prewashing/preshrinking fabrics?

[Honduh Chicken]

Do you have to prewash your material before you use it?

My situation, I have hemp, OBV, and PUL that i'm going to be sewing to make diapers, what would happen if I just cut and sewed together?

[oneofsix]

The material would shrink and could pull away from the stitching and pul. If you made a fitted and all was unwashed then when you washed it it would all shrink up. Also you will have to wash before first use because it won't be at all absorbent. And if any of it is colored esp dark colors it will bleed onto everything else. Including babies butt.

[Honduh Chicken]

Originally Posted by oneofsix The material would shrink and could pull away from the stitching and pul. If you made a fitted and all was unwashed then when you washed it it would all shrink up. Also you will have to wash before first use because it won't be at all absorbent. And if any of it is colored esp dark colors it will bleed onto everything else. Including babies butt.

well that wouldn't be good. I'll wash first.

Next question, if it will shrink, I should cut oversized squares out, wash/dry them, THEN cut my pattern out, but how much excess should I leave on the square? I mean is it going to shrink down to 3/4 it's original size? or will I lose an inch around the whole thing? or what? Also, If I wash it will it destroy the fabric with unfinished edges? I don't have a serger, so I can't serge the edges of the squares before I wash them, will they be okay in the wash this way? or should I somehow seam the edges first?

Thanks.

[WeeEssentials]

Wash the whole yardage first, and dry it on hot/cotton dry so it will shrink the maximum amount. Then you should be safe to cut it out, and it's a whole lot easier than trying to guess how much it will shrink. I use a lot of flannel and bamboo, and it's anyone's guess as to how much a particular yardage will shrink!

It won't fray a whole lot with unfinished edges. You can usually just cut the strings off and go. My experience with bamboo (I use loop terry and fleece) is that there were no strings at all that had come loose. Flannel and woven cotton I usually have to pull a couple strings off that have come partially loose, but they tend to tangle in the washer and dryer which makes it pretty easy then to remove all together.

[Honduh Chicken]

Originally Posted by cmarie14 Wash the whole yardage first, and dry it on hot/cotton dry so it will shrink the maximum amount. Then you should be safe to cut it out, and it's a whole lot easier than trying to guess how much it will shrink. I use a lot of flannel and bamboo, and it's anyone's guess as to how much a particular yardage will shrink! It won't fray a whole lot with unfinished edges. You can usually just cut the strings off and go. My experience with bamboo (I use loop terry and fleece) is that there were no strings at all that had come loose. Flannel and woven cotton I usually have to pull a couple strings off that have come partially loose, but they tend to tangle in the washer and dryer which makes it pretty easy then to remove all together.

The whole yardage? Well I have 5 yards of hemp, and 5 bamboo, and 4 PUL. Is it okay to put that much in the wash? Should I drape it in there, or leave it folded up and just drop it in? Sorry to ask so many questions, just never did anything like this before.

[yakochica]

It depends on how big your washer is and the color of the fabric. The biggest thing you need to be concerned about is the colors bleeding in the wash; the colors are similar like then it should be fine but if they are different like yellow and red I would wash them separately otherwise your yellow might turn orange. It is best to unfold and drape things in the washer.
As far as how much to put in your washer is something you will have to determine. If you decide that it can all be washed together then put it in the washer until it is full and then do a second load with the remaining fabric.

Also: wash the fabric in hot water, this will help set the colors meaning they will not bleed when they get wet.

Hope this helps =)

[Honduh Chicken]

Originally Posted by yakochica It depends on how big your washer is and the color of the fabric. The biggest thing you need to be concerned about is the colors bleeding in the wash; the colors are similar like then it should be fine but if they are different like yellow and red I would wash them separately otherwise your yellow might turn orange. It is best to unfold and drape things in the washer. As far as how much to put in your washer is something you will have to determine. If you decide that it can all be washed together then put it in the washer until it is full and then do a second load with the remaining fabric. Also: wash the fabric in hot water, this will help set the colors meaning they will not bleed when they get wet. Hope this helps =)

okay GREAT! The only "color" I have is lavender PUL. The hemp and bamboo aren't died. so they're more of an off white.

thanks again for the info.