A glass-fibre pencil is among the most useful tools I have. I first came across one 30 or more years ago in a home-electronics shop, where it was intended for cleaning metal contacts. I bought it on the off-chance that it would be handy for scale modelling too, and a quick experiment revealed it was also ideal for working with plastic and resin.

Basically, it works like a propelling pencil - except, instead of a graphite lead, it contains a core of glass fibres. It's extremely versatile because, depending on the length of the exposed fibres, they'll either work as a quite a gentle abrasive that's ideal for cleaning up mould lines and removing burrs after sanding, or a really aggressive sander on soft material like styrene. Basically, the shorter the “nib”, the harder it sands and, because you can adjust the length, it’s easily variable to suit the job at hand.

You can use it to level areas - it’s great for tackling ejector pin marks - or even “sculpt” with it, sanding away material to replicate dents and uneven surfaces.

All the fibre pencils I've seen over the years have been 4mm in diameter - so I assumed that was the only size available. That’s fine for general tasks, but struggles to get into nooks and crannies, so I was excited to spot Shesto's Modelcraft 2mm pencil when shopping online recently. As you can see from the comparison shot alongside my trusty 4mm pencil, it will be ideal for more detailed work.

The pencil arrives in a blister pack with a cardboard backing. The pencil itself is good quality, with a clutch-release (as against the screw-thread I've found on 4mm pencils) and is comfortable to hold and easily adjustable.

A really nice surprise was the length of the 2mm glass-fibre core, which basically occupies the entire length of the plastic body. This is much longer than I've found in previous 4mm pencils and should last for many years’ worth of normal use.

Shesto includes pencils in 2mm, 4mm and 1cm sizes in the Modelcraft range. I’ve never tried the largest, but I’ll definitely get one now I know such a thing exists. This 2mm pencil was more expensive than the 4mm ones I'm used to (shopping around, you'll see prices between £8.50 to £12.00 or higher), but its refill is much longer, so things balance out. I imagine a smaller diameter core might wear out faster, but refills are readily available and cheaply priced.

A few words of warning

As much as I rate glass fibre pencils as supremely useful, I also have a love/hate relationship with them - probably more so than with any other tools I use. The reason? Simple; no matter how careful you are, the fibres inevitably break off - and when they do, they are like splinters from Hell! They pierce the skin like a hot knife through butter and are extremely painful. The tiny individual fibres are hard to see, so removing them usually requires a magnifier and fine tweezers. I don’t even want to think what it would be like to get fibres in your eyes...

So - while a glass fibre pencil may look harmless, it’s a tool you need to treat with respect, just like scalpels and razor saws, and keep safely out of harm's way when not in use (especially if you’ve got children who can access your work space).

Conclusion

Bearing the caution above in mind, I thoroughly recommend including a glass fibre pencil in your tool set if you don't already have one. Just be careful, and you'll find it invaluable.

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