Never had any dealings with that material...but it appears that it is very weldable according to this:
http://www.alloysinternational.com/category/6/Aluminum-2219-Sheet-Bar-Plate.html

http://www.thefabricator.com/article/aluminumwelding/weldable-and-unweldable-aluminum-alloys

Only two common structural alloys in the 2XXX series are weldable: 2219 and 2519. Alloy 2219 is very easily weldable and has been extensively welded in fabricating the external tanks for the U.S. space shuttle. This alloy gets its good weldability because of its higher copper content, approximately 6%. A closely related alloy, which is also very weldable, is 2519. It was developed for fabrication of armored vehicles. Although there are detailed exceptions to this rule, the designer should probably consider all other alloys in the 2XXX series to be non-weldable. - See more at: http://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/aluminum-design-mistakes-detail.aspx#sthash.mSu6qVuu.dpuf

Here's an interesting paper on scandium containing 2319 filler metal for GTAW of 229 Al:

http://www.igcar.ernet.in/transiim/2004/TP-1902.pdf

As is this one from NASA:

http://oce.jpl.nasa.gov/practices/1205.pdf

This one is also from NASA although it's a bit ancient as it was published back in 1962 (Note: It may take a while to upload this .pdf):

http://ia600300.us.archive.org/35/items/nasa_techdoc_19630013148/19630013148.pdf

This is from the Sarabbai Space Centre in Trivandrum, India:

http://www.ias.ac.in/jarch/bms/19/00000561.pdf

This one is a better written article:

https://www.jstage.jst.go.jp/article/jmmp/1/4/1_4_469/_pdf

Here's a nice little welding guide for Aluminum you might find useful:

http://maxal.com/files/QuickSiteImages/Maxal_Guide_for_Aluminum_Wldg_9-12_doc.pdf

Oh! And finally, here's a great site to visit and explore a huge variety of articles with 2219 Al as one of many topics related to the metallurgy and welding science of this alloy:

http://www.science.gov/topicpages/a/aa2219+aluminium+alloy.html

Of course there's more but why bother when you now have a link at you disposal such as the last one above that should help you out in other ways with respect to other topics of interest in the future!

Enjoy!

Respectfully,
Henry