stop and restart with mig question.

[thames1948]

Hello
I am having problems with starting and restarting my weld when going around tubeing. you can really tell where I start and stop. Is there anyway to make it look any better? I can't turn it so I have to run the mig around it.
Also the tube is aleast 3/8 thick and being butt welded to 1/8 flat steel,do I need to bevel it or can I just run a hot pass keeping it mostly on the thick tubeing? I am using a mm185 with .035 wire. Thanks
Dennis

[HAWK]

thames 1948,

I don't think beveling is a have to here. Although if you do bevel your pipe, you can turn down your heat and run a little slower. Without a bevel I think I'd go with in position spray arc if possible. You might try restarting your bead about 1/2" to 1" ahead of your last stopping point and pull the arc back to where you last stopped. Also when you stop don't fill in the crater or keyhole. Let your restrike pull back into and fill the crater or keyhole from your last stop. I hope this helps. It's getting late and morning is not far away. Have fun!

Good Luck

[HAWK]

BEVEL

thames 1948,

What kind of load is going to placed on these welds? What kind of penetration are you getting without the bevel? I think I WOULD bevel the pipe for a couple of reasons. The lower amperage and wire speed will allow better control of your starts and stops. Your penetration should be better. Also the 1/8 plate should exhibit less warpage at the lower heat setting.

[thames1948]

Thanks alot for the info. I think I will bevel it and practice what you said on some scrap first. I am not sure of the load, it is a spacer for lower tubular a-arm on a Mll front crossmember.
dennis

[PISTOL8]

MIG WELDS

DENNIS I AGREE WITH HAWK BEVEL YOUR TUBES AND START YOUR WELDS IN THE AREA OF THE KEYHOLE. I THINK PRACTICE AND ALITTLE TIME WILL HELP TOO. I KNOW IT TOOK ME AWHILE TO GET A SYSTEM THAT WORKED FOR ME. GOOD LUCK PISTOL8

[Kevin Disney]

Dennis,

What type of load is on the weld? Shear, compression, or tension. If the weld is in shear or tension you definitely want good penetration, so beveling as previously recommended is the prefered way to go, in addtion to the lower amperage and speed. But it is not a good idea for the bevel to go any deeper than 1/2 the wall thickness of the tube.

Also what is the finished weld size? For 3/8" thick tubing to 1/8" plate a mimimum 1/8" fillet weld is required by most codes. For your application I would recommend 3/16" fillet weld.

[thames1948]

Thanks again to everyone for taking time to answer my questions. I am not sure about how low should I go on amps and wire speed. I thought I would crank up the power to get good penetration. Also would it be better to just push in a straight line or zig zag? I will try to post pic of spacer with lower a-arm. I need to weld it to the crossmember. and then I will gusset it with 3/16 plate. In this pic I added more steel so the frame passes through crossmember instead of just butt welded to it.

[HAWK]

thames1948,

You will find a slight weave will help keep the heat up on the pipe bevel letting the pipe body sink some of the heat input preventing burning through. A straight push may work since the pipe bevel will closely match the plate thickness. Try both methods on scrap and see what works for you. Everybody welds different. Some people are able to run a hot torch, stick, etc and make it look easy. Others have to take more time making the weld to achieve the same results. Just do what works for you. I tend to run on the hot side. No matter how you run your beads(fast, slow, weave, straight push or pull) remember to WATCH THE PUDDLE AND KEEP THE WIRE IN THE LEADING EDGE. If you don't, cold lapping may occur.