Removing old caulk

angus99 · Jun 1, 2016

I want to recaulk many of the external seams on our boat. Looking for recommendations for tools and techniques to remove the old, dried out caulk without damaging or marring the gel coat. I'm guessing it will involve careful use of a heat gun and some kind of plastic scraper. (Not talking about rebedding fittings here; I'm using butyl rubber for that.) Thanks.

Phil Fill · Jun 1, 2016

I use a small wire wheel on a variable speed drill. The wire wheel may damage the surface under the old calking but the new calking will cover. As the wire wheel gets wider crip off the excess wire. A sharp putty knife works well also. What ever method some damage will be done so keep it so the new calking will cover.

Bacchus · Jun 1, 2016

I've had reasonable luck w/ a sharp scraper - one tip is to sharpen the edge but round the corners a bit. Most damage I've had was from a sharp corner of scraper or razor blade.

an extension handle works well for razor blades when used w/ a heat gun.

bilge53 · Jun 1, 2016

Removing Caulk

There is a tool sold by hardware stores like Ace that has a handle and a V type blade. It is relatively cheap also; under $10. This is easy to use (as easy as it can be) and gets into the crack. I would suggest take a look at one and see what you think. The metal blade can be reshaped a bit with a file or grinder and maybe even do a better job.

Northern Spy · Jun 1, 2016

I've had good results with a chemical caulk remover. The one by boat life specifically.

koliver · Jun 1, 2016

I just did the bottom of my leaky aluminum beach boat. I tried several different tools before settling on a very sharp 1" chisel. Flip it so the bevel is down and control the angle to get the sharp part of the blade as close to the original surface as possible without digging in. If I can get it to leave few marks on soft aluminum, you should be able to get the same results on gelcoat. Then, as Fill says, cover the marks when you recauk.

Pgitug · Jun 1, 2016

When you do caulk, consider Sikaflex instead of any silicone based sealer.

HopCar · Jun 1, 2016

Star Brite makes a tool for that.
Caulk-A-Way

angus99 · Jun 1, 2016

HopCar said:
Star Brite makes a tool for that.
Caulk-A-Way

That looks interesting, Parks. May have to try it.

angus99 · Jun 1, 2016

Pgitug said:
When you do caulk, consider Sikaflex instead of any silicone based sealer.

Yeah, I'm almost as phobic about silicone as Mr. RT. The PO of my previous sailboat must have used a case of it to chase leaks. He ran an ungodly thick bead of it on the toe rail/deck joint and just about every other seam on the boat. Was so long ago, I forget how I got it off. :oldman:

Removing old caulk

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