Getting ready for a BP hunt and have been doing 6 mile hikes with 40# packs. The bottom of my feet get really hot, which can and will cause blisters. I am wearing smartwool socks and Danner hiking boots.

Is there a powder or something to put into the boot to reduce the heat or something else that helps?

Maybe just time and miles will toughen the soles more.

Toughening your feet is certainly part of the process, but what are you using for boot insoles? Are your feet slipping around and creating friction, or are you just using too much insulation?

Are you using a liner sock?

Bushcraft; I have recently been diagnosed with Plantar Fasciitis and was able to get a foot mold and custom made inserts. The inserts have a leather type top covering, so I am not certain if I am slipping around causing friction or not. The Danner shoes are actually a regular fit and I have started wearing wide now that I am getting older (55). As far as the insulation, that may be it. The Danners are the GTX waterproof type and they do not breath and my smartwool socks are quite damp/wet at the hike's end. It's still very hot here in North Carolina.

Kcnboise; I am not wearing a liner. I never have, but could be something I need to do. What type of liner would be best(material/brand)? Is the liner just intended to wear with wool socks?

Try a liner. I cannot wear any of my boots without liners, my feet sweat, are super hot and my socks get soaked. With liners I don't seem to have any of those problems. I have also gone away from smartwool socks but thats another story and I dont want to get into that with the die hard smartwool fans.

My feet sweat badly. I also have Plantar Facilitis.

I had insoles made by the podiatrist. However, while I wear them to work in my street shoes, I don't wear them in my hiking boots. Not saying it's the wrong thing to do, I just don't.
Like yours, the surface of my orthotic insoles is not breathable and I believe they would be very hot. They're hot in my street shoes. However, like I said, I've never worn them in my hiking boots.
I sometimes wear a very thin polypro sock then a Merino wool hiking weight sock. Sometimes I wear just the Merino.

I can't tell a lot of difference, my socks get wet regardless, however, I'd give a nod toward the liner sock option as being a little more comfortable to my feet. Can't say why, just that my feet seem to feel better, a little less tired with the liner.

Maybe try a hike without your custom orthotic insoles just to see if you have the same issues. An insole that is a little more breathable may just solve your problem. Then just wear your orthotic insoles in your everyday street shoes.

My feet haven't been too particular about type of liner sock, as long as it's not cotton or wool. I've used men's nylon dress socks, silk, polyester, and coolmax; all worked. You want the liner form fitting on your foot so that it does the sliding on your wool sock, instead of your skin sliding on the liner. Don't get them so tight that they cut off circulation, though; especially the tops on your calves.

Liner plus a good quality deodorant on your feet.

You mean anti-perspirant? Deodorants don't have the aluminum salts that stop sweat. That's what I've always used on my feet, anti-p that is.

Now you know why I don't use goretex boots unless it below 45F most of the time.

Take a knee; I also have wondered about the goretex lining and sweating feet. Its got to be a lot hotter, even if they claim they breath and wick away moisture.

When I ordered my Danner Pronghorns I got the uninsulated ones just for that reason. They are still too hot if its not cold weather.

Obviously everyone is different, but I have no problems with gortex boots. I'm wearing Crispi Kanada rated to 0F in 100F texas weather. Without liners it sucks, with liners is not bad. The type of liner makes a big difference. Best one I've found is Inijin performance sock liners. They are a god send.

http://www.amazon.com/gp/aw/d/B003WWKXLE/ref=aw_d_detail?pd=1&qid=1345411459&sr=8-1

Are you a big guy? The location you talk about getting hot makes me think so, but I've been wrong before