Welding Tips and Tricks

I'm trying to weld a table top into a work bench and it's going to involve welding 3/16 channel to 3/8 plate (the top). I'm thinking this size difference might be a little bit of a challenge. I'm using 7018, 1/8" rods. But happy to change if something else might work better.

What technique should I use? I could preheat the plate. The channel flat side is against the plate and I'm thinking to put 2 inch horizonal fillets along the channel every 8 inches or something.

Personally I wouldn't weld it. If you have enough material, make a frame out of the channel weld the legs to the frame and bolt the top onto the frame. That way the top becomes reversible, and you can shim it flat as needed. But yeah, if you are dead set on welding, pre- heat and go with fresh 7018 or another low hydrogen rod.

delgriffith wrote: What technique should I use? I could preheat the plate. The channel flat side is against the plate and I'm thinking to put 2 inch horizonal fillets along the channel every 8 inches or something.

2" stitches every 8" is way overkill. Putting that much weld down will surely warp the table.

1" stitch every 18"-24" depending upon the overall dimension of the plate. I don't think I'd even preheat it because 1/8" rod at 120+ amps will weld them together perfectly fine. It's a tabletop, not a structural beam.

Another vote for limiting the amount of welding. I made a table with a 3/8" top on 1/4" tubing frame a while back...general work/fab/light welding table for a friend. I had to limit the number of welds to keep from warping it...as suggested, something like 1" or so spread out will work. It really doesn't take much to warp 3/8" plate.

I'd fasten it down as others mentioned. Otherwise, I'd just tac it down myself. 3/8 plate isn't going anywhere.

Thanks, glad I asked. I actually meant to say 2-10 pitch when I said 2 inches every 8 inches. But sounds like that's a warp risk and 1-18 pitch or 1-24 would be better. Wouldn't have thought.

I'll think about bolting it down. Don't like the heads sticking up but maybe it would be a non-issue after just doing it that way.

Don't think just tacking is a great plan. I'm planning to put a vise on one end and can fully imagine clamping a wheel hub in it and driving out a bearing with a mini sledge or some similar antic involving heavy impact.

I posted a pic of the frame in the new members section. I'll try to update when I finish.

Use countersunk bolts. Easy peasy

https://www.youtube.com/watch?v=QzNaZFEQiM4&t=1s

delgriffith wrote: Don't think just tacking is a great plan. I'm planning to put a vise on one end and can fully imagine clamping a wheel hub in it and driving out a bearing with a mini sledge or some similar antic involving heavy impact.

1" of 7018 weld (stitch) will hold the world. Several of those around the perimeter and I'll give you $10,000 if you can break that top loose.

The tensile strength of 7018 is 70,000 PSI. How strong do you think you are actually? Or how much leverage can you truly apply? I've welded heavy equipment buckets in a similar manner and I assure you, you got nothing on a 250HP CAT. But feel free to bolt it down if you prefer.

Sure sure. When you said "tack" I envisioned a half dozen pea size beads around it such that you could zip it off with a grinder to flip it if you wanted.

Counter sink is a good thought too. Tapered with flush torx head might look very clean.

I would have no issue with small (1/4 or 3/8 inch for example) tacks on my own table.

In the nicest way I can say it, the great thing about building your own stuff is you get to do it how you want, and nobody can say you did it wrong. If you want to weld it go for it, if you want to bolt it, do it.

I get you're trying to get some pointers, so I'd pick a reasonable approach you are comfortable with. If you are going to be hammering on the table, don't worry to much about it being perfectly flat. You can use things like precision squares, fireball squares as an example, to handle flat and the table can be a nice work surface but not critical or anything.

So she's done. I posted in Member Introductions with more photos. I took Louie1961's advice and bolted the top. With my plan of countersunk flush socket head Allen bolts (couldn't find torx easily). I'm really glad I accepted that advice. I can remove the top for various reasons, no heat distortion issues. However his comment "Easy Peasy" was like the exact opposite "Tough Rocks" or something. I spent a ton of time locating each hole to make sure it was precise. I special ordered a 7/8ths countersink bit. I hefted a drill press into position for each hole, drilled a pilot, intermediate, and then full size hole. But I'm still happy about bolting vs welding the top on.

The footings are 3/4" adjusting thread. I have 4" casters with 3/4" mounting thread that I can put on if I want. It's at 35.5" right now and I am thinking maybe I should cut the legs about 2" so that it sits at a good height with both the stationary feet on or the casters. I'll use it a bit before I tackle that project.

But so now I don't want to mess it up with weld spatter, grinding, tacks etc. Looks so nice

Congrats on the sharp looking table! I am sorry you had difficulty with drilling the holes. Did you drill through the square tube? When I did mine, I made some gussets out of 1/4 inch flat bar and pre-drilled them before welding them in. I then laid the steel plate on some 4x4s, turned the frame upside down and laid in on top of the plate. After I positioned everything just so, I drilled the holes with a 1/2 inch hand drill. I am not sure how you managed with using a drill press??!! I also did the countersink with the hand drill, but if I had to do it over again, I would rent a mag drill for that part of the operation.

FWIW, I am 6'4" and I have a hard time working at standard table heights of ~36 inches. I actually raised mine up to 39 inches from the top surface of the table to the floor. Depending on your build you may want to vary the height to suit your needs.