New Permatrim/5200 question

R

Roy & Dixie

New member
Yesterday I installed a new Permatrim on my F80 Yahama up to the final step of applying 5200 sealant and tighting the 10ea 1/4in bolts and nuts. The online pix of the install steps that I viewed showed 5200 smeared only around each of the bolt holes between the 2 plates. I was considering coating the entire surface between the plates so that when the bolts are tightened, all the mating surface is sealed so that no water can get between the surfaces. Would this be a good or bad idea?
 
Probably a bad idea.

You'd never be able to get the two plates part again, with a full bond of 5200.

If you
1.) damaged the Permatrim and wanted to replace it, or
2.) bought a new motor and wanted to remove the Permatrim to re-sell the old motor,

you'd be "stuck" together permanently.

Just my first-thoughts on the subject!

Joe. :teeth :thup
 
Sea Wolf":1079olj6 said:
Probably a bad idea.

You'd never be able to get the two plates part again, with a full bond of 5200.

If you
1.) damaged the Permatrim and wanted to replace it, or
2.) bought a new motor and wanted to remove the Permatrim to re-sell the old motor,

you'd be "stuck" together permanently.

Just my first-thoughts on the subject!

Joe. :teeth :thup
Click to expand...

Yes sir-ee, agree totally. Once it's done, it's done. :D
 
I used 4200, which is also a polyurethane, but with less "permanent" tenaciousness (although it does still have adhesive properties). I applied it evenly over the whole Permatrim, because... well... that's just the way I do bedding compound usually, but also because I wanted to even out the stresses. Not sure if it ultimately would make a difference, but it's the way I felt more comfortable with, in the absence of the ability to make comparative tests.

Actually, I didn't use a spreader, but just made long squiggles of sealant such that I knew the clamping force of the fasteners would spread it out evenly (it did ooze out on all edges, which I then cleaned up).

I read Dora~Jean's excellent photo essay before I did mine - he installed a pair of Permatrims on his twin F80's. He also used 4200, btw.

http://www.c-brats.com/modules.php?...ame=gallery&file=index&include=view_album.php
Sunbeam
 
There are ways of removing 5200--Debond, and a hot wire. There are also different amounts of adhesion depending on the material. (See the 5200 data sheets)

I have used a liberal coating of 5200, in that then it spreads out the load over the entire antiventillaiton plate.
 
Hey guys - Please educate me on the install. I know the instructions say to use some type of marine sealant around the bolt holes but my question is why do you need it? I totally understand if you are drilling into your boat to use a sealant but why on the motor?

thanks
 
If you want to improve the streamlining/reduced the hydrodynamic drag created by the mating of the two surfaces, why not use some sort of softer filler?

According to the first post above, there are 10 1/4" x 20 threads per inch bolts holding the plates together.

And,

Ten 1/4" x 20 18-8 Stainless Steel bolts have a combined minimum tensile sheer strength of 27,800 lbs, and

Ten 14" x20 316 Stainless Steel bolts have a combined minimum tensile sheer strength of 46,000 lbs.

Do you really need a high quality adhesive between the plates?

Seems to me you could get by with Polident, or something/anything a little easier to remove later, than 3M 5200! :lol:

But everyone to their own tastes/adhesives/and space fillers!

And be sure when you're done, to put the Polident back in your medicine cabinet, and not the 5200…………:wink

Joe. :teeth :thup
 
My guess is that it's not the strength of the fasteners that's being thought of, but rather the strength of the aluminum plates (also, the holes aren't tapped but rather simply drilled), and/or the compatibility of the metals involved.

My feeling was that if there was any hint of unfairness in either plate or any of the holes (not that there was anything obvious), that it would help to distribute the load to add sealant. While the fasteners should be plenty strong, what about any point loads? Maybe a non-issue, but since 4200 is removable, and since removal is not a planned event anyway (in other words, I want to be able to do it, but it doesn't have to be super convenient), I went with an all-over bedding of 4200 (less adhesive than 5200). In reality now, the fasteners are probably just backing up the adhesive of the sealant.

Another reason: In the case of stainless fasteners in a sandwich of aluminum plates that may sit in saltwater, I think the sealant would provide some isolation and help to prevent galvanic corrosion. Perhaps in that case Tef-Gel would be even better in the actual fastener area. (I actually used aluminum fasteners because their specs still looked plenty strong, and I didn't want to introduce steel into the aluminum sandwich.)

There's probably no way to know whether a given installation is overkill unless one tests to destruction - at least I don't know of a way to calculate it. I did select the fasteners and caulk type with knowledge of their specs, but there was a certain amount of "gut engineering" as well. I didn't want to be worrying about it, and the way I installed it felt comfortable to me.

Sunbeam :hot
 
bought a new motor and wanted to remove the Permatrim to re-sell the old motor,

This thought came to my mind after I posted the question. After reading all the answers before this post, I feel using 4200 would be the best way to go. Unless there is further advice or warnings, I plan to go with 4200 to meet Permatrims requirement, be able to spread-and seal all the surface area, and be able to later separate the 2 surfaces if necessary.

This forum is great. Thanks everyone!
 
My feeling is that you actually do spread out the load on the cavitation plate (anti ventilation plate) which is the weakest point in the equation.

I am not aware of any of the Permatrims breaking. However there have been reports of the anti-ventillation plates breaking. The stronger adhesive would be preferable to prevent this.

Streamline the lower unit? Not a lot of streamlining that is going on here. The Permatrim should run just on the surface of the water at speed. When coming up to a plane, there is a lot of turbulence.

There is not going to be any isolation issue by any of these compounds. Hopefully you will not leave the unit in salt water.

If you sell the motor, most likely you will sell it with the Permatrim in place. Very few C Brats own their boats long enough to repower, but some do. It is usually with a different motor, and thus a new Permatrim, if you add one.

I have put 5 Permatrims on outboards, and used 5200 on each of them, with no complications.
 
I should clarify that by "sit in saltwater," I didn't mean that you wouldn't tilt the engine out of the water when not in use, but just that a boat used in salt water is going to have the lower unit immersed part of the time. In that situation I like to keep stainless and aluminum isolated, if practical.

Sunbeam
 
"]My feeling is that you actually do spread out the load on the cavitation plate (anti ventilation plate) which is the weakest point in the equation.

I am not aware of any of the Permatrims breaking. However there have been reports of the anti-ventillation plates breaking. The stronger adhesive would be preferable to prevent this.

Streamline the lower unit? Not a lot of streamlining that is going on here. The Permatrim should run just on the surface of the water at speed. When coming up to a plane, there is a lot of turbulence.

There is not going to be any isolation issue by any of these compounds. Hopefully you will not leave the unit in salt water.
If you sell the motor, most likely you will sell it with the Permatrim in place. Very few C Brats own their boats long enough to repower, but some do. It is usually with a different motor, and thus a new Permatrim, if you add one.

I have put 5 Permatrims on outboards, and used 5200 on each of them, with no complications.

Most use will be in fresh water, but long trips on ICW, Fla Keys, and Chesapeake are planned. The boat will be on trailer when not in use. I would tip engine up when not underway in salt water.

I hope the 1999 F80 will last me several years, It has less than 500hr on it now. If I repowered, the cost of a new Permatrim would be a very small part of the total cost.

Decision might come down to if local marine store has both 4200 and 5200. I have called, and they do have 5200. It appears from the different posts that most every user has had successful installations which ever way they decided.
 
Thanks to the tip from a fellow brat, Home Depot has 5200 for about $8.00. Alot cheaper than WM. Did not see 4000 or 4200 at my Home Depot but maybe they have it at yours.
 
I read the directions 2 years ago and decided that 5200 was not needed for the application. I used silicone and have put over 500 hours on it without any sign of problem. Would I do it different now? No...
The product is a very good improvement to the boat's overall performance, so I am glad that I spent the time and money to install it.
 
From the Permatrim instructions "Small amount of 101, 4200 or 5200 marine sealant. Silicone is not recommended. Must be rated for underwater use."

Also the bolts should be torqued to spec, and the nylox nuts on the top of the unit, not the bottom as I have seen some.
 
THATAWAY,
I torqued the bolts when installed and at 200 hours performed an inspection of the GE silicone and it was still where placed and still in very good condition. Just performed 750 hour maintenance last week and the Permatrim and fasteners were inspected when changing the water pump and everything remains in very good condition.
 
Youse guys have some good points, but I still think the 5200 is a bit of overkill with 4200 and lesser evils abounding in the stick 'em game. .

The Polident was, of course, in jest only, but I didn't notice any laughter lightening up the site. '

Don't take me seriously, I don't, for the most part.

Joe. :teeth :thup
 
I just ordered a Permatrim from Andy last week. This thread comes at a good time for me. I think I'll use the 4200.

BTW, I liked the Polident comment, Joe.
 
Let us know how a permatrim works on cc23 I have. A cc23 with a f115 it does not seem I need it. Just cut a hatch in forward. V berth great storage plus extra weight. Up front. The boat seems better balanced. Then my older cd 22cruiser just some thoughts. Jim
 
Joe, Seriously? I just ordered a pair of permatrims and a case of Polident. Figured I couldn't go wrong, it being waterproof and all :oops: :oops:

Now if I can just figure out which one is the anti-cavitation plate :shock: :disgust :wink:

Still trying to decide......

Harvey
SleepyC:moon
 
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