Dealing with warped parts

Jon, have you got a hot hobby knife yet?  I would get one of those for this kind if thing. It sliced through the abs like butter. I would use a zip tie to clamp them into place, fuse them in a vapor bath, use the knife to mate the edges cleanly, sand with a belt sander and give it one more bath. It has been my process for joining large prints and I've been quite pleased.

I think he means to go ahead and fuse them together with the edges aligned closely as you can through the brute force of the zip ties.  Some edges might still be sticking out a little, so trim or sand them flush, then clean up the mess with another shot of vapor.   If the dimensions of the final pieced together part are critical. then this might not be good enough.  If it just needs to look good and you have a couple mm to play with you might be able to get by.

Even if it isn't the intention, or you will paint it later, I think the alternating black/white sections look cool.

Ian hit it right on the head. With that design, you could put zip ties at the top and bottom and get them pretty close to aligned. Then a quick vapor bath would fuse them together so that you could work on cleaning up the whole thing together. Then one more shot in the bath to give it a polished look...  Another suggestion that I've tried on pieces needing closer tolerances and you don't want to remove any material if possible, is to clamp them together, again probably zip ties in this case, and bake them for a little while. If you set your oven to 200-300 and let it sit for a while, it may try to unwarp into the an easier mate.  Then go through the above process.  I've tried this a few times and it seemed like it worked well, but I'm not sure if it was dumb luck or a great idea.

The nylon has a similar melting range of ABS, but should be fine at 200-300*F  I think it depends on the exact kind of nylon that is used as some melts lower and some melts higher than the transition of ABS.  I wouldn't expect it to deform your parts much, but when I tried, it did remove the small warping, letting the parts line up better.  I did take it straight from the oven to my vapor bath so that it would fuse together while still hot and mating well.  Sometimes these parts have a tendency to warp a decent bit over the next day or so.  It is better to let them warp together if they do warp at all. 

It took about 10 minutes in the oven when I tried it.  I just put a webcam in the oven and monitored it from across town and then used my iphone app, post-process pre-presto (C), to jack it up and give it a quick broil to crisp the edges before shutting it down immediately.

I printed an ipad stand, it warped like crazy,
had to print thing thing 4 times due to clogs or step skips, was just about to give up when I finally finished.

the straighten the warped parts I put it into a low oven for ten minutes, to soften the whole model, then bent the whole thing so that it sat flat on the table.

you may find this useful warm the whole part then make the little adjustments that you need to make to the model to get it to all fit together.

Maybe create a  tab on the part that you can cut away after the parts have cooled.