| Filling the seam [message #295171] |
Sat, 06 February 2016 12:36  |
Who_dun_it
Messages: 176
Registered: April 2007
Location: Thousand Oaks, CA
Karma: 1
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Senior Member |
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Sealing the joint at the metal roof and fiberglass cockpit cap - I find that I need to reseal this joint. What have others done with cleaning, prep, seal
material? Do rivets need to be added along the seam?
Thank you
Les
T.O. Ca
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| Re: [GMCnet] Filling the seam [message #295173 is a reply to message #295171] |
Sat, 06 February 2016 12:56  |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Les, two dissimilar materials are joined there. Sheet Moulded Compound or
SMC for short, joins Aluminum sheet. One expands and contracts in one
plane, the other in a total different direction. So, what is needed is a
self leveling SEALANT, NOT A RIGID ADHESIVE. A number of different brands
will work. Sika-flex makes several different compounds that do well, as
does 3M. I personally do not think that riveting the joint will lead to a
leak free joint. Heating and cooling will cause any of them to leak,
eventually. Obviously, it is not a "once and done" job. But , clean out all
the old sealant, if it is silicone based, EVERY TINY SMIDGE MUST BE
REMOVED. Have the joint surfaces clean and dry, apply the new sealant and
give it adequate drying time. Repeat as needed. Just how it is.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Feb 6, 2016 10:37 AM, "Les Leach" wrote:
>
> Sealing the joint at the metal roof and fiberglass cockpit cap - I find
> that I need to reseal this joint. What have others done with cleaning, prep,
> seal
>
> material? Do rivets need to be added along the seam?
>
> Thank you
> Les
> T.O. Ca
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Filling the seam [message #295175 is a reply to message #295171] |
Sat, 06 February 2016 13:24 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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Hi Les
I had a leak in a small crack where the aluminum meets the SMC (fiberglass) portion of the roof.
I used PL Urethane that I bought at Home Depot.
It appears that Loctite bought PL so at Home Depot you will find the product as Loctite PL. It comes in caulking gun tubes. Some are for Windows & Doors, Concrete, Foundations, etc. The only difference is the color.
Some are black, grey, brown, etc.
Home Depot also sells Sika Flex which will also work fine. Sikh Flex has been used in boat yards for years.
Make sure its the sealant and not the adhesive.
To fix my leak I cleaned out the crack and used MEK to clean things. You can also use acetone, Lacquer Thinner or any other fast dry solvent.
Don’t use paint thinner or mineral spirits as they have oil in them.
Once you have things cleaned run a strip of painters masking tape (usually blue) along each side of the area you are filling. Run a small bead of sealant and then run your finger along it to push it down into the crack.
Before it cures pull the masking tape and you will have a nice clean filling that you will not have to cut level or otherwise work on. I filled the whole groove across the roof a few years ago and have not had any more leaks in that area. The last time I looked the sealant was till in place and doing its job.
Polyurethane sealant can be painted after it cures.
I used this same sealant in the rear wheel wells where I had developed a crack just above the plywood floor where the wheel liner meets the floor. When traveling in rain I found that I had water in my carpet in the hall area of the rear wheels.
Filling that crack solved the problem.
One nice thing about polyurethane besides the ability to hold paint is that it gives a flexible seal that will not harden and crack. But it is not like silicone sealant which will be affected by the sunshine.
Emery Stora
77 Kingsley
Frederick, CO
> On Feb 6, 2016, at 11:36 AM, Les Leach wrote:
>
>
> Sealing the joint at the metal roof and fiberglass cockpit cap - I find that I need to reseal this joint. What have others done with cleaning, prep,
> seal
>
> material? Do rivets need to be added along the seam?
>
> Thank you
> Les
> T.O. Ca
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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