Nice Caulk?

[Kahi]

Looking to re-caulk several locations on my boat, including where the wrap-around windshield meets the deck (like on a water-ski boat) and a few hatch covers. The original factory caulk has started to break apart, blacken or is just gone after 6 years. I presume it's the use of chemicals drying out the caulk.

I plan on removing old material by hand and maybe a tool....a few questions on the task..

1. What is the best caulk/silicone to use?

2. What is the tools/products I might need to remove the pre-exisitng caulk?

3.Would the caulk gun be the best way to apply or a smaller tube which might be easier to handle?

Thanks,

Kahi
Miami, FL

[giantfan]

This is what I have done in the past and it has worked fine so far. Take blue tape and mask off all areas around the section you want caulked. Use a caulk gun to apply the caulk and then tool it with your finger. A little spit on your finger helps to get a smooth bead. As soon as you have it all tooled out and everything looks good, pull off the blue tape being careful not to drag it thru the wet caulk. The tape will give you nice straight lines.

I have used Boat life caulk in the past and haven't had any problems with it.

[Logan9581]

I've heard that an ice cube works well for smoothing out the lines.

[canyongear]

Become one with the blue tape and for curves go to an auto parts store and get some 1/4" or 3/8" pin striping tape to follow the curved edges and then overlay the pin stripe tape edges with blue tape to prevent over runs.

If you use your finger you will indent the caulk into a "U" shape which is fine for some applications, others you will need a straight edge a bit wider than the seam to make a flush look.

A good tape job makes for a great caulk job!

Take your time, a gun is better for larger app's, and make sure you have plenty of paper towels and a box or bucket to throw all the used stuff in as you go along.

Take the tape off immediately, work an area not too large and complete then move on, caulk skins over fast ..don't try to do too much at once.

[SNAKE EYES SPORTFISHING]

TRUST ME ON THIS, I USE THIS PRODUCT ALL THE TIME.

USE BLUE TAPE. APPLY WITH GUN. BUT YOU REALLY WANT TO GO TO A GLASS OR MIRROR STORE AND GET WHAT IS CALLED A "SLICKER" . AND A GALLON OF DE-NATURED ALCOHOL IN A SPRAY BOTTLE.

APPLY TAPE, OVER FILL VOID WITH CAULK GUN, SPRAY ALCOHOL OVER SILICONE , USE THE CORRECT SIDE OF SLICKER,[ TO ACHIVE STYLE BEAD DESIRED} REMOVE TAPE AND ADMIRE YOUR WORK, IF YOU NEED TO CLEAN ANYTHING UP , SPRAY ALCOHOL LIBERALLY AND WET RAG WITH IT ALSO , SILICON WILL CLEAN UP LIKE SPILLED COFFEE.

[Hunter's Haven]

I just did some caulking yesterday and used 3M 5200 Marine Sealant. Got it at Ace Hardware. This stuff is the real deal. Dried in a couple hours. Highly recommend for marine applications. I used the small tube but they do make the larger for caulk guns.
Gery

[Fortunate One]

Caulking is a science in itself.

The best thing you can do is to remove all existing sealant completely including all residue. Silicone will bond to silicone but it bonds to clean surfaces better.

Tools to remove it include plastic scrapers and there are some wheels that body shops apply to drills and use to remove automotive glues that can get the stuff off. But be careful not to heat the stuff up and be careful not to heat up the fiberglass with friction. if you decide to do it use it on your aluminum first like the underside of a flange frame of a hatch.

There are silicone's made by Dow series 790 and 795 which are commercial grade silicone's which are used in applications that allow for 50% movement. On a boat that's a good thing.

I think this stuff is much better than "life caulk" which the boat supply places sell at a premium to the general public.

There are "release agents" chemicals, out there that will aid in the removal of caulk.

The thing about a good caulking application is to insure that you have a decent width to depth ratio. It's not like caulking a bathtub to tile. You want to apply a joint that only adheres to 2 surfaces. Foe example if you're caulking your windscreen down, as long as the joint is say 1/4" high the depth should be 3/8" deep and you only want caulking touching the underside surface of the windscreen and the surface below that it's attached to. You do not want the caulking to also touch the back of the wind screen where it makes contact with the boat. That's referred to as 3 sided adheasion and over time it will shear. You can avoid 3 sided adheasion by using a close sell foam backer or apply what is refered to as a bond breaker tape.

Lastly, never, never use water to tool the caulking. Caulking needs to be tooled dry. Water will can create problems. Caulking can get overlapped onto the wet area and then start to fail.

You can use a plastic tool shaped very easily to the shape you are trying to tool the caulking into.

Keep plenty of rags with you to keep clean.

[Innovator]

I've heard that an ice cube works well for smoothing out the lines.

Soapy water in a spray bottle also helps smooth out the caulking/silicon

[Judith A]

http://www.valco-cp.com/Tube%20Grip%20Dispenser.htm

If your using a tube for smaller jobs or tight places this will be the best tool you ever bought. It gives you better control and uses every bit of the tube

Mark

[Kahi]

To begin with I am extremely thankful to all of you for taking the time and energy to give me advice based on you experience. I'm always amazed at sportfisherman.com's community and generosity. Thank you.

Now......some refer to silicone and others to poly based caulks.

Is there a rule of thumb when to use one vs. another?

Does living in a freeze free area like Miami have an impact on the final choice.