Received a new to me product that I have heard good things about and this page will cover the use of Condursal Z1100
While this product is expensive initially a quart will provide oxidization protection for 100 plus knives and in the end will be cheaper than using tool wrap (stainless foil) on stainless steel knives.
link to product page: http://www.canadianknife.com/store/p7/Condursal_Z1100.html
This post will be showing my second batch of knives using CPM 154 stainless steel. First batch was of 6 knives in AEB-L with perfect results.
Benefit is this anti-scaling paint will provide protection of both carbon steels and stainless steels from atmospheric oxidization and that means no need to remove decarburized layer after heat treating. The part I appreciate the most is less time spent sanding on a hardened blade and being able to finish 90% of the sanding on a blade in the annealed state.
Cleaning of the knife prior to heat treating
The steel must be very clean which involves removing any oil, grease and finger oils. Anything left on the blade with affect the knife and can prevent the Condursal product from achieving complete coverage. I wash with soap and water first then wipe down with alcohol, if heavily oiled from drilling holes I will give the blade a wipe down with acetone first.
Condursal can be applied by dipping or brushing and only needs to be a 15um thick layer too be effective. Secondary coating attempts can result in the product falling off during the heating process.
This is a CPM 154 blade given a single coating of the Condursal Z1100. Blade finish for this one is only 400 grit.
Into the furnace
Condursal has a minimum temperature that it can be used at which is 600C or 1112F. For my heat treating schedules on stainless steel I used the preheat temperature and insert the knives when this is reached, typically in the 1200F to 1500F range for stainless steels.
With carbon steels I will be revising the heat treating schedules to include a step for 1200F that will be 5 minutes long. This will meet the requirements of the Condursal and should be long enough for the furnace temperature to recover after insert a couple of knives.
Two knives put through their paces, should have done a better job on cleaning since it looks like something was on the surface and gave the blades a interesting color pattern.
Top one lightly sanded after quenching and the coating came off easily. From here temper as per normal, coating not needed or functional at a 400-500F temper range.
Latest picture of polishing in progress, if the color was robust and actually cooked on I would have kept it but a light touch with 800 grit removed it completely.
The most significant advantage I can think of with the Condursal product is that it can be used just as easily with air quenching with plates and compressed air or a oil quench. In either case no fussing with tool wrap envelopes or risking having the foil stick to the blade and causing warpage, especially on very thin sections like fillet knives.