Making Scuba Dive Weights

How to Melt Fishing Sinkers to Make Lead Weights for Diving

© Bruce Iliff

Mar 8, 2008
Scuba weight mould and completed weight, Bruce ILIFF
Divers can find many lead fishing sinkers while diving. These can be melted down to make weights to be used while scuba diving.

A satisfying exercise, and one that can save money, is making your own scuba weights. And finding the lead to use is the fun part! Keep your eyes open for lead sinkers when diving at a spot that is also popular for fishing,

Equipment Needed

You don’t need much equipment: a gas stove, aluminium saucepan, a mould, and a ladle. Moulds come in different shapes and sizes but the best is one that doesn’t have complicated curves and edges.

You’ll need an aluminium saucepan large enough to hold at least twice the amount of lead. Aluminium has a higher melting point than lead, so the saucepan won’t melt.

A standard gas camping stove will give off enough heat. Make a ladle to transfer the molten lead from the saucepan to the mould from an old tin can. Form a spout in the lip of the can and bend a piece back to make a handle. Have a pair of pliers or multigrips handy as the ladle filled with molten lead will get hot!

Melting the Lead

Always melt the lead in a well-ventilated area, as exposure to lead fumes can be toxic over a long period. Before starting, give the sinkers a good clean. Make sure no fishing line is stuck to the sinkers and that the holes are not filled with sand.

Put the lead in the saucepan and turn on the heat. Three kilograms of lead will take about 15 minutes to melt. This will vary depending on the shape of the saucepan and the amount of heat.

Once the lead has melted, the impurities will float on the surface. Try to scoop off as much as possible so there is just the clean molten lead. The pure lead will be a bright, shiny silver.

Pouring the Lead

Before pouring the molten lead into the mould, ensure the mould is completely clean and dry. Any moisture in the mould will instantly vaporise and explode when the molten lead is poured in and could spray the hot lead. To ensure it is dry, hold it over the gas flame for a few seconds.

Use the ladle to carefully transfer the lead or pour from the saucepan. For the first pour, let the lead sit in the mould for a few minutes, then pour the lead back in the saucepan. This is to evenly heat the mould to allow the lead to cool in a uniform way so no air bubbles get trapped.

When the lead is completely re-melted, fill the mould again. Leave it for fifteen or more minutes then gently place it in a container of cold water. This cools it down enough to handle. Tip the weight out and you’ll have a perfectly good dive weight.

Customising the Weight

It can now be painted to make it distinctly yours. If you have access to letter punches you can further customise it with your initials or name.

If there isn’t enough lead to make a full weight, simply make a smaller weight. Then after a few more dives, and a few more recovered sinkers, you can remelt it to make a full sized weight. This smaller weight might even come in handy if your buoyancy is right in the middle where a full weight is too much.

Diving seems to consume money quicker then you can consume a full tank on a dive, but making your own weights is one way to get a bit back from the sport.

For related articles on scuba diving refer to:

The Scuba Dive Ascent

Scuba Diving Buoyancy Control

Scuba Diving Anxiety and Panic


The copyright of the article Making Scuba Dive Weights in Scuba Diving is owned by Bruce Iliff. Permission to republish Making Scuba Dive Weights in print or online must be granted by the author in writing.


Scuba weight mould and completed weight, Bruce ILIFF
Dive weights and mould, Bruce ILIFF
     


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Comments
Mar 7, 2009 12:02 AM
Guest :
Pretty cool story, thanks!
Mar 30, 2009 6:50 PM
Guest :
Sorry but using aluminum is not a good idea since aluminum melting point is only 40 degrees higher.
For the best result you need to use a ceramic coated metal pot.
If you use aluminum and your temp gets to hot you will spill all of your lead to the ground along with some aluminum.
Jun 8, 2009 9:47 AM
Guest :
errr... melting point of aluminum is about 300°C hotter then lead.
cast iron lead pot (also known as a 'plumbers pot') is my favorite.
Jun 16, 2009 11:11 AM
Guest :
Guest #2 isn't remotely correct. Aluminum should be fine.

Lead - Melting Point: 327.46 °C (600.61 K, 621.43 °F)
Aluminum - Melting Point: 660.37 °C (933.52 K, 1220.666 °F)

That's a LOT more than 40 degrees higher. You were probably comparing the lead melting point in Fahrenheit with the Aluminum melting point in Celcius. Apples and oranges...

Jul 13, 2009 9:13 AM
Guest :
If melting lead, an aluminum container (pan) would be ok, but it would be easier and cheaper to use steel can: large soup can, steel coffee can, large fruit can.
Then you can bend a spout on the top and even keep the lid partly attached to form a make shift handle. Pure steel has a melting temp of 2800 degrees F. Well above both lead and aluminum.
Jul 28, 2009 1:52 PM
Guest :
Could you use wet sand for a mold?

(looking for custom shapes)
Sep 26, 2009 12:24 PM
Guest :
Good article! I've been making my own weights for many years. The cost of a new 4 pound wieght can reach $15 or more. Using old car tire weights (minus the metal clip) is also a good source of scrap lead.
7 Comments