Metal Bottle Caps – 38-400 Tinplate Screw Caps
Metal bottle caps give glass bottles and jars a classic, premium finish and a strong seal. This category carries 38mm (38-400) continuous-thread tinplate caps with knurled edges, in gold and black-and-gold, including a plastisol-lined cap that forms an airtight seal for food and high-temperature use. Both fit glass bottles and jars with a 38-400 neck finish. Order online with delivery to the United States and Canada.
When should I use a metal cap instead of plastic?
Use a metal cap on glass jars and bottles when you want a premium shelf look or an airtight seal for food, sauces, preserves or hot-filled products. A plastisol-lined metal cap seals hermetically. For HDPE bottles, induction sealing or lighter-weight packaging, a plastic cap is usually the better fit.
Caps in This Category
- The 38-400 gold metal cap with plastisol liner is made from electrolytic tinplate (tin-coated steel), gold inside and out, with a knurled edge for grip. Plastisol is a common liner for food canning and vacuum packing because it creates an airtight seal, and it is recommended for high-temperature applications as long as the container can handle the heat.
- The 38-400 black and gold metal cap is a continuous-thread screw cap with a black exterior, a popular choice for glass jars. See the product page for liner details.
Matching the Neck Finish
Both caps are 38-400: a 38 mm opening with a 400 thread. They fit containers with the same finish, such as the 2.5 oz. amber glass packer bottle (38-400). Note that our 32 oz. and 64 oz. growlers and 1 gallon glass jug use a 38-405 finish, which needs a 38-405 cap rather than 38-400. When in doubt, check the finish listed in the bottle's product title.
Tinplate and Liners Explained
Tinplate is thin steel coated with tin, which resists corrosion and takes printed or colored finishes well. The liner is what actually seals: it compresses against the rim of the jar as you tighten the cap. Plastisol creates an airtight seal, which is why it is chosen for hot-fill and vacuum-packed foods.
Common Uses
- Sauces, jams, honey and preserves in glass jars
- Hot-filled and vacuum-packed food products
- Spices, dry goods and gift packaging
- Cosmetics and apothecary jars
Need a different size or liner? Browse plastic bottle caps from 20mm to 38mm, return to all caps and closures, or shop glass bottles and jars. For production quantities, contact us for a quote.
Metal Bottle Cap FAQs
What is a 38-400 metal cap?
It is a 38 mm continuous-thread screw cap with a 400 thread finish. It fits glass bottles and jars with a matching 38-400 neck.
What is a plastisol liner?
Plastisol is a liner compound that forms an airtight, hermetic seal against the jar rim. It is common in food canning and vacuum packing and suits high-temperature filling.
Can metal caps be used on plastic bottles?
They can fit any container with a matching finish, but metal caps are mainly used on glass. Plastic bottles are usually paired with plastic caps.
Will these caps fit a 38-405 growler?
No. Growlers and jugs with a 38-405 finish need a 38-405 cap. These metal caps are 38-400.
