Message: Hi,
I wanted to colour my dress and sell it. It says it's 100% cotton but I don't know about the material used to sew the dress. If it happens that the sewing thread was not cotton, what do I do?


If the dress is not marketed as having cotton seams, then it is almost certain that the seams are sewn with polyester, which will not take the color from any cotton dye. In some cases, the undyed stitching looks like a decorative touch, but in others it will ruin the style, making a more formal dress look too informal.

It is impractical to try to dye the stitching. You could boil the whole dress in polyester dye, such as Jacquard Products' iDye, but this requires the use of a very large cooking pot which will never again be used for food. A good dyeing pot is an excellent investment if you will be doing a lot of hot water dyeing, but it is too expensive for a one-time use. It is possible that the polyester dye may temporarily stain the cotton, and wash out gradually, giving the impression of non-washfast dye. Another way to dye polyester stitching would be to buy disperse dye fabric crayons and color with them on paper, then iron them on over the polyester stitching. Excess disperse dye that is inadvertently placed on the cotton will eventually wash out. Considering how many meters of hems there are in even moderately-sized garments, I cannot recommend this approach, because it will take too much time and trouble.

It is sometimes possible to find undyed cotton clothing blanks which have been sewn with cotton thread. Look for clothing blanks labeled PFD (for "Prepared For Dyeing"), RTD (for "Ready To Dye") or PFP (for "Prepared For Printing"). Searching with these keywords may help. Most sellers of PFD clothing have minimum orders of at least ten garments. I do not know of suppliers of PFD garments in the UK, where you are, but there are some in the US, such as Dharma Trading Company, which sells a wide range of dyeable clothing sewn with cotton thread, with no minimum purchase. Perhaps you will be able to find a local source. PFD, RTD, or PFP garments have additional advantages for hand dyeing, in that they will be free of starch sizing and other surface finishes which can interfere badly with dyeing.

If that fails, you should be able to find a local tailor or seamstress who can sew for you. There are then two possible approaches. One is to have them sew garments using undyed but prewashed natural fiber yardage and dyeable cotton thread, which you can then dye as you like. The other approach is to dye your own fabric yardage, using any dyeable natural fiber, and take it to be sewn into garments with an appropriate matching color of polyester thread.

(Please help support this web site. Thank you.)