What is a weld?

[Fat-Fab.com]

As taken from ANSI/AWS A3.0-89

Let’s start this with the thing we all want to or think we know “weld”

Weld: the coalescence of metals or nonmetals produced either by heating the metals to the welding temperature, with or with out the application of pressure, or by the application of pressure alone with or without the use of filler metal.

So to produce a weld we must first achieve enough temperature via pressure or heat to get the two pieces to coalesce. What is coalescing, the growing together or growth into one body of the materials being welded?

This will take us to what is a good weld: my thinking tells me it is a weld free of “objectionable” discontinuities, (defined as any of the following)
This subject is covered by 17 pages in the AWS book Welding Inspection.
I will deal only with a discontinuity as it relates to the weld only.
1. Porosity
2. Slag inclusion
3. Tungsten inclusion
4. Incomplete fusion
5. Inadequate joint penetration
6. Undercut
7. Cracks
8. Surface irregularities
9. Other irregularities
In my next post I’ll cover each discontinuity, with pictures too!



TJ

[Sberry]

So, is gluing plastic pipe really a weld?

[KB Fabrications]

So, is gluing plastic pipe really a weld?
If a weld fails in the forest, would anyone really know? :eek: Oh, one more, I wonder if a JB Weld could pass an x-ray test. :rolleyes:

[Fat-Fab.com]

So, is gluing plastic pipe really a weld?

Yes some are.

[monte55]

If a weld fails in the forest, would anyone really know? :eek: Oh, one more, I wonder if a JB Weld could pass an x-ray test. :rolleyes:

I am gettings some x rays taken next week. I didn't know there was a test. I better
study.:p

[Skipper]

Sure it could as long as you prep the area really good and try to mash out all of the air bubbles. Remeber not to undercut.

[harcosparky]

So, is gluing plastic pipe really a weld?

Nah .... but there is chemical bonding, and plastic welding.

Somewhere I have a plastic welding kit, it uses heat. Works great for those types of plastic that refuse to be chemically bonded.

I use the term chemical bonding, because well, I don't use glue. I use plastic solvent chemicals.

You can weld metal and plastic .... but man trying to weld wood with an O/A torch setup, just don't work! :)