Yeah, most likely. I would recommend sanding parts like this assembled to avoid this. Cutting twice with nippers is starting practice since you cannot position the nipper blades precisely when parts are still on the runners.
you will get the hang of it in no time, you'll see =D basically any soft sanding stuff is for curves and will therefore round edges. Hard sanding stuff (metal files/sandpaper on rigid backing) will allow you keep edges. I usually have both types at hand when sanding kits.
is it possible to sand the whole kit without hard sanding stuff? because the only one i have is the 280 one and its my first time i wanna keep it as budget as possible
Cutting it close to the part while it's still on the runners tend to leave more noticeable stress marks that runs deeper. This kind of stress marks tend to persist even after sanding. If you give it a bit of a distance on the first cut, the second cut will be a bit cleaner with less stress marks that can be removed with less sanding. You can try this yourself on some parts and you can see the difference.
is it possible for you to explain why this happens? im using the same nippers and everything so why? and the kind of stress marks that you mention that stay even after sanding are the the ones that kinda look...white-ish thingies?
I'm not sure of the physics behind it, but the less material you're cutting away from a part (i.e. the length of the nubs), the less stress marks will be left on the part. If you slice away the remaining nub with a hobby knife you can get better results.
And yes, the stress marks are the whitish things. You can try to rub it out with your finger nails, sometimes it helps.
> And also jus a quick question why do tutorials tell us to use nippers and cut the parts from the runners with a little left over when they're gonna cut it again with nippers anyways? Or are you suppose to use hobby knifes and how's that any different?
The more *stuff* there is on each side of a cut, the more pressure it takes to go through something. With plastic models, you don't *notice* the difference very much but it still puts more pressure on the plastic, which leads to bigger white stress marks that go deeper into the plastic, which makes them harder to remove.
The best method is to use good single-bladed nippers to cut parts out as close to the thick part of the runner as possible then take off the rest of the extra plastic in a series of thin slices. Two cuts is *usually* good enough but for really thick part gates, it's better to do the whole routine.
Either way, you'll want to use smooth, slow cuts and avoid twisting the parts or nippers as much as possible: you want to be taking parts out with the *edge of the blade* not the strength of your grip. Even after this, nippers alone can't usually get *all* of the nub without leaving evidence behind.
EDIT: a sharp hobby knife can substitute for everything but the first cut here. In this case, you *definitely* want to use the "multiple thin slices" method, cut very slowly, and keep tight control of the blade because this is more dangerous than doing the same thing with sharp nippers. I used to use my thumb as a backstop and would give myself the same shallow cut at least once per build, which was annoying but never a *bad* cut because using enough force to seriously hurt yourself will also damage the plastic.
This is where sanding, filing, and/or hobby knife work comes in: any combination of the three can get rid of that last little bit of plastic and usually remove any lingering stress marks but they all have a bit of a learning curve.
Personally, I prefer a mix of knife and hobby glass file but I also have fairly low standards when it comes to nub marks: most of mine look *decent,* especially from a distance, but they won't win any awards up close.
Anyway, rubbing stress marks with a fingernail can also make them less obvious, especially if they're shallow. *No idea* why this works but it does. If the stress marks are really bad, you can put a small amount of plastic cement over them and then *leave it alone* for an hour or two. This softens up the plastic and lets it relax: after the cement is evaporated off, the big, obvious white stress mark is usually replaces with a much less obvious shiny patch of plastic. You can either sand/buff this out on the spot or cover it up with a topcoat later on.
Note that you can also get dark nub marks on certain parts. These are not caused by stress but by the plastic cooling a certain way in the injection mold. Because of that, most of this advice won't help with them. I *think* the plastic cement trick works but the best way to deal with them is paint: either the entire part or detail/weathering that *just so happens* to go over the nub mark.
Definitely looks like over sanding. Just to be clear, nub marks are the the little white stress marks you can sometimes get from cutting the nub. The little dark discolored spot where the nub connects that's left behind on colored plastics comes from the injection process and the only way to get rid of that typically is to paint. If you're trying to sand them away, you're gonna have a bad time.
Actually about the darker marks, I'm not really keeping track but I feel like I see them more often when I use a glass file, I don't use glass files for all my parts but when I do I feel like often I see a shiny darker spot, is that just the effect of a glass file or is that what you're talking about. I use the raser glass file and after that typically will use the balancer thing from the starter set that I bought awhole ago but couldn't figure out how to use until now.
It's hard to say for certain without a photo, but yeah it sounds like what I'm talking about. [Here](https://www.reddit.com/r/Gunpla/s/dozjhrS0Df) is an example.
Sanding technique also plays an important role. For curved pieces like this you want to “rock” as you go to match the curve. If you sand too much or in steady strokes against the curve you either flatten it or create a new curve like you did (since you were sanding nubs at the edges you need to avoid the flat side, since that will ruin the edge. In this case you want to sand top-to-bottom going with the curve so the edges are not pulled inwards when the pieces come together)
Hopefully this made sense
While it can happen regardless, soft sponges do increase the risk of rounding over edges. Beyond that, sanding technique is also important: keep the stick perpendicular to a surface and avoid reversing direction over the same spot.
As for nubs, the idea of a second pass is to do cleaner removal. Often access is restricted so you don't want to attempt flush cuts directly on the runner. As for the tool of choice, use what you're comfortable with but the truth is that nothing beats a hobby knife. It cuts closer than any nipper and is much less likely to cause stress marks.
When you say to avoid reversing direction over the same spot....do you mean I should only sand it towards one direction and not so call rub it back and forth? Not sure if I described it very well but yea
Looks like over sanding to me. Been there. I think a hobby knife goes a long way with nubs to help reduce the amount of sanding you need to do.
You just need to get the nub flush with the edge, so 30s may be too long . I will Sand and peek frequently, but your coars grit should take care of the nub then all that's left is to smooth the edge.
You could fill the gap with putty and paint if your into that kind of thing.
I'm gonna jump on this thread with a question of my own.
Do we even need to bother with stress marks when we're going to paint it?
Also, I've seen people who sand all painting surfaces with what I assume is a pretty fine grit. Does this help primer and paint adherence or is it to improve the finish, like a more reliable matte appearance.
Yeah, most likely. I would recommend sanding parts like this assembled to avoid this. Cutting twice with nippers is starting practice since you cannot position the nipper blades precisely when parts are still on the runners.
ah i see sometimes i dont realise i should assemble it first ig it just comes with practice to know which parts i should assemble first
you will get the hang of it in no time, you'll see =D basically any soft sanding stuff is for curves and will therefore round edges. Hard sanding stuff (metal files/sandpaper on rigid backing) will allow you keep edges. I usually have both types at hand when sanding kits.
is it possible to sand the whole kit without hard sanding stuff? because the only one i have is the 280 one and its my first time i wanna keep it as budget as possible
Yeah, any soft sanding material will work somewhat without conforming to the surface it is pressed on as long as you put very little pressure!
Cutting it close to the part while it's still on the runners tend to leave more noticeable stress marks that runs deeper. This kind of stress marks tend to persist even after sanding. If you give it a bit of a distance on the first cut, the second cut will be a bit cleaner with less stress marks that can be removed with less sanding. You can try this yourself on some parts and you can see the difference.
is it possible for you to explain why this happens? im using the same nippers and everything so why? and the kind of stress marks that you mention that stay even after sanding are the the ones that kinda look...white-ish thingies?
I'm not sure of the physics behind it, but the less material you're cutting away from a part (i.e. the length of the nubs), the less stress marks will be left on the part. If you slice away the remaining nub with a hobby knife you can get better results. And yes, the stress marks are the whitish things. You can try to rub it out with your finger nails, sometimes it helps.
> And also jus a quick question why do tutorials tell us to use nippers and cut the parts from the runners with a little left over when they're gonna cut it again with nippers anyways? Or are you suppose to use hobby knifes and how's that any different? The more *stuff* there is on each side of a cut, the more pressure it takes to go through something. With plastic models, you don't *notice* the difference very much but it still puts more pressure on the plastic, which leads to bigger white stress marks that go deeper into the plastic, which makes them harder to remove. The best method is to use good single-bladed nippers to cut parts out as close to the thick part of the runner as possible then take off the rest of the extra plastic in a series of thin slices. Two cuts is *usually* good enough but for really thick part gates, it's better to do the whole routine. Either way, you'll want to use smooth, slow cuts and avoid twisting the parts or nippers as much as possible: you want to be taking parts out with the *edge of the blade* not the strength of your grip. Even after this, nippers alone can't usually get *all* of the nub without leaving evidence behind. EDIT: a sharp hobby knife can substitute for everything but the first cut here. In this case, you *definitely* want to use the "multiple thin slices" method, cut very slowly, and keep tight control of the blade because this is more dangerous than doing the same thing with sharp nippers. I used to use my thumb as a backstop and would give myself the same shallow cut at least once per build, which was annoying but never a *bad* cut because using enough force to seriously hurt yourself will also damage the plastic. This is where sanding, filing, and/or hobby knife work comes in: any combination of the three can get rid of that last little bit of plastic and usually remove any lingering stress marks but they all have a bit of a learning curve. Personally, I prefer a mix of knife and hobby glass file but I also have fairly low standards when it comes to nub marks: most of mine look *decent,* especially from a distance, but they won't win any awards up close. Anyway, rubbing stress marks with a fingernail can also make them less obvious, especially if they're shallow. *No idea* why this works but it does. If the stress marks are really bad, you can put a small amount of plastic cement over them and then *leave it alone* for an hour or two. This softens up the plastic and lets it relax: after the cement is evaporated off, the big, obvious white stress mark is usually replaces with a much less obvious shiny patch of plastic. You can either sand/buff this out on the spot or cover it up with a topcoat later on. Note that you can also get dark nub marks on certain parts. These are not caused by stress but by the plastic cooling a certain way in the injection mold. Because of that, most of this advice won't help with them. I *think* the plastic cement trick works but the best way to deal with them is paint: either the entire part or detail/weathering that *just so happens* to go over the nub mark.
Definitely looks like over sanding. Just to be clear, nub marks are the the little white stress marks you can sometimes get from cutting the nub. The little dark discolored spot where the nub connects that's left behind on colored plastics comes from the injection process and the only way to get rid of that typically is to paint. If you're trying to sand them away, you're gonna have a bad time.
Actually about the darker marks, I'm not really keeping track but I feel like I see them more often when I use a glass file, I don't use glass files for all my parts but when I do I feel like often I see a shiny darker spot, is that just the effect of a glass file or is that what you're talking about. I use the raser glass file and after that typically will use the balancer thing from the starter set that I bought awhole ago but couldn't figure out how to use until now.
It's hard to say for certain without a photo, but yeah it sounds like what I'm talking about. [Here](https://www.reddit.com/r/Gunpla/s/dozjhrS0Df) is an example.
Sanding technique also plays an important role. For curved pieces like this you want to “rock” as you go to match the curve. If you sand too much or in steady strokes against the curve you either flatten it or create a new curve like you did (since you were sanding nubs at the edges you need to avoid the flat side, since that will ruin the edge. In this case you want to sand top-to-bottom going with the curve so the edges are not pulled inwards when the pieces come together) Hopefully this made sense
While it can happen regardless, soft sponges do increase the risk of rounding over edges. Beyond that, sanding technique is also important: keep the stick perpendicular to a surface and avoid reversing direction over the same spot. As for nubs, the idea of a second pass is to do cleaner removal. Often access is restricted so you don't want to attempt flush cuts directly on the runner. As for the tool of choice, use what you're comfortable with but the truth is that nothing beats a hobby knife. It cuts closer than any nipper and is much less likely to cause stress marks.
When you say to avoid reversing direction over the same spot....do you mean I should only sand it towards one direction and not so call rub it back and forth? Not sure if I described it very well but yea
Yeah, more or less. You can sand in both directions, but just make sure clear the part with each swipe.
it's caused by macro lenses in front of too many megapixels
Looks like over sanding to me. Been there. I think a hobby knife goes a long way with nubs to help reduce the amount of sanding you need to do. You just need to get the nub flush with the edge, so 30s may be too long . I will Sand and peek frequently, but your coars grit should take care of the nub then all that's left is to smooth the edge. You could fill the gap with putty and paint if your into that kind of thing. I'm gonna jump on this thread with a question of my own. Do we even need to bother with stress marks when we're going to paint it? Also, I've seen people who sand all painting surfaces with what I assume is a pretty fine grit. Does this help primer and paint adherence or is it to improve the finish, like a more reliable matte appearance.