Rüzgar

These are almost certainly moulded thermoplastic rather than cast resin — mass-produced toys use the cheap high-volume process — and that is good news, because thermoplastic polishes beautifully.

The approach is the same one used for scratched watch crystals and headlight lenses: progressive abrasion, from coarse enough to remove the damage down to fine enough to restore gloss.

1. Clean thoroughly first. Polishing dirt into the surface adds scratches.
2. If there are real nicks, start with a very fine wet abrasive paper — the sort sold for finishing paint — used wet, with light pressure, in small circles.
3. Step down through progressively finer grades. Do not skip grades; each one is removing the scratches left by the previous one, and skipping leaves marks the finer grade cannot reach.
4. Finish with plastic polish or a fine automotive compound on a soft cloth.

The two rules that matter: keep it wet, and keep it cool. Friction melts thermoplastic, and a melted spot is much harder to fix than a scratch.

For the tube down the centre, whichever material you choose, the practical concern is shrinkage pulling away from the insert.

Wax shrinks noticeably as it cools and will often leave a visible gap around anything rigid in the middle. Two fixes: pour in layers so each is thin, or top up the dip once it has set and cooled.

Also worth roughening the insert slightly where it will be embedded. A smooth tube gives nothing to grip and can rotate or slide; a scuffed one holds far better in any of these materials.

If you do want marks directly on the card, the mechanism matters and it explains why your inkjet fails.

Inkjet ink soaks in. On black paper the ink is absorbed and sits below a black surface, so nothing shows. There is no ink density that fixes this.

Laser toner sits on top. It is melted plastic fused to the surface rather than absorbed, so a light toner colour on black card is often faintly but usably visible. If you have access to a laser printer, printing your lines in yellow or light grey is worth one test sheet.

White toner printers exist and are genuinely the right tool, but they are specialist equipment and a print shop is the realistic route if you need it often.

For one-off marking by hand, a white or silver gel pen, a chalk pencil or a white coloured pencil all show clearly on black card and rub off or hide on the inside of a fold.

Practical safety point since powders are involved: dry pigment is very fine and easy to inhale, and titanium dioxide dust is not something to breathe casually.

Mix it in a way that does not raise a cloud — add it into the liquid rather than the other way round, work with the container low, and wear a dust mask while handling the powder. Once it is in the resin it is bound and harmless.

Same goes for the resin itself: gloves, ventilation, and no skin contact. Epoxy sensitisation is cumulative and people who get careless with it early tend to regret it.

The framing-supply version of the same product is worth knowing about: gummed linen or paper hinging tape, sold for mounting artwork.

It is more expensive and better made — finer paper, more consistent adhesive, and designed to be archival. For small models where the joint quality matters more than the cost, it gives a much neater result than carton tape, which is fairly coarse.

Either way, the general principle is the one to hold onto: for a joint that will be finished like paper, use a paper-based joint. Any plastic film will always be a different material under the paint, and no primer entirely hides that difference in sheen and texture.

Worth checking two practical things before you pass it on.

The steel. Cheap cards are made of mild steel that rusts quickly in a wallet and holds no edge. Better ones are stainless. A magnet tells you little, but a drop of water left on it overnight tells you a lot.

Local rules. Some places have restrictions on carrying items with blades, and a card with a stamped blade in a wallet can technically fall under them. Worth a quick check for wherever your nephew lives before it goes into a pocket rather than a drawer.

Three days is at the far end but it is not alarming for a month in, and the explanation is that gym strength transfers to surfing much less than you would expect.

What you are doing in the water:

• Paddling, which is prolonged, continuous shoulder and upper back endurance work. Weight training is typically sets and rests; paddling is twenty minutes of unbroken effort at a moderate load. Completely different demand, and it is the main reason beginners are wrecked.
• Holding an arched position on the board for long periods, which loads the lower back and neck isometrically in a way essentially nothing else does.
• Repeated pop-ups, which are explosive and eccentric and land in unfamiliar positions.
• Being cold and being knocked about, both of which cost more than people account for.

Beginners also spend far more time paddling and far less time riding than they expect, so the session is mostly the endurance component.