Removing skin fittings.

I cannot offer any science but my experience is that cutting with an angle grinder generates considerably more heat than a hole saw. You could lubricate/cool with a saw but not an angle grinder I think.
Both of them generate heat, hence my saying that it's far better to do it the proper way (which you agreed with above).

I actually did look it up and it seems around 120C is the limit for GRP, which would easily be reached without proper technique, taking time with breaks, and cooling, so Tranona's flippant comment could have been quite dangerous.
 
I have never liked or trusted angle grinders I am afraid. Admittedly with bigger old machines and different blades that there used to be but I saw the results of too many building industry accidents ever to own one myself.
Use a multi tool with a suitable blade. Cut through the nut, or nearly with two cuts and then a cold chisel to remove.
 
Use a multi tool with a suitable blade. Cut through the nut, or nearly with two cuts and then a cold chisel to remove.
For preference I would always cut outside the boat. Mess, space and the possibility of damage mitigate against inside for me.

Years ago I took out a well seized 1.5 inch seacock, one with an internal protrusion that can be used to prevent rotation. In the end I welded a short piece of inch angle to a 3ft long heavy tube for outside and an 18 inch adjustable inside. Even then it took considerable effort.
 
For preference I would always cut outside the boat. Mess, space and the possibility of damage mitigate against inside for me.

Years ago I took out a well seized 1.5 inch seacock, one with an internal protrusion that can be used to prevent rotation. In the end I welded a short piece of inch angle to a 3ft long heavy tube for outside and an 18 inch adjustable inside. Even then it took considerable effort.
Very good sales pitch for Trudesign, i’ve never heard of one seizing 🤣
 
Well this escalated quickly :unsure:

All I can say is I had 14 to do on my current boat and some broke off in my hand when removing hoses, the rest came of in seconds with a small angle grinder. My bare hands managed to handle the remains so I guess the temperature wasn't quite that of molten lava, having no ill effect to the grp.
 
My bare hands managed to handle the remains so I guess the temperature wasn't quite that of molten lava
I’ve seen the sealant bubbling when this has been done. Surely prudent to be careful rather than sarcastic?

You’re certain the GRP didn’t go above 120?
 
I’ve seen the sealant bubbling when this has been done. Surely prudent to be careful rather than sarcastic?

You’re certain the GRP didn’t go above 120?
I was only giving my real life experience having done it several times and demonstrating that the very fact I can handle the remains of the metal after a few seconds of grinding that it actually didn't get that hot
 
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