Partial Boil or Full Boil

I do all grain but I do partial boils because I have a 5 gallon brew pot. The most I can boil is 3.5 gallons. I just bought another 5 gallon pot that I found real cheap and I was wondering if I could do a full boil using two pots. Just do one pot the way I always have, add the wort, my hops and irish moss and the other pot just boil the wort. Then combine them in the fermenter after they have been cooled. I can't think of a reason this wouldnt work, but I bet someone out there can poke holes in my theory. Thanks in advance for your help.

That's how a lot of people (largely apartment-dwellers like myself) do "full boils". However, rather than having one wort-only pot and one with hops, etc., I'd suggest splitting all additions evenly between the two. This is particularly important with IPAs and hop-forward beers, as hop utilization will change depending on the level of sugars (and other materials) in the boil. By splitting additions, you'll be keeping the ratios equal. It could still differ slightly from a true full-boil, but it's as close as some folks can get .

Yup doesnt have to be exact but the additions should be split.

What kind of volume loss have you experienced using two pots? I want to have a 5.25 gallon batch so do you think 6.5 gallons should do the trick?

Volume loss will vary depending on how vigorous a boil you get (dependent on burner type--e.g., gas, electric, IBU output, etc) as well as the shape of the pot (wider pots will lose more). That said, I usually start in the vicinity of 7-7.5 gallons and come down to around 5.5 with my own setup on a standard 60-minute boil. As a gut feeling, I'd go closer to 6.75 gallons if you're aiming for 5.25, but it'll certainly vary.

If you really want to dial it in, it might be worth doing a quick calibration test. Add 2 gallons to one of the pots (I'm assuming they're identical, or mostly so), boil for 60 minutes, and measure how much remains. That should let you know how much boiloff to expect for each pot.

Thanks guys. I am excited for my first full boil.