filling box radius

[Joe777]

Hi all, is there recognised method for filling large gaps when jointing box section (end to edge) for example 120x120x8 big rad. (not prairie wire) normally run a couple of passes onto the rad then bridge across and build up but not exactly pretty from inside and will be doing a hi spec job shortly.any info appreciated

 

[Tigman]

you could grind out to make a nice fit , ie like a saddle !

 

[Joe777]

agreed, but material came in cut to size, minus all the mitres so that was fun to cut!

 

[Welderpaul]

Just treat it as a vee prep. I usually put a root run in, then as many runs to fill as necessary.

 

[Joe777]

maybe 8mm of air on some rads, wondered if a piece of bar could go in there or if it would affect bs/en standards

 

[Welderpaul]

If it is something important, i wouldnt go using filler strips personally. I'd want it fully welded. 8mm isnt really a big gap tbh.
Did some 300x300x16 SHS butt joints a while back; they took some filling

 

[oilcooled :)]

maybe 8mm of air on some rads, wondered if a piece of bar could go in there or if it would affect bs/en standards

it works but i wouldnt reccomend it as being great practice, and i personally wouldnt do it

 

[Joe777]

ok cheers guys .

 

[backpurge]

Get as tight a fit as possible and treat it almost like a butt weld, root run, hot pass and filler runs and cap, dont get into the bad habit of weaving or going too slow to build the weld size up.

 

[Engineer1964]

Just treat it as a vee prep. I usually put a root run in, then as many runs to fill as necessary.

I agree with WelderPaul, I regularly weld box section to pressed 6mm channel and the large radius on the pressing makes me want to treat as a Vee Prep.

However this would normally take about 3 runs with a cap on top, so you can imagine the heat. The issue i had was with strinkage with two of these joints either end of a framework could reduce the overall width by 2mm to 3mm.

What i do normally, i know by experiance to fabricate the frame a couple of mill either side to allow for shrinkage, works for me and final size fall in tollerance of -2 +0