How to Choose a Seal Wire for Your Chamber Vacuum Sealer
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The seal wire is the heated element that melts the pouch film and fuses the seal in your chamber vacuum sealer. The pump, lid and gasket all exist to get the pouch ready for that one moment. Seal wire is a wear part: it heats and cools hundreds of times a week, gets scraped by pouches and stretches a little every cycle. Replacing it is routine maintenance, but only if you order the right one. This guide covers the wire types we carry, how cut-off wires fit in, and how to match a replacement to your machine.
Signs your seal wire needs replacing
- Weak or inconsistent seals: some pouches seal and others peel open or leak on the same settings.
- Visible thinning, flattening or discoloration along the wire where it touches the pouch.
- Film sticking or scorching at the seal line instead of forming a clean weld.
- A snapped or visibly broken wire.
- On machines with a cut-off wire, a good seal beside a ragged trim line.
If seals fail across the whole bar but the wire looks intact, check the Teflon tape and lid gasket, which are separate wear items. See replacing Teflon tape and gaskets. Before any work, unplug the machine, let the seal bar cool, and follow your manual.
Profile and width must both match
Most confusion comes from treating a seal wire as one spec when it is two. The profile (the shape) and the width (in millimeters) both have to match. A wire with the right width but the wrong profile, or the reverse, will not seat in the seal bar properly even if it looks close.
- Flat wire is a straight ribbon, used as a standalone sealing wire on many machines.
- Concave wire has a slight inward curve on its sealing face and is usually paired with a cut-off wire. We carry 2.5mm, 3.5mm and 4mm versions.
- Double seal wire makes two parallel seals, such as the Sipromac/Berkel 8mm double seal wire.
- Round and T-profile cut-off wires trim and finish the seal. They are always used alongside a flat or concave wire, never on their own, so ordering only a cut-off wire will not fix a failing seal.
Browse the full range in our Seal Wires collection.
Pairings listed on our product pages
Always confirm your exact model before ordering.
| Machine | Seal wire | Cut-off wire |
|---|---|---|
| Sipromac and Sipromac-built Berkel | 2.5mm flat (used for side-by-side twin seals) or 2.5mm concave | T-profile cut-off |
| Webomatic and Webomatic-built Berkel | 4mm concave | T-profile cut-off |
| Promarks | 3.5mm concave | Round cut-off |
| Henkovac | 3.5mm concave (or two side by side for a double seal) | 1.1mm round cut-off |
| Promarks double chamber (DC) models | 10mm flat | See product page |
| Promarks single chamber (SC and TC) models | 6mm flat (also works in double chamber machines) | See product page |
| Bizerba (Boss) | M-profile 6mm | See product page |
Check the seal bar fitting too
Even with the right wire, the ends must seat in the seal bar fittings, and the fittings are not universal.
- One fitting takes 6mm and/or 10mm flat wire.
- A different fitting is made for the concave plus cut-off wire combination.
- A white nylon insulator with a stainless steel screw is used in some setups to insulate the wire ends.
Match the fitting to the wire combination you are installing, not just the brand.
Same badge, different wire
Brand labeling does not guarantee fit. A Sipromac-built Berkel and a Webomatic-built Berkel use different wire combinations (2.5mm flat or concave with a T-profile cut-off, versus 4mm concave with a T-profile cut-off). Match by profile, width and fitting, and use your machine's actual maker as the reference. See Berkel vs Sipromac vs Webomatic.
Measuring how much to order
Seal wire is priced and sold per foot, so measure carefully.
- Measure the full length of the seal bar from end fitting to end fitting, not just the visible sealing surface.
- If your machine has more than one seal bar, measure each, since lengths can differ.
- Order a little extra if you can, because trimming is easier than running short.
- Keep the old wire on hand to compare profile and width directly.
How to identify the right replacement
- Find the brand and model on your machine's plate and open the matching brand collection.
- Check the installed wires: how many, how wide, and flat, concave or round.
- Match profile and width to the product page, and order the cut-off wire too if your machine uses one.
- If anything is unclear, send us your brand and model number.
Frequently asked questions
Why does my seal wire keep breaking?
Repeated heating and cooling gradually thins and stretches the wire. Frequent breakage can also mean the width or profile does not quite match your seal bar, which stresses the wire unevenly.
Can I use a wire from another brand?
Do not assume so. Profile, width and fitting all have to align. Send us your model number and we will confirm what fits.
Flat or concave: what is the difference?
Flat wire is a straight ribbon used alone on some machines. Concave wire has a slight inward curve and is usually paired with a round or T-profile cut-off wire.
Are Sipromac and Berkel seal wires the same?
Sipromac-built Berkel machines use the same combination as Sipromac. Webomatic-built Berkel machines use a different one, so confirm who built yours.
Find the correct seal wire
Shop the Seal Wires collection or contact us to confirm compatibility before you order.