How do you know if you have a good weld, especially on the frames.
Do I take a sledge hammer to it, or is it all visual???? The last thing I want
is to be driving down the road in my 51, and a weld cracks.

 

Hi sancochojoe,
I don't think many people are going to want to touch this one. In my opinion, weld strength ranks #1 on my list of safety concerns when making modifications to my truck. When welding in my ifs crossmember and my 4-link brackets, I tacked them in place and then paid a certified professional welder $200 to weld it together. Money well spent for piece of mind. I think I'm a good welder but I'm not about to put my life, the life of my family, or any of your lives in jeopardy with out knowing for sure.

If your concerned about the quality of your welds, I wouldn't hesitate to pick up the phone and call a professional to come take a look. Slip him a $20 and he'll probabily be happy and honest.

Good luck - Brad

 

pro help is always a good idea if you are not sure, and an x-ray is the only way to absolutely tell. The appearance of the weld can tell you a lot or if you look at the back of the parts and can see the ''shadow'' of the heat it will indicate how well it penetrated. Watching the pool as you run the bead is probably the best. Make sure that the top surface of the material is not undercut. Some manuals on welding will give you pictures of right and wrong beads and at least give you a visual to go by. I am sure someone out there can add to this

 

Joe -

I'm a newbie to welding myself. But I have been around welding for years in my job and know some really gifted welders. Before I bought my equipment and started learning, I talked to a couple of certified welders that I have known for a while. The clues they gave me were:

1. Good preparation of the joint edges is essential to a good weld resulting. Beveling the edges of thicker parts and constant gaps between thinner edges allow the weld to penetrate the parent material.

2. If possible, try out the weld setup on practice pieces of the same gage. Then try to break them after they cool. If the break occurs outside the welded areas, that's a great weld.

3. Look at the drop-through on the back side. Good penetration will result in a melt-through condition indicating that the whole edge is involved.

4. A hotter setup is better than a colder one. i.e.: using more heat is better than less. More heat will tend to melt too much of the edge, however, welding is all about getting the edges molten, fused together, then cooled together. A cold weld is no weld. The filler just lays on the top of the unmelted parent material. The trained eye will see a sharp edge to the weld filler material on the parent (imagine a drop of mercury on a table top). A good weld will show fusion of the parent and filler material at the edge of the weld bead.

5. When a good structural weld (frame/chassis) is needed and you are not sure, then tack it and take it to a pro, like Brad said.

my .02

 

if you look in the mirror, and your trailer is 100ft behind you, you might be a redneck welder, like me, I have a freind do the important stuff, nothing beats years of experience, most of us home mechanics don"t ever do enough of it to get really good

 

I'm with tacking it in place & hiring a pro. However, I also like to do stuff myself, as learning is a great thing. Especially if I do the work myself and spend the money on tools that I would have given to a professional. That said & speaking just for myself, knowing my welding skills: If I was able to weld in confortable conditions in the flat position (no vertical, as I know that I have trouble with them), and had a good looking weld, I wouldn't worry too much. If I wasn't sure, I'd take and open up a section of the weld with a carbide tipped air tool. Open it up slowly, taking a little off at a time, inspect after each grind, looking for voids/slag/inclusions/lack of penetration/etc. If the sample section is good, I've help assure myrself that I've got a good job. If the section shows voids/slag/etc., I'd chase it till I get to good weld. In a critical area weld, if I found bad weld with long continuous defects (lack of penetration/fusion), I'd buy a dye penetrant kit, grind it out, re-apply the developer (white powder) and continue grinding until the defect is gone, followed by a final dye check. Occassional isolated slag/voids/inclusions, I'd ignore as long as they weren't present in pockets. The last step would be to taper the sample grind area as a prep for the repair weld. Just my 2 cents worth.
Regards,
Jon

 

Been around welding for 50 years and I pretty much know a good one when I see it. Best advice is to have a pro look at at. Can tell much by looking(except for spot welds).
Fred

 

What I did was take a welding class at night after work. I was working 10 hours a day so it was a rough 6 weeks but I really enjoyed it. There was a welding store next door to the school and while we were in class everything was 10 percent off. I bought a mig, plasma cutter and torch/bottles. She said no more school for me.
____________________
XFM
'53 F 100

 

If your concerned about your own welding then test yourself.weld something togather then cut the weld and look at it.If a ok do it ,if not practice.

 

One of the things the pro's looking at the weld will be looking for, is if the weld bead is slightly concave indicating it has been hot enough to flow into the parent metals as opposed to a bead that is standing on top of the metal like water drops on a newly waxed car. Have a pro look at it and critique it.

 

Sancochojoe,

The answer to your question depends on the type of weld. Butt welds can be radiographed. This is the best method of inspection. Attachement welds are more difficult to radiograph but it can be done. For that extra sense of security, there are other methods of non-destructive testing you can employ such as die penetrant testing, magnetic particle testing, wet flouresent magnetic partical testing, or ultrasonic testing. These NDT methods can be used to inspect the final completed weld only or they can be used to inspect the weld after a given number of passes to ensure that you do not have a defect that will be welded over and embedded in or covered over by the final weld passes.

If it's a critical weld, pay to have it done or find someone who does critical type welds for a living. A couple of suggestions for you. Avoid the guy with the welding shop in his backyard unless you know what he does for a day job. Stop by the local iron workers, boilermakers, or pipefitters union hall and tell them what you are doing. You're apt to find someone that will do this for you for nothing if you ask real nice.

Another suggestion - if you have good friends or family in the Hampton Roads area, they have to know someone who welds for a living in one of the shipyards. These guys (and gals) are some of the best welders in the world. One from Newport News Shipbuilding would be my preferred choice but if they work at another yard in the area, they probably started and learned at Newport News. Amost every weld these folks make is closely inspected. In any case, offer up a Redskins weekend (or something equivalent) this fall in exchange for the welding.

 

dffay, these are the difference I see in some of the welds, like you mentioned.

"One of the things the pro's looking at the weld will be looking for, is if the weld bead is slightly concave indicating it has been hot enough to flow into the parent metals as opposed to a bead that is standing on top of the metal like water drops on a newly waxed car."

I welded two large bulky pieces of metal, about 1/8 and when I made welds that looked like water drops across the two pieces where I welded, I took the two welded pieces of metal, threw it up in the air, and when it landed, they both split apart at the weld. But when I rewelded the two pieces had had the concave appearence, the two pieces did not seperate after throwing it in the air a couple of times, and slamming it with a sledge.

 

Something not mentioned, but equally important, is someone with some knowledge of the service the welded joint is going to see needs to look at it (perhaps ahead of time) to see what type of weld needs to be used -- like how much length of weld, the throat thickness, etc. It isn't just the quality of the weld, but the joint type and comparison to the stresses that will be on it. A full-penetration weld isn't always needed, and sometimes a stitch weld is better than a continuous weld. What type of rod (or wire) is also important; E70xx rod isn't always better than E60xx - sometimes a more ductile weld is better than a stronger, stiffer weld. Long-winded way of saying that the person you may consult needs to understand cars/trucks as much as welding.