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Author Topic:   Solvent for Silicone Sealant
jimh posted 10-13-2003 01:39 PM ET (US)   Profile for jimh   Send Email to jimh  
The previous owner of my 1987 REVENGE 20 added two large stainless steel mounting plates to the rear of the cockpit to which he fastened a home made rear seat. The seat was removed long ago, and now I am in the process of removing the mounting plates.

The plates were sealed to the cockpit deck with some material which appears to be clear caulk, perhaps silicone based. It does have a rubber quality to it. I have removed most of it by pulling, scraping, etc., but now there is still quite a residue which is embedded into the non-skid pattern of the deck.

So far the best tool for removing it has been the finger nail on my thumb, if I remember not to trim my nails for a couple of weeks.

Accounts of first hand experience in the rapid removal of this type of residue would be much appreciated.

Is there a good solvent to loosen the caulk without doing more harm than good to the gelcoat?

knothead posted 10-13-2003 02:12 PM ET (US)     Profile for knothead  Send Email to knothead     


I've tried several solvents, none seem to work great on dried silicone, but I've had some luck using acetone to clean up the leftover residue from scraping. It took some vigorous rubbing with an old towel and acetone but eventually it all cleaned up.

Good luck


Montauk posted 10-13-2003 08:28 PM ET (US)     Profile for Montauk  Send Email to Montauk     
The auto parts store should have a rubber eraser type wheel that you mount in a drill, it is used for removing vinyl decals and such. It should work great on silicone, without subjecting yourself to unwarranted chemicals.
JayR posted 10-13-2003 08:55 PM ET (US)     Profile for JayR  Send Email to JayR     

I've used it with no ill effects. Eats right throught the stuff. I just scrubbed it off with a stiff brush and water.

JayR posted 10-13-2003 08:56 PM ET (US)     Profile for JayR  Send Email to JayR     
I'll try again...
JayR posted 10-13-2003 09:01 PM ET (US)     Profile for JayR  Send Email to JayR     
I am refering to the Goof Off. I have not tried the Goo Remover.
Really stinks..... use in a well ventilated place.
Barry posted 10-13-2003 09:49 PM ET (US)     Profile for Barry  Send Email to Barry     
I've had some luck with Boatlife Release Adhesive and Sealant Remover. It is "formulated to remove cured or uncured silicone, polyurethane, and adhesives. Great for clean-up on hands, tools and equipment. Will not harm metals, fiberglass gel coat, glass, or plexiglass. Safe on most carpets, vinyl, plastics and painted surfaces."
PFSQUAN posted 10-14-2003 08:51 AM ET (US)     Profile for PFSQUAN  Send Email to PFSQUAN     
I also have used Release with fair results. The key is to mix it with patience and allow it to work. A toothbrush should bite into the nonslip pattern well enough without marring the gelcoat. But the loosened caulk will fly when you start scrubbing so keep a rag handy to prevent the stuff from scattering.
jimh posted 05-17-2004 07:29 PM ET (US)     Profile for jimh  Send Email to jimh     
I am still working on removing this old sealant. Any new suggestions?
Tom W Clark posted 05-17-2004 08:12 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

In my experience as a contractor, home owner and boater for most of my life and having dealt with silicone sealant from many different manufacturers in many different applications I have yet to come across *ANYTHING* that will cut high quality fully cured silicone. Period.

I believe the only way you will remove that silicone is mechanically.

After sanding the affected area down with a hard block and perhaps 220 sandpaper to the tops of the "tits" of the non-skid I would use the same tool I use for patching the non-skid in Whalers, the edge of a furniture scraper.

Procure a scraper like this one:

Sharpen it and run it on edge down each and every "valley" in the non-skid until all the silicone is scraped/gouged away.

Good luck.

Random notes on silicone caulk:

When I bought my Outrage 18 in 1989 there was a teak enclosure mounted to the face of the console that partially housed the previous owner's VHF radio. This teak enclosure was sealed to the fiberglass console along the 3/4" wide edge of the teak.

After I removed all the screws that secured it, this small enclosure would still not budge. I ended up putting all of my 170 pounds of weight on it and it finally tore loose taking some gel coat with it! This was even more remarkable because the force I was applying was in shear, not simply an up-lift which would have a greater tendency to pull the finish off.

Uncured silicone can be cleaned up with any penetrating oil. I often use WD-40 for this purpose when tooling a caulked joint. After applying a bead of silicone, I over spray the bead and the surrounding area before running my finger down the joint. The oil will impair the adhesion of the silicone as it is smeared over the surrounding area and it will clean up with paper towel.

Water or window cleaner can be used to do the same thing, but you must work quickly. Good shower door installers use the window cleaner method and they generally are very good and neat at applying silicone caulk.

jimh posted 05-18-2004 12:57 AM ET (US)     Profile for jimh  Send Email to jimh     
Tom--Thanks for the advice. I have found that the human finger nail is about the perfect hardness for scraping. It is hard enough to get the silicone out, but not hard enough to scratch the gelcoat. However the tool wear is excessive. :-)

I would be afraid to take a metal scrapper to the gel coat. I have a plastic pick tool which I use when installing telephone wiring on dense punch blocks that might work well. I'll give that a try next weekend.

davej14 posted 05-28-2004 11:52 PM ET (US)     Profile for davej14  Send Email to davej14     

I just had my motor raised with help at a local marine repair shop. They removed the old silicone caulk with spray carburetor cleaner which the buy from Wal-Mart at under $1.00 per can. It was pretty effective and didn't damage the gel coat in any way. They told me they use it all the time for clean up on boats and never had a problem.

Clark Roberts posted 05-29-2004 07:50 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Since the subject of silicone solvent has been brought up I'll relay a true story of about two weeks ago. A friend of mine went into a local marine surplus store and asked the rather well endowed clerk if they knew of any solvent for silicone. Her answer was, "have you tried saliva?". Beam me up! Happy Whalin'... Clark... Spruce Creek Navy
jimh posted 05-29-2004 09:34 AM ET (US)     Profile for jimh  Send Email to jimh     
Dave--thanks for the tip, I'll give it a try.

Clark--Very funny story!

Barry posted 05-29-2004 11:38 AM ET (US)     Profile for Barry  Send Email to Barry     
Check out this page on cured sealant removal from the GE Sealants & Adhesives site.

Permatex makes a silicone stripper.

Dicone NC9 sounds interesting.

gtcway posted 06-08-2004 10:58 PM ET (US)     Profile for gtcway  Send Email to gtcway     
Gasoline will eat silicone and seperate it from the deck. Then you can just wash it away with soap and water.
tkassner posted 05-20-2008 09:01 AM ET (US)     Profile for tkassner  Send Email to tkassner     
Which method is the least damgaing to the gelcoat? Does acetone damaged the gelcoat?
HomeOwnerAZ posted 05-01-2009 07:13 PM ET (US)     Profile for HomeOwnerAZ  Send Email to HomeOwnerAZ     
I had recently installed window panes using silicone sealant with some getting on the pane nothing seemed to work in getting the residue off in desperation I finally tried the clear packing tape that I had it lifted the film residue and globs right off leaving the panes easy to clean. Maybe this will work on other surfaces.
David Pendleton posted 05-01-2009 07:28 PM ET (US)     Profile for David Pendleton  Send Email to David Pendleton     
This stuff looks interesting.

AtoZ posted 05-01-2009 09:54 PM ET (US)     Profile for AtoZ  Send Email to AtoZ     
Try "3M 2153 REMOVER CAULK LIQUID - 8Oz." about $5
deepwater posted 05-02-2009 07:53 AM ET (US)     Profile for deepwater  Send Email to deepwater     
well jimh,,its been 6 years now and your thumbs are now either gone and you need help opening things or the removal is complete ,,what did you use ?
jimh posted 05-02-2009 08:28 AM ET (US)     Profile for jimh  Send Email to jimh     
The plastic telephone installation tool was effective. Its hardness was greater than my fingernail and less than gel coat resin. I do not recall if a complete removal was obtained. I sold the boat!
PeteB88 posted 05-02-2009 10:08 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Hey Clark - uh, what was the name of that marine surplus store? GPS coordinates? We need to get to know her, I mean the store! Sounds like excellent customer service.

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