Will be fixing the bike rack very soon.  My  1998 Opel has, on both roof edges, usually covered with molded plastic, a water channel.  I've removed the plastic, totally unneeded now.  This channel has in the center a projecting upright piece about 5mm tall.  The thickness of this steel is about 1 or 2 mm.  I plan to weld a strip of angle iron onto the upright piece in 2 places on each side giving me 4 supporting members.  Then onto these i'll be fitting, maybe bamboo, strips to support the bike.

 

Q for you guys is what is best thickness of angle iron?  I'll be tacking along top and edges of projecting piece.  

Sorry to say but sounds like an unsightly bodge job. Cars are made of thin steel, angle iron is usually quite thick. Welding 2 metals of different thicknesses together is not easy. I would suggest searching lazada and/or hardware stores/Amorn shop for some kind of clamp instead. A photo of the section might bring suggestions from others.

How right u r Lad.  I gave it a shot but started to burn up the car metal before melting the angle iron.  The differential was too great for me to handle: i'm a welding beginner.  I'll try a auto body shop.

I would use clamps but there is very little space.  I will look again, maybe a tiny bolt could fit.

 

botch it enough, and it may become noticeable to a Land Transport Dept patrol

 

 

 

19 minutes ago, jobin said:

How right u r Lad.  I gave it a shot but started to burn up the car metal before melting the angle iron.  The differential was too great for me to handle: i'm a welding beginner.  I'll try a auto body shop.

I would use clamps but there is very little space.  I will look again, maybe a tiny bolt could fit.

Hope you remembered to disconnect the battery before welding, if not it can damage the diodes in the alternator.

4 pieces of 2mm thick 35x35 mm x 100mm long angle iron cut one side down to just under 20mm  2 6mm holes in that side place in roof side of water channel  35mm side against centre  (can position where factory holes in plastic strip are may be able to re-use) drill 8 6mm holes down through channel and roof lining (will have to remove all the upper plastic trim panels and lining to avoid) 8 button head bolts from the inside washers & nylok nuts in channel you then will have 4 100 mm stripes about 30mm high you can weld or bolt to,Bob's your uncle job done.