Removing silicone sealant

share hints, tips and experiences
Post Reply
slimtim
Posts: 56
Joined: Thu Nov 20, 2014 8:23 pm

Removing silicone sealant

Post by slimtim » Fri Oct 06, 2017 9:25 pm

Next week I will be starting work on the wooden hull of my new boat.

One question I have relates to how best to remove cured silicone sealant which has been put in place to cover some screw holes.

Having done some investigation, it is clear that the sealant has stuck with some force and can't be scraped out.

I've looked at chemical sealant removers but they are for non-porous surfaces and I am concerned that using them will leave a residue which will make it more difficult to get a two part wood filler to bond over the hole.

Can anyone suggest alternatives?

chris
Posts: 2420
Joined: Sat Sep 18, 2004 7:43 pm
Location: somerset

Re: Removing silicone sealant

Post by chris » Sat Oct 07, 2017 10:38 am

I'm not recommending this for a boat but I was told you can removing silicon sealant from round a bath by spraying it with wd40 and then warm it with a hairdryer, not a hot air gun, and then it will easily peal off. I've never tried this so don't know if it works anyway but you would have to chemically clean the oil off before you put any new sealant on.

JimC
Posts: 1707
Joined: Sun Oct 03, 2004 10:24 pm
Location: Surrey
Contact:

Re: Removing silicone sealant

Post by JimC » Sat Oct 07, 2017 10:51 am

chris wrote:I'm not recommending this for a boat but I was told you can removing silicon sealant from round a bath by spraying it with wd40 and then warm it with a hairdryer, not a hot air gun, and then it will easily peal off. I've never tried this so don't know if it works anyway but you would have to chemically clean the oil off before you put any new sealant on.
Its amazing the magic people think there is in WD40, but most of the components are utterly irrelevant to anything like this. The solvents in WD40 seem to be basically kerosene/white spirit types, maybe a tad more refined, and in the way of solvents I'm quite sure that at least 99% of the things WD40 will do white spirit will do. However the lubricants and dewatering agents in WD40 will not do any subsequent finish any good at all. A bit of white spirit might help in removing the silicone, I don't know, but if all else fails just drill the hole a fraction larger deep enough for the filler to get a decent grip.

User avatar
trebor
Posts: 957
Joined: Mon Jan 02, 2012 1:53 pm
Location: West Midlands
Contact:

Re: Removing silicone sealant

Post by trebor » Sat Oct 07, 2017 6:32 pm

pick it out with a needle until you can get screwdriver in, wd40 will soak into wood and cause you no end of issues when you come to put a finish on.
Robert
Minisprint 4230
Tinker Traveller 160
Mirror 61147 Anastasia
http://www.aquabatdinghy.co.uk

chris
Posts: 2420
Joined: Sat Sep 18, 2004 7:43 pm
Location: somerset

Re: Removing silicone sealant

Post by chris » Sat Oct 07, 2017 8:23 pm

Indeed that why I said don,t do it on a boat.
Jim, I'm sure you are right. Perhaps it acts as a release agent in the way that water will in ,certain circumstances.

Slingbat
Posts: 4
Joined: Mon Jun 26, 2017 1:15 pm

Re: Removing silicone sealant

Post by Slingbat » Mon Oct 09, 2017 2:22 pm

This is by far the the best stuff I have ever laid hands on for removing old gunk, can be a little expensive but performance is well worth it, I get lucky on occasion and I dig it out of the scrap bin at work



http://www.paintservices.com/pf-sr-solvent-wipes/

Tom

chris
Posts: 2420
Joined: Sat Sep 18, 2004 7:43 pm
Location: somerset

Re: Removing silicone sealant

Post by chris » Mon Oct 16, 2017 12:47 pm

I learnt this from my 11yr old grandson at the weekend...you must never use wd40 to oil the bearings on a skateboard because they are made of silicon and wd40 damages the silicon.

So perhaps it does actually do more than just act as a release agent on silicon.
Learn something every day!

Post Reply