Hi guys and the answer is yes each pass through a solder temp cycle destoyes the board a little more. most .062 1 oz plated boards can only withstand 2 or 3 cycles before they start to crack at the via to joint. now as most things are cumilitive and definable it may take 4-5 to acualy open but I have and can easly find cracks starting as low as 2 cycles. remeber the board manufacturer takes two cycles away because he hot oil reflows and he oven cures for solder mask. I have a chart where I did a test of copper thickness vers's heat cycles. 1 oz fialed in 5 to 7 cycles ( no pcb manufatures cycles) 2 oz survived 7 to 12 3 oz 15 to 20 4 oz threough 10 oz were not realy affected. it appears that the heaver copper vias are able to resist the push of the expansion forces happening when you solder. the initial question was does high temp affect a board and the answer is more then you think. So if you want a very reliable board add extra plating, this can be done quite easly by starting with 1/4 oz copper and use 3 or 4 mil dry film and plate up . The etching is faster and the line definition will be much better, but best of all your board will withstand twice the relfow solder cycles. Robert tarzwell author of high powered printed circuits and, flex circuit design Megadawn.com --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------