There’s a joke in welding circles that if you have to grind your welds that makes you a grinder not a welder.
But as a novice welder myself I would totally recommend doing it.
Back in 2009, I installed some new gates and a short section of fence. It was not until the following year that I purchased a welder. So that fence was made from 3 pieces of decking panel bolted together.
Over the years those bolts became loose and the fence has become a bit bendy. So I decided it was a good time to take them off and weld them up straight.
My first thing was to use some of the plates I’d used for bolting them together to do a test weld. I cleaned up the ends that were to be welded using a flap disk, bevelled them slightly and put a bit of a gap between them. After checking my manual to see which was the earth connection, I connected that up to the table and tried to weld them together.
But absolutely nothing happened. After checking everything, I looked at my test pieces again and on the back of each of them was a thick layer of paint. So I used my grinder again to clean that off and then had good contact on the table. I did a couple of test welds and got my welder dialed in for the right current. I’m always surprised how high I need to set this. 90A seemed to be about right.
After welding my first section, I chipped off the slag with a hammer and ground it flush. There was a big hole hiding in the middle, so I ground that out in a bit V shape and did a second pass. After that, I ground it back again and you can see that I managed a solid enough weld on the second attempt.
So as you can see the grinder is very handy for preparing your weld, inspecting it and getting a great finish.
After welding up the other 2 panels, I turned them over and did a quick pass on the back side. I’m sure a better welder could get this done without needing to flip it. Perhaps a wider gap?
I then gave the exposed metal and rusty spots a coat with some red oxide primer, followed with an over all top coat of black. The repaired fence section was then bolted back in place with rather fewer bolts this time.