Removing stuck on gasket - aluminum surface?

Hey guys. So, I’m trying to get old gasket material that is REALLY stuck on the aluminum mating surface of the rear coolant neck housing of my Miata so I can install a reroute. Usually, what I do is get the big chunks off with a plastic blade, then use a razor blade to get some more off, and then I spray carb cleaner and brush with a brass brush. Just out of curiosity, is the brass brush going to damage the aluminum? Should I be using something else? So far it seems the brass brush was okay when I had tough gasket stuck to the throttle body surface on my Accord and the carb mating surface on my snowblower.

So, should I stop using the brass brush and use something else, or will I be fine?

If it was a steel surface I'd recommend using a bronze hammer to tap the gasket, then you can remove it fairly easily with a razor.  The hammer kind of crushes and moves the gasket?  Its hard to describe.  However bronze is harder than aluminum so it would damage the mating surface.  

You could use a copper hammer or use another type of hammer that is under the hardness of aluminum (Rockwell hardness of ~70 if I remember correctly)

Thanks guys! The light switch plastic trim piece sounds like an interesting idea. I could give it a go, but plastic parts (so far) just haven't been doing much for me. I wonder if maybe there is something else out there that is plastic that may be hard enough that it can work like a metal scraper.

In that application I just use a razor blade.  If I were to dig up the housing I'd sand it flat.  It's just not that critical.

I've learned a couple new tricks from this thread. Thanks

Can confirm that the electrical plate trick works great.  I like to swat one with a hammer to get a nice sharp edge.

I like to use WD40 with the electrical wall plate. I think it helps to soften the gasket and generally lubricate the whole process. I played with lots of stuff and it's the best most accessible thing I found. Use the stiffest cheap ones you can get at the hardware store or even better, ones that have been on your walls for years hardening. Short of tracking down something like Loctite Chisel or something terrifying like that, it's your best bet. As a note, the Loctite chisel stuff will turn anything that is vaguely organic to goo. It works. It's scary. 

I have used paste style paint remover. It won't hurt the metal and it will soften the gasket. Covering the paste while it works with aluminum foil or plastic wrap helps as it cuts down on evaporation of the paint remover. 

If you do end up damaging it, it can be salvaged pretty easily.

I take a pane of glass or a good flat piece of steel plate and spray a wee squirt of spray adhesive on it, then lay a sheet of medium grit sandpaper on it.  Even a good sanding block will do.  Scrub that mating face on it until it's true again.

I have re-surfaced motorcycle heads that way and it worked well.

In reply to Curtis73 (Forum Supporter) :

I've resurfaced Subaru heads (easy) and a BMW inline 6 head (not easy) this way using 600 grit sandpaper and WD-40 as a lubricant. Grandma's old 1/2" thick plate glass coffee table top has come in handy a few times :)

Hey,

When I was reworking aluminum Buicks, I used this stuff:

https://www.permatex.com/products/gasketing/gasket-removers/permatex-gasket-remover-low-voc-formula/

It worked great.

Rog

In reply to adam525i (Forum Supporter) :

I wouldn't do that for anything but an emergency.

Float glass isn't very flat.

Honsch said:

In reply to adam525i (Forum Supporter) :

I wouldn't do that for anything but an emergency.

Float glass isn't very flat.

Float glass is known to produce flat glass, usually within about .05mm-.1mm per 12 inches.  How much flatter do you want it to be? 

For a surface that is getting a gasket that is better than good.

Mr_Asa said:

Float glass is known to produce flat glass, usually within about .05mm-.1mm per 12 inches.  How much flatter do you want it to be? 

For a surface that is getting a gasket that is better than good.

Considering the out of flat spec for any of the heads I've worked with is 0.003in, that's not good enough.  For a water outlet with a thick-ish gasket?  More than good enough.