Hi there!

I have been reviewing your web site and found it very helpful! I am wanting to take on two projects for my best friend who is having a baby in March.
 
I want to have my friends' children decorate onesies and quilt squares (both 100% cotton). I obviously want them permanent and washable...so in your opinion should I go with the Marvy fabric marker or use the Pentel fabric crayons?

This is a great idea for a project. It's good to get the children involved. 
        
I personally prefer the Marvy markers to the Pentel Fabric Crayons. The markers are easier to work with, and their pigments seem to penetrate further into the threads of the cloth. 

The Pentel Fabric Crayons feel very much like oil pastels, to use; it takes a lot more work to fill in color, and, while heat is used to set the binders that hold the pigment to the fabric, the pigments do not really seem to soak in. The more a pigment remains on the surface of fabric, the faster it will wear off.

In my experience, Marvy fabric markers are not as permanent as Procion MX dye, though they are easier for children to use. Be sure to mark the items you have decorated with them clearly, "Do not use bleach!" Physical wear, such as the abrasion of clothing in a dryer, will accelerate the fading of markers and fabric paints. Whenever possible, turn the items inside-out before laundering, or place them in a mesh lingerie bag.

Another brand of fabric marker you should consider using is Jacquard Tee Juice, which comes in both thin and wide points, with the added advantage of allowing you to squeeze the pen to get more pigment coverage. They are otherwise similar to the Marvy Uchida markers. Both the Pentel "dye" sticks and the Tee Juice markers require heat-setting with an iron, which you can easily do. Marvy markers do not require heat-setting, but it's not a big enough reason to choose one brand over another.

In general, fabric markers will work better on 100% cotton than on synthetic fibers. Be careful that the fabric you buy does not have any stain-resistance or other surface finishes that might interfere with the pigment's reaching the fibers. The Pentel fabric crayons should be used only on 100% natural fibers, but both Marvy and Jacquard say that you can use their markers on cotton blends and synthetic fibers, as well. Given the choice, I think it's better to use them on cotton.

If you have a project that will use polyester or other 100% synthetic fabric (but not rayon), consider an entirely different product, Crayola Fabric Crayons, which are to be used on synthetic fibers only. They are used by having the children color on paper, creating iron-on designs, which you then iron on to the fabric for them. See "Iron-on Fabric Crayons for Synthetic Fibers". Unfortunately, you are not supposed to machine-dry items decorated with these polyester dyes. When my babies were small, I did not have time to remember to line-dry any of their clothes.

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