somewhat removable. It will still have moderate adhesive qualities, which will help keep the hatch in place in combination with the deck screws if it's in a high traffic area.

LifeSeal is a combination of polyurethane and silicone. It advertises a greater sealant property than polyurethane alone while having a stronger bond than silicone. Personally, I'm suspicious of silicone contamination with this product (discussed below) but don't have any experience with it first hand.

3M 4000 UV is a polyether base. It seems to advertise similar characteristics to LifeSeal, without the silicone content. However, it seems to have bad reviews. I don't have any experience with this one either; I'd imagine it's similar to LifeSeal.

Silicone sealant has no place aboard a boat, in my opinion. It's almost impossible to remove; new sealant will not adhere to cured silicone; and the sealant itself offers no performance benefit over other sealant options. There are many better alternatives to silicone sealants that do not have these issues. Most fittings on a boat will have to be removed and resealed at some point; using silicone immensely complicates this process due to the need to mechanically remove all traces of the old sealant before reapplying. If I pull a fitting and see old silicone in the hole, I know I'm probably in for an annoying afternoon (and am likely reaching for a drill or a Dremel).

Bottom line: I'd use 4200. It's a known performer without the danger of silicone contamination or possible poor performance. But your mileage may vary. The sheer amount of information available online on the subject (and the amount of contention over it on pretty much all of the online forums) shows that there's a fair amount of room for preference and interpretation in this area.

 

[Swatski]

3M 5200, what I would do. These hatches are not going anywhere.

I try to buy as much as I need, once unsealed need to be used within 24hrs, albeit it stores fine in a freezer for few months.
check the exp date - the fresher the better. I would have lots of spare rugs handy for immediate cleanup, this stuff gets on EVERYTHING. That's what it is designed to do, lol, spread.

 

[Swatski]

I probably should have qualified my statement above. Not saying the 5200 is the best for this particular job in general, but it is the best for the job if I do it.
Whenever I'm do anything anything thru hull or deck I want maximum strength, holding power, to compensate for any potential small errors I make. Not being a pro, those are by definition one-off jobs for me.

 

[warthog5]

3M 5200, what I would do. These hatches are not going anywhere.

Oh HELL No! It's the most misunderstood and abused product used by people that don't know.

What happens when the hatch breaks? If you ever have gone behind someone that has done this you will understand.

I don't even use 5200 on thru Hull X-Ducers. [4200]

A VERY good product for this is 3M 101.....Problem is getting it....People think 5200 is strong so I'll use that the 101 is designed for this application.....But people didn't buy it so places stopped carrying it.

The ONLY thing I use 5200 for.....is a engine bracket install.

 

[MickeyB]

Ok, thanks for the great feedback from knowledgable folks. I appreciate the differing opinions as well. Kinda where my head was at .....

pelagic2530 I really appreciate the detailed discussion. Very informative and Makes sense to me.

I‘ve always used 5200 on my boats and thought the life caulk was possibly a better option.

i think I’ll stick with the 3M products. I’ve never seen the 3M 101, I’ll have to research that some.

gotta love the knowledge shared on this board!

 

[pelagic2530]

Ok, thanks for the great feedback from knowledgable folks. I appreciate the differing opinions as well. Kinda where my head was at .....

pelagic2530 I really appreciate the detailed discussion. Very informative and Makes sense to me.

I‘ve always used 5200 on my boats and thought the life caulk was possibly a better option.

i think I’ll stick with the 3M products. I’ve never seen the 3M 101, I’ll have to research that some.

gotta love the knowledge shared on this board!

No worries. Most of the time I learn something myself when I'm fact checking before posting!

For the record, 3M 101 sealant (which I don't think is available anymore) is a polysulfide that is almost the same as the LifeCalk and therefore will have the same issues with plastic. That said, I've seen LifeCalk used on common boat plastics such as Starboard and deck hatch/pie plate material and haven't run into the issues with plastic degradation that are mentioned. I think that more applies to Lexan, polycarbonate, and other more "sensitive" plastics. It does list it as "not recommended" however, so buyer/user beware.

 

[pelagic2530]

3M 5200, what I would do. These hatches are not going anywhere.

I try to buy as much as I need, once unsealed need to be used within 24hrs, albeit it stores fine in a freezer for few months.
check the exp date - the fresher the better. I would have lots of spare rugs handy for immediate cleanup, this stuff gets on EVERYTHING. That's what it is designed to do, lol, spread.

I'll jump on the bandwagon with Wart here as well. 5200 doesn't offer much benefit in this application, with a LOT of downside.

Most hatches will at some point break or degrade with time, weather and/or UV exposure. That might be 10 years or more down the line, but if you use 5200... the PITA is still going to be there whenever you need to remove it.

Furthermore, as I found out when working in the tight spaces on my 1700, it can be SUPER helpful to pull out a hatch to give yourself an extra couple inches of working space. Doesn't seem like it, but it makes a big difference. With a hatch bedded with 5200, that's not going to be a good option. With other sealants, it's simply a matter of cleaning up the surfaces and applying a new bead of sealant.

The only benefit of an adhesive in this case is that they will add some adhesion to the hatch frame. If you're stepping on it a lot, that may help to keep it in place a bit better, which could make it feel slightly more solid and possibly prolong its lifespan a bit by avoiding deformation (debatable). Doesn't really warrant the hassle of using 5200, in my book.

5200's primary purpose is as an adhesive, rather than a sealant. Look at what you're trying to accomplish: if you're using the material to keep something in place, as permanently as possible, 5200 is a good option. If you're trying to seal water out of something that's otherwise fastened in place, one of the other products is better.

I've had tubes of this stuff stay good for upwards of a year if refrigerated. If you're tackling a big job, I would recommend buying the tube that fits in a caulk gun. When you're done, remove the tip, and clean it out as best you can. Put a piece of wax paper over the threaded tip of the tube, and store it in the refrigerator. The caulk tubes work better for long term as you're exerting force with a caulk gun, rather than trying to squeeze it out with your hand, so the stuff will flow nicely when it's still cold. It's also much easier to apply uniformly.

 

[Swatski]

I guess it really depends what you want to achieve. For anything thru hull or going into fiberglass and especially - WOOD (Parker boats = made of wood) - I want to set it and forget it. Use the 5200. I don't plan on moving or removing what is bedded in 5200. But either way, I can cut out or drill out the screws or hatches, or whatever plastic is deteriorating; or use Debond from Fawcett Boat Supplies to remove 5200. Not that difficult - if you a knowledgeable DIY-er (like myself! lol)
Fawcett Boat Supplies

5200 is better than any other caulk/sealant in preventing water intrusion into fiberglass/core etc. - where hard epoxy filling/re-drilling is not an option or not practical.

Can we agree on that^^^^?

Yes, 4200 is rated for below the waterline, and yes, it is best used for applications where you may need to remove like sealing wiring where it may need to be replaced. 5200 is stronger. Only real disadvantage of 5200 is that it yellows if exposed to sun/UV. Curing time is not much of an issue as there are fast cure formulas (as long as you okay with white - there is no black fast cure 5200 - that I know of).

 

[jamesd156]

I would use 4200 for sure and FYI it cleans up well with mineral spirits

 

[sailmaster]

MSSR Warthog do you have any experience with adhesive sealents for LEXAN Polycarbonate to Fiberglas bonds?
Thanks I am 20 years away and not sure of any improvements

 

[sailmaster]

I’m getting ready to install new hatches In 21’ SE center console deck and am trying to decide best bedding material to use.

seems to be a few choices to consider

3M 4200 or 5200

marine silicone

life caulk ( this was my choice but specs say not for use on plastic - ok for aluminum leaning post bedding I suppose )

other options?

any feedback / recommendations appreciated.

One not mentioned that I have used by the carload is SIKAFLEX
bit stiffer than 5200 and faster curing
Comes in different curing rates
Comes in different colors
https://www.emisupply.com/catalog/s...1011&msclkid=e470aa3d851e17247230cab18b5da3c4is black for underwater
has issues with removing plasticizers from acrylic and causing crazing
should be excellent for glass filled nylon hatches that are one and dones

This is a class A company and product

As a rule the longer the cure time the better the adhesion

 

[pelagic2530]

I guess it really depends what you want to achieve. For anything thru hull or going into fiberglass and especially - WOOD (Parker boats = made of wood) - I want to set it and forget it. Use the 5200. I don't plan on moving or removing what is bedded in 5200. But either way, I can cut out or drill out the screws or hatches, or whatever plastic is deteriorating; or use Debond from Fawcett Boat Supplies to remove 5200. Not that difficult - if you a knowledgeable DIY-er (like myself! lol)
Fawcett Boat Supplies

5200 is better than any other caulk/sealant in preventing water intrusion into fiberglass/core etc. - where hard epoxy filling/re-drilling is not an option or not practical.

Can we agree on that^^^^?

Yes, 4200 is rated for below the waterline, and yes, it is best used for applications where you may need to remove like sealing wiring where it may need to be replaced. 5200 is stronger. Only real disadvantage of 5200 is that it yellows if exposed to sun/UV. Curing time is not much of an issue as there are fast cure formulas (as long as you okay with white - there is no black fast cure 5200 - that I know of).

4200 is essentially 5200 with an additive that decreases its adhesive strength to 50% that of 5200, which is still substantial. It has the same sealing properties, chemical resistance, and range of materials to which it will bond. It also has the same lifespan, in that it will fail in around the same timeframe due to UV exposure. The difference being that when it does fail (or preferably prior to it happening), 4200 is easier to remove, clean, rebed, and replace. 5200 does not offer any greater "sealant" properties over 4200 for preventing water intrusion when adhesive qualities are not required.

The only application for which 5200 offers a unique advantage is one in which high adhesion is a desired trait. Like Warthog mentioned, adhering an outboard bracket to a transom, or adhering a keel to a sailboat. In both cases, the application primarily calls for an adhesive, as opposed to a sealant. Hence, the use of 5200.

In a case where properly sealing a core penetration is not possible, you need to think long and hard about how you're going to prevent water intrusion into that space. Neither 5200 or 4200 is a permanent solution, and again, unless adhesion is required per the application, neither is appreciably better than the other. In practice, there are very few occasions where the penetration absolutely CAN'T be sealed properly with epoxy. There are many in which the DIYer and especially a hired tech aren't going to put forth the effort needed to do so. If using 5200 in those cases makes you feel better, then have at it.

I'd humbly suggest that in absolutely all cases, proper surface preparation by way of thoroughly cleaning, degreasing, and decontaminating the surfaces to be bedded will go a lot further than using a sealant with high adhesive qualities to "make sure it sticks".

 

[GotChrist?]

Marine Sealant Adhesion Tests | Practical Sailor (practical-sailor.com)

Read the conclusion. They make note of what to use for hatches.

 

[chas650r]

plus 1 on the silicone advice from above. imo there are very few times when it should get even near a boat mostly because as said above, nothing sticks ever again where it has been unless it is literally ground down to raw material. the 1 exception to the rule is on new port lights I installed , the manufacture stated clearly neutral curing silicone only to bed the windows . so for how expensive they were I stuck with the recommended.

 

[99Parker2520]

pelagic has it.....

 

[Swatski]

5200 does not offer any greater "sealant" properties over 4200 for preventing water intrusion when adhesive qualities are not required.

5200 absolutely does offer greater sealant properties - this is the whole point: if it adheres better, it will protects better against water intrusion.

I agree with most of what you are saying, and yes - using 5200 may not be the best approach, or not as good as an epoxy job, it maybe harder to remove etc. That's all true and I believe it.

BUT

If I'm bedding something permanently into fiberglass or wood using sealant, and I want to maximize prevention of water intrusion, I am going to use 5200 rather than anything else (that I know of).

--

 

[warthog5]

If I'm bedding something permanently into fiberglass or wood using sealant, and I want to maximize prevention of water intrusion, I am going to use 5200 rather than anything else (that I know of).

Name those spots

 

[warthog5]

experience with adhesive sealents for LEXAN Polycarbonate to Fiberglas bonds?

No experience. Never ran into that....Most Lexan is mechanically fastened. IE: Windshield to a center console.

 

[sailmaster]

No experience. Never ran into that....Most Lexan is mechanically fastened. IE: Windshield to a center console.

we always used gaskets and mechanical fasteners also
have a bunch of sailboats ( J22) with lexan side lights that are screwed and gooed to the side of the cabin that all leak
was hoping there was a magic trick