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Hey folks!

New to modeling here. How do you clean up mold lines like those on these legs? I've tried scraping with the back edge of sprue cutters. I've tried scraping with an exacto knife. I've used a small flat file. I also have a nail file that I've tried, but its a bit unwieldy to get into small places like that. I could use some advice

I just use the sharp side of a scalpel blade, either cutting or scraping where applicable but its all about the angle. Too steep and it will scratch the hell out of it too shallow and it will cut, generally about 30degrees off vertical seems to work best. Files of various shapes can be useful but rarely do I use them on plastic.

I always just use my exacto knife, but it sounds like you've tried pretty much everything I'd suggest. Must be some tough mold lines!

Don't remember my SM scouts being that bad but its a pretty old kit so could it be slip from where the mould has worn out? If that's the case then files and greenstuff?

I use the flat edge of my hobby knife, turned to a slight angle.

Not sure how you're using your xacto knife but that should absolutely get able to get in there with no trouble. Time consuming, yes, and I sympathize as a mold-line-hater.

xacto knife, with 45 angled blade, 60 degree for hard to reach areas.

https://www.hobbylobby.com/Crafts-Hobbies/Hobbies-Collecting/Tools-Blades/X-Acto-%231-Knife-With-Replacement-Blades/p/27544

45 degree blades:
https://www.hobbylobby.com/Clearance/Clearance---Crafts-Hobbies/Clearance---Hobbies/%2316-Stencil-Edge-Blade/p/21487

60 degree blades:
https://www.hobbylobby.com/Crafts-Hobbies/Hobbies-Collecting/Tools-Blades/X-Acto-Z-Series-%2311-Blades/p/34637

You can use the x-acto knife in place of the mouldline remover if you want (personally I like the mouldline remover).

Two kinds of "lines".

Mold Wear
Mold Slip

Worn molds lead to excessive "flash" but generally both sides of the flash are even with each other. Scrape and remove flash and its a snap.

Mold Slip (incorrect mounting of fixture.. these things cast in pressures measured in TONS so if its not perfect the mold can de-align a mm or so quite easily, esp if worn). Depending on how bad it is you can scrape it level with an exacto or cut it level.. or sand it level. Either way you are going to lose detail because the two sides of the "line" are not level with each other so you have to either add (Tamiya White Putty or greenstuff, or white stuff, etc) and re-sculpt or remove and try to make a good slope. Usually details are going to get lost in the process.

I hate mold slip. Yes I have two boxes of scouts recently and they were "update" boxes for 8th ed. All of them had some limited mold slip and or excessive thick flashing. Either way, non-sniper scout mold is spent and GW needs to get their chinese casters to replace it.

I use the most appropriate tool. Craft knife or files depending on what the mould lines are like and where they are located.

You need a file set with a little grit there. I have a great little set with a round file, square, flat, curved, tapered, etc. A nail file is far to smooth.

Hope that helps,

CB

Citadel tool I find more forgiving than a hobby knife personally

small folding knife that is semi dull.

the blade tip can get to about 98% of the places where mould lines are.

Reading all of these comments...I may be using my exacto knife wrong. I'd been keeping it perpendicular to the surface of the mold line at 90 degrees, and scraping it along the edge. Apologies for the newbie question here...is this "tilting it 30 degrees towards you, and pulling the blade" kind of thing?

Also, I just did a few strokes with the back side of the exacto knife, and that seems promising. I do have a small file...I'm going to look for a needle file or something even smaller. Or a pocket knife.

Diamond or jewelers files are your friend, get a pack with flat, curved, round etc. they are pretty cheap. But yeah technique is all.

I use a scalpel. Of course you have to be very cautious as it is extremely sharp but it does the best job as you can reach even the smallest pesky lines.

Someone on here once suggested the Modelcraft 3-sided scraper, I found it much better than the edge of a knife.

I use it in conjunction with needle files and very fine sandpaper, depending on how much work is required.

Sadly I dont remember who, and I know I could search, but meh, either way, cheers to whoever it was!

A few thoughts on what I use:

1) Scalpel Blade. Any sharp blade works, a scalpel has the bonus that the blade is often very thin near the tip so it gets into tight spots or fine areas really easily. Tools like larger knives or GW's own moudline remover work great, but often have to thick/chunky a blade to get into the smaller gaps.

For the blade you do want to angle it, you are scraping not digging. A 30degree angle or thereabouts tilted toward the direction of travel is good because you still get the cutting/scraping effect, but its more muted and easier to control and less likely for the blade to dig into the plastic and then end up "jumping".
You're only working down the line not cutting into it so a few passes is better than trying to do it all in one go.

2) A fine grit diamond file. 600 grit or greater is what you need. The higher the grit the smoother the finish and as plastic/resin/metal is soft to start with you don't need coarser grits.
A diamond file is good because you can move the file in any direction and it will file/cut. Whilst toothed files (lots of ridges) often only cut in specific directions. So a diamond is superior in that you can work the file in line with the model and the details in any direction you need; good for tight spots.

NOTE a file (any kind) will clog up as you work with it; very fast with plastics and similar soft materials.
For a Diamond file the solution is to get a normal rubber/eraser that you would use for rubbing out pencil and rub the file over that. It will take a while but you should see the lumps of rubber worked off go from dirty to clear and the file visibly clean (and cut better).

For a toothed/regular file then a brass comb/brush works best, just scrape in the direction of the ridges so that your'e running the bristles down the grooves and it will scrape out the muck.


Note never worry about over-cleaning; if anything its better to have a clean file than a dirty one.


3) Patience and a DVD/Tv/music/audiobook - yeah cleaning mouldlines takes AGES and there's no getting round that. Once down the path to cleaning them off it will take time and can be a real slog, but its worth it for the end result of clean models that you can be proud to paint

 Dashofpepper wrote:
Reading all of these comments...I may be using my exacto knife wrong. I'd been keeping it perpendicular to the surface of the mold line at 90 degrees, and scraping it along the edge. Apologies for the newbie question here...is this "tilting it 30 degrees towards you, and pulling the blade" kind of thing?

Also, I just did a few strokes with the back side of the exacto knife, and that seems promising. I do have a small file...I'm going to look for a needle file or something even smaller. Or a pocket knife.

You are close, tilt the sharp side of the blade AWAY from you at about 30 degrees and pull toward you. Give that a shot and let us know how it goes.

I just use my knife for most things. I use the mold line remover for larger stuff and quite like it.

Saw someone on Facebook removing them by painting them off with plastic glue. Haven't tried it myself but might experiment on an old crap marine.

For this kind of job I'm using... xacto hobby knife. For me it works very good, when im scratching with it perpendicularly to the mold line. Are you sure your xacto knife is sharp enough or maybe blade is to big to get there?

 Eldarain wrote:
I just use my knife for most things. I use the mold line remover for larger stuff and quite like it.

Saw someone on Facebook removing them by painting them off with plastic glue. Haven't tried it myself but might experiment on an old crap marine.

This can work and it can backfire. Plastic glue very readily and quickly melts plastic so it only takes one little mistake and you can cause yourself a huge amount of pain.

In general if you get plastic glue in the wrong place the best thing to do is NOTHING. Trying to scrape or clean it away early will just cause it to smear and melt even more plastic. Instead let it dry and set fully before cleaning away the damaged area with a blade.

 ingtaer wrote:
Diamond or jewelers files are your friend, get a pack with flat, curved, round etc. they are pretty cheap. But yeah technique is all.

This. I have a couple of sets, as they do wear out.
The main one is the flat-wide one, for general use.
The most useful one is a wing-shape, with a flat side and a curved side. That gets in behind knees and other nasty joints.
The round one can be handy for small gaps.
There's also a sandpaper-on-a-handle, like this:
https://www.antenocitisworkshop.com/product/finger-sander-40mm-belts/

 Dashofpepper wrote:
Reading all of these comments...I may be using my exacto knife wrong. I'd been keeping it perpendicular to the surface of the mold line at 90 degrees, and scraping it along the edge. Apologies for the newbie question here...is this "tilting it 30 degrees towards you, and pulling the blade" kind of thing?

Also, I just did a few strokes with the back side of the exacto knife, and that seems promising. I do have a small file...I'm going to look for a needle file or something even smaller. Or a pocket knife.

Looking at the pic, I would guess this is a problem with technique rather than a really hard model.

Exacto knives can be used more than one way. A lot of people just pull it across the surface of a model. You can also 'scrape' back and forth to get rid of persistent lines, going over it a bunch of times to wipe the line away.

Try that. Also, the quality of the blade matters. If it's bending at all when you try to slice, you're not getting maximum tension. Quality blades are cheap.