Glen-L.com

There's lots of articles extolling the virtues of a 5200 bottom, mostly in terms of restoration of hardwood planked bottoms of vintage boats. Here's a link to just one - http://www.antiqueboatshop.com/5200whatis/. I'm presently building a boat in which I plan to use a double layer of 1/4" plywood for the bottom and am considering using 5200 instead of epoxy for the lamination between the plywood sheets and also between the frames and inner layer of plywood.

I'd be interested in hearing any comments, suggestions, and concerns regarding using 5200 in this way.

The professional shops swear by it over regular epoxy. Their contention is that the 5200 is somewhat flexible and allows a hull to move a little.

There are hundreds of boats built using the Glen-L method of cold molding using regular epoxy without any troubles. I can assure you that my boat has taken some very hard abuse on my lake and there has been not so much as a hint of a stress crack anywhere.

I can tell you this. If there is any movement at all between planking your finish will crack. If 5200 really is flexible then I cannot help but believe there will be cracks in the finish

But 5200 is tried and tested as a trusted adhesive and sealant for boat bottoms. You cannot argue with that at all

I know that VanDam boats use it exclusively for their cold moulding and I have not heard a peep out of problems.

The decision is yours, just giving you some information

dave

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Dave

My Riviera build - the Midnight Cry Project

Video of Midnight in Action
Blog

Few things in the world measure up to the thrill and satisfaction of boating in a boat that you built.

Thanks Dave for your insight. By the way, we'll be in your area in September for the ACBS Convention. Are you going to be attending?

Am I ATTENDING??????? Dang it, I am the lead boat on the 82 mile cruise up the lake. I will be working the loading ramp every day when not on the water. And I am helping the local boys ranch build a little boat in one day for the benefit auction.

And Midnight Cry will have a 4 Sale sign on her.

Glad you are coming and anxious to see you

dave

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Dave

My Riviera build - the Midnight Cry Project

Video of Midnight in Action
Blog

Few things in the world measure up to the thrill and satisfaction of boating in a boat that you built.

I haven't been keeping up for a while I see

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Bob
Sea Knight on the water/Malahini in progress

To me 5200 is expensive and a pain to use! For new construction that is very stiff I think epoxy. For restorations of old flexible boats use 5200.

Bill

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Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Interesting comment, Bill. Most all the articles relate to restoration and I've yet to see an article regarding using 5200 on a non-coldmolded, non-hardwood planked boat. I'm using regular sheet plywood planking. A friend of mine who restored a 57 Chriscraft Continental keeps telling me that I'd be crazy to not go through the extra expense of using 5200 and says it doesn't matter how I plank it because if I do it with 5200 I'll never have any leakage and thus, never have to deal with possible rot.

He restored his boat about 4 years ago and says what little leakage he has is from his stuffing box, he has no hull leakage whatsoever. For the first few months after building my Squirt, it didn't leak at all, but then did start to develop some leakage over time (it would take on about 2 inches of water over a few hours). I never could pinpoint where this leakage was from, I assumed the hull, but it could have been through hulll penetrating tie-down eye openings or drain plug. Never the less, I've been told by many builders and restorers that it occurs over time due to stress and an epoxied boat's inability to flex.

This is the first I've heard that 5200 is difficult to work with. What makes it difficult?

I may be wrong but in my book if a plywood planked boat leaks you have a problem/error that needs to be addressed - it shouldn't. Neither one of my boats leak a drop. And if what ever is causing you Squirt to leak is duplicated in the new boat built with 5200 it will leak too. I just don't think it can be blamed on epoxy in the construction.

As to working with 5200 to laminate sheets of plywood, I believe it will not only be more difficult to use but yield a bond that is inferior. 5200 is fairly thick stuff and when laminating sheets - particularly thin sheets - it is difficult to insure you get 100% contact with sufficient pressure for the adhesive to bite. Because 5200 is thick it doesn't readily penetrate or soak into the wood. Because of this I would want to spread it on and work it into the grain of both surfaces to be bonded. This way you will know if the two faces just lightly touch the probability is higher you will get a solid glue line. Also, it will need to be spread very evenly. If it is thick in one area it will actually hold the sheets apart and prevent the surrounding area from touching and bonding. If using a notched trowel to spread it it need to have fairly small notches.

So, your job will be to empty multiple tubes on to both the plywood faces, try to smooth it out and get the sheets positioned and secured before it starts curing.

Epoxy on the other hand can be mixed to get the consistency you want. For me when laminating sheets it would be much thinner than the 5200 and as a result will go on both easier and much more quickly. Plus it will do a much better job of penetrating the grain and providing a higher probability of a solid bond.

I not running down 5200 as it is some incredible stuff - unbelievably strong waterproof. In my opinion, it is just not the best choice for this type of joint. And no, I have never actually tried laminating large sheets with it but I do have extensive experience laminating using "PL Premium Polyurethane Construction Adhesive" and it is similar in consistency.

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So Many Rivers,
So Little Time....

We use 5200 to seal seams and rivet holes (dip the rivet in the stuff prior to driving) in aluminum sections on Lake aicraft . It is miserable to work with, ruins your tools and clothes. Nobody likes using it however it works very good. Has flex which the airplane needs, does not leak, and seems to last forever. Is extremely difficult to remove. Must be cleaned up quickly. I have read how the wood boat restorers use it for planking and can see how that would be a good way to go but have a hard time trying to picture using it on sheets of plywood and getting it to a consistent thickness. I'll bet their is a way if others are doing it. If you use it and I think it would work please let us know and post pictures.

ps I used epoxy on my build but it has not floated yet.

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John Amundsen
Monte Carlo
Winter Haven, FL

Maybe it will be done by G6 and maybe not.

I find 5200 extremely messy. When you get it on your gloves that's it. It won't just wipe off. It seems to get on everything. It stays tacky for days. If you touch it to check... It gets on more stuff.

Don't use it on anything that may need to come apart someday. It won't.

Bill

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Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build