zim Posted April 18, 2011 Share Posted April 18, 2011 Evening, Not LR related, sorry My brother is looking for another cage for his track day peugeot 106. OMP do a chromoly weld in cage. I've been searching google, and have read mixed reviews about not using mig on it ? What are peoples thoughts ? If it's tig...then i'll get him to buy the half welded cage to save us work ! Cheers Gordon Quote Link to comment Share on other sites More sharing options...
forkrentfitter Posted April 18, 2011 Share Posted April 18, 2011 i think custom cages can supply a suitable mig wire for cromoly,but it is kin expensive!!!!!!!! Quote Link to comment Share on other sites More sharing options...
B reg 90 Posted April 18, 2011 Share Posted April 18, 2011 You want the right wire to get a weld that has the same properties as the tube, other wise your buying fancy high strength tube then doing a mild steel weld at the ends, kind of defeats the point... However before you buy a chrome molly tube consider the heat treatment side. Cromo tubing will be available in different conditions, i.e. annealed up to be heat treated to get a higher strengths - they will probably be using anealed tube otherwise it would be a bugger to bend. When you weld the tube the welds will cool rapidily and create a hard 'brittle' (compared to the tube condition)section at and around the weld (Heat affected zone - 'HAZ'). Theoretically to get the same strength/ductility through out the cage you need to do post weld heat treatment. That said I understand that it's rairly done. Adrian Quote Link to comment Share on other sites More sharing options...
longlandy Posted April 19, 2011 Share Posted April 19, 2011 Nothing to add to the above other than tig is my prefered, though there has to be enough weld bead as is specified on structural drawings for other critical/load bearing parts. All to often one sees a tig weld with just a surface fused joint and undercut Quote Link to comment Share on other sites More sharing options...
dangerous doug Posted April 19, 2011 Share Posted April 19, 2011 all the frames on my bmx (that i havnt broken) have been made from 1430 cromolly there ALL tig welded, for that sort of thing you would have thought mig would be the cheaper quicker option but there all tig. enough said i think. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted May 14, 2011 Share Posted May 14, 2011 or is it 4130 cM ? If so then er70-s6 tig rods is what I understand to be the babies, and erm "Not Cheap" is an understatement However, you need to be sure what spec the CM is so that you can match to the most suitable rods, guessin' is not a great idea Posty up spec of the tube ? Nige Quote Link to comment Share on other sites More sharing options...
brighouse shed Posted May 14, 2011 Share Posted May 14, 2011 Nige is spot on, TIG only as it's a controlled weld so good heat spread, essential you get spec of alloy then select rod, if you struggle try metrode who are superb and they will sort you. As previous post usual quality rules about undercut apply. Quote Link to comment Share on other sites More sharing options...
Kobold Posted May 18, 2011 Share Posted May 18, 2011 TIG +1 Quote Link to comment Share on other sites More sharing options...
inaine Posted May 18, 2011 Share Posted May 18, 2011 There will be bits you wanna Tig and bits you'll wanna Mig If wires expensive then Tig will work out cheaper, remember to cut the holes in the floor and drop the cage down to do round the top of the roof bars If your not compitent on the Tig hire a synergic pulse mig, mine runs it in so well you can even program the ripples into the weld like Tig! Quote Link to comment Share on other sites More sharing options...
integerspin Posted May 19, 2011 Share Posted May 19, 2011 Long time since I welded it, I used normal A15 rods, which is what most chassis builders use as far as I know. I think A18[ER70S-6] rods n wire are more or less the same price as A15s. Will be plenty online about welding 4130. Quote Link to comment Share on other sites More sharing options...
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