Welding magnets for pipe, sheet and box section
Updated: 18 October 2026
You place an arrow magnet against a length of tube, but only an edge touches and the far end drops before you can tack it. Welding magnets for pipe behave differently from the same holders on flat plate because contact area, section length and leverage change the practical hold. These ten amazon.co.uk products are mainly flat-faced arrows and angle holders; none includes a dedicated V-pad. The [welding magnet comparison](/hub/soldering-and-welding/welding-magnet) shows their stated forces and angles. This guide maps those specifications onto plate, box section and round tube so you can recognise when support or a different clamp is necessary.
You place an arrow magnet against a length of tube, but only an edge touches and the far end drops before you can tack it.
You place an arrow magnet against a length of tube, but only an edge touches and the far end drops before you can tack it. Welding magnets for pipe behave differently from the same holders on flat plate because contact area, section length and leverage change the practical hold. These ten amazon.co.uk products are mainly flat-faced arrows and angle holders; none includes a dedicated V-pad. The welding magnet comparison shows their stated forces and angles. This guide maps those specifications onto plate, box section and round tube so you can recognise when support or a different clamp is necessary.
Our top picks
| Badge | Product | Stated pull | Contact | Use it for | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  AB Tools AB Tools AT847_4PK | 25 lb (about 11.3 kg) | Flat faces, 45°, 90°, 135° | Supported plate and short box | 9.1 | about £11.03 | View offer |
| Alternative |  Neilsen Neilsen CT1930 | 10 lb (about 4.5 kg) | Small flat faces | Tabs and short edges | 8.2 | about £7.89 | View offer |
| Best value |  S&R S&R 290.803.000 | 9 kg and 13 kg | Flat multi-angle faces | Some pipe; thin box can slip | 8.7 | about £11.95 | View offer |
On this page
Flat plate and why length matters
A flat mild-steel plate gives an arrow its best chance because the magnet face can sit across a broad, even area. The surface still needs to be free from loose rust, scale, paint, filings and spatter. Comparable clamp data rates pull on thick clean mild steel and shows that thinner material and air gaps reduce force, so the number on a packet is an optimistic comparison point rather than a guaranteed workshop result.
Length matters even when thickness stays the same. A long plate creates leverage around the contact area, and an upright plate asks the magnet to resist gravity in a direction that may not match the quoted pull. One Neilsen owner reported that roughly 500 mm of 3 mm steel was too much for the 10 lb mini holder. An AB Tools review says even a 25 lb arrow had limited success with upright 3 mm stock beyond a small area.
Keep the plate on the bench or support it on trestles so the holder only establishes the angle. For a short tab or gusset, a mini arrow may be enough. For ordinary light fabrication, a 25 lb-class four-pack gives more margin, but it still should not suspend a rail in free space. If movement would injure someone or spoil a critical joint, use a mechanical clamp.
Our welding magnet buying guide explains why a 25 lb pull figure is not a safe working load. Thickness alone does not define the job; dimensions, orientation and support matter just as much.
Box section needs support, not just a bigger number
Square and rectangular box offer flat faces, which makes them look like an easy magnet job. Short pieces resting on a table can be: four arrows at 90° are convenient for arranging a small frame before checking the diagonals. Trouble starts when the section is long enough to twist, when one end hangs beyond the bench or when the wall is too thin to make effective use of the magnet.
The available owner evidence shows these limits clearly. An AB Tools user reports that a metre of 50 x 50 x 3 mm box section fell despite the 25 lb specification. A Spurtar owner says 25 mm box fell, while an S&R pair was reported unable to keep 1-inch box with 1.5 mm walls square on a table. These are individual experiences rather than controlled tests, but they reject the idea that any headline pull guarantees a box-section size.
Use blocks, trestles or clamps to carry the length and weight. Let the arrow establish the local angle, tack the joint, then secure the assembly before removing the holder if the tacks are not enough. Check the square after every tack because shrinkage can move a joint even when the initial setup was accurate.
Buying a 50 lb-labelled arrow may add margin, but it does not solve poor support. The YESWELDER 50 lb listing shares its UK review block with the brand’s 25 lb model, so comments about light plate and tube cannot validate the larger model independently. Choose support first and the magnet second.
Round tube reduces the contact area
A flat arrow face meets round tube along a narrow strip rather than over its whole surface. That smaller contact patch behaves like an air gap across much of the magnet, reducing the hold and making the setup easier to roll. A seller may say “pipe installation”, but that phrase is not a diameter or load rating.
The reviews are mixed rather than uniformly negative. One S&R pair owner likes the holders on pipes, while shared YESWELDER text mentions light tube up to about 5 mm. That latter comment does not state a diameter and belongs to a review block shared by two models, so it cannot become a rated 5 mm capacity. A positive report on one small tube also does not prove that a long or heavy pipe can be held without support.
A V-pad is designed to create two contact lines around round stock and resist rolling more effectively. UK suppliers sell magnetic V-pad kits and pipe clamps for this purpose, but those are different products and are not an eleventh contender in this comparison. If tube work is your regular job, a suitable V-pad or mechanical pipe clamp is a better starting point than repeatedly forcing a flat arrow to do the wrong geometry.
Whatever the holder, support both ends of long tube. Make the initial tack, then remove the magnet before the full bead. The step-by-step guide to using welding magnets covers cleaning, placement, removal and fume control without inventing a safe distance from the arc.
What to choose for light supported work
For small mild-steel plate and short box section supported on a bench, a four-pack in the 25 lb class is the practical default. The AB Tools set costs £11.03, covers 45°, 90° and 135° and has enough review evidence to show both useful everyday performance and a limit on long box. That honesty is more valuable than an unexplained larger number.
The 10 lb Neilsen minis suit tabs, tinplate and compact edges but should be skipped for long 3 mm plate. Multi-angle QWORK and S&R sets make sense when the joint needs 30° or 60° rather than a standard square corner, although unusual angles do not increase pull. A switchable S&R holder is easier to place and clean, but its lever does not improve contact on a curved pipe.
The best welding magnets by job page gives product-specific choices and the caveats around conflicting YESWELDER, Swpeet and Spurtar claims. For this use case, support long work, maximise clean flat contact and use a clamp or V-pad when the geometry does not suit an arrow. A magnet should make alignment easier, never become the only thing preventing steel from falling.
Common questions
Will an arrow magnet hold round tube?
It can help position small ferrous tube when the work is otherwise supported, and one S&R owner reports a good result on pipe. The flat face touches a curve over a narrow area, however, so the practical hold is lower and rolling is possible. A V-pad or pipe clamp is better for regular tube work.
Why did my welding magnet fall off 3 mm steel?
Thickness is only one factor. A long or upright piece creates leverage, while rust, paint, scale, swarf and a curved or uneven face create gaps. Owner reports show 3 mm plate and box overwhelming both 10 lb and 25 lb holders when the pieces were sufficiently long.
Is 50 x 50 x 3 mm box section suitable for a 25 lb arrow?
Short pieces resting flat may be positioned successfully, but one AB Tools review reports that a metre-long section fell. Do not convert that into a universal maximum length. Support the section mechanically, use the magnet for the local angle and clamp it when release would allow movement.
Does thin sheet hold better because it weighs less?
Not necessarily. Thin sheet weighs less, but it also provides less steel for the magnetic circuit and can flex away from the face. Comparable clamp guidance shows lower pull on thinner material. Keep the sheet flat, clean and supported rather than assuming low weight guarantees a secure hold.
Do I need a V-pad for pipe?
Choose one when round stock is a frequent job or when a flat arrow gives only unstable line contact. A V-pad is shaped to contact tube more securely and reduce rolling. None of the ten products in this comparison includes one, so it is a separate tool rather than a feature to assume.
Can I hold a long rail in the air with welding magnets?
No consumer arrow in this comparison should be treated as a rated lifting device. A long rail creates substantial leverage and can fall if contact changes. Use trestles, blocks and appropriate clamps to carry the weight; use the magnet only to establish the angle for a tack.
Related pages
Sources
Public UK sources and the amazon.co.uk listings in this set, last checked on 16 October 2026.
- HSE, Protect your workers from welding fume (retrieved 16 October 2026)
- HSE, Change in enforcement expectations for mild steel welding fume (retrieved 16 October 2026)
- HSE, Guidance on the safe use of magnetic lifting devices (retrieved 16 October 2026)
- Consumer Rights Act 2015, section 9 (retrieved 16 October 2026)
- Eclipse, heavy-duty welding clamp data (retrieved 16 October 2026)
- Euromag, ferrite magnets (retrieved 16 October 2026)
- Tec Products, welding magnets (retrieved 16 October 2026)
- Goudsmit, feasible forces for magnetic grippers (retrieved 16 October 2026)