welding steel base or just getting aluminium extrusion

[Desertboy]

I only have 15mm Hiwin's but I have originals on the Y axis and clones on the X I can't see a difference but let's see in a year lol.

Would I buy clone again without blinking but get the right clones so the rail is compatible (Like mine) then you can swap original Hiwin's carriages onto the rail if you're carriages ever failed.

I was thinking of buying 2nd hand next time
http://www.ebay.co.uk/itm/THK-NSK-IK...19.m1438.l2649

carriages can be repacked with new bearings if needed which is essentially a recondition as long as the rail is not nicked. I have seen lots of 2nd hand rail never seen it physically damaged, rusty yes but not chipped. The carriages are what seize on old machines left outside. The rails do go rusty but much slower than normal untreated steel possibly due to years of greasing in their pasts.