Seams are the type of connection of two or more wetsuit panels which are usually glued together to create a waterproof seal. Most wetsuit seams are then blindstitched together with a needle that doesn’t penetrate the neoprene completely to prevent leaks. Seams can be reinforced by a liquid rubber outside seal and a neoprene tape inside taping on more high-end wetsuits. A more cost-effective type of seam is done by flatlock or overlock stitching, but this seam is not glued, which causes it to not be waterproof. This is why it’s only used on summer wetsuits and shorties used in warm waters.
GBS / Glued and Blind Stitched
The most common seam construction for cold water wetsuits is glued and blind stitched seams. This seam construction prevents water from entering your wetsuit. Firstly, GBS seams are constructed by gluing the edges of the neoprene panels together. Usually, this is done 3 times to create triple glued seams. Thereafter, the seams are blind stitched together. Blind stitching offers additional strength: The needle doesn’t penetrate the neoprene completely, but only stitches through half of the neoprene panel to prevent leakage. More high-end GBS seams can be covered with a liquid neoprene seal on the outside and/or neoprene taping on the inside for extra seam reinforcement. The strongest blindstitch seam, only used without seal, is double thread blind stitch. This seam has double the amount of threads, making the seam extremely strong. Other stitching techniques used to stitch wetsuit seams are flatlock, overlock, e-stitch, double-needle, zigzag stitching, etc.
Liquid sealed seams
To reinforce a traditional glued and blindstitched seams, a seal can be applied on top of the stitching to create a sealed outside seam, mainly used on high-end wetsuits only. The liquid rubber seal gives it an extra layer of protection from water entering the wetsuit. It’s a more durable construction that lasts longer than normal GBS (glued and blind stitched) seams. The technical name for this seam construction is S-seal. Although not as good looking, s-seal is found to be more durable than powerseams.
A narrower version of a liquid neoprene seam without blind stitching on the outside. Usually, powersems have blind stitching on the inside of the wetsuit or are completely stitchless. Powerseams come in a variety of colours. Found to be less durable than s-seal or liquid rubber seals.
Taped inside seams
Some high-end wetsuits feature an even more durable seam construction by reinforcing the inside of the GBS or sealed seams by applying neoprene tape. Neotape inside seams make the seam even more waterproof by forming an extra layer of protection against water leaks. It also protects against seam irritation to the skin. Neoprene tape can be applied with normal glue, which can leave some glue residue visible on the tape’s edge. A neater way with better protection against skin rash is Neotape 2.0 or New neotape. These types of tape are machine heat-welded onto the fabric using a hot melt glue layer instead of being applied by hand by using the traditional method of brush on glue.
A much more cost-effective way to make wetsuits is using flatlock seams. Flatlock is a wetsuit stitching technique used mainly on warm water summer wetsuits, such as shorties or other wetsuits under 2.5mm thickness. A flatlock seam is not glued and not waterproof. During manufacturing the sewing machine needle penetrates both overlapping neoprene panels at the seam to create the most affordable seam construction used in wetsuits. Flatlock stitching can not be used in winter wetsuits, as it lets water through and won’t protect against cold. An even cheaper way of making wetsuits is overlock, these seams are rarely used on wetsuits, but can be found in very cheap products. You might see them more often on rashguards or other lycra products.
Inside seam joint reinforcements
Wetsuits get a lot of abuse from wear during surfing but especially when putting on and taking off your wetsuit. To prevent overstretching and damage to the seam joints and stress areas, a reinforcement patch can be applied on the inside to strengthen these fragile areas. The so-called Melco dots are a Japanese reinforcement material that is heat welded on to make a wetsuit last longer. Melco dots prevent overstretching, which can lead to tearing the wetsuit. It can be used as heat welded tape or heat welded patches or dots. This patch is usually found on the inside of the wetsuit where multiple seams meet in one place, or where less flexible material is stitched to a more flexible material to create an even stress release area.