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2120Tom

Re-Caulking cap and rubrail?

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My memory seems to be failing me (CRS - and I didn't write it down) but I believe it was 3 or 4 summers ago I decided to re-caulk the cap and rubrail of my 2120. I do recall working my butt off from a step ladder while the boats on the trailer, cleaning the old and prepping for the new caulking. I'm pretty sure I used 3m 4200........but it is disintegrating BADLY, soft and chalky, it rubs off with your finger and sticks to anything it contacts making a mess.

I would like to believe that 3m products would perform better and last longer.

 

I also wonder, question, if the StarBrite waterproofing sealant I applied to the mooring cover a year or so after caulking isn't washing away in the rain and breaking down the caulk? Seems some areas of the underside of the rubrail caulk isn't soft at all compared to the upper areas with more direct runoff contact from the cover,, and then I'll find areas of soft, chalky sealant up at the bow underside rubrail where the cover doesn't cover at all? a real puzzler.

 

Appreciate any and all thoughts and if there's better caulk product(s) for use. Thanks

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That sounds odd about it rubbing off and sticking. I have had issues with 4200 that I used to seal the perimeter of my transom bracket to the transom where it as small surface cracks and that chalky look to it. Then again, it is 10 years old and exposed to sunlight, so I guess it has done ok in a wet environment.

 

I have wondered over the years if the stuff available to us non-commercial users is not as good as what the boat builders use. When I say not as good, I mean the chemical composition may not be as strong to minimize exposure to hazardous materials. I can remember buying Dupont automotive paints where the can was clearly labeled "Professional use only" and I was positive what I had was the same stuff body shops and dealerships were spraying. I bet it would be a lot more difficult to walk into a supply house today and purchase the same stuff!

 

3m 5200 that I have bought both from a supply house and at the big box hardware stores - make damn sure you don't intend of removing whatever you put it on without a lot of work and cussing! I bedded a thru hull fitting in 5200 the same time frame I installed the transom bracket. Had to remove the transducer last year due to the temp sensor failing. That stuff was still flexible and had a death grip on the fitting! I eventually got it apart, but I can assure you the 5200 held up way better than the 4200.

 

Also look at the SikaFlex products.

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Thanks Dan. As I have been looking around the internet, I came across the West Marine sealant chart of best used products and I'm fairly certain this chart was in print back when I re-caulked, so now I'm also fairly certain that I used 4000 or 4200 as both have the "2 dot best" use for my application.

I also read somewhere that IF a silicone seal was used prior,, a poly-sulfide sealant as 4000/4200, would not adhere well over silicone. So in trying to recall my earlier process as being "tiring" with the use of a razor knife/putty knife removal of old seal then donning latex gloves and rubbing/cleaning the area with acetone, I seem to recall it was silicone AND I thought I had all residue cleaned thoroughly.....but possibly I didn't get it all from the seams...and the two sealants counter-acted?

 

I have no way of knowing if what I removed initially was factory seal or done by a previous owner, so this time maybe I'll just use GE exterior window silicone and see where that takes me.

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That is the good and bad about silicone. It works great but cleaning the residue is darn near impossible. Try dealing with it when painting. Just when you think it is all gone and the primer coat layed down good, topcoat with the good stuff and darn if a fisheye would pop out where some of the silicone contamination worked its way through the primer!

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