I'm not trying to knock you or him, but since this is a welding thread and I'm a pipe welder by trade, I feel it needs addressed. So many people throw around the term "certified welder". The term is a giant misnomer, unfortunately. The big dog on the global stage is the American Welding Society. It's effectively the last word on welding, weld engineering, etc. Essentially, they set the standards for certification. The ironworkers union uses welding tests developed and administered by the AWS. The UA (pipe fitters union) has it's own testing, under the oversight of the AWS, which will be fully handled by AWS from 2018 onward. Boilermakers have a similar system. These certifications are numbered, which corresponds with the welding process and specifications for position, root, filler, cap, etc. These are nationally recognized, transferrable certifications that must be maintained with continuity tracking and renewal via weld test and send off. They get x-ray and deformation testing to insure that only acceptable welds are being made before a person is deemed to have completed the requirements for certification. This falls back to a lot of ASME codes and what not, but that's a whole different story.
Anyhow, when a person tells you they're a "certified welder", ask them what certificates they have. If they only mention a process, it's only a shop certification which is virtually meaningless in industry where welds count. If they say something like "I've got UA-21, 41, and 63." you're dealing with someone that actually has globally recognized training.
I used Kreem years ago on a 1984 Honda XR-80. Never noticed any separation, but that was damn near 20 years ago to be honest. I've had good luck with Tractor Supply's tractor paint and hardener. In particular, I've used their New Holland yellow for the inside of jerry cans. I haven't had any issue.