[CadRhino]

I have a carbide countersink that I ran dry and has some pretty good chip weld on it. Anyone have any good ideas on how to remove it?
Thanks
Nathan

[Lomach]

I have used Caustic soda before. It is available from most diy or hardware stores as drain cleaner. Just add about 100g to a litre of water and let the cutter soak for half an hour or so. The mix is very dangerous though and you must were rubber gloves and goggles but it will dissolve all of aluminium.

Hope this helps

[alan_3301]

Thanks for the idea. I have a couple cutters that I wrote off as wasted because of chipweld.
I have used a wire wheel in the past to clean them up, but assumed that it was dulling the bit as it cleaned.
Sodium Hydroxide (Lye) should work very well.
I will try this soon.

[popspipes]

I dont know if this a correct way but I put the cutter in the Bridgeport and cut into a block of steel at a low rpm, usually the aluminum will come off at some point.

Sounds like the caustic is a better idea....

[GLCarlson]

I have used Caustic soda before. It is available from most diy or hardware stores as drain cleaner. Just add about 100g to a litre of water and let the cutter soak for half an hour or so. The mix is very dangerous though and you must were rubber gloves and goggles but it will dissolve all of aluminium.

Hope this helps

This should work fine- it's essentially dilute Drano. As noted 10% lye should be treated with respect, but from a chemist's perspective it's a 3 or so out of 10 (gloves & goggles, but as long as you don't get it in eyes you can -with caution- skip the gloves. Just rinse quickly). I'd add time and lower the concentration. 1-2% lye should be just as good, though slower, as it'll get behind the chip and destroy the bond and it's somewhat less aggressive to skin. Remember: base solutions are slippery!

Same method should be OK for HSS, too. Generally, steel tolerates basic conditions reasonably well.

See this link for a summary of WC resistance.

Corrosion Resistance of Tungsten Carbide Grades by Federal Carbide

I should have included: I rarely use the chemical method. Usually a Stanley knife, center punch or light cut on steel does it. I always try a physical method first.

[CadRhino]

Thanks for everyone's input. I am a little wigged out by caustic acid so will try the slow rpm milling into steel and see what that does. Thanks

I dont know if this a correct way but I put the cutter in the Bridgeport and cut into a block of steel at a low rpm, usually the aluminum will come off at some point.

Sounds like the caustic is a better idea....

[WOTDesigns]

Thanks for everyone's input. I am a little wigged out by caustic acid so will try the slow rpm milling into steel and see what that does. Thanks

I've pulled big chunks out with needle nose many times and thinner stuff I usually run into steel like already mentioned. Works well and only takes a minute to load the steel

[shred]

Those $1.99 Harbor Freight automatic center punches work OK to chisel it out if you don't want to mess with lye.

[rowbare]

Drano works well. I used a tablespoon or so in about a cup of water. With mechanical means you risk chipping the cutter.

bob