Input/Suggestions on smoothing ridges

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AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

Hi Gang,

I’d like your thoughts and/or guidance on how, or what, I should use to smooth ridges between Aluminum pieces before priming/painting.

For example, once I reattach my rub rails, there is about 1/16” height difference between the rail and the deck of the boat. I want to smooth this out before paint.

I was thinking bondo, but then I thought any flexing of the hull will crack that. Then I thought Latex caulk but my primer and paint is oil based. So I then thought, silicone caulk but my experience with that is nothing sticks to it!

What could I use that would be flexible, something I could smooth out (or sand ideally), and have primer stick to it and be durable?

Thanks in advance for your help!

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LDUBS
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Input/Suggestions on smoothing ridges

Post by LDUBS »

Epoxy paste & do a fillet? It is used on think skin plywood boats. Don't know why it wouldn't work for your application.
Last edited by LDUBS on 17 Sep 2019, 19:59, edited 1 time in total.
Have Rod - Will Fish

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maintenanceguy
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Input/Suggestions on smoothing ridges

Post by maintenanceguy »

I need photos.
-Ryan

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

LDUBS wrote:Epoxy paste & do a fillet? It is used on think skin plywood boats. Don't know why it wouldn't work for your application.
What’s an epoxy paste? Like fiberglass?

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

maintenanceguy wrote:I need photos.
Here are some examples...

[ external image ][ external image ][ external image ]

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LDUBS
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Input/Suggestions on smoothing ridges

Post by LDUBS »

AnglerRoy wrote:
17 Sep 2019, 20:22
LDUBS wrote:Epoxy paste & do a fillet? It is used on think skin plywood boats. Don't know why it wouldn't work for your application.
What’s an epoxy paste? Like fiberglass?
It is two part epoxy with a filler to give it a thicker paste like consistency. It can be used as a gap filler. It is frequently used to makes fillets where two pieces come together.

Now that I've said all that, after looking at your photos I would probably use an aluminum friendly caulk that that I could apply using a standard caulking gun. I hope DaleH is reading this because if memory serves he had a marine caulk product suggestion that might work well for this application. I'll circle back with the name if I can find it.
Have Rod - Will Fish

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LDUBS
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Input/Suggestions on smoothing ridges

Post by LDUBS »

I found the product DaleH mentioned.

Here is a copy of his post from another thread:

"by DaleH » 19 Jun 2019, 20:05

I like and prefer LifeCaulk by BoatLife, and it too is a urethane goop like 3M 5200, but it is not a traditional caulk. It too is sandable and paintable.
Their tubes last year's, whereas 3M tubes don't last a season or as long (as they harden up)."


Hope this helps (thanks to DaleH).

PS: I've never used this or other marine caulk products on a seam. For typical silicone or latex or painters caulks, I keep a spray bottle of water with a little dish soap mixed in. A light spray after applying the caulk makes it easier to work consistently with less "smearing" and makes it easier to remove any excess.
Have Rod - Will Fish

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

Thanks a ton LDubs! I’ll look into that!

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

So I ordered a tube of this stuff, it states that it needs to be applied over paint. Has anyone tried applying primer to it and then painting it?

I’ll do a small test bead of it on a strip of sheet metal and report back but was curious if others have painted this stuff (once cured of course)?

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DaleH
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Input/Suggestions on smoothing ridges

Post by DaleH »

Yup, LifeCaulk by BoatLife ...

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

DaleH wrote:Yup, LifeCaulk by BoatLife ...
Hey Dale, is that yup that it must be on top of paint, or yup it can be painted? Thanks!

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DaleH
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Input/Suggestions on smoothing ridges

Post by DaleH »

To both, ideally should go over primed tin, but can apply over paint and is sandable and paintable. I actually use a gloved finger wetter in dish of dishwashing detergent to blend a nice smooth radius or contour and never sand it myself.

AnglerRoy
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Input/Suggestions on smoothing ridges

Post by AnglerRoy »

DaleH wrote:To both, ideally should go over primed tin, but can apply over paint and is sandable and paintable. I actually use a gloved finger wetter in dish of dishwashing detergent to blend a nice smooth radius or contour and never sand it myself.
That’s perfect. Thanks Dale!

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