Smoothing out welds

nitromor'ed a aluminum frame ( specialized own a1 tubing )
first bottle worked, went to get the bits i missed with another bottle and it didn't work, i don't know how, i used it exactly the same as the first ( must be a dodgy bottle or something)

anyway i wet and dried the patches of paint off, then rubbed down a tube to see if i liked it ( using 180.280,400 and some fine wire wool) i'm going do the whole frame

problem is the welds are still outlined with paint and i cant get in there with wet and dry
i know enough about welding to know it will depend how much the weld has penetrated the joint to know if its safe smooth them out, i don't want to take too much material away just enough to get rid of the paint

i figure specialized welds would have decent penetration and they will be uniform welds
any one else smoothed out welds on a specialized a1 tubed frame,good or bad idea

ATB
Dean

I would be wary of taking any of the weld metal away as it will weaken the joint. Ali is brittle enough as it is without taking away the re-inforcement of the weld metal.

Paint stripper and a wire brush should get the paint out of the grooves.

i would just be taking off the hight spots, not sanding down into the weld

but if its a bad idea i will have to buy more stripper

A little bit is ok but as you mentioned there is a lot of strength in the re-inforcement metal. Make sure when you are trying to get the paint out of the edge of the weld that you don't take any material out, or undercut where the weld joins the tube - otherwise this will be the starting point of a crack in future. Not a great diagram but I'm sure you'll see what I mean

photos....
the fact that the second bottle isnt working, makes me think that it is the filler that they use to smooth over the welds that you are having trouble removing.

don't think spesh use filler

a bit blurred, but you get the idea
toptube

forgot to put that the welds on the rear triangle ( connecting the drop out) have been smoothed out, i brought the bike new so they must have done it in the factory

A little bit is ok but as you mentioned there is a lot of strength in the re-inforcement metal. Make sure when you are trying to get the paint out of the edge of the weld that you don't take any material out, or undercut where the weld joins the tube - otherwise this will be the starting point of a crack in future. Not a great diagram but I'm sure you'll see what I mean

thats what i was thinking
i suppose i would have to work along the tube and into the weld and try to only take away the high spots

my other option would be to use a trimming blade to get up to the weld the gouge out the pain in the weld with one of the craft scrapers, like the ones you use to remove the black cover of one of those metallic boards

With welds like that I'd be inclined to powedrcoat ever them...

Is the black stuff the original paint or filler? In parts (the black sections across the face of the weld) it looks like the welder has touched the tig tungsten into the weld, in which case paint stripper will do nothing. Acid etching would clean it up a little but comes with it's own problems.

If you are going to try and brush it out use a stainless steel wire brush, not plain steel and be aware it will mark the frame a little. Some thick scotchbrite pads and elbow grease is all thats needed needed to blend the brushmarks back into the frame. You can use the pads to put a nice grain into the whole frame if you want.

its the original paint

It may just be that the paint lies thicker in the grooves of the weld and you just need to give the thinners more time to penetrate through the layers. Try it again before resorting to sanding it and see how you go.