Welding a Glass Lined Pressure Vessel

After the terrible tragedy at the shipyard :), I had to get to work somewhere. I picked up a few inspection jobs around the area and gave a few welder tests but needed a little more. I called a sister company of a company I provided CWI inspection for and asked if they had any welding jobs coming up. They said they did and I went to their shop and tested. The welding was all going to be 7024 and 7018. I tested with 7018 both on a 3G plate and a 6G pipe. It all went good.

The job itself wasn’t too bad. It was a top access pressure vessel about 12′ in diameter and probably about 15-18 feet tall. It was lined with a thin layer of glass that had chipped off in various places over the years. I think it was built around 1993. There was a mixer inside and the ladder that made access to some of the worn spots a little tough.

The owner did a great job of keeping it ventilated and was very safety conscious. One person in our crew decided to test the sharpness of a welding rod can on a pair of leather gloves. He should have done it WITHOUT his hand in them though as the blood caused quite a stir!

We were running 1/8″ to 3/16″ diameter electrodes and basically just “pad welding”. No preheat was required and the welding was easy. The only thing that was “bad” about the glass lined vessel was the fact that as you welded, more glass chipped off making an even larger “exposed” area. The small pieces of glass flying around were a bit of a safety concern. Eye protection was a must. Even when not welding, the glass would sometimes pop off in small pieces.

The company has been doing this specific repair for a few years and closely monitors the corrosion rate. The minimum design wall thickness was around .6 inches. The as-built thickness was 1-1/2″ so there was plenty left but the company liked to err on the safe side. No problems on my end. It just means work and $$ and taking precautions when it comes to hot corrosive chemicals is never a bad idea.

We worked from 07:00 till 21:00 for 3 days and finished up about 5:30 on the 4th day. It was good work, paid the bills, let me weld some, and allowed me to work with some new people. As a person almost 54 years old, I can say that climbing that ladder and trying to get out the small manway after a few trips in and out is rough on you if you have been a little on the sedentary side for a few years.


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