I have it in mind to make a red and white quilt. I have heard that dyes can be set with either warm water and vinegar or cold water and salt. Has anyone had any luck setting red dyes so that they don't bleed on the white fabrics?

I use color catchers.

I did the quilt in my avatar and just washed it with a color catcher when finished...no bleeding! There are dozens of red prints in the quilt.

The dyes commonly used on cotton fabrics work best in an alkaline environment. A small amount of vinegar (say a tablespoonful per full washer load) may help keep the pH low enough not to break the molecular bonds of the dye particles with the fabric receptor sites.

Salt does very little; it is used as a booster in a dye bath with fibre reactive dyes to make the dyes less likely to react to the water molecules, which leaves more dye molecules available to react to the fibre receptor sites.

If you're really concerned, I suggest washing with Synthrapol (or Dharma Trading's knock-off version). Synthrapol is as close to a neutral pH as a detergent can get. Pre-wash in warm water (unless you have an old pre-Energy Star washing machine; if you have an oldie, pre-wash in cold).

After the quilt has been made, wash in cold water with Synthrapol (or Dharma Trading's knock-off).

I've tried all the methods listed above and all have failed on certain fabrics, certain being kona. Just make sure you prewash and test the bleeding before you start cutting.

yes vinegar in the washer with the material does set the color. Always wash on cold though.

I just test my reds before I use them - never prewash. I wet a white washcloth and rub the fabric.

Never having pre-washed, I only once had a red bleed. Found that out the hard way... Ever since, I've tested my reds as above. Not one has bled since. I think reds get a bad rap!

There's been ever so many threads on this subject and specifically about red, vinegar and salt.

While I recognize perhaps you have not read them, might I suggest you use the search function above and you'll have more than you ever wanted to know, to make your decision on the matter.

Good Luck!