I have a shot at multiple small aluminum repair jobs this summer if I am mobile. I decided that I should consider adding a Hi Frequency box to my 1980s Lincoln Weldn'Power AC/DC 225 (no CV Tap/MIG capability). I found an old Lincoln Hi Freq Box on Ebay that would likely work, and contacted Jeff Noland at HTP. Jeff has always been a reliable resource for consumables and torch replacements even though I don't own a HTP welder. We swapped some emails, he offered some ideas, then suggested I contact Lincoln Service Tech Dept to confirm it would all work. Yet another good experience. They confirmed Jeffs ideas would work well. Then they offered that while it would work. I should be aware that not only would it not pulse. But, it wouldn't have Balance control. I knew about the pulse. I hadn't considered that it wouldn't give me Balance. Balance control is critical for Aluminum. As it provides control over the cleaning and welding phases of the sine waves. I've decided not to make the investment. Instead I'll be saving for a used mobile unit with TIG and MIG. This was a good learning adventure, and am once again in debt to HTP (Jeff) and Lincoln.