checking weld quality...

You really should have someone who knows welding check out your results before doing mission critical things like trailers. Or at least do some non critical projects like a welding table and a welding cart first.

Once you conistently get a nice uniform bead, you really need to test them. Take some material that is similar to what you plan to use on a the trailer, weld a 4" long 90 degree fillet weld, try and break the weld by hammering the vertical section over. If it goes 90 degrees, bend it back and forth until it breaks. If the ultimate break is in the base metal, you are doing fine. If the weld bead snaps off cleanly from one side, you have a classic cold weld.

Newby stick welders tend to have relatively strong but UGLY looking welds. Newby MIG welders tend to have nice looking but cold and weak welds. Which camp are you in?

Plan on doing some reasonable edge prep so that you can get the penetration you want.

For example: John Smith wrote:

I use a Hobart 175 mig. We've had it at the shop for a couple years now and I was definitely a newbie back when I began but I think I graduated to the next step up whatever that may be. I was starting to be able to make some really sound welds but it has been very long since I have done any welding and I don't want to re-learn on something like a trailer and I just want to make sure that I am doing as good a job as I think I am. The other thing is that there is nobody I really know who can tell me whether or not I am doing a good job. Thanks again.

Please advise me what state you will be hauling this trailer in so that I can make alternate travel plans.

Steve

Generally if welds pass a visual inspection they are good. If you are not sure what a good weld looks like or the more common weld faults a decent welding textbook would give you some guidelines. As Roy suggested a few samples bent to failure will give you an indication. Unless you change the type of joint , filler metal, shielding gas, or machine settings it is unlikely you will encounter problems from then on. Having a welding ticket is not a prerequisite for a welding inspector to qualify. He just has to be able to identify the faults. If you weld on a pressure tank or a steel building you will be subject to inspections and welders will have to test to assure their skill. These requirements are in the building code or the appropriate boiler code. If you weld on a piece of road equipment there is no formalised inspection procedure. In Western Canada logging truck trailers are welded on regularly. There is no requirement that the repairs be inspected by an authorised welding inspector. The legal onus is on the truck owner and the company that does the repair or build. Pretty scary eh?? What I am trying to say is if you use a reasonable amount of concerned care as you have indicated you will build a safe trailer. If you are concerned about a critical corner add a gusset. Lastly regularly inspect any trailer or welding structure that you are using. Welds rarely snap apart. There will be cracks and tearing of a connection before the unit breaks apart. Paying a few bucks for a set of plans never hurt also though I have seen a wide range in quality of trailer plans. Randy

"For example: John Smith" wrote in message news:V_tNf.49615$ snipped-for-privacy@tornado.tampabay.rr.com... I use a Hobart 175 mig. We've had it at the shop for a couple years now and I was definitely a newbie back when I began but I think I graduated to the next step up whatever that may be. I was starting to be able to make some really sound welds but it has been very long since I have done any welding and I don't want to re-learn on something like a trailer and I just want to make sure that I am doing as good a job as I think I am. The other thing is that there is nobody I really know who can tell me whether or not I am doing a good job. Thanks again.

Mig welders have a tendency to lay down a nice looking bead without getting any admixture on one side of the weld. When you do the bend test it just pulls away cleanly on that side. Another test is to section the weld. If you have pits or voids you have trouble.

If you have a 14" abrasive sh> I use a Hobart 175 mig. We've had it at the shop for a couple years now and

Hi

I can hardly say how much doing break tests is part of improving your welding skills.

At college I reckon it's hardly worth "practicing" if you don't break your welds to see how they are really doing. In UK, when doing "City and Guilds", you do a "nick-break" on a cut out 2inch/50mm section from the weld. The "nick" is a saw cut down the 45deg angle towards the fillet corner, going 1/3rd of the way from fillet surface to corner. Then you break open the sample. The effect of the nick is to focus the break into the corner.

The one about hammering without a nick sounds like it will seek if one of the fillet to plate joins isn't that much of a join. Is there a recognised standard describing performing this test?

There is a British Standard describing the nick-break test, I believe.

Richard Smith

RoyJ writes:

Run yourself a test plate.

3/8 inch thick mild steel single vee joint with a backing bar about 10 inches long. Saw cut 4 transverse strips about an inch and a half wide. Grind off the backing bars and then do two face and two root bends around a 1-1/2 inch diameter mandrel.

You can make a wrap around bending jig pretty easy. Depending on how you're going to hold the pieces your test plate can be from 6-10 inches wide.

If you have no open defects greater than 1/8 inch, you're doing ok.

Then the drivers get all up in arms when the RCMP or OPP or whoever the police and ministry of transport are int hat province run a blitz and pull off all the rusting hulks of trailers and trucks.

Some of those drivers are living too close to the edge to do full maintanance. As much as i dont like people going out of work i'd love to see heavier use of rail transport

BUt the same rules apply > In Western Canada logging truck trailers are welded on regularly. There