How do you know?

G

GonzoF1

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How do you know what adhesive, caulk, bedding compound, or just general goo to use for a specific project? The aisle of this stuff has products for every application and for every problem. However, they all say the work great for almost anything. How do you know if you want to use silicone, 4000, 5200... or a treasure trove of do-all sticky things. Is there an online resource that can help?

(I don't have a specific project in mind. I just want to learn.)
 
My understanding is 4200 is very strong, but can be removed if needed. 5200 is almost permanent and difficult to remove.

What is the project?
 
Temporary hold or a mount I want to be able to remove easily later: Silicone

A more permanent mount that can be later removed with effort: 4200

A very permanent mount that will outlast the fiberglass in my boat: 5200
 
quote:
Originally posted by FlyWright

Temporary hold or a mount I want to be able to remove easily later: Silicone

A more permanent mount that can be later removed with effort: 4200

A very permanent mount that will outlast the fiberglass in my boat: 5200

Click to expand...


Can't explain it any better than that, other than ask, "above or below" the waterline?
 
My experience and opinion.
Nothing on my boat should be assumned to never have to be dismantled. 5200 is a great product but a real PITA and i simply dont use it.
For caulking windows I use GE 50 year silicone, comes in white, clear and gray. Its cheap works and can be easily removed and reapplied.
On everything else I use 4200. It works and can be removed if need be.
 
Experience. Yours and that of others. All the glues will do everything except, probably, that which you want to do right now.
 
What about materials? Are there rules-of-thumb based on the specific material? And what is better for the above/below waterine contingent? As in, silicone versus polyester (<--- unknown if this is right).
 
Don't depend on silicone underwater, particularly in saltwater, it seems to not do as well in the marine environment as it does shoreside. Silicone is tends to dissolve in the presence of petroleum products, as well. I think you are trying to come up with "polyurethane" when you say "polyester". There are some other choices, too, I believe that 3M 101 is good for bedding things like deck stanchions which may undergo some movement in normal service, I understand that it can "flow" even after it is set so that the movement doesn't open up a leak. This thread could get interesting, lots of info and opinions on this topic, I am by no means an expert here.
 
I have a wooden boat that must be maintained with paint and varnish so silicon is not used anywhere on the boat. Silicon is very difficult to remove completely and will mess up the adhesion of coatings.

BEST for general sealing and bedding: Sikaflex 291 LOT*
OK for general sealing and bedding: West Marine Polyether Multi-Caulk Sealant*
IF you can't find anything else general sealing and bedding: Boat Life: Life Calk Sealant*

Glazing (bedding glass): Sikaflex 295 UV
Permanent sealant/high strength adhesive: 3M 5200*
General high strength epoxy filler/repair adhesive: Marine Tex*
Small crack sealer: Captain Tolley's Creeping Crack Cure
Water resistant wood glue: Titebond II

* for use above or below waterline

You'll find lotsa goops and goos in my paint/sealant box.
 
Those are the products I've used over the years.

Sika had a full line of polyurethane marine sealants when I started boating (and boat restoration) in the mid-90's. The only 3M poly sealants I remember from then were 5200 and 4000. I'm sure a lot of people use and like the 3M polys. Sika has improved it product line steadily since the 90's with new formulations and product numbers, so I've stuck with them.
 
Silicone has no place in a marine environment. It does not wear well; it definitely does not hold-up under stress; and as YZER points out, one can never remove it completely. Best to use any caulk or sealant designed specifically for marine use.
 
Tom

Let me preface my remarks by saying that I've worked for two different adhesive/sealant/coating manufacturers over the course of 30 years. I was responsible for sales, technical support and management at various periods, so I believe my understanding and knowledge of the industry is a little better than most.

To answer your question about online resources for product recommendations: I don't know of any that would benefit you. I would suggest that you contact the manufacturers directly, about specific applications and or discuss your application with someone who knows what they're talking about. I cringe at the responses that individuals give to your type of question. In some instances, the application is not critical and the use of an improper product is not going to cause undue harm. However, in other cases, the use of the wrong product might be life threatening, depending upon your boating situation. Proper joint preparation is critical to product use.

I have to give Yzer his due. He knows what he's talking about when it comes to the different sealants and their effectiveness.

Sika, Boat Life, and 3M all hve good quality products. The only problem with Sika is that their products are not as widely distributed as the other two manufacturers, so they might be a little more difficult to find.

My whole point behind this post is not to disparage any individuals or their opinions, but rather to say consult the experts with specific questions and heed their recommendations.
 
Yzer's got it right! I use the Sika line per same applications. I use Sika 295uv or 3M4000 uv for finish beads. They will not yellow. I use Sika 291 or 292 for bedding and adhesion strength similar to 5200. I avoid regular 5200. It is too messy, too slow, and sags if you put it heavy on a vertical surface. Sika will not sag. Sika is not as available as 3M so on that very rare occasion that I run out at the jobsite, I use quick cure 5200.

No silicone! It can be a nightmare for paint adhesion (fisheyes). As a finish bead, it is a soot (and sometimes mildew) magnet.
 
BobV1

What you state is the most desirable way of handling this. And I actually do have great faith in the "experts" and chemical engineers etc. The problem is that the -good information- from the experts gets mangled in the marketing dept. The marketers want to sell, sell sell ( it's their job, after all ) and word the virtues of their chemical in such a way as to make it seem like a miracle cure.

I would LOVE to see a detailed spec sheet for such products that state clearly the strengths and weaknesses of that particular product. ie: Suitable for submerged saltwater use but susceptible to UV degradation, so avoid use in full sun areas.

As for contacting the experts by phone/email for every sealing/adhesive usage, well, it is a nice plan, but it cam become very impractical. Especially true when the response ( for each potential product ) is, "I'm not sure so I will check and get back to you. They might even be pretty quick, but if I have 4 sealants in my "goo box" and I have a hull ot of the water, waiting for me to install the thru-hull, the problems are massive.

What is needed are straight forward statements on the strengths and the weaknesses so that the end user can quickly and easily assess which product to use and move on to the next issue.
 
Let me second the caution that you DO NOT want to use silicon on any fiberglass or gelcoat surface, per Rub Rails's post. The only thing I use it for is things like sealing electrical boxes. Unfortunately the PO used it to try and seal some old snap holes.. yuck! When the time comes to paint those areas it will be a real PITA; fortunately they are very small .

DIY Boat Owner is an excellent source of info on this subject, BTW.

George
Hatteras 56MY
Boston Whaler 130 Sport
 
Good advice. If you had to put a few different tubes onboard to have for those little projects that may pop up, what would you have and what is the best method to store them? (both before and after they have been opened)
 
Finding small tubes of these sealants can be a problem. The Sika website (which has a lot of product info) lists a 3 oz. tube available for some of their best selling products but I've never seen these in the stores.

When I'm doing a seaming project the caulk gun tubes are just the thing. Following the advise from another BE poster years ago I store the tubes in a freezer (tips attached) when not in use. The tips can be replaced and re-used. This greatly extends the shelf life. For small jobs I load an epoxy syringe from the caulk gun. Those work fine for small jobs.
 
A freezer? Really? That would be tricky on the boat itself. There's already limited space for food. Do you have to defrost them?
 
I generally agree with YZER as well on this, but with a couple of, I think, important nuances that I'm a tad bit passionate about.

Sika has changed their forumlations, so none of us can credibly say that we have used a particular product for so many years.

I do subscribe to the notion that experience with a particular product is what counts. That's why I don't comment much, positive or negative about the "newer" polyeurethane based sealants though I've been hearing good things, not bad. With the exception of 5200 which has been around for quite awhile. I take comfort in what I know.

I also USED to use a lot of the SIKA based products. I don't want to use the product number as I don't believe what is in the tube now is what used to be in the tube. Rather the mfg decided to recommend their new product to the same old consumer base. Maybe their right, but who says the way I was using the prior product is what it was designed for. I'm just saying neither I or others can say they have been using a particular product forever....because other than 5200, its not the same product in the polyeurethane lines. 3m now has a whole range of polyeurethane's that have properties that are meant to be as good of sealants as 5200 is a good adhesive and can also be removed later without fanfare.

I have been a big fan below the water line for sealing/bedding of polysulphide based products in the past. That's what my favorite SIKA product USED to be made out of. My understanding of why the mfg went away from the polysulphide's was because of cost, not performance. It's easier to engineer a number of variations of polyeurethane on similar mfg equipment and that is the trend away from polysulphide's. However 3M still produces 3M101 which is STILL a polysulphide forumulation, and like 5200 has done so for a long time. I switched to 3m 101 for all of my general sealing/bedding needs, especially below the water line. It's great stuff, cures underwater, and can be easily removed at any time, while staying flexible for years. I trust it and in the same way that I trusted the similar SIKA product for many years. It has a known reputation.

Maybe the newer polyeurethane products will have the same experiences, but the fact of the matter is that they have not been out as long, at least in the applications we are talking about. I want bedding compounds that have been tested for 20 or 30 years, cause that's how long some will be expected to perform.

I'll continue to use 3M 101 as long as they produce it (and 5200 for jobs I want a better adhesive/sealant). When they stop, I'll take everyone elses recomendation on the best sealing/bedding polyeurethane's and thank them for doing the testing on their boats to validate the mfg's claims so I don't have to be the guinnie pig on my own boat. There's no question that the products i'm using now will do their jobs, they are long proven. Who knows on the new stuff, its not like you can exactly take the mfg's at their word. Because they chose to change forumulations and stick them into the old wrappers, I think SIKA is an experiment. Maybe an experiment based on the proven track record of the companies positive reputation, but an experiment none the less. Chances are, it will come out well, and again I thank those of us who use it for doing the experimentation on your own boats. Personally, I wish they had chosen to introduce NEW products and let them prove themselves in parallel, but then both YZER and me would likely be obstinately using the older products and not even trying the new ones, so I understand why they did it. But since I'm a label reader, they lost me as a customer. Most consumers are not label readers.
 
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