Removing old gasket

[Alfetta77]

Hi, I am preparing to re-install the inlet manifold on my Alfetta GTV engine. The remains of the old gasket have dried to a hard, gummy consistency and I am struggling with how to remove them. I have tried a scraper and a razor blade, but am worried about scoring the mating surface. I have watched a couple of videos with opposing views here https://www.youtube.com/watch?v=Uy5p-cUge5s and here https://www.youtube.com/watch?v=OQNvxJk-FUs. Having watched the first video I am not inclined to use the roloc disc, looks like it is removing an awful lot of metal! Is there something I can use to soften the old gasket (e.g. aluminium-safe paint stripper?) so it will scrape off more easily, using light pressure and less risk of scoring? Any thoughts or other ideas welcome!

[Craig_m67]

Dry ice?

[bazzbazz]

An addition to the dry ice idea, you can buy aerosol cans of "Freeze Spray" from electronic stores (Jaycar).

It is used to freeze electronic components to test for intermittent faults, should do the same job, but be a little more user friendly and less messy, plus the benefits of being able to freeze sections of the gasket directly and allow you to remove bit by bit.

Just a thought.

[MD]

Alfetta77

Good on you for having some forethought however you are over thinking this basic job.

Standard fare in any mech. workshop is a carpenter's chisel. Just quietly and gently use such a tool to remove the material. Practice on something irrelevant to get the skill if required. As long as you don't make furrows deep enough to plant the next years spud crop, the function of the gasket and any combined sealant (if required) will deal with the finish. It's standard practice. Economic realities would dictate it to be so.

[Beatle]

I agree with MD.  Use a FLAT blade tool such as a wood chisel.  Keep it flat to the surface and apply a push/pull force to keep it under control with front guiding fingers up close to the sharp edge.  I like to knock the sharp corners off the chisel with a sharpening stone (or concrete if it's not your good chisel....) to reduce the risk of the edge pulling into the surface.  You are only deburring it, not adding a chamfer, so you only need to dress the corners lightly with the stone.

If you are really concerned, fashion a non-metallic scraper out of some acrylic (Perspex).  It'll need constant sharpening but adds considerable safety margin (nothing is foolproof...).   

The Rolac rotary gizmo has its place, but I certainly wouldn't use it or similar' tools on soft, narrow, alloy surfaces. 

I prefer gasket surfaces to be flat and clean rather than have a homogenous looking finish via the use of a rotary scotchbrite type pad.

[Alfetta77]

Thanks for the advice and ideas everyone. While looking for freeze spray at Burson's I found the CRC product pictured. It needed several applications but softened the gasket enough to remove it with a plastic scraper from Bunnings https://www.bunnings.com.au/pure-line-38mm-abc-plastic-scraper_p1660091. Went through three of them (!) but was able to really scrape away at the gasket without damaging the head. Finished off with some Autosol to get the metal really clean. Really pleased with the end result, as pictured. Agree with your over-thinking diagnosis MD, however as an amateur I'm always conscious of the risk of buggering stuff up!