I made a new tool. I do not know whether someone else is already using it in a knife-making context, I would not be surprised if it were so. But I never heard anyone talk about it – a small chisel made from brass. I think it is a very good addition to my toolbox, well worth the ten minutes or so that I have spent making it. The inspiration were tools that I was using in my previous job to clean burnt plastic off of various testing devices.
This may sound like a joke tool, akin to the inflatable dartboard, chocolate kettle, or ceramic rivets, but it is not. But why would anyone make a chisel out of a soft material like brass, that will not hold an edge?
I am glad you asked.
When making knives with the use of epoxy glues and resin, an inevitable problem arises – epoxy stuck to places it should not be stuck to. I am always doing my best to clean any rogue epoxy from the bolster/blade boundary etc before it hardens with a towel soaked in denatured alcohol, but the epoxy tends to flow and bleed over during curing too, plus there is often some contamination on the blade where I fail to spot it in time. That needs to be scraped off, very carefully, without damaging the blade surface.
With my last batch of knives, I have used with great success a square piece of brass, so for the last few pieces, I ground it roughly into a chisel shape and fixed it to a handle. And it works great, exactly as it is supposed to work.
There are several reasons for using brass and not other materials like alluminium or mild steel:
- Brass is harder than epoxy, resin or wood, but softer than even unhardened steel. So it can be used to scrape the glue off steel not only on the blade but also on the tang, without damaging the polished surfaces.
- Unlike alluminium, Brass does not come with a hard-oxide layer from the shop, neither does it form one over time. It forms a patina, but that patina is not hard enough to scratch steel. Alluminium does scratch steel, partly due to the oxide layer, partly due to galling. Ditto mild steel.
- Brass is one of several so-called non-galling alloys, but alluminium is a strongly galling metal. That means that brass does not lead to wear and tear when it slides on a steel surface, whereas alluminium will tend to contaminate, even if not necessarily scratch (if you remove the oxide layer beforehand thoroughly), steel on contact.
And thats all, folks. If you need to scrape glue off of polished surfaces, a brass chisel might be just the tool for you.