Mould lines and sprue joins

[Buggane]

How does everyone get them off and leave a smooth finish? I can just about manage to scrape off an mould line with either side of my craft knife, but it often leaves a bit of plastic behind that looks quite different to its neighbours, as you

Remove the top level of plastic and it's not as smooth as the rest

 

And then there's the sprue joins, same problem but worse, when it joins into somewhere obvious and on display, like the centre of a should (I'm looking at you space marine scouts)

 

I've tried my finest file but that just scratches the surface up and doesn't leave a smooth finish at all...am I just being too much of a perfectionist?

[Kinstryfe]

Not being snarky, but you may be being too much of a perfectionist. That sounds like pretty much what I do, and once painted I usually can't tell where those little scrapes and rough spots were. A sharp hobby knife is usually enough to get it smooth enough that it won't show post-priming.

[Stercus]

If you check in the beauty aisle of the supermarket, you can pick up emery boards of various grades for filing fingernails. However smooth you want your models, these little fellas are your new best friends.

[Tyberos the Red Wake]

How does everyone get them off and leave a smooth finish? I can just about manage to scrape off an mould line with either side of my craft knife, but it often leaves a bit of plastic behind that looks quite different to its neighbours, as you

Remove the top level of plastic and it's not as smooth as the rest

 

And then there's the sprue joins, same problem but worse, when it joins into somewhere obvious and on display, like the centre of a should (I'm looking at you space marine scouts)

 

I've tried my finest file but that just scratches the surface up and doesn't leave a smooth finish at all...am I just being too much of a perfectionist?

 

No, you're not. Some people don't care about model prep as much, and that's fine, but it's a sliding scale. If you argue "Well why do you care if the surface looks slightly different", you can just as easily say "Well why do you care if the model has mold lines and sprue nubs on it".

 

I struggled with perfect sprue nub removal and severe mold slips for a long time. I thought I could do it with just a knife or other mold scraper, and maybe a hobby file. But you can't, as you've found out. You NEED sandpaper and some kind of filling putty. I find emery boards as Stercus suggested a bit too wide for my taste, but the sandpaper-attached-to-foam-stick method is still good. I use Flory Model Skinny Sanders imported from the UK. They're pricey, but they finally allowed me to get perfect, flawless surfaces on my models, whether it's stubborn mold slips or sprue nubs that just won't disappear with knife shaving. I use the very thin, black colored one that's rough on one side and smooth on the other.

 

Here's a video explaining them and a demonstration in action. It really convinced me to buy them, not because they're super special or amazing, but just because they're so easy to use and fit our needs as miniatures modelers the best. You can probably do the same thing with thin stripes of sandpaper you cut down with a knife, or for large surfaces, a cheap beauty salon nail emery board.

 

Just keep in mind these things are REALLY expensive for what they are. Like half the price of a box of GW infantry, but one pack will last you a lifetime. I found it worthwhile because I'm not the best hobbyist, so buying tools made for a specific purpose even if it costs more generally helps me do a better job than just using "basic" tools that are cheaper, but you have to know how to use them (like sheets of sandpaper, or hobby files).

 

[Adeptus]

Go to the hardware store. Buy some sandpaper that is 1200 grit, and some that is 1400 grit.

 

These are what you use to 'polish' a miniature to get a perfect, smooth finish.

 

You can use a hobby knife to or a file to do the bulk material removal when snipping away sprue connectors and mould lines, but when you're finishing the piece and want that totally smooth finish, use very fine 1200 to 1400 grit sandpaper.

 

Also, for seams between parts you can use greenstuff to fill the gap, then file/sand it smooth after its set, or you can use plastic cement sometimes as well.

 

One trick when you're gluing two parts together can be to overload the join with glue, then clamp it together as it's drying, so that a fine bead of glue is pushed out between the two pieces. Then when the join is set and the glue is dry, you can file/sand that seam till it's smooth, knowing that any gaps have been filled by the glue. You can try the same trick with superglue on metal or resin models but it's not as effective as it is with plastic models.

[Brother-Chaplain Kage]

600 to 800 grit should be more than enough for your figures. 

[Stoic Raptor]

If you use too much cement, it can distort the surface or mar the features.  You don't want a bead of glue... you want a bead of plastic.  The best way to do that is to apply a thin line of glue to each of the surfaces to be joined, then wait a moment.  This allows the plastic to melt, and when you press the surfaces together good and hard, that bead of plastic will fill the gap - essentially turning the parts into one.  When it's dry you can scrape or file or sand it down and the seam will be invisible - because for all intents and purposes, it no longer exists.

[Bung]

For filling gaps i use Mr. Hobby Surfacer 500 which can be thinned with Mr. Hobby Thinner.

Its far superior to Liquid Green Stuff and other Plastic puttys i encountered. It can be sanded when dry and thinned to flow into the smalles gap (but be carefull with details).

Even works well on old metal miniatures.

 

The 1200 Surfacer can even be used in an airbrush and acts as a primer too.

 

I am good with fine sandpaper for the mold lines like Adeptus suggested, most competition painters here use it too.

[Buggane]

Thanks all, theres a bunch of ideas on here for me to try. Hopefully other kits don't have their mold nubs in quite such a stupid place as the scouts...i can see why everyone hates those models.

[Stoic Raptor]

If you have a good pair of clippers you can usually trim pretty close to the surface when removing them from the sprue.  Don't go too close because it's easier to remove a small nub than it is to fill a gouge.

[JeffJedi]

The mold line remover is a really great tool. I laughed when I saw it but now it's a vital tool that I use on every model.

[White Wolf]

Try a "flex i file" from Albion Alloys. Available from a variety of outlets. Used by the scale modelling community. I absolutely swear by mine.

 

ATB WW

Edited September 17, 2017 by White Wolf

[Slave to Darkness]

Think the scouts are bad try Daemonettes, the Mold lines go down the front of their faces. 

[Xenith]

I go with a gentle scrape with the hobby knife, then buff with 1000 grit sandpaper.

[Tyberos the Red Wake]

Think the scouts are bad try Daemonettes, the Mold lines go down the front of their faces. 

 

Good thing they're already noseless, or that would be a lot of scraped and sanded off noses.