I was pretty upset when I found out that my 12 year old Burnham V8 5-section boiler needed replacement due to corrosion in the flue passage above the water line. While in the process of making arrangements for replacement I thought I'd have some fun. All my life I'd been "Mr. Fixit" and this seemed like a good time to play. The Burnham V8 boiler has a vertical pinned flue passage. The perferation was in the rear flue towards the top so I had easy access.
The material selected to patch the holes must have good adhesion strength and have high heat tolerance. I found that JB Weld, a two part steel reinforced epoxy with a bond strength of 1800 psi and a heat tolerance of 550 deg F was worth a try. I applied the JB Weld to the hole near the top row of pins resulting in reduced water consumption, I went hunting for more holes which I found and patched. Water consumption went down some more. Still loosing water, I flooded the boiler and to my great dismay water was flowing out of the boiler into the flew-way about 2.5 inches down. The pins in the flue made these holes inaccessable. I thought this might be the end of the road for my "fun".
Thinking this over for a few days I stopped by Harbor Freight and picked up an angle grinder and proceded to cut those pins away to get access to those dam holes causing me so much grief. The grinder sliced through those pins like butter. The only problem was that I was only able to remove the first row of pins and I needed to remove 3 rows. I went out and got a 6" wheel which got me through the second row of pins. With one more row of pins to remove I needed a tool with a deeper reach. I found the the blades for oscillating multi tools have a 2.5" reach so I bought one with a metal cutting blade. I removed the third row of pins, flooded the boiler and could clearly see the leaking holes and had full access to them. I patched the entire leaking area with JB Weld with an embedded layer of fiberglass mesh for added strength. I let the patch cure for about 8 hours, flooded the boiler and Holy S. NO LEAKS!!!! I let it cure for 24 hours and fired up the boiler closely monitering the water level. The boiler has been running for a week with no perceptable water useage. And a visual inspection of the patch showed no deterioration.
I noticed that all the corrosive perforation occured in the top 2.5" of the flue-way which corresponds the the area of the boiler that is above the water line which is exposed to much higher temperatures than the area below the water line. It appears that elevated temperature is part of the cause of the corrosive perforation. Another cause might be chemical in nature either from the flue side or most likely the steam side. Removing the top 3 row of pins will lower the temperature of the boiler flue section which might be a good thing in this case.
It has been pointed out by members of this forum that this DIY fix is very dangerous however I wanted to document my little adventure for others to read. Should this patch fail wile the boiler is making steam, my whole basement could fill up with steam. Caveat Emptor!
First Attempt Before Pin Removal
Second Attempt After Pin Removal