I was asked to build a live bait rod for a 8 year old. His father wants it to be 6 to 6 1/2 foot regular conventional (I'm trying to talk him in to a spiral. I'm thinking a Seeker CLB since it's composite and will be lighter then a E-glass.
Anyhow, My question! What do I need to know about him? arm length? height? weight? I know I need to find out what reel and line test. I really only have built for my self and never for a kid.

Shorter may be better for a kid. Just don't trim from the tip to get the length you need. the tip is where all the action is at in a live bait rod.

John, for a comfortable butt grip have him hold a baitcasting rod by the reel plate like he normally would when reeling in the line. Measure the distance from his hand just past his elbow when his bicep/forearm are in the 90 degree position. That is the length to build the butt grip.
Did that make sense ????????????????????

It makes sense except I can't have the kid do that since it's a surprise for Xmas. I have his height as 40" and arm length at 18". It's going to be a spiral and the blank is an old NOS Fenwick E-glass LB model I had in stock.

John, are you sure he's 40" tall?
My 4 yr old is 43" tall.........
Steven

Well, I can't be sure but that's what I was told! His old man isn't very big...... about 5' 5". I can only go by the info I got from him. Either he's small or your kid is big!!

John ,
I would build this as a 6 foot rod, with a 9 inch back grip and with no fore grip or a 2-4 inch fore grip.
I would size the grips to be no larger than 1 inch.
At that age, the hands are not too large.

The spiral is a good idea if you want to. However, a conventional rod will be good as well.

Take care
Roger

I agree with roger here. 8-9" rear grip and a 4" fairly small diameter foregrip. Spiral wrapped will be nicer for the kid when fighting a fish, I only can look back and wish I was using them on certain occasions...the word amberjack comes to mind. And if you think futuristically, the only really available spirals are all custom rods anyways, so he will try one store bought conventional at some point and never use another one because he has been spoiled by the quality difference in a custom spiral. Basically equates to more business for you is what I am getting at (and doing a bad job at it I might add).