Removing skin fitting sealed with sikaflex?

[PetiteFleur]

I'm replacing my 1.5" toilet outlet fitting with a Trudesign ball valve etc. The original bronze/brass fitting is secured with sikaflex - can sikaflex be softened with a heat gun to make it easier to remove? Tried unscrewing it but whole fitting & nut just turns. Or do I have to cut it off?

 

[Tranona]

If you are replacing the whole assembly including the through hull then cut off the external flange and pull it out. Might need a bit of persuasion from the outside.

 

[thinwater]

Marine DeBond. Read the instructions FIRST. It really helps.

 

[lustyd]

I'm replacing my 1.5" toilet outlet fitting with a Trudesign ball valve etc. The original bronze/brass fitting is secured with sikaflex - can sikaflex be softened with a heat gun to make it easier to remove? Tried unscrewing it but whole fitting & nut just turns. Or do I have to cut it off?

Usually you can hold it still from the outside with a tool inserted into the fitting, then use stilsons on the inside for leverage. Cutting them off is a last resort as it generates a lot of heat and dust, and takes far, far longer in my experience. Remember that it's GRP it's connected to so while the old metal fitting will happily take the heat you could damage the hull and not realise it.

 

[Tranona]

If you are worried about heat (not my experience though, the flange is thin and does not need much grinding to cut through) plug the hole with wood and use a hole saw.

 

[lektran]

I used a dremel with a tiny cutting disc to split the nut, then it was easy enough to pry off and push the fitting through from the inside.

 

[rogerthebodger]

Cut off the outside flange with a hole saw and centrig plug . cut the flange off the hammer and drift to knock the rest of the fitting out to the inside of the boat

 

[bluerm166]

If you really can't move the nut when you are holding the body firm using a tapered bit of 18 ply driven in against the nibs ,wrench applied,and someone on the nut inside ..................

Put a wooden plug firmly in the hole.(The holesaw will cut you one that you can taper.)
Establish the centre point of the plug.
Drill a 6mm hole at centre.
Use a bosch hole saw of the same diameter as the o/a diameter of the inlet.
Aim to cut out the red bits.

 

[PetiteFleur]

Hmm - Marine debond - never heard of it but a local chandlery stocks it! Looks good and I'll get some tomorrow as I'm going to our boat. I also like the tapered plug driven in, held from the outside and stillsons on the inside. Probably if used together should do it. There is restricted access internally though. Lots of ideas - thanks everyone.

 

[seaangler23]

I’ve drilled them out with a step drill from the outside , quick and takes the head off cleanly and doesn’t touch the hull

 

[Baddox]

I used an angle grinder on a stainless steel through-hull. A very wet rag stuffed into the fitting helped keep the temperature down while grinding the flange off the outside.

 

[lustyd]

I can only assume those saying cutting or drilling was quick had lower quality fittings than my boat had! 1/4 inch of bronze was not a fast operation by any stretch of the imagination.

 

[rogerthebodger]

I can only assume those saying cutting or drilling was quick had lower quality fittings than my boat had! 1/4 inch of bronze was not a fast operation by any stretch of the imagination.

Cutting 316 stainless steel wit a hole saw is not easy.

Drilling bronze needs a drill with the correct point profile

 

[justanothersailboat]

If the whole fitting and nut turns - does that mean the sika has debonded from the hull so the flange can turn, but the nut is fairly stuck to the fitting? not sure I am visualising the right thing from your description...

I am dealing with sika'd flanges at the moment. I was able to take a Stanley knife blade (without handle) and sort of roll it around the edge of the flange to free the sika. I had to scrape away some antifoul to do that.

Not yet run into a through hull flange that doesn't have two bumps on the inside, allowing a correctly whittled bit of scrap hardwood stick to be jammed in and used to stop it turning (I'm sure there is a correct tool for this that I should be using instead). But I have not examined all that many and maybe they are out there.

 

[lustyd]

am dealing with sika'd flanges at the moment. I was able to take a Stanley knife blade (without handle) and sort of roll it around the edge of the flange to free the sika. I had to scrape away some antifoul to do that.

If the nut is off just stand on the through hull inside the boat.
Yes, there is a correct tool, but bits of wood are infinitely easier to find

 

[justanothersailboat]

I looked up through hull tools after I posted that and at least one available option had a price that shocked me! I think the bit of wood has a bit more work to do.

I gave the throughhull a medium tap with a hammer to push it through. seems to work. If it were well stuck I'd worry about causing gelcoat damage, though.

 

[Cptsideways]

Angie grinder with a coarse flap disk from the outside, will have the outer flange off in seconds.

 

[Pye_End]

Boat yard uses angle grinder as it is quick. My first took a bit longer than it should. Next one took seconds. The trick is to focus on where the flange joins the tube, and not try and grind the whole thing off. Not sure about the 'flap disk' idea - not tried it - just used a metal grinding disk.

 

[PetiteFleur]

Update - I used debond on the inside and sprayed it on the outside. My friend made a tube with two slots to fit the internal 'bumps' with two holes for a tommy bar. Internally I had an adjustable spanner on the nut lodged against the bulkhead, then used the tommy bar to unscrew it and once the bond loosened it unscrewed fairly easily. Then I fitted the Trudesign seacock to which I fitted thr loo outlet.

 

[justanothersailboat]

Thanks for the update. Sounds like it went well - glad to hear it!