Welding to the frame OK or NO?

[SBK1000]

Is welding going to weaken the frame? is it better to drill and bolt on parts?

[Gixer1460]

Steel or aluminium - either is suitable. Steel is probably easiest for welding, ali is maybe best to use bolts. After all, the manufacturers didn't / don't heat treat their frames after welding!

[Swiss Toni]

If you're talking Harris...Bronze Welding. Similar to brazing. 

[Dezza]

Going further from what ST says, I suppose it depends on the material the frame is made out of, and how the frame was made. With a Harris frame you can get a good result working with the lugs weleded on by Harris and using alloy sheet/plate to mount things on, e.g. coils. I would also add that it also depends on what the intended outcome on building the bike will be. The devil is always in the detail and for example on an alloy framed bike, ancillaries mounted on welded-on lugs trump those bolted to frame spars when someone has obviously drilled a hole into the spar and then tapped a thread in the (relatively) thin alloy.

[SiBag]

As said above what frame / material ?

If its Raynolds tubing DO NOT MIG it. (you can get away with MIG Brazing).

Bronze welding is the preferred method, but you do find some frame builders using TIG on Reynolds tubing. (may depend on what grade)

[Gixer1460]

2 hours ago, Dezza said:

 The devil is always in the detail and for example on an alloy framed bike, ancillaries mounted on welded-on lugs trump those bolted to frame spars when someone has obviously drilled a hole into the spar and then tapped a thread in the (relatively) thin alloy.

Don't see why - there are plenty of Suzuki fitted RivNuts applied to GSXR frames so would be an alternative method !

Any method -  brazing, welding with TIG / MIG / Stick, bolting or gluing (yes its possible) is only as good as the muppet doing the work!

[kiwi]

Like above what Material ?, plus what are you trying to attach or add on ?

[nlovien]

picked up another wee tweak last week - bronze welding ( or is it brazing ?) anyway using TIG takes a bit of learning when you use rods that have good strength and dissimilar metal or chrome moly compatibility - also, although much less heat than actually welding the bits - still needs a fair amount - ok thats the high stress parts

use a basic bronze tig rod ( low silicon)  - cheap, flows easy on low heat for all your other needs  - recon you could include bracing flanges in this list, where there isn't an obvious high bending force across the work - TBH i'd be confident using this stuff on any steel based frame as a means to stick low stress bits onto it - i'm using maybe 40 amps with a bit of higher pulse just to start it off, once it starts flowing - maybe down to 30 amps

[dupersunc]

Those Bronze tig rods are mint, make a lovely job.  Silicone Bronze is not suitable for 4130 Cro-moly though.