Question: We have owned a Franco Belge coal stove over 15 years. This year we have had some problems. After looking at many possiblities we noticed that when starting the fire at the beginning of the season smoke was coming out around one spot on the heat exchanger. It seems the heat exchanger is bolted on and cemented. The cement seems cracked and letting the smoke escape. We cannot run the stove like this. Do we need to remove all the bolts and heat exchanger and re-cement? After all this time we probably can't remove the bolts. Can we just add some calking or cement around the edges? What is the cement called? Where can we purchase it? Is it safe for us to do. Answer: Chances are that you need to do two or three of the steps below: 1. Clean all the fly ash from the heat exchanges, stove pipe elbows and other areas that it might accumulate. This ash will block the draft and make the stove smoke. 2. Re-cement any joints. It can be done either from the inside or outside if you cannot take the seams apart. Clean and dampen to area before applying the new cement. Use black furnace cement which is available from most stove and hardware shops. 3. Check the stovepipe and stove seams for integrity and tightness.