A dented ping pong ball only needs a little heat to return to its original spherical shape; do not rush to get the lighter, however, because you would risk setting it on fire! Instead, try one of the following methods. Remember that the ball, after you fix it, will be less resistant and will bounce with more difficulty than when it was new, but you shouldn't have any particular problems playing friendly games - or "beer pong".
Steps
Method 1 of 2: Use Boiling Water
Step 1. Heat a cup of water
Bring it to a boil, then pour it into a ceramic cup.
You can dip the ball directly into the pot, but be careful not to leave it there for more than a couple of minutes - it could melt or burn if it overheats
Step 2. Put the ball in the cup full of water
The heat will heat the air contained in the sphere, making it expand and returning it to its initial shape.
Step 3. Push the ball under the surface of the water (optional)
To increase the heat received (and therefore the internal pressure) you can use a spoon to force the ball to remain completely immersed; keep it submerged for about 20 seconds (or until the dent is gone).
Step 4. Remove it from the cup
Use a spoon or kitchen tongs to retrieve the ball; the water will still be very hot, so don't use your hands, you risk getting burned.
Step 5. Hang the ball using a handkerchief
Wrap a handkerchief or tea towel around the ball, joining the corners to form a small bundle; then hang the assembly on a nail or a hook until cooling is complete (about 5-10 minutes). Don't fool yourself: you won't get the performance of a shiny new ball, but it will still be as round and usable as before.
Allowing the ball to cool on a flat surface could cause it to warp again, forming irregularities
Method 2 of 2: Using a Hair Dryer
Step 1. Set your hair dryer to blow out hot air
As in the previous method, here too heat will be needed to ensure that the air contained in the ball expands.
Fast-moving air also has a lower pressure; in this way it will be even easier for the internal pressure to push out the dent
Step 2. Keep the ball inside the flow of hot air
Keep it quietly in your hand, placing it in front of the jet of the hairdryer. Ping pong balls are flammable, but the risk of this happening is minimal as long as you can hold it without burning yourself. The temperature of the air heated by the hairdryer varies from model to model, but a distance of the ball of 15-20 cm should be sufficient to avoid overheating.
- Alternatively, you can direct the hairdryer upwards and let the ball levitate inside the hot air jet.
- By letting the ball fly like this you shouldn't risk burning it; instead it could happen if you put it on a hard surface and hold the hair dryer too close to it.
Step 3. Wait until the ball expands
It may help to hold it so that the dent is on the opposite side of the hair dryer; moreover it would be better to heat it in several times, turning the hair dryer on and off, thus allowing it to cool down periodically, avoiding causing further deformations.
After the repair, the ball will still be slightly "crooked" compared to a new one
Step 4. Cool the ball in a hanging handkerchief (optional)
To avoid new dents during cooling, wrap it in a handkerchief and hang it on a nail for a few minutes; since the air in the hairdryer is not as hot as boiling water, however, this step may not be necessary.
Advice
- Do not rest the ball on a hard surface, leaving it still when it is still hot, otherwise it will create a flat area; keep it suspended until it is completely cooled.
- Not all ping pong balls are made of the same material: cheaper plastic balls are more fragile, while celluloid balls are more flammable than others.
- Do not expect the repaired ball to be as reliable as before: after each repair it will lose some resistance, until it gets punctured or cracked. Also, it may be bigger than before and bounce worse, although this shouldn't be a problem for friends games.
Warnings
- Ping pong balls are highly flammable; do not be convinced by the videos you find online about the "lighter method": it will be very likely that you will burn your fingers and leave a shapeless heap of plastic on the floor.
- If you smell bad, remove the ball from the heat and ventilate the room.
- Never put a ping pong ball in the microwave oven: a few seconds of heating will be enough to heat it up enough to bring it to self-ignition, causing it to burn completely.
- These methods will not work for cracked or broken balls; you can attempt a glue repair, but the ball will still remain weak and unreliable. It's best to throw it out and use a new one.
