Is Fixturing Really Important?

[Chips O'Toole]

I keep making projects that are somewhat large for my 3'-long Northern Tool table. I keep thinking about getting a 3x4 table, which would have twice the area.

My table came with a lot of fixturing stuff. I really like using it. I learned about fixturing from Youtube. Unfortunately, I saw some misleading claims.

People said fixturing would prevent things from warping and coming out crooked. Of course, that's a lie. Fixturing has nothing to do with warpage. I found that out later. You can clamp things all you want, but if you don't plan your welds correctly, your work will still come out of the clamps crooked. The clamps just keep it square until you release it. And you can't call yourself a real fabricator unless you know how to straighten things after they're welded.

The guy from Fireball Tool made a video the other day in which he made the ridiculous claim that fixturing would keep things straight. I know he knows better, but he sells fixturing tables and tools.

I enjoy using a fixturing table, but I wonder: is it really important to have all those holes and a really flat table, or is the hype just a way to sell tools?

I know there are things that are very hard to put together without fixturing, because they have to be held together until the welds go on, but workholding and warpage prevention are two completely different things.

Siegmund makes a very nice 3x4 table that comes with fixturing tools. It's really tempting. I would have to put out around 5 grand to get it here. Will something like that really make life easier than a plain old mild steel FabBlock or a table from Texas Metal Works?

 

[Ulma Doctor]

lots of things can create warpage, but heat is that the top of the list
a good table and a good plan will help to mitigate warping, but i don't think there is a one best way of doing it
i generally weld, then straighten (if necessary ) afterwards
i've welded on everything from the ground to , sitting on the pieces to be welded, to prepared welding tables
sometimes there is no way but on the fly with little thought of table support

 

[Chips O'Toole]

It seems to me that if fixturing doesn't prevent warping, which it does not, then all it does is hold things in place so they don't move while you add filler. If that's true, then a fixturing table is not really essential unless you weld a lot of things that will take off or fall over unless they are fixtured.

 

[GeneT45]

I **don't*** think a fixturing table is essential - witness all the welding done in situ without a flat table. It's just an awesome convenience. Even if you need to straighten things later (which is not always the case) starting out with something that's not flat then adding warpage isn't going to be easier to fix... Oh, and fixturing, whether it's a pro table or just some cobbled up (but sturdy) work holding can definitely reduce or eliminate warpage. How flat you need depends on what you're doing. There are 'tricks' to get a perfectly planar surface on your garage floor.

The spacers (pads) used with most (all?) welding tables are 1/2" tall. If you don't need super-flatness, a 1/2" thick CRS bar (I have some 1/2"x3" that I use) can be clamped to the top to create outboards for supporting work larger than the table. I usually use this just for support and try to keep the area being welded on the table itself to maximize the benefit of its flatness.

Tables aside, getting your work held firmly in place is *very* important and will make a big difference in your weld quality, particularly if you're not a great welder and you've been trying to weld stuff that's laid down in some approximate position - a guarantee of more distortion than necessary.

I welded for probably 15 years before buying a (small) table and it still made a difference in both quality and convenience.

GsT

 

[Chips O'Toole]

I'm watching videos shot inside professional shops. Most don't have fixturing tables. But the popular tool guys on Youtube all seem to have high-dollar tables manufacturers gave them in exchange for advertising.

 

[johnnielsen]

Whenever I need multiples of something welded together, I use a jury rigged fixture made by tacking stops to my welding table and clamping the components in place. It is used to assemble by tacking the pieces in place, not welding in place. After tacking, I flip the piece over and do some welds that I know will minimize warping. Then I flip it back and do some welds, again relying on the tacks to hold everything in place. A tip: weld over top of the tacks as late in the welding process as possible.

 

[akjeff]

I've found that( along with planning the sequence of your welds ) the best defense against warpage, is tack welding the living crap out of your assembly. I do love having a fixture table. Really speeds things up, and holds your work in a very comfortable position to weld in.

 

[wayback machine]

I do small scale TIG welding in my little shop, and use a little 2x3 Certiflat table on a hydraulic lift cart - The whole thing fits under my workbench when lowered, and works great, as the height is completely adjustable, for whatever I'm doing.
I made a bunch of drop-in fixture clamps from cheapo HF bar clamps, and those, along with a small articulated vise, and a couple "grasshopper" magnet hold downs, allow me to weld up some pretty small and intricate things, if I need to.
I've found, that if I tack everything, and move around randomly for the finish welds, I don't get much distortion - Maybe, because it's TIG, the HAZ is much smaller, and helps with that.
This set up does well for me, and helps me do better work - I need all the help I can get.

 

[epanzella]

A fixturing table will go a long way towards getting a straight and true project but won't eliminate the need for good weld planning. The first benefit is that it keeps parts where you put them while checking square, measuring diagonals, ect. and allows you to tap them into perfect alignment. The second benefit is that it prevents warping while you make opposing tack welds around the piece before finish welding. Even if you use so many clamps that the piece can't move, thoughtless full seam welding will cause stresses that will warp the piece as soon as you unclamp it.

 

[Harry Knutz]

I learned from the old guys in the 80's when I was working in Fab shops, That after tacking everything good, You make a weld on one end, Then go all the way to the other end and make a weld and the come back to the other side in the center and so on, Kind of like torquing the head bolts on an engine, It really does work.