Ah yes, any baby powder will work....it doesn't have to be Lavender scent. 
So anyway, for this tutorial, I'll be using one of the 1/100 HG Gundam Wing kit hands. They're generic, and are ugly with that nasty seam line down the back of the hand. Yeah, and I didn't do a clean cut when getting them out of the parts trees either. Now, you'll notice though how obvious that line is down the middle. You try painting over that and you'll find that the line will be made more visible. So yeah, we need to cover it up. Taking the two parts check out where the seam line would appear when the parts are assembled. 
Usually, it will be the areas that don't have a hollow portion as seen in the picture on the left. When you glue, make sure you're putting enough so that the glue will ooze out, but not so much that the entire tube empties out. Depending on your glue, it may dry pretty fast so make sure you have the parts already
to go for assembly. Otherwise, in your haste to get the parts together you may find yourself getting glue all over your hands and becoming distraught at the amount of skin being torn. Super glue should bond pretty easily, but still push the pieces together just to make sure. You should have 
something that looks like this. This part is now ready for sanding. What...where's where's the baby powder come in...you're asking. Actually, I'm going to show why just using super glue alone as a filler is a bad idea. And then repair the process. Depending on the super glue you have, it's possible that it won't sand very well. So what if it doesn't sand well? This is how you get misshapen pieces. The sanding you're doing is so the glue line is level with the plastic, thus eliminating the seam. However, if the glue doesn't sand as easily as the plastic, then the plastic will wear down faster and your piece will no longer have its original shape. That is bad! Normally, this is why you mix the powder in with the glue. The powder will alter the properties of the glue making it less brittle, and more easily sandable. However in the 
e
vent that there's still a hole you can still use some sort of powder/glue mixture. See, after sanding with only super glue it looks right, right? However if you 
put powder on top and it sticks, then you know there's still some gap of some sort. See? There's still somewhat of a gap on the lower portion of the back hand. Also, the area I messed up on when I cut the part from the tree is still very visible. Where the white powder is right now would show up when I paint the hand. That is bad, and is very very unprofessional looking. So then, this can still be remedied. No
w...Dump more powder on the hand and blow at it. If done right the powder in the crevice should remain while the excess flies off. Now apply the glue and mix it in with the powder. All righty...now sand the sucker.
So anyway, for this tutorial, I'll be using one of the 1/100 HG Gundam Wing kit hands. They're generic, and are ugly with that nasty seam line down the back of the hand. Yeah, and I didn't do a clean cut when getting them out of the parts trees either. Now, you'll notice though how obvious that line is down the middle. You try painting over that and you'll find that the line will be made more visible. So yeah, we need to cover it up. Taking the two parts check out where the seam line would appear when the parts are assembled. Usually, it will be the areas that don't have a hollow portion as seen in the picture on the left. When you glue, make sure you're putting enough so that the glue will ooze out, but not so much that the entire tube empties out. Depending on your glue, it may dry pretty fast so make sure you have the parts already to go for assembly. Otherwise, in your haste to get the parts together you may find yourself getting glue all over your hands and becoming distraught at the amount of skin being torn. Super glue should bond pretty easily, but still push the pieces together just to make sure. You should have something that looks like this. This part is now ready for sanding. What...where's where's the baby powder come in...you're asking. Actually, I'm going to show why just using super glue alone as a filler is a bad idea. And then repair the process. Depending on the super glue you have, it's possible that it won't sand very well. So what if it doesn't sand well? This is how you get misshapen pieces. The sanding you're doing is so the glue line is level with the plastic, thus eliminating the seam. However, if the glue doesn't sand as easily as the plastic, then the plastic will wear down faster and your piece will no longer have its original shape. That is bad! Normally, this is why you mix the powder in with the glue. The powder will alter the properties of the glue making it less brittle, and more easily sandable. However in the event that there's still a hole you can still use some sort of powder/glue mixture. See, after sanding with only super glue it looks right, right? However if you put powder on top and it sticks, then you know there's still some gap of some sort. See? There's still somewhat of a gap on the lower portion of the back hand. Also, the area I messed up on when I cut the part from the tree is still very visible. Where the white powder is right now would show up when I paint the hand. That is bad, and is very very unprofessional looking. So then, this can still be remedied. Now...Dump more powder on the hand and blow at it. If done right the powder in the crevice should remain while the excess flies off. Now apply the glue and mix it in with the powder. All righty...now sand the sucker.
Excellent. Now when you go about painting, that seam is gone brotha, and you now have a very nice looking hand.
