: Just started on my shear strip. Doing the scarf joints as I go.

Off the forms, scarf together enough strips to make 6 or 7 strips that can go the full length of your boat -- and then some. Put down newspapers. Work on the floor if you don't have a long enough table. You'll find these few full length strips very useful for aligning the forms, and if you staple a few on they'll stabilize the forms a bit, too.

: The one scarf joint I did last night moved 1/32 in. will this sand out?

Depends on which way it slid. If you are working with bead and cove strips then the cove will be more of a problem at this point that the bead.
If it sliped at the scarf then there is also a chance that it is not straight.

If it moved sideways, then even if you taper the wood gently on each side of the error you'll still end up with a strip that is narrower in the middle than at the ends. Fitting the next strips to this might lead to gaps, or you'll have to force the strip to bend a bit into the area where you sanded.

Safest bet at this point is to make a couple of good full-length strips for our shears, pull off the one that is there, and replace it. It will take as much time to replace it as to fix it, so you might as well get a good start with a fresh, straight strip.

You can cut out the bad scarf later and use those strips in other areas, so all you lose is about 3 inches of wood strip.

After you get a few full length stips on the boat you can use shorter strips. Butt joints work just fine for these. you may want to trim 1/2 inch off the ends of the strips, though, to get a fresh, clean, neat cut. Old lumber tends to discolor slightly on the ends, probably from humidity soaking into the exposed endgrain. removing this makes the joints less noticeable.

hope this helps

PGJ