Originally Posted by
workingonit
Currently I'm dealing with 4 areas of rust on an 84 RRC body and wondered if people could offer some advice on which welding technology and wire specification they have been using to make malleable welds. The aim is to produce malleable welds which can be hammered to relieve stress and distortion. Been watching Meccles work, by way of example.
I'm particularly concerned about avoiding distortion of the box section channel that is associated with the RRC drivers side lower door frame. The box was originally made with folded sheet, the flap forming the footwell is substantially wider than the other three sides. Seems you can buy ready made replacement piece, but I don't think my rust issue warrants such a major bit of work ie re-attaching 'A' and 'B' pillars.
What I've done so far is remove the rusted drivers floor area (the widest flap of the box so to speak) and exposed the remaining 3 sides of the channel, which look in good nick. Now I want to weld new floor paneling to what remains of the channel without distorting the channel.
Because its box section with no hand access I've ground a high tensile bolt to have a small dolly head, which I can shove through slightly enlarged drain holes in the bottom of the channel - with support of the ground bolt head under the weld area I can then hammer the weld from the top, the outside. That's the theory.
The second patch of rust is in the front passenger well, very small and easy.
The third and forth rust patches are significant and are found where the rear passenger flooring meets the rear wheel arch, both left and right wheel arch and floor areas are affected, directly above the body to chassis mount point. The mount points in these areas also need replacing.
I'm not overly worried about being able to fabricate the replacement pieces, more the sorting of wire specs and welding technology to use to create malleable welds.
TIG and oxy/acet seem to be preferred for producing malleable welds. In a sense I'm looking for justification of using what I've got ie the MIG, but how.
By way of background.
I've done butt patchwork on old vehicle floors, tractor and machinery panels, using mix of oxy/acet and MIG, where weld hardness and bit of distortion could be ignored.
Have a MIG, only ever using core flux wire. The machine can take gas. I'm working in the open breeze. Reading and from experience MIG welds (buttons in this case) cool too quickly and result in hard welds (alloy content influence as well), generally way stronger than parent material being welded. Reading the web, if persisting with MIG (not preferred choice by many panel people) then switch to solid core and argon shield. Trouble is the varying opinions. Some like 'mild steel wire', ER70S-6, ER70S-7, 'Easy Grind'. For every adherent of a wire type there is someone who has had a bad experience trying to hammer it and if they succeed it often splits. The adherents retort poor technique, poor cooling methods, manufacturer has changed composition, isn't made anymore etc. Local advice 'the boiler makers use lots of this MIG wire, so must be good (for panels)'. So can you really create good malleable welds, consistently, with MIG?
Have stick but not suitable for really thin stuff.
Have oxy/acet gear but gave bottles back to BOC years ago because of high rental costs. There are few businesses in Darwin that offer bottle swaps - one did then stopped because supplies from down south were erratic - one was, but now suspended sales until certification issues sorted, and who knows when - one with prices a bit over the top by comparison - Bunnings not certain, being evaluated, if 'yes' then in the new year.
Don't have TIG, but not against getting one. Again, working in the open breeze.
Prefer oxy/acet over TIG because can do other things, breeze not such a problem for oxy/acet, repairs not an issue up here (BOC MIG, got to go south!!), handy when remote from electricity, contamination less of a worry, can have a water supply at hand (misting hose) to stop old sealant fires without fear of electrocution. Could hire oxy/acet for the duration but really like to 'buy' bottles and to have a good heat source on hand all year (using small can MAPP at the moment).