5200 vs epoxy for bilge area?

B

bshillam

Member
I recently paid someone to replace the twenty year old Rule bilge and had asked for all holes to be filled with epoxy, knowing it's one the water, used and this area sees lots of water, weekly. I found out that the repair was done with 5200 instead of being filled with epoxy. I specifically asked for epoxy thinking this was a perminent fix to the various holes in the bilge.
I would like some personal feedback from you gents. I am a bit concerned about their repair job. It simply came to time vs paying someone. I think 5200 was used because it saved a lot of time, squirt and go instead of mixing the epoxy and filling then smoothing the area. But that's my opinion....
 
Depends on whether there was any water under there. If there was, it should have been undercut and filled. I would suppose that 5200 would do in that case as well as epoxy although that's not what it's for.

Charlie
 
To my mind, it's not the same thing. Filling with epoxy essentially makes the boat "whole again"* (as much as possible since you can never get a primary/chemical bond once the boat sets up in the first place - all bonds will be secondary/mechanical ones from there on out). Epoxy is very good at secondary bonding, and (once it cures well) can be gelcoated over (if you want to) to make the boat "like new." Also, you can mix the epoxy to a runny (yet structurally thickened) consistency so that it fills (and bonds to) all the nooks and crannies. Usually when I'm filling a cored hole I will actually dig out core beyond the size of the hole - so then the epoxy runs back/under and fills that too.

Polyurethane caulk (of which 3M 5200 is one variety) is an adhesive/bedding compound/caulk. I don't believe it would run in and fill any nooks or crannies (or at least not like epoxy). It also doesn't set up in the same way, so can't really be gelcoated (or painted) as a hard surface can.

I would be completely disappointed (well, make that steaming mad :amgry) if I had asked for holes to be epoxy backfilled and they were filled with 5200. The good thing is that you can probably overdrill the whole mess and remove it, then fix it properly. It will be a pain though and why should you have to when you already paid someone else to do it (the first time, when it was easier). I'm sorry that happened to you.

In practice, I have seen some holes filled with caulking not take on water into the surrounding core; however the bottom of a bilge sump is one of the last places I'd want to try it, since by definition water will be sitting there on a regular basis.

Sorry if I sound like a downer, but this sort of thing just shouldn't happen. You knew what you wanted and specified it. Blargh.

Sunbeam

*I should add that there are even more thorough ways of making the boat "whole again." For a larger or different hole you would fill with epoxy and also put layer(s) of fiberglass cloth over a tapered/prepped area. In certain other situations one might close out (remove) the core (say a through-hull on a cored hull). Not that these would typically be used for a small hole like you are talking about, but just that since I used that phrase I figured I had better come back and clarify.
 
I spoke with the mechanic that did the work. He assured me all he used was 5200 and nothing more. I am a bit confused since the work order was specific. Fill any holes and over drill with new epoxy then set should different holes need to be drilled due to the pump not being the previous unit installed.
I have other gel coat work that needs to be done and the thought was once epoxied I could have those holes gel coated so the surface was true again. :cry
 
Regardless of what was done this time - get the current and old set of holes filled with thickened epoxy and then don't drill new holes for the bilge pump. It can be held down with 4200 just fine. There's really no need for holes into the floor.
 
I have asked the shop that did the work for a full refund. As it's going to cost more to have the job undone and then completed properly. :sad I am going to begin working with epoxy in two weeks. Maybe I should just learn how to deal with gelcoat too. It seems there are far and few that complete a job well and take too many shortcuts. Just because it's faster doesn't mean it's the right way!
I am contimplating build boats (wood tenders) on a very small (on a per order) scale because of this. It only re-enforces what I already know.
 
Let's see. What is important in filling those holes? You want to eliminate any soaked balsa/filler and seal the area so no more water intrudes, right? So if the holes are clean, the the stuff you fill it with has to both structurally support the hull, hold the screw and prevent water intrusion.

I submit that epoxy is certainly strong structurally, but is not the beat sealant in the world. For example, JB Weld is an epoxy and if you use it to rebuild corroded or stripped holes in metal, you need to use a gasket afterwards. 5200 is not as strong, but if one inserts the screws whilst the sealer is wet, it certainly bonds and prevents water intrusion. More than adequate for supporting a bilge pump. So that's what I use instead of epoxy. Certainly; one can use both and get the best of strength and sealing. I prefer to keep it simple.

I also understand that Bob/thataway doesn't agree with me. Personal preference.

If you want your money back, I'd base it on the fact that they didn't do what you asked, not that what they did was wrong.

Boris
 
I drill and under cut, epoxy then redrill the epoxy then put the screw into the epoxy plug on work that I do. I do it because thats what what is preached as right way to do it on this site. But I wonder why does the factory or trusted dealers rarely install anything doing the drill under cut and then epoxy routine and redrill the screws into epoxy?
Did anyone ever request and get a new boat be finished in this manner for the addition of trim tabs, motor bolts, windlesses, etc. Just wondering why these boats that are touted as being so well built have have all this type of redo done after you get it home? Do dealers and the factory view this as overkill?
D.D.
 
Perhaps the old pump housing was just secured with adhesive, if that was the case there would have been no holes to seal. 5200 would be fine if all you wanted to do was secure the pump base to the hull.
 
If there were holes, they should have been undercut and filled with epoxy. Unfortunately many boat workers do not understand that.

5200 is a sealant/adhesive--but there are times it does not adhere well. I agree 100% with Sunbeam. 5200 will not work down into the holes (assuming that they were there in the first place.

Now....it depends on where the bilge pump was. IF in one of the sumps, all of the way aft, or inside of the aft cabin bulkhead, these areas are not cored--are fully glassed, and there a screw can be inserted without fear of going into the core. If the pump was in one of these places--then you are OK--and relax!

Great idea to begin working with small wooden craft. Many of us have done this for fun--and the Stitch and Glue method, makes great boats with epoxy. A number of different tricks in doing the job--but all work out well!

Have fun!
 
Between the tanks infront of the motors. I am not sure if this is a cored area. However I do want to put gelcoat over the holes so I just have the piece of mind. 5200 wouldn't be the appropriate fill then has it won't support gelcoat and ultimately I would have to remove it and fill with epoxy.
It does appear we have a general concenses though.
I'll keep everyone apprised
As well I'll be taking pictures of my new build. A 17' row Dory.
 
Gel coat does not always adhere will to epoxy. (There are bonding agents, and some epoxies bond better with Gel coat. Gel coat is pigmented polyester. You would be better served to pigment epoxy--that what you know you have a good bond.
 
If the work was done within the depression area in the center you are OK; I had a similar concern on our 22 Angler, and was told by the dealer (Les) that the depression is not cored, but rather solid glass. Main concern is screw length. It is a pisser that you were not given what you had specifically directed the shop to do. Good luck, Mike.
 
Bob, I'm not sure what you mean by "sometimes 5200 will not adhere". Do you mean, if the surface isn't prepared properly? Since 5200 has been used to hold decks on hulls, it does adhere, and is really tough to de-adhere. We've had 3 Catalina sailboats which used 5200 to bond the deck to the hull and never had a leak. Any place where adhesion and flexibility are required, I would prefer 5200.

Also, you mention that "5200 will not work down into the holes". While 5200 will not flow as easily as epoxy, it certainly flows. In addition, I take for granted that one would work the 5200 down into the area to be sealed. I use toothpicks for small screw holes.

I've had better luck sealing screw holes in fiberglass with 5200 than epoxy. Though I love JB Weld (an aluminum filled epoxy) for rebuilding engine cases, and I just got through gluing some broken wood together for one of the kids, using epoxy. So it all depends on the job.

So I feel there's the right adhesive/sealer for each job. For some, as in embedding screws, I prefer 5200; for other repairs (joining 2 rigid blocks,) I use epoxy.

Boris
 
Boris,
There are many cases of 5200 bond failing--some have involved hull to deck joints. If you look at the spec sheets you will see the adherence properties of each of the 3 M products.

Some cases of failure are due to improper prep. Often screw threads do not bond well to 5200.

The issue is if there is core (which there may not be if the pump is in one of the areas of a sump--any moist core needs to be removed, before a sealant is applied. This involves drilling out the area, inspecting the core, and then filling with epoxy. Even with a tooth pick, you will not get good flow of 5200 into a hole or a wet core....

JB weld is only one epoxy product--and it has some very specific uses at which it excels.

Regards,

Bob
 
My new 1985 16 Angler had a number of old holes that had been drilled in the area under the motor well, some for fuel tank braces and some for battery hold-downs.

After reading the methods you guys are using, I drilled the holes out to 1/4" and then filled them with epoxy, sanded them down and am applying one coat of good paint. I am doing this abbreviated fix to get through the rest of our salmon run.

This off season I will try to follow your recommendation and re-drill the holes, only the second time around I plan to core out the softened balsa and backfill with epoxy.

My questions are how large of diameter holes should I drill to then core out the softened balsa? Maybe that depends on how big the damaged area is? On the holes I just filled I used a matchstick to get a fair idea of how deep the wet stuff was; does that sound reasonable?
And am I correct in thinking that you want to remove the wood all the way down to the next layer of the hull?

Sorry for all the questions but its obvious there is a lot of experience here regarding this topic and I want to be sure I understand how to do this job right. (Right after salmon season.)
 
do dawdle":34snb669 said:
My question is how large of diameter holes should I drill to then core out the softened balsa?
Click to expand...

A few factors when I'm deciding what size bit to use:

1) If there is wet core, then I need to figure out how far out it extends, and in which direction(s). Sometimes a hole isn't enough and then you're into removing sections of the top skin and patching over the re-filled area with fiberglass cloth. Moisture meters can help, but sometimes "core samples" (can use very small drill bits) are better to be sure.

2) If there is not much wet core, then I like to keep the hole small enough that I don't feel it needs an actual fiberglass patch (i.e. cloth), but large enough that I can get in and dig out the core wider than the hole. In other words, the hole can be the "tip of the iceberg," and you can dig out core in a larger diameter inside the hole - you just need a bit or working room for access. So it somewhat depends on your tools, and patience. Obviously with a very small hole you can't reach very far in/as easily. For digging out balsa I use a variety of tools. A favorite is an old dental pick; sometimes a Dremel tool with a sort of knurled metal bit works too. Other folks chuck a bent nail into a drill.

3) If it's just a prophylactic job, then a smallish (say 1/4" to 3/8") hole is often fine.

4) Another note is that with a dead-end hole, you have to be ready to deal with air entrapment when you're adding the epoxy. I find that using a syringe and trying to get it down to the bottom of the hole, then forcing "extra" epoxy in, causes epoxy and entrained air to bubble up out of the hole (I tape around the hole on top so no problem there). I try to leave a small mound so that if/when more air finds its way out during cure that the epoxy doesn't sink in and become concave. If you then catch it during the green (rubbery) stage, that excess carves off neatly with a sharp chisel.

5) Also note that it's good to paint a layer of neat (un-thickened) epoxy on the inside of the hole first, then follow that with the thickened epoxy.

6) If going back in with a fastener, then I like to have a comfortable annulus left over after I re-drill, not just a thin bit that could potentially crack. As a side note, this annulus also resists compression better than core when you later tighten the fastener, so that's good.

I'll see if I can come back and post some photos, as I've just been doing some overdrilling/filling on my boat recently.

Sunbeam
 
Yep--Sunbeam has the correct answers. Some also use bent coat hangers in a drill rather than a Dremel tool. I happen to love Dremel tools for this type for work--there are a variety of bits, including some small router bits.

Another option is to reuse the old inner skin, and soak the new core with epoxy, and then past the new core and epoxy back in place. This sometimes is easier than glassing in.

Bilge paint is an excellent way to cover this area after repairs.
 
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