List of "Apparatus" you will need
Pin vice drill
guitar strings (Bass guitar strings work better since theyre thicker also this is optional)
green stuff or some type of epoxy putty.
something thin and sharp tipped ( i used a sewing needle)
Ok all ive done here in this pic to make the big bullet hole is drill a hole into the armour jsut deep enough so it looks black at the bottem of the hole then ive stuck the craft knife into it and pulled it at the sides to make it look cracked.
For the big puss balls on his leg i drilled out 3 holes grouped close together, then with the craft knife cut the part in the middle of the 3 holes out then rolled my modelling putty into balls, start with big balls and keep getting smaller till u get the look you want.
And finally for the respirator tube i used the guitar string, i used the smallest string on my bass guitar since it wasnt too thick and not too thin. I drilled two holes for where i wished to attach each side of the string then bent it into place added a little super glue to each end to hold it in.
for this one ive used pretty much the same techniques for the big hole, for his leg i just drilled lots of holes grouped together and cut out the middle parts but instead of filling it with putty i just used the craft knife to make cracks the same way i did with the bullet hole and for his shoulder pad i put a hole at the end of the long crack on in the middle and one at the bottem then used the knife to join the holes together and then added cracks the same as the bullet holes.
now heres where it gets intresting
ok before u start the burst open nasty belly u need to have an unbuilt marine. you take the torso part of the marine and the front section u need to cut out the part under where the ribs would be and then u can build the marine as normal but dont add the arms since that will make it harder to sculpt the belly, when ur ready take ball of putty roughly the size of the belly u want, attach it then with the sewing needle, make sure its wet so the putty doesnt stick to it and ruin it, start digging a hole out of the putty this is where you'll put the guts that are hanging out, after that leave the putty around 5 mins to cure and then start rolling tiny sausage shapes small enough to fit into the hole you can also try experiment with differant shapes if u want or even have tentacles bursting out from it if thats ur thing. but most likely your going to need to stick them into the hole using the sewing needle then after you've filled the hole
ahem... you can begin on sculpting details into the bellys outside i stabbed 3 circles in the shape of the nurgle symbol on and spinned the needle around a bit to give them a swollen look and i also added some veins, and puss balls but again you can experiment here and get whatever tickles you pickle here, it will take some practice to get it right and you'll probly mess up the first few times but the end results are worth it ;)
(ill add a painting tut later)
Thats all folks!