froggy
Posted a lot
Posts: 1,099
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Dec 11, 2011 12:32:32 GMT
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i need to clean the end tanks of a cheapo intercooler for welding but whatever they use to polish them is a swine to clean off . ive tried acetone ,blow torch etc even a soft pad on the grinder just seems to move it around rather than get to good metal .
it isnt the metal as i tried a weld inside the cooler and its fine .
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Onne
Part of things
Posts: 822
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It's not a clear laquer of sorts is it? Depending on the type that stuff can be tough as anything...
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1990 Mercedes W126 300SE
1997 Mercedes W140 S320L
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MrSpeedy
East Midlands
www.vintagediesels.co.uk
Posts: 4,786 
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Dec 12, 2011 13:16:42 GMT
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Could be a clear powder coat
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Dec 12, 2011 14:37:52 GMT
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Is it anodised? If so you can clean if off with caustic soda, just don't leave it too long or it'll eat the ally
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froggy
Posted a lot
Posts: 1,099
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Dec 12, 2011 17:06:50 GMT
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pretty sure its just been wheel polished so it might be a wax based polish , last thing i tried to weld was a bracket on a chinese intercooler and it just kept pulling dirt up into the weld. il try some caustic soda see if it does anything
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B-8-D
Posted a lot
down to one car!!
Posts: 4,038
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Dec 16, 2011 20:39:13 GMT
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cheap cast ally can be a pain to clean prob quite pourus and impregnated with polishing compound and kinda burnished over during the polishing process i expect..
hit it with sand paper then sand blast the area to be welded to try to open up the pores so to speak.
then soak it in thinners over night warm is best.. then heat with a torch to dry out then finally a clean stainless wirebrushing just before welding...
sometimes there is just so much curse word in castings its never going to be shifted..
things like gearbox casings etc are often terrible ive done all the above at least twice before welding and it still sweats out oil when welded...
si
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froggy
Posted a lot
Posts: 1,099
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Dec 17, 2011 16:32:02 GMT
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a soak in trafic film removal and then prep with acetone and a stainless wire wheel seems to be working ok .
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