Welding rods 3.2mm vs 4.0mm: which size, holder and mask to buy
The choice between 3.2mm and 4.0mm welding rods comes down to the thickness of the steel: 3.2mm rods are the everyday size for light to medium work such as grilles, gates, window frames and general fabrication, while 4.0mm rods suit thicker steel and heavier joints where more weld metal is needed. As a general rule, the thicker the metal, the thicker the rod. In Nairobi in October 2026, Hero Welding Rods, Stone Bridge are KSh 4,785 for a 20 kg carton of 3.2mm and KSh 5,220 for a 20 kg carton of 4.0mm.
Welding rods and supplies at a glance
| Item | Options | Typical use | Wholesale pack and price |
|---|---|---|---|
| Hero Welding Rods, Stone Bridge | 3.2mm | Light to medium steel, everyday fabrication | KSh 4,785 / carton of 20 kg |
| Hero Welding Rods, Stone Bridge | 4.0mm | Thicker steel, heavier joints | KSh 5,220 / carton of 20 kg |
| Knicker Electrode Welding Holder | 500A, 800A American, 1000A American | Grips the rod and carries the current | From KSh 7,250 / carton of 50 |
| Knicker Welding Mask | One type | Face and eye protection while welding | KSh 17,400 / carton of 20 |
| Knicker Welding Glasses, Retractable (Flip-Up) | Clear, Grey, Black | Eye protection with a flip-up lens | KSh 27,840 / carton of 480 |
| Hand Gloves (leather) | Leather 16" Red, Leather Long Grey and more | Hand and wrist protection from heat and spatter | From KSh 34,455 / bag of 144 pairs |
What is the difference between 3.2mm and 4.0mm welding rods?
The number is the diameter of the metal core of the electrode. A thicker rod carries more current and lays down more weld metal on each pass. That makes it faster on thick steel, but harder to control on thin material, where it can burn through.
A 3.2mm rod is the size most fundis reach for first. It handles the bulk of everyday welding in Kenyan workshops: burglar-proofing, gates, grilles, door and window frames, shelving, brackets and light structural work. It is easier to control in awkward positions, such as overhead and vertical welds.
A 4.0mm rod is for heavier work: thicker plate, heavy angle and channel, base plates, trailers and structural joints that need more weld metal. It covers ground faster on flat, thick joints, but needs a machine that can deliver the current it calls for. Check your welding machine's own guidance for the current to use with each rod size.
How much do welding rods cost in Kenya?
Hero Welding Rods are sold by the 20 kg carton. In Nairobi in October 2026:
- 3.2mm: KSh 4,785 for a carton of 20 kg, which works out at about KSh 239 a kilo.
- 4.0mm: KSh 5,220 for a carton of 20 kg, which works out at about KSh 261 a kilo.
Keep rods dry. Store cartons off the floor, closed, in a dry place. Damp rods are harder to strike and give a poorer weld.
Which electrode holder: 500A, 800A or 1000A?
The Knicker Electrode Welding Holder comes in three versions, and the 500A, 800A and 1000A figures are the maker's own labels. All are sold in cartons of 50:
- 500A: KSh 7,250 a carton, about KSh 145 a piece. A lighter holder for general workshop welding.
- 800A American: KSh 14,500 a carton, about KSh 290 a piece.
- 1000A American: KSh 15,950 a carton, about KSh 319 a piece. The largest of the three labelled ratings.
Choose a holder that matches the welding machine and the cable you use, and replace any holder with cracked insulation or worn jaws.
Welding masks, glasses and gloves
The arc gives off intense light that can injure unprotected eyes and skin, and welding throws hot spatter. Every welder needs face, eye and hand protection.
- Welding mask: the Knicker Welding Mask is KSh 17,400 for a carton of 20, about KSh 870 a piece. Use a mask to cover the face while striking and running the arc.
- Welding glasses: the Knicker Welding Glasses, Retractable (Flip-Up) come in Clear, Grey and Black, each at KSh 27,840 for a carton of 480, which works out at about KSh 58 a pair. The flip-up front lets the user lift the lens between tasks. Clear lenses are for chipping slag and grinding, not for looking at the arc.
- Gloves: long leather gloves protect hands and wrists from heat and spatter. From our Hand Gloves line, the Leather 16" Red is KSh 55,680 for a bag of 120 pairs (about KSh 464 a pair), the Leather Long Grey is KSh 35,670 for a bag of 120 pairs (about KSh 297 a pair) and the Knicker Leather 10.5" is KSh 34,455 for a bag of 144 pairs (about KSh 239 a pair).
Weld in a ventilated space, keep flammable material away from the work, and screen the area so others are not exposed to the arc. For dressing welds afterwards, see our cutting and grinding discs.
Which one should you buy?
- Gates, grilles, window frames and general fabrication: Hero 3.2mm rods.
- Thick plate, heavy sections and structural joints: Hero 4.0mm rods.
- A workshop doing both: a carton of each size.
- General workshop holder: 500A holder; long heavy jobs: the 800A or 1000A American.
- Protection for every welder: a welding mask, flip-up glasses for chipping and grinding, and long leather gloves.
Where to buy
Everything in this guide is in our Welding Supplies range, part of the wider Tools & Hardware range. These lines are sold wholesale only, by the pack (carton, bag or packet), never as single pieces. If you need only one or two pieces, share a carton with other fundis or shops, or buy for stock. Collect from our Nairobi trade counter at Royal Business Park, opposite Complast, Old Mombasa Road (Mon–Sat 8:00–17:30), or order for countrywide delivery at KSh 350 flat, free on orders over KSh 15,000. Pay by M-Pesa or card. Trade buyers can request a quote on the trade page, or send your list on WhatsApp +254 724 505 919.
Related guides
- Cutting disc vs grinding disc: which disc, blade or cutter cuts what
- Construction site PPE checklist: what each crew member needs
- Adjustable spanner vs pipe wrench: which tool for which job
Common questions
Can I use 4.0mm rods on thin metal?
It is harder. A 4.0mm rod puts in more heat and weld metal, so on thin steel it can burn through. A 3.2mm rod is easier to control on lighter work.
How much is a carton of welding rods in Nairobi?
In October 2026, Hero Welding Rods, Stone Bridge are KSh 4,785 for a 20 kg carton of 3.2mm and KSh 5,220 for a 20 kg carton of 4.0mm.
What amps should I set for 3.2mm rods?
Follow your welding machine's and the rod maker's guidance. The right setting depends on the machine, the joint and the welding position.
Can I buy welding rods by the kilo?
No. Hero rods are sold by the 20 kg carton only. If you need less, share a carton with another workshop or keep the rest in dry storage.
What do 500A, 800A and 1000A mean on an electrode holder?
They are the maker's ratings printed on each holder. A higher figure marks a higher-rated holder in the range.