Scratch building/Molding your own figures?

It's a matter of practice and preference. Media available are

Duro, Fimo, AB putty, Apoxie Sculpt, Sculpey, Super Sculpey, Milliput (in various forms) and it really comes down to experimenting with what works best for you. Some figure sculptors will rough out the figure and then carve detail after its dry or will build up detail and work it soft beore the material dries/cures or is baked. With the availability of heads from companies like Mig and Hornet, the hard part of faces and heads is taken away and you can work on details with the body and pose.

My advice would be to pick up a good anatomy book for artists. This will help you with proportion and scale with your figures. There are  few sources for 1/35 scale and proportional cards that will give you a heads up on the height and proportions of your figure.

Get some workable wire for an armature and then buld up from there. Make a wire figure first to check your height, where the hips and shoulders are, the posing of the legs and arms and then build your sculpt around that.

If you dig around enough on the link that Al provided, you'll find plenty of material there to help you along. There are several sbs in the archives of that forum that you should get a good idea of what your in for.

With practice comes success so don't expect to come out with a masterpiece off the starting line. Build your techniques as you practice. A good starting point is figure conversion. This will help you build the skills to tackle a sculpt.Matching fabric drape or re positioning limbs and bodies is a great way to work out the kinks. After all if you can't make a seamless conversion, you won't have a great success sculpting.

Good luck

Musat figured out that 1/24th scale easychair build and moved up to scupting figures, eh? 

Nah Its just my mind goes on tangents with my projects.  I felt like scratch building, the project for that chair is anything but, same with my kubelwagen wip and my tank kits.  This is entirley scratch building and moding.

I am using figures as a base for mine, its just I didnt know what kind of products to use to bulk them up, or how to modify things like arm and leg positions to make them how I want them appart from sculpting my own.

I was just pullin' yer leg a bit.... I modify figure poses by cutting heads. arms and legs at the joints, either partially or all the way through, depending on the degree of "bend"...  If I cut all the way, I drill a hole in each part and insert a piece wire with the desired angle, then putty in the joint to fill it back out...  Heads always get a wire "neck" and I fill all the joints I do with plain ol' Testor's tube putty.. Scuplting folds and such, I just use various shapes of tools, paintbrush handles, drill bits, knife, etc, to make soft or sharp folds, creases, or to smooth skin... 

Partial cuts are usually wedge-shaped notches at the joint, then heat is applied with a candle to make the bend and to keep the arm or leg from "going spaghetti" on me...

I agree with Hans; you're better off modifying existing figures than trying to scratchbuild your own right from the git-go.