backing strip

By Blaster (***)

Date 01-14-2007 18:14 Edited 01-14-2007 18:20

I cut the pieces for side bending or face and root bending out first. Then depending of the width of the test piece, I use a rivet cutting tip (face & root samples, Victor 2-1-112), or a plasma cutter (side bend samples) to remove the bulk of the backing bar from it. I then go to a flap disc for the fine work.

Not for cert testing but just for a visual inspection of a root pass to see if a welder can weld, air arcing off the entire backing is the way to go.

By dringge (*)

Date 01-14-2007 20:17

I have a fixture that holds the coupons in a mill while I remove the backing strips. This keeps me from having to do a lot of cleanup grinding and polishing. I am, however, always looking for a better, faster method.

By hogan

Date 01-15-2007 17:06

i've always used a mill

By thcqci

Date 01-16-2007 16:49

I cut my strips out first with a bandsaw, then I only have little pieces of backing to remove. I then cut the non-fused parts off with the saw leaving only a small square of fused backing to either grind off or cut off. Then I radius the edges and "polish" the faces with a 4½" sandpaper grinder disk. Reduces need to worry about which way the grinding marks go.

By eekpod

Date 01-16-2007 21:40

I'm similer to you, Cut out the 3/8" wide strips from the coupon in the band saw., this way minimal backing bar is remaining to deal with. If I have time I also trim the excess non fused backing bar in the saw, if I'm patient enough and I'm allowed the extra time at the saw I can usually cut right through the backing bar almost flush against the back side of the test piec, but be careful, don't cut into it. Then grind the cover pass and root. I use a dyna file ( the air tool with the small belt sander belts) to make everything nice and smooth, especially the corners. They should have a 1/8 radius when finished. Chris

By aevald

Date 01-16-2007 23:34

Hello folks, I do a lot of 1" plate certifications. To start, I place the vertical and overhead plates face to face and tack them at the four corners and in the center of each end. I then place them in the saw and cut off the required amount of end drop(in my case 1"), I then cut the required amount of coupon thickness(in my application this amounts to 3/8"+). Next, I turn the coupons over and repeat the same steps to get the other two coupons for a total of 2 vertical coupons and 2 overhead coupons. To remove the backing strips from the coupons I clamp the backing portion of the coupon in the vice and carefully grab the coupon with a vicegrip or between the jaws of a crescent wrench and rock the coupon back and forth until it shears the backing from the back of the coupon. Finally, I use a belt sander to shape up the coupon to the correct finish and shape and as well, radius the corners to the appropriate amount. This is a rough description of my method for preparation of test coupons. Regards all, aevald

By tsalagi (*)

Date 01-17-2007 03:06

all of my tests have been open root or back gouged but, i was wondering if you could use a brass backing plate on a test?