Cleaning up welds for paint....

TAHOE · **Posted:** Fri Jun 25, 2010 1:48 pm

I know we have quite a few fabricators on here, wondering how you all clean up the welds to make them "pretty" before painting i.e. finished bumpers, etc? I just got a wire welder using flux wire ( yeah, I know, I will upgrade eventually to gas) and made some steel pipe safety handrails for my parents, but can't get the welds to clean up as nice as I want. I got them ground off, but would like them smoother, my sanding wheel is probably a 40 grit, too coarse... & the hand sanding with sand paper just ain't cutting it. Maybe I'm just missing that middle finer grit stage.
Sooo, what you all use, maybe 80 or 120 grit flap wheels, or the small 3-4" sanding disc's?
Any techniques shorts of learning how to lay down a nice weld to start with :dizzy:

?

KJ 119 · **Posted:** Fri Jun 25, 2010 4:09 pm

If you are painting the rails,grind them the best you can with sidegrinder,and bondo smooth before paint.
If not painting,practice makes perfect.

Budke · **Posted:** Fri Jun 25, 2010 9:12 pm

wire wheel on a hand grinder. Makes the weld nice and shiney.
Its what I used to use before I painted the trailers I built.
Little wire brushes work good too.
Small brush with a lot of bristles.

As for how to law down a good bead, practice makes perfect.
Follow the puddle is rule #1.
Watch some youtube video's or buy some dvd's, best thing to do.

warp2diesel · **Posted:** Fri Jun 25, 2010 11:08 pm

With the Waste Water Equipment made from Stainless Steel. They grind and sand blast and then passivated.
Skip the passivation for carbon steel.
For carbon steel, they grind and sand blast, then paint with tnemec epoxy paint.

ridenby · **Posted:** Sat Jun 26, 2010 12:47 am

Flapper wheels are good,ideal is to lay bead smoothly to begin with,if it does not look right after grinding consider laying a better bead on top of first. Flux core wire is not the problem IF you buy good wire from Lincoln,miller,etc.

kskj · **Posted:** Sat Jun 26, 2010 1:05 am

I grind the weld down smooth as possible. Sand it smooth and bondo and sand it again. Her is a pic of a bumper i made for my sons truck.

TAHOE · **Posted:** Sat Jun 26, 2010 3:00 pm

kskj, that's what I was looking for....what do you use to do the grinding?
I'm just making these safety hand rails as my first welding project, bondo not needed to get them that smooth. just wanted to get the welds smoothed off some , but I have heavy grind marks, probably need finer grit materials for my grinding.

kskj · **Posted:** Sat Jun 26, 2010 4:02 pm

I just use a regular grinding wheel but you are right it will make some deep marks. I try not to go to deep and then I use grinding pads. Made by 3m they Velcro onto a Velcro grinding wheel. I have been on a lot of construction sites and when they put up the hand rails in the stairway they just cut the ends to fit, weld them in place,grind down the welds, then bondo, sand until smooth. When you use the bondo all you are really doing is filling in the scratches from grinding. These pads do come in coarse,med and fine.

Budke · **Posted:** Sat Jun 26, 2010 7:45 pm

Just make good welds and you don't need to grind em down.

kskj · **Posted:** Sat Jun 26, 2010 7:54 pm

Not all of us went to a welding class. :lol:

I just picked up the welder and learned on my own. So the welds are not perfect but I still get things made. :lol:

TAHOE · **Posted:** Sun Jun 27, 2010 8:54 am

kskj wrote:

Not all of us went to a welding class. :lol:

I just picked up the welder and learned on my own. So the welds are not perfect but I still get things made. :lol:

Exactly!!!! I wanted smooth weld joints anyway whether they were "good" welds or not.
Thanks for the pics, those pads were what I had in mind. I did some more sanding last night, smeared a little spot filler on it, and lightly sanded. Going to finish sanding and paint today most probably.

Budke · **Posted:** Sun Jun 27, 2010 10:16 am

TAHOE wrote:

kskj wrote:

Exactly!!!! I wanted smooth weld joints anyway whether they were "good" welds or not.

You got that backwards.
You want good welds, whether they're smooth or not. :seuss:

When I first started welding they may not have looked good but darn were they hard to break. Called 'em gorilla welds.

Now they look good and are even harder to break. :BANANA:

kskj · **Posted:** Sun Jun 27, 2010 12:21 pm

My welds only look good part of the time. Not enough practice. But I have came down hard on my rock rails a bunch of times, and use them for a jacking point and they don't even have dent after 3 years. :lol:

TAHOE · **Posted:** Mon Jun 28, 2010 7:06 am

Budke wrote:

TAHOE wrote:

kskj wrote:

Exactly!!!! I wanted smooth weld joints anyway whether they were "good" welds or not.

You want good welds, whether they're smooth or not. :seuss:

You know what I mean mr expert :goink:

I think I've became an expert at Gorilla welds then :jester:

Cleaning up welds for paint....

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