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Removing Nub Marks

Authored by: Bryan Lee - Mechamind

Often when parts are removed from the runner, nub marks will be left behind.

Sanding the nub marks is the most common way to remove them and in this article I will be sharing the process. This article is not meant to be a comprehensive guide that will cover all aspects of sanding nub marks.

For this article, I will be using the following tool:

AS-GN15 Sanding Board

800# Die-cutting Adhesive Sandpaper

1200# Die-cutting Adhesive Sandpaper


Sand Down the Nub Marks

For thicker nub marks, I will use a #800 grade sandpaper to sand it down. You want a grade that allows you to sand down the nub mark but at the same time minimize the scratch marks on the surface. It is recommended to use a sanding stick that does not warp so that you can get a straight edge when you sand down the nub. Sand it down gently without applying too much force and try to keep the board parallel to the surface edge.

Smoothen Down the Nub Mark

For small Nub Marks (see image below) I will use a #1200 grade to sand down the Nub Mark. You can also use this grade to smoothen the Nub Mark after sanding down using the #800 grade.

Generally for non gloss paint job, you can consider stopping at #1200.

If you plan to do a high gloss surface paint job for your model kit (e.g cars), you will have to go up the grade progressively until #2500.

Hope you have found this article useful!

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