Best way to "invisibly" remove sprue nubs?

[David Hingtgen]

Trying to perfect some techniques before I do my VF-25, so I'm quickly building a Gundam. I've noticed over the years that whenever I build "unpainted" kits like MG Gundam and Zoids, I tend to spend a LOT of time very carefully slicing the sprue nubs with my xacto (seriously, 25 mins doing the thighs and feet of an HG kit--that's like 8 parts), trying to get them perfectly flush and smooth and hopefully invisible. However, a lot of the time in my quest to get every last bit of nub removed, I end up going "too far" and remove some of the plastic of the piece itself in the provess. It's usually subtle, but especially noticeable when two pieces butt together--you'll see a bit of curve/depression. No matter how careful I am, it seems impossible to remove every bit of the nub with an xacto held as perfectly flat to the piece as I can without inadvertantly shaving out a bit too much.

Suggestions? Should I switch to "slice off most of nub, but always remove the last bit via sanding?" (of course, that always dulls the surrounding area) Or do I just suck at "slicing off nubs without taking too much"?

I tend to prefer "slicing" a nub vs sanding on a part that won't be painted, since slicing leaves a shiny remnant that matches the bare plastic, and can sometimes be invisible, or nearly so. Sanding always roughs up the area, requiring polishing etc, and takes a lot longer. But if I keep getting those annoying little "shallow depressions" from trying so hard to slice off every last bit of the nub it may be worth it to change.

[yellowlightman]

Wet sanding might help a bit with the "dulling," but there probably isn't a perfect option unless you start painting.

[Vifam7]

For dark areas, a bit of gray Gundam marker paint will help cover those sprue marks. I've used this technique and it works. The gray blends in and is pretty much invisible.

I've also read that a bit of sanding and a coat of clear flat at the very end would help make the sprue marks disappear.

Edited October 5, 2008 by Vifam7

[azrhino]

Should I switch to "slice off most of nub, but always remove the last bit via sanding?" (of course, that always dulls the surrounding area)

That is the best and cleanest way to remove the attachment points. To get the "shine" back on the plastic, you need to polish the area with succesviely finer grits of sandpaper. One of the best (and cheapest) ways is to get a Nail Buffer from a beauty supply shop that has four grades of abrasive. Use each grade in succession, and you will notice the plastic start to pick up its previous shine.

[Valkyrie addict]

get a very fine grit around 1000-1500 sand paper and to get the sanded are to shine back again...

[miriya]

Please excuse my ignorance as I may not know what I am talking about, being a noob at this model stuff. But from some stuff I have been reading, one technique is to use a side cutter Like THIS ONE to cut off the sprue, leaving slack, not cutting all the way to the end, and then once the pices is off the tree then cut the rest of the sprue off using the flat end of the side cutter. There is actually a diagram depicting this technique in the VF-25 instructions. I have not tried it yet myself as HLJ has taken over a week to acknoledge my order and is not sending me a payment request. I may just go to my local hobby shop to see if they have one.

[Valkyrie addict]

yes, you can use a sidecutter to cut the piece of the sprue, but you need to cut leaving a small tab off the sprue cause if you cut too closely to the piece you risk snapping a chunk off it, you usually cut, leave a nub, then with an exacto knife get rid of that nub (putty if needed) and the sand smooth

[David Hingtgen]

The problem isn't how to make it shiny again (I actually often make it TOO shiny when polishing it back, as Bandai plastic isn't THAT smooth and shiny when it comes out of the mold) The problem is physically removing the protruding nub itself, without removing any of the "original" part itself. I am quite familiar with basic parts removal from the sprue using nippers. And no nipper does a perfectly flush cut---you always have a nub left. Here's my typical part removal sequence:

Use sprue nippers, have 1mm of nub remaining. Use x-acto, .25mm remaining. Use x-acto again, .1mm remaining. Then I start trying to get that last little bit of nub off---.05mm, .02mm, etc. That is when I start "taking out" plastic OTHER than the nub itself, in an attempt to get it perfectly level.

[MechTech]

OK, what everybody else said and...this is something that drives me nuts too! You're not alone. The Bandai Votoms kits are awesome in several aspects that the sprue ends are on the INSIDE of the seam! Genius! NO MARKS when cut flush. I wish ALL kits could be like that.

Flush cutters make all the difference in the world like Miriya said (he won't be much of a newbee at the rate he is going). Make sure they are sharp. Don't be cutting wire with them as when they dull, they pull the plastic away. LEAVE A LITTLE ON, THEN if you have room, slice the remnant off with a razor blade. Sand off the rest carefully; or just do the whole seem.

As an alternative, leave a little tab on the parts, cleaning the mating edges so they fit smoothly and glue (or snap). Then clean up the edges all together by sanding down the whole area.

I NEVER paint a model if I can help it. Chipping sucks. I always cover a marked / marred area with like color paint similar to what was said before. I've gone as far as splotching a whole model with similar color and it simulates dirt and wear great! Less pastel work needed and very realistic. Scratches show up less too. A clear coat helps cover the FINE scratches as mentioned earlier.

Hope that helps. The alternative is counseling which costs way too much - MT

[big F]

I use a nail buffer and some plastic polish. Works ok although painting it only takes a bit longer on some bits.

[Fly4victory]

My wife gave me a nail buffer last year and those things are great.

For unfinished plastic yes it will shine more than the unpolished Bandai plastic.

Yet, If you clear coat to protect decals or dull coat then the shine completely disappears and blends perfectly.

Have started using the Gundam markers to color in the nub area after using the cut then knife trim method.

Plus, have ordered the flat cutters from HLJ and a set of Gundam markers hoping that they will be close to the Macross colored plastic.

Other than landing gear, cockpit, and position lights I don't see much painting.

On an interesting note, I used X-21 mixed with future sprayed over the white stripe foil stickers on a Flight Gouf and they didn't lift or peel. Time will tell if I do the same on the 25.

[David Hingtgen]

How much X-21 did you use in the Future? It's hard to measure, as it's so thick you can't count by drops or milliliters or anything. I think I'll go for a "satin" appearance.

PS--Partly I think I was out of practice, partly "trying too hard to use knife alone", and I am doing much better lately regarding sprue nubs. (That's why I'm building my practice Gundam before my VF-25).

PPS---I tried the Gundam marker method, and surprisingly it works VERY well. On red plastic at least. I wonder if my Gundam grey 02 marker will match the dark grey parts in the VF-25 kit...

[anime52k8]

How much X-21 did you use in the Future? It's hard to measure, as it's so thick you can't count by drops or milliliters or anything. I think I'll go for a "satin" appearance.

how thick is X-21? I normally use droppers to measure out paint/thinner. is it too thick to draw up in one? also, I've read that for a satin finish it's 15-20 parts future to 1 part X-21 depending on how dull you want it.

[David Hingtgen]

X-21 is really thick, you could use a fork to get it out of the bottle.

[anime52k8]

X-21 is really thick, you could use a fork to get it out of the bottle.

maybe those little Baskin-Robbins sample spoons will work.

[Fly4victory]

How much X-21 did you use in the Future? It's hard to measure, as it's so thick you can't count by drops or milliliters or anything. I think I'll go for a "satin" appearance.

Mix .4 ml X21 to 10ml future. It is more satin than dull.

I have a marked eye dropper. Since I thin the Future X21 mixture by 50% with 91% alcohol use the eye dropper to transfer the alcohol and it gets most of the X-21 out. Also when mixing keep running the mixture in the dropper.

Yes, that stuff is think. There is a solid ring about an 1/8 of an inch thick inside the bottle.

One bottle that I tossed out had white flakes floating and never mixed properly with the future. Guess it doesn't age well.