Dyeing bra fabrics, laces, elastics and notions is ridiculously easy and quite economical since I want to make multiple different bras with my limited stash. I purchased many yards of this very nice quality nylon/spandex white galloon lace at FIFTY CENTS a yard over a year ago at a clothing & lingerie manufacturer's warehouse sale. I need only so many plain white bras. I used plain white everything else for dyeing purposes. Note that polyester materials will not dye well, or at all. All of my stuff here is a nylon based, the rings and sliders are nylon coated. I used a medium/heavyweight powermesh and a nylon/spandex fabric that might technically be a swimsuit fabric. My wide elastic for the bottom of the bra was a surprising polyester/spandex and took on only a hint of my dye. It somehow didn't get photographed above but it's evident in the finished bra pics.
I dye all my materials before sewing because there may be variations in the dye job on the fabric, I can cut around them if it happens, but I've not had that issue anyhow. For this green bra I used liquid RIT dye in Apple Green (I know, the photo has brown). I often will mix colors for custom shades but I kept it straight up green today. I use a large pot usually meant for canning and a plastic spork thingy, both I've allotted for dye jobs only... no cooking ever with these. I cut the recommended amounts of fabrics and elastics. I fill the pot about 1/2 full with hot water, place it on my stove to heat it while I dye... but flip the heat off after 5 minutes so. I used about 1/3 of the bottle of RIT dye and about a 1/2 cup plain white vinegar. The vinegar helps the dye to do it's job on nylon materials.
I pre-wet my materials with plain tap water-- this allows the dye to absorb evenly when you dip it in, helping it to not soak up in some weirdo way causing a messed up, uneven dye job (this has happened to me before). I throw EVERYTHING in. I toss in the itty bitty bits first (the sliders & rings, the hooks and elastics) so they don't get wrapped up, lost and wonky mixed in with the larger bits-- the fabrics. I use my mega spork to constantly stir (*gently* for a maximum non-splashing experience). Constant agitation makes sure I have an even dye job-- letting it sit quietly in the pot un-stirred=icky, uneven color (been there, done that). I keep it moving. I usually leave it all in about 10 minutes or so until I see a color result I like. So no one is breaking their arm stirring a pot of bra stuff.
I fish it all out with my spork or go right in the pot with gloved hands-- the reason why I don't REALLY heat up my dye water to boiling or something. I toss it all in a plastic bag, run to my basement to pour the pot of dye into a slop sink that has years of dye and paint splatters already on it... no worries there with dye. I rinse my bra materials then hand wash them with detergent. Then everything air dries on plastic hangers above the same sink in case I haven't washed the dye perfectly out and residual dye drips down.
I used my very favorite bra pattern here: The Orange Lingerie Marlborough Bra. You can see previous ones I've sewn and my alterations right here on past blog posts. The basics: I make a 38B, altering the upper cup and bridge for my figure.
Yes, I forgot to dye any lining fabric and that support elastic across the lacey upper cup. But I did use a non-stretch beige nylon tricot for the cups-- the green nylon/spandex fabric on the outside is pretty stretchy and needed to be stabilized. The beige elastic on the lace upper cup is a 1/4" (.635 cm) wide. You can see how the wide elastic on the bottom of the bra is a faint green-ish color... this ended up being a polyester based material that doesn't dye well with the dye I used. There is RIT dye for polyester but that stuff is wicked nasty toxic smelling and gross to breath in--- I used some of that stuff to dye my wedding dress a crazy pink to make a new dress from it last year.
I had a little fun improvising with my laces. I added a bit next to the hook and eye bits on back. I also extended the lace of the side seam. To hold it in place, I just use a small zig zag stitch around the lace edges.
I made my own little bow from a roll of skinny ribbon. It was already green, no need to dye! I love these shades of green. As soon as I saw the dried materials after dyeing I realized that it's the exact same color as the green shag rug I had in my bedroom growing up.