Travis.

Your inspection experience would make the learning curve in welding a bit shorter I expect.

That being said... It will take Years of welding experience and fortunate circumstances for you to out earn your inspection salary.   Maybe your a hands on kind of guy and it's just the work that you love...  But I would not go too far into the move before your SURE you love welding.

Entry level welders are making between 9-14 an hour in post places these days....  If you can take that kind of paycut until you get your years of seasoning than go for it!  There are plenty of folks here that will get in your corner and help with technical questions.

best place is to look towards a local community college or vocational school, most have flexible enough scheduling that you can continue to take night classes or what not while you still work. picking up at the barebones a certificate or A.A in welding will usually help you get a foot in the door.
As mentioned though beginning welders never get a ticket to big bucks without usually a few years of paying their dues or working their way up the ladder. It's definitely not a ticket to the gravy train right away.

Depending on your experience interest etc, have you thought about making the jump to CWI/ NDT level 2 or expand your skill set in the quality world?  I'm not sure where you're at but at the shops I've been in our lead quality guys were making on par if not more than lead welders. Then again this wasn't independent contract or field work.

I noticed from your profile you are in Arizona. I do not know your level of experience, but if you have 4-6 years in the NDT industry, you should be making fairly decent wages.
However, you need to move or be willing to travel to where the $$ is.
Unless you have your own welding rig working in Phoenix/Tucson as a production welder is not going to be very lucrative. As a rig welder, it will take 3-5 years to become proficient in the skills needed to make decent coin. If you are going to run around welding carports burglar bars and fences you will be in the 40 -50 dollar range. That is not too bad, but you have to hustle to string together 10 hour days. Putting together a decent rig will run you $20 to 30K
Then you have all the expenses to buy, outfit and operate the rig.
Taking that same money and getting a CWI, and NACE at least level 2 if not peer review if qualified can put you in the $ 40 to 50 per hour range, IF you are willing to travel. If you have some drawing experience working as a helper for a API 510, 570 or 653 inspection company and gaining the experience necessary to qualify for the API certifications can put you in the 6 figure range.
Again, depending on your level of industry experience, you are in a industry where you can make as good $$ as welders, and you can inspect a lot longer than you can weld.