after the sprue cut

I cut my parts close leaving a small nub and then sand it off with a sanding stick. Much safer this way.

A knife can do damage.  Consider using a medium grade sanding stick, or a fine metal file, or a product called "Flexi-File", a flexible band of abrasive on a metal frame, available from Sprue Brothers and other on line suppliers.  I seldom use a blade for clean-up.

And for small parts, I do it under an illuminated magnifier glass- makes for a real nice result.

That's your problem, I think...you can't clean up a part with just a knife...you have to get the final clean-up done with sandpaper, a sanding stick or steel wool...don't be tempted to try to cut all of the extra sprue to the part...

I used to try & get as much as possible removed with the knife, but found as often as not that the final trim with the blade would damage the kit part, sometimes pulling extra material away, almost like the plastic right at the joint has a more brittle, grainy consistency. Typically where the sprue joins the part is thinner than both the sprue & the part, possibly the area is so thin that it gets slightly hotter than the surrounding plastic during moulding & that causes the difference?

Now I do what everyone else has said & on obvious "eyesore" areas like fuselage joints or leading edges, I will get the meeting faces as perfect as I can, but leave a tiny bit on the outer surface. I find it easier to finish these bits once the parts have been joined, because with a complete surface / edge I'm less likely to remove too much material & get flat spots or create a wavy edge - if that makes any sense. 

Agreed Agreed,,,,   cut close and then sand or file (typically I file). I have a series of smallish 6" fine metal files in different shapes.

It is very rare that I use a blade to clean up an area.           And even if I do I always file afterwards.

Jester75

I cut my parts close leaving a small nub and then sand it off with a sanding stick. Much safer this way.

And if i can't get close enought to the part, i use the cutters to trim it down once the part is off the sprue.

Jester75

I cut my parts close leaving a small nub and then sand it off with a sanding stick. Much safer this way.

I always use a hobby knive with a number 11 exacto blade to clean up. The trick is to change blades regularly so they do not get dull (forcing you to apply to much pressure) and not to remove the exces plastic in one go, take you time.

I kind of agree with others- cut close with an X-acto, then finish up.  But rather than use sandpaper for that finishing, I use a flat needle file.  Works faster than very fine sandpaper, but with just as nice a finish.

You can get nail file/buffing sticks at places like rite aid. Found them on one of my trips to the USA and took some with me for just this kind of thing. You can also buy these "sponge blocks" that have fine grit sandpaper like surfaces. They have proven very usefull to me for sanding filled seams. You can always use ultrafine sanding paper to finish up after doing the big sanding part using these tools.

I do have to admit that, on perfectly straight and square parts i have no difficulty cleaning up the stubs by simply putting a no.11 blade flat on the surface and slicing the stubs off a little bit at a time. Patience and moderation is your friend here

Richard

Depends on the part and depends on the location of what is to be removed.

A. I don't always care, and a knife is fine if it simply doesn't matter.

B. sometimes a file is both better and faster.

C. I have found that a knife can also cause 'tear' ie the plastic pulls off the opposite side of the sprue nub and thus have discovered that  straight type nail clippers can eliminate the effect as they sheer from both sides simultaneously. Often they can clip very close to the surface too reducing filing time.