Al,
I feel that the 8" pipe passed because we did side bends and got lucky. The 8" would of opened up like the 3" if it was bent in the same way. The joint of these two procedures follows Figure 3.30 for tubular groove welds in D1.2(2003)and has no gap. I would never run a gap on a aluminum full penn weld because the penn you end up with is not as good as when you have a tight butt. So if the metal was not cleaned properly would I still get hydrogen porosity? Well, here is a little run down of our cleaning procedure. The coupons are machined to get rid of the high low and the groove type put on, then they get stainless steel wire hand brushed, then we use ARCAIR Protex ALLclean aluminum cleaner with a good scrub, that gets washed off with alcohol and dried, then we tack up and weld.
Do you think if some of the acid residue was not all the way cleaned off it would cause my problem? I'm just curious as to why this happens because like I said before this isn't the first time I've seen this. The last time I saw it I know for sure it wasn't because I had a gap (because I never use one) or lack of cleaning and we never found out what caused it. Maybe it's acid residue, or maybe the pipe had condensate on it while it was coming up to temp. I didn't see any while our guys was putting the root in, but ya never know. Maybe I'll take the chill out of the coupon this time just as a precautionary measure. Al, I appreciate all the help you've been giving and I will get to the bottom of this. I hope.;-)