Preparing Seams and Basic Seaming Considerations
©copyright 2002 by wetseal_rubber
From: Rubber The Right Way - A Condensed Primer on Making Your Own Latex Clothing
All seam preparations discussed here assume the use of solvent based adhesives.
- You can glue latex seams immediately after cutting. In loose garments, poorly joined seams peel away slowly over time. However, armpits, crotches, zipper bases, and some necklines experience considerable stress, particularly when putting on or taking off the garment. Under stress, poor joins often give way suddenly. As the stress is relieved down the opening seam, the first well-bonded section encountered usually redirects the stress, splitting the rubber in the process.
- Clean surfaces ensure a 'good bond' between two materials.
- A prepared clean surface ensures the 'best bond' between materials.
- Latex usually comes dusted with talc or other 'anti-sticking' powder. To get a 'good bond', wash all cut pieces of latex in a clean sink or bath tub using a weak lukewarm solution of plain yellow dish soap (or Johnson's Baby Shampoo). Rinse thoroughly and allow to dry completely without letting the drying latex touch itself.
- For some high stress areas, inflatables, and accessories glued on the shiny outside surface (such as pockets), you need a 'best bond'. Gently go over both sides of the seam to be joined using a very small rag and solvent in a well ventilated area.
- Pockets are particularly tricky to keep glued reliably. Many commercial latex manufacturers overcome this with rivets, but some rubberists dislike them. Lay the pocket out and very lightly mark its outside edges to be glued on the garment surface. Take a coarse rag and form a narrow tip with it. Apply solvent just inside the markings in about a 1/4" (0.7 cm) width and rub firmly. Go right to the top edge of the pocket. You will scour the shiny latex surface, preparing an excellent bonding site for the pocket. Do the same for the pocket inside edge to be bonded. Pockets done this way hold well without rivets provided care is taken to scour and glue right to the edge of the pocket.
Basic Seaming Considerations
Matching Seam Overlaps
- For best appearance, think through the pattern of seam overlaps as you assemble.
- Ex. On a tee-shirt with raglan sleeves, you join the front and back of the bodice (torso) and in a separate step join the sleeve around to itself. Afterwards, you set the sleeve into the bodice of the tee-shirt. When you join the bodice, decide if the front will overlap the back, of vice versa. Overlap the left and the right side seam the same way. Raglan sleeves are opposing cutouts. Ensure the left and right sleeve underarm seams overlap to match the side seams of the torso. You avoid that 'home grown' appearance when your seams match correctly.
- Latex 'stretchiness' is both an asset and a liability when seaming.
- Join seams with even pressure and tension on both the upper and lower layers being joined. Excess tension (lengthwise stretch) on either layer will cause rippling of the seam and curling at the hemline.
- On relatively straight seams, you can avoid this risk by applying low-tack masking tape to the side of the latex opposite the seam join before glueing.
- On tightly curved seams where one piece to be seamed is cut in a different direction than the other (crotch seams are a good example), some light and even stretching of the outside seam may be required to make the join. Join very small sections at a time for tightly curved seams. Curved seams may try to ripple or rise off the table at the ends as the curve is established. Only work the section of the seam that you can reasonably keep in contact with the table at a given time.
- Excess finger pressure in one spot when joining will cause small dimples in the seam because you are compressing the latex while joining.
- Take limited advantage of the latex stretch to make up the difference over the length of the seam when one side appears slightly longer than the other. Use very light tension only. You can safely make up about 1/2" (1.3 cm) over a 10" (4 cm) length of seam provided the material that is .43/.50 mm (.017"-.020") or thicker.
Seaming Start Points
Begin seams based on the most critical spot to be joined accurately. The following are a general guide:
- Shoulder seams- start at neck, trim at shoulder.
- Raglan sleeve seams- start at armpit, trim at sleeve hem.
- Adding set-in sleeves- start at shoulder seam (center top), fold the sleeve seam over itself in half with the glue side out to establish sleeve center top. Join at the center top and work towards the armpit on each side.
- Adding raglan sleeves- match seams at armpit, work towards shoulder on either side.
- Side seams with set-in sleeves attached- match armpit seams, complete sleeve seam, trim at sleeve hem. Complete torso side seam (and leg seam if needed). Trim at hem.
- Vertical bodice seams- start at neck or underarm, trim at hem.
- Inside leg seams- start at crotch, trim at hem.
- Outside leg seams- start at waist (or the underarm if needed), trim at hem.
- Other vertical seams from the waist- start at waist, trim at hem.
- Waistbands that are not 'pull up' (they have a fly, buttons, or skirt zip)- start at center back, work towards the front on either side, trim leaving a 'tongue' for closure if required.
- Continuous waistbands- start at the center back seam, finish and overlap there.
- Collars with an opening- start opposite the opening (if opening is center front, start center back) and match the center of the collar seam by folding the collar in half with the glue side out. Join the center and work around the neck towards the opening. Trim at the opening.
- Non separating zippers- set the zipper inside so that the stops at the top of the zipper sit at the edge of your intended hem or if no hem is needed, at the top of the material (ensure that any collar, waistband, or cuff is in place first). Start at the base of the zipper. Work up either side and end at the hem.
- Separating zippers- trim zipper and re-stop to fit space, start at neck or waist, making allowance for hems if required and set the zipper stops at the top of the intended hem (or if there is no hem, at the top of the material), end with allowance for bottom hem.
General Seaming Points
- Most latex is constructed using lap seams. Lap seams:
- Are where one piece of material is simply overlapped over another.
- Are flat, easy to construct, least intrusive on the smoothness of the latex, but appear 'industrial'.
- Are generally constructed with an overlap of about 1/2" (1.3 cm).
- When glueing seams in the round, such as joining raglan sleeves to the bodice or adding stockings / gloves to a catsuit, turn the garment inside out and use paper in the round opening to be seamed to protect the exterior surface from glue. Glue the seam in two halves, flipping the garment over between halves.
- When using latex that is glossy on both sides, ensure you join your pattern pieces with the proper side up (especially sleeves, pant legs, and bodice panels).
- Rub up excess glue from your work table after each seam is completed to prevent glue and latex crumbs from sticking to your work.