Hot take: skip the preheat on a big patch job if you're short on time

Old timer told me to always preheat the base metal before welding a patch on a boiler tube. Tried it his way on a job in Detroit last month and spent an extra 45 minutes just getting the temp up, then the weld still cracked. Who else thinks preheat is overrated for smaller patches?

3 comments

3 Comments

the_richard1d ago

Tbh skip preheat on thin patches, just watch for chill cracks.

wesley1811d ago

Hear you on that, but its the same kind of shortcut that can bite you later, like skipping a step on a brake job to save five minutes. Good call from @the_richard on those thin patches, but consistent heat management usually saves you from chasing more cracks down the road. Ever had a small skip turn into a full redo the next day?

torres.grant20h ago

Get at it long enough and you realize skipping steps has a way of snowballing. I remember rushing a patch on a rusty trailer frame a few years back, figured the heat from welding would soak in fine. Next morning saw a hairline crack spiderwebbing from the edge, had to grind it all out and start over. @wesley181 is right, it's like half-assing a brake pad slap - you might get away with it for a day or two, but then the squealing starts and you're kicking yourself. Shortcuts save you time until they cost you double, whether it's a patch, a brake job, or even just rushing through sealing a cracked driveway.