Overheard a foreman say you should always preheat a 4 inch pipe to 400 degrees before welding

I always just winged it with the temp until I saw him check it with a temp stick and the weld came out way cleaner, has anyone else found a specific temp that works best for different pipe sizes?

3 comments

3 Comments

betty_palmer1mo ago

Yeah @luna891 nailed it, temp sticks are the way to go. I blew a root pass on a 4 incher once cuz I eyeballed it, been using a stick ever since and it's night and day.

luna8911mo agoMost Upvoted

Get a temp stick and don't guess. I saw a guy blow a root pass on a 6 inch schedule 40 because he thought it was hot enough and it wasn't. For 2-4 inch pipe, I run 350-400 and it lays in nice. Bigger stuff like 8 inch or above I bump it up to 450-500 because the mass sucks the heat out faster. You can usually feel it when the pipe starts to sweat a little before it really gets going. A laser temp gun works too but temp sticks are cheap and never lie.

jamie_smith1mo ago

Learned that lesson the hard way myself once. Was running some 3 inch stainless and thought I had the heat dialed in, turned out I was about 50 degrees low and the whole root pass looked like a bird's nest. Now I just keep a pack of temp sticks in my lid pocket, saves me the embarrassment.