Triumphman
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Does everyone remove mill scale from bar bar before mig welding? Or just cut to length and then weld?
Where do you get good ones? I've tried a few but they are expensive for what they are and never lastI always start, intending to only clean just the immediate weld areas . . . . . . but then clean further and further . . . and further. I must try to learn how to stop!
I now use those "roughy, foamy, paddy type things" on an angle grinder - whatever they are called. They strip off mill-scale faster than you can sneeze, and leave a nice shiny polished finish to the metal.
I think with Tig welding it is essential to clean off the metal.
Malc.
Where do you get good ones? I've tried a few but they are expensive for what they are and never last
I've bought them off Fleabay in the past. The last pack I bought I saw at a local agricultural hardware shop nearby. They were a little more expensive and do last a little bit longer - but they must be viewed as a consumable - much the same way as using, for example, acetone for cleaning.
Flap discs work very well to remove mill scale by harsh abrasion, but its easy (for me, anyway) to 'overdo' it and leave a gouge. The 'spongy things' rip the scale off very quickly but then 'polish' the raw metal rather than grind it. With persistence you can achieve a mirror finish - although original contours from rolling will remain.
I suppose it really depends on the application. If you are welding something that is simply functional and 'out of sight' - use a flap disc for economy. If you are producing something that should be visually attractive, you will get a much better finish with less work by using a 'spongey thingy'.
Malc.
Pretty expensive especially if they don't last long!They're called non-woven rapid strip discs. I use the orange Norton Blaze ones which are very good. Have used Abracs before, but they don't last as long and i had a few disintegrate while in use.
None of them last that long, and catching them on sharp edges will damage them and cause them to come part quite quickly.
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Always grind it off is what I was taught.
if you want to de scale a batch of pieces for a reason like paint, a acid bath works
They last for ages if you use a variable speed grinder at low speed the makita variable brushless is perfect for them, it's amazing how fast they take rust and millscale off.Pretty expensive especially if they don't last long!
Thanks, that's what i like to hear I'll pop out and get a couple later in that case.They last for ages if you use a variable speed grinder at low speed the makita variable brushless is perfect for them, it's amazing how fast they take rust and millscale off.
I think citric will do it.Scale is a pain to strip with grinder, it will take all day.
Is citric acid the one I want? Could use a rough idea how much can be done per kg.
Disposal I assume neutralise it, it will only contain iron oxides and no nasties?