Adhesives!! need some help Sikaflex vs 3M vs???

[bee]

I am looking for structual adhesives for bonding fiberglass, aluminum, stainless. Preferably 1 part, but not ruling out 2 parts as long as they have a reasonable work time.

So far I have gathered this info correct me if I am wrong.

Sikaflex
252 is the same as 292?
552 is the alternative to above. Weaker by itself, but might bond better to your surfaces? Anyone have any experience comparing?
Are these the right sikaflex, they have so many options its confusing.
Does new stainless and aluminum need priming?


3M
5200 spec sheet I found make it sound more flexible the sikaflexes, much longer to cure, possibly available at local hardware store. How does it compare to the above what are the differences and similarities.
Why should I use sikaflex over this product or vise versa?

Are there other options? pros cons of those options?

What is the expected life span of these polyurethane adhesives?

 

[bee]

Talk to a rep

I tend to distrust salesman.

Looks like I have another brand to add to the list Silaprene. Might be sold local to me. Anyone ever heard of them?

Does anyone know the life expectancy of these adhesives? do they dry-rot/crack? Is 50 year life span sound reasonable? 100 year? 5 year lol?

 

[southpier]

most companies have an 800 technical assist line. they would also have a proprietary interest in selling you their product. asking on an internet forum will get you a lot of opinions, but if the project fails, you have less recourse than manufacturer's literature might support.

I think about 95% of all problems are application rather than faulty product or manufacturer defect. they'll find a way to wiggle out of it or end up sending you a replacement 20$ tube of adhesive and a note thanking you for choosing their product.

 

[bee]

I am fine with opinions as long as the person with the opinion also explains it. For example (I am making this up completely) I like sikaflex 552 because it is easier to work with then 252, you can keep an open tube for a month and it won't dry out. Don't worry about it dry rotting you can see in there literature here on page 2 that they say it lasts 75 years as long as its out of the sun. Or how about. Don't use 3m 5200 it attracts mosquitoes for the full 5 days it takes to dry!

While I have never used these products before. I have used many products that come in the same shape tubes that fail after a couple of years. So I am pretty concerned about longevity if lets say I decide to glue my camper together with it in a load bearing fashion, not just for adhering a skin.

What does their primer do? As far as I know it helps stop rust. Is that it?

 

[doug720]

I have used 3M 5200 on boats for years and it works great. It is rated for below waterline use and is an adhesive/sealant. When you use 5200, assume it is a permanent installation as parts do not come apart! I can be painted also.

Silkoflex is also common in marine environments, but I do have personal experience with it.

Doug

 

[bee]

So you would use it to seal a hole on the boat below water line and consider it a permanent repair? How long would you expect it to last?

 

[sixbennetts]

I second what Doug says. 5200 is THE product that professional marine repair guys turn to. Below waterline, above, direct sunlight, fuel, coolant, I have NEVER, EVER, seen the stuff deteriorate.

I used it to secure a rudder stuffing box on the bottom of a cabin cruiser in 2003. Sold the boat last year and checked it, still solid as hard rubber with no cracking.

Trust it.

 

[Mo4130]

We used sikaflex 292 on the bottom of our boats at work. And it worked well enough,but I have heard good things about 3m

 

[bee]

Alright so after extensive research it sounds like polyurethane adhesives last about 20 years before failure. Sounds like they progressively harden over time.

I take it you can't buy 3m 5200 in caulk tubes at the local chain store like homedepot anymore? That is a thing of the past?

 

[doug720]

It ay harden over many years, but it is used for permanent underwater hardware installations on boats. So it lasts a long time.

Here in SoCal, Home Depot sells it. You likely have a West Marine or some kind of marine store around that probably stocks it.

Doug

 

[bee]

Thanks for all the help. I think I have made up my mind. I will not glue my camper together with urethane adhesives. My main interest was in its flexible nature. The problem is it will stiffen up over time and need repair in 20 years or less. While there have been numerous composite fiberglass builds where these high tech adhesives have been used to actually assemble the box, I would like to be optimistic in that whether I own it or not my camper will still be around in 20+ years.

Anyone know of a more permanent flexible adhesive I could use to glue the actual walls together.

Just a heads up to others who might be shopping for these products I found that even though none of my local hardware stores have 3m5200 in stock in a caulk gun sized tube, it looks like lowes.com has it for under $10 a tube online. Its the best price I have found.

 

[doug720]

3M makes many other adhesives in the marine line. I would research it with them. I know auto manufactures use "Glues" to assemble new cars, and have seem body panel adhesives at auto body supply stores.

Good luck.

Doug

 

[Stumpalump]

I just went out to the shop to check on the 5200 I used 32 years ago on mahogany file handles I made while working as a boat builder for Post Marine. It's still perfect. It's holding strong and still flexible enough to dig a finger nail in. My favorite 7/16 wrench is also still covered with it after the same amount of time and its been used a 1000 times. It goes on like grease not like glue and takes weeks or months to get really firm. In other words its a sealant that bonds like glue over time. Last week I got some in a small tube from Home Depot to install a solar panel on the fiberglass van roof. It's just metal brackets with a bolt thru to the interior. It will come right apart after only a week but by next year I could remove the bolts and the panel would not blow off. After a few days you can still wipe it off with a rag because its not really a glue. It's in it's own magical league.

 

[magentawave]

I just saw 5200 at Home Depot last week in caulking tubes at $11 per tube. I don't remember if it was the "fast cure" stuff or not. Plan carefully how you'll use it because once you open the tube you need to use all of it immediately or you'll have to throw away what is left.

I take it you can't buy 3m 5200 in caulk tubes at the local chain store like homedepot anymore? That is a thing of the past?

 

[pugslyyy]

I've bought 5200 from Jamestown - they had the best price when I was shopping (the Home Depot's in my area don't carry it)

http://www.jamestowndistributors.co...02&familyName=3M+5200+Marine+Adhesive+Sealant

I don't get the fast cure, I like the longer working time - and it means I can use a tube over a week or so and still have it be just fine.