How to control tension when knitting t-shirt yarn bags

What does “tension” mean in t-shirt yarn?

Tension is how tight or loosely you knit: the force with which you hold the yarn, the actual size of the loop, and the space you leave at each stitch. It's more noticeable in t-shirt yarn than in other materials because:

• T-shirt yarn usually has elasticity and "memory" (it stretches and returns).
• There are natural variations in thickness, which amplifies changes in hand.
• The bag needs structure , so any irregularity is visible in the shape.

Objective: a constant and suitable tension for the structure you want (firmer or more sagging).

Signs of incorrect voltage (quick diagnosis)

If your blood pressure is too low…

• The base is wavy or has "ruffles".
• The walls give way and the bag “opens”.
• The stitches look large and the fabric seems loose.
• The bag lengthens with the weight (especially in the handles and top edge).

If your tension is too tight…

• You struggle to get into crocheting and end up with pain in your hands/forearms.
• The base "bows" (curves upwards) or shrinks.
• The fabric becomes very stiff and loses its drape completely.
• Visible marks or changes appear between weaving sessions.

How to adjust your blood pressure without going crazy

1) Adjust the tension with 3 levers (in this order)

1. Your hand: loosen or tighten your grip on the yarn and adjust the size of the loop.
2. Crochet: if it's too tight, go up a little; if it's too loose, go down a little (or compensate with your hand).
3. The point: a more compact point (low point or centered low point) gives structure without the need to "tighten to death".

2) Make a mini “useful” sample (not 10x10)

For bags, a practical sample works best: a circle (base) of 8–10 rounds or a small rectangle. That tells you if it ripples or curves, which is what matters.

3) Learn to “read” the fabric

• Compact + flexible texture: this is usually the ideal tension for everyday bags.
• Very rigid texture: you're probably squeezing too hard.
• Very open texture: you're probably too loose or the point is too high for the structure you want.

Perfect base: the point where it's most noticeable

Your foundation is the "thermometer" of your blood pressure. If your foundation is good, almost everything else will fall into place.

Wavy base (ruffles)

It usually happens for two reasons: excessive increases or too loose a tension .

• First, check that you're not increasing it too much.
• If the increases are good, tighten the tension a little or lower the crochet hook by one stitch.
• Another tip: switch to a more compact spot for the base.

Base that basins (rises)

It is usually due to a lack of increases or excessively tight tension .

• Check if any increases in the turns are missing.
• If the sequence is correct, loosen the tension or increase the crochet hook by one stitch.
• Do 1-2 more rounds and reassess: sometimes the circle "settles" with a little height.

Walls and edges: maintain consistency

How to avoid “switches” between sessions

• Start each session with 5–10 “warm-up” points (this can be in a separate sample).
• Try to repeat your posture: same chair, same hand height, same type of grip.
• If you notice you're more tense that day, compensate by using a slightly larger crochet hook or loosening the loop.

The upper edge: where the tension is “sung”

If the top edge opens or becomes uneven, it is usually because at the end of the project we relax our hand or change the rhythm.

• Finish with 1-2 compact turns with controlled tension (no looser "because you're almost done").
• If the bag will have handles or hardware, the firm top edge helps prevent it from becoming misshapen.

Practical 5-minute routine to stabilize tension

1. Breathe and release hands: open and close your hand 10 times and relax shoulders.
2. 10 warm-up stitches: Knit 10 stitches on a strip/sample. Adjust yarn over until smooth.
3. Check texture: touch the fabric: it should feel compact but flexible, without "boarding".
4. Return to the bag: knit a complete round maintaining the same rhythm.
5. Quick check: prop the bag/base up and see if it holds its shape without extra tension.

Typical mistakes (and how to correct them)

Error 1: pressing to “give structure”

Tightening too much gives rigidity, yes, but it also deforms the base and makes you suffer.
Solution: Use compact stitch + appropriate crochet hook + reinforcements where needed (edge, handles, base).

Error 2: accidentally changing crochet hook

Sometimes the crochet hook "looks" the same, but it isn't, or you switch to a different crochet hook material with a different glide.
Solution: Keep the same crochet hook for the whole bag (or make a note of when you change).

Error 3: tensioning differently when closing turns

The closure is noticeable as a vertical “mark”.
Solution: Keep the same loop when closing and check the closing column every couple of turns.

Error 4: knitting for many hours at a time

The hand gets tired and the tension changes.
Solution: short breaks, stretch fingers and come back with 10 warm-up points.

FAQ

How do I know if my strap tension is "correct" for a handbag?

If the base stays flat, the sides don't splay out with use, and the fabric feels compact yet flexible, you're on the right track. The bag should maintain its shape under the actual weight without becoming plank-like.

Is it better to tighten or use reinforcements?

Reinforcements. The professional structure comes from distributing stresses (edge, anchors, base), not from tightening each point.

My foundation is wavy, do I need to undo it?

It depends on the level. If it fluctuates a lot, it's usually best to correct it soon (increases or tension). If it's slight, it sometimes stabilizes when you build walls, but it's advisable to check before continuing.

Can I change the tension halfway through to make it firmer at the top?

Better not. Instead of abruptly changing tension, reinforce the top edge with 1–2 tight turns or add internal structure.