I have lost my mind...
 

...as I've found a challenge, so, I'll cope! Ok. I picked up a bag of hundreds of triangles, in ten different colors, all solids, already cut for $1.00. ( Don't tell me you don't get inspired from time to time and have lots of "great ideas" floating around in your head! :D )
Anyway, they're all 3" on the straight of grain edges, and just a hair over 4" on the bias edge.
I'm considering a dutchman's puzzle block, and can find lots of info on making flying geese units from squares, but none for using pre cut triangles, and I need handling guidance for these small triangles, as well as how to sew them so the tips don't get sewn into the seams when the units are joined and then the finished blocks are joined.
Does anyone have a video so I could see how it might be done? (Truthfully, the later it gets, the harder to follow written directions! :p
Other blocks might work better, like broken dishes, so I can sew together the bias edges carefully, then only have to deal with the straight grain edges.
Thoughts?

I would experiment with spray starching the triangles before you sew them together. Starching stabilizes fabric so bias edges are less likely to distort when you machine sew them together. There are some tricks to using starch, though, and depending on the quality of the fabric spray starching may cause the pieces to shrink (thus distorting them).

Honestly, since the triangles are already cut out, I think this would make a good hand piecing project. It's much easier to avoid stretching bias edges and make joins meet with hand piecing, and you wouldn't have to spray starch. Jinny Beyer has a DVD out that demonstrates her method of hand piecing (which is very fast). Also, there are a couple of HGTV Simply Quilts excerpts of her demo'ing hand quilting. I posted the link to the HGTV videos in another thread. I can find them and repost here if you are interested.

That would be great, Prism! Any and all info is helpful!

I had some pre-cut units that were on the bias. I used tear away interfacing. Ask at joann's, you can buy it by the yard. Pellon Stitch 'N Tear is one type, it's 20 inches wide. Cut a piece about 24" or so, by the width of the the interfacing. Lay the interfacing down, then a row of the 2 pieces of fabric, right sides together, matching the edges of the triangles with the right edge of the interfacing. Pin the triangles in place to keep them from falling off. Now sew your 1/4" seam thru the fabric and interfacing. Fold the interfacing back on itself at the seam and tear it off at the quarter inch seam. The interfacing keeps the triangles from stretching and also from getting 'eaten' in the plate. Since you only loose 1/4" of the interfacing with each bunch of triangles, you can really sew a lot with one piece.
You actually can use paper for this. Adding machine tape, THIN copy paper etc. The stabilizer is made to tear away so it's easier to remove.

Also, for any pattern that uses a flying geese patch, you can always substitute 2 half square triangles. You will just have an extra seam.

I think doing BOTH suggestions would help. I do spray starch fabric and I have use cheap computer paper as a stabilizer. GOOD LUCK !!

Are these HST or quarter square triangles? What they are will determine what you can do with them. For QST thousand triangles would work....and many other patterns too. HST are almost usable in many ways. Have fun

They are all HSTs. I'm floored at all the block options out there, but heaven knows I'll be making most of them "the hard way" ! LOL!

Sounds like you have half square triangles. 3" on the 2 straight grain sides, and just over 4" on the bias edge. They should be 4 1/4" on the bias edge, though, unless the corners were trimmed off, in which case just over 4" sounds about right.

I actually prefer making half square triangle blocks by sewing on the diagonal of a square (two stitching lines 1/4" from a diagonal drawn line). There are also methods for making larger numbers of half-square triangle blocks.

But since they're already cut, I'd probably choose some kind of block that didn't just require you to sew two of these together, such as making some quarter square triangles to connect to the half square triangles, or something more complicated.

How about sewing 2 HST's together making a square. And then cutting them all down to the same size.

A friend did this, using white for the opposite colored triangle. She pressed open all the seams and make a quilt featured by Laundry Basket quilts. The HST's made a WOW quilt.

Take them back!!!! HA HA I did that once at a garage sale for 50 cents and I could not figure it out, It was flannel and I finally made a cat blanket. Good luck