I keep trying slightly different routines with the ATP-641 with some spectacular failures, a couple times it would have been better not to have used it. Never did find any real instructions but there are days I am Google impaired so something may be out there. 1) The steel must be clean enough you would use it for surgery 2) Was the heat gun and warming the steel up to the point I could not hold it plus a little. 3) Stir the compound for a couple of minutes so it is very well mixed 4) dip the blade into the compound then hang to dry. 5) Subsequent coats can be applied with brush so they are nice and thin, heat the blade very well before each application. Top blade (T1 steel) was dipped twice and ATP blew off in furnace even with a preheat cycle of 100F then 250F for 15 minutes before ramping up to 1500F then 2275F. When dipped blade was room temperature both times with three days between coats. You will notice the top blade has spent some time on the belt sander, took ten minutes to get the decarb cleaned to this point and some still remains. Crack like lines are were the ATP failed and surface was damaged from exposure to the atmosphere. at about Rockwell 64-65 this little guy should be an adventure each time it needs sharpening, the chisels I don't mind as they will see a hone and compound primarily but a knife may be less fun. Lower blade 1084 that was dipped then remaining layers brushed on with a foam brush with lots of heat before each layer. All the compound fell off or brushed off easily and the surface even in the black areas is still at the 400 grit level and with any luck the extra five layers on the spine formed a nice hamon.
Hi John, I don't know how ATP-641 compares to Z1100. This video on YouTube is basically what I follow. I don't think the compound is meant for low heat. Dan
Now that stuff is several times better, the ATP is a clay and water mix and needs more care in application
Notice that they didn't stick it in the oven until it was past 600°C? The datasheet on Condursal states its range is from 600 to 1100°C. Weird I know, but I wonder if ATP-641 has similar characteristics.
Never found anything other than coat the blade and let dry however the old squirrel cage was going full speed yesterday and the idea that if the clay hardens on the outside it may trap moisture. This trapped moisture would expand and blow off the clay which happened several times even after a week of sitting and adding in moisture cook off steps to the heat treating cycle. The latest knife I would call 95% successful since I had two tiny spots of decarb but the idea of heating the blade caused two things to happen. Clay dried from the steel outward and was hot enough the moisture was evaporating as soon as the clay touched the blade. My thought is this gave me a zero percent moisture coating and why this cycle went 10 times better than anything previous.
I contacted the manufacturer of the Condursal Z1100 and the recommend preheating to 600C then putting the knife in the furnace. Starting from cold the paint will bake on the knife and have to be ground off potentially as it can leave a black coating that is difficult to remove.
Old post but the ATP-641 and others like it have a minimum and maximum temperature listed, 1000-2400F in this case.
