Caulking aluminum gutters

My aluminum gutters are leaking where they are joined at corners. What kind of caulk works best to fill and waterproof the joints, preferably while they are wet.
Thanks
Walter The Happy Iconoclast www.rationality.net -
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Nothing will work well when it is wet. When it dries out use silicone caulk.
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Nothing much sets well when surface is wet, outside of roof repair goop. Use either silicone sealant (not paintable kind), or polyurthane gutter and downspout caulk. Both require dry and clean surfaces.
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This is turtle.
Like Roger said Polyurthane caulking sold at walmarts and other places for repair of flashing of sheetmetal roof joints and seams. The Good stuff will sell for about $3.00+ or so. Now this Urthane stuff says it will take in wet areas but you really need to dry it , clean it, and make it set real good and not test the product and your luck also.
TURTLE
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I agree with others that the gutter must be dry to repair effectively.
IMHO absolutely do not use silicone. Butyl rubber makes an excellent caulk for gutter and sheet metal joints. I would deliberately remove the pop rivets and open the joint. Smearing caulk on the top of the seam is temporary at best.
If you want to install something without opening the joint, or if you have actual holes in the gutter material, I have had good success with the following: http://www.steels.com/pdf/vicryl-cp10.pdf
I actually use the cp11 with fiberglass reinforcement cloth.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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Why? That would have been my first choice..
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I have removed literally miles of failed silicone caulk. The one possible exception might be Dow 795. Grab one end of the silicone and peel it off the joint. I am sometimes glad that others have used the silicone, it sure makes cleaning the joint out easier. Try removing butyl, thiokol, or urethane.
Successful use of silicone requires primers, proper joint preparation, and skill on the part of the installer. 3 point adhesion will destroy any caulk joint, but silicone in particular.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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