Also See: Soaking Saw Tips in Oven Cleaner

First, there are thousands of grades of carbide so discussing the properties of carbide is like discussing the properties of wood. Therefore, I suppose, everybody is right. 

Freud is an excellent organization with a fine reputation. If they say that caustic solutions damage their blades then I believe them. However that is not what my research has shown on other grades of carbide. It is not what my research has shown of Freud blades either. I think there may be a bit of an effect but too small to be of practical concern. See the SEM argument above.

I think maybe this whole caustic thing started with my research. I have two patents (5,624,626 and 6,322,871) where we use a caustic solution to change etch the surface of tungsten carbide and related materials so we can braze them. This gets changed on the Internet over and over. 

However the caustic has little or no effect on the carbide by itself. When you run an electric current through the material, as in EDM or in electro etching, the caustic solution serves as a medium to carry the current and the current acts on the difference in electrical susceptibility of the tungsten carbide and the cobalt to remove material. In order to make any practical difference in the surface of the carbide you need an extremely strong caustic solution and a lot of current for a long time.

The whole point of our research was to develop saw tips that stayed sharper much longer than carbide. To do this we wanted materials that resisted chemical attack of any kind. (See Forintek (University of British Columbia) report) Our saw blades cut green cedar, MDF, OSB and everything else you can think of. 

Chemical attack is one of twelve factors we assess in building superior saw blades. Email me for a complete list. We are working on getting it on the web. It is in my book Building Superior Brazed Tools. 

The handbook of Physics and Chemistry shows Cobalt as being soluble only in acid only. Even then an acid attack will create an inert surface on the cobalt that will slow or prevent any further attack. 

I do not know what braze alloy Freud uses. Common braze alloys are about half silver and about a quarter copper and zinc with maybe a little nickel or tin or manganese. (AWS Bag-3, 7, 22, 24, etc.) Chemical attack on copper or cobalt as a pure metal is different than a chemical attack on a metal alloy. Iron corrodes differently than steel which corrodes differently than stainless steel. 

Much of this argument is similar to arguing about whether you can lose weight by getting your hair cut. You can but it is not practically important. 

Again I do not know about Freud blades but most blades are not significantly affected by any commercial chemical cleaner. In our test we found that BBG grill cleaner from a janitorial supply store was cheapest and worked best. Simple Green was good. 

Anyway, that’s what my research shows. If you are interested I have primary sources for this. 

Can cleaners hurt braze alloy?

When we want to remove braze alloy we use a combination of acids such as 1/3 hydrochloric acid, 1/3 Sulfuric acid and1/3 water.   This works but is horribly strong.  

We have soaked braze alloy in oven cleaner for a week with no discernible damage to the braze alloy.