...Did I forge weld?

[wooginator]

So I'm not quite sure where to put this, and this seemed the most plausible category, but if it's not please bear with me. I bought some flux with iron filings in it and I decided to try a fagot weld using a doubled over piece of half-inch mild steel stock for my first weld. The thing is, I'm not entirely sure whether I did in fact weld it together, or whether the iron filings just melted and filled the little gap in between (I bent it when it was round and then hammered it square so there's still a bit of a depression in between the two sides), or whether there is in fact a difference between those two things. Is there? Sorry for rambling.

[pkrankow]

Did you leave a tail? Try pulling it apart cold. Use a cold chisel if you must. You are going to have to break several welds to determine the quality of your welds (and build confidence)

Phil

[781]

Heat the bar with one side down in the hotter fire
If one side gets orge and the other has a darker spot it is not welded there
If the whole piece comes up to an even heat it is welded

When grinding something like a knife blade made of damascus and you see a blue spot it was not welded there

[evfreek]

781, that's a good way. Phil is right, though. Might be a good idea to destroy this one. Did the poke test with a thin rod stick? If so, it is likely welded. How strong? First, cut through the U bend so that the little faggot piece is no longer attached except at the weld. Make sure to cut well into the weld. Still holding? Good. Now put the faggot into the vice and start twisting and yanking on the long end. Still holding? Good. Put the bar in your post vice with the cut facing upwards, and give it a pop with a cold chisel. Still holding? That's great, you're doing better than I am. Now, heat to a very dull red and give it another pop with the chisel. Still holding? That's great. By the way, even if the weld fails one of these tests, it will often fail cold under use away from the weld. That's just the way stresses work (stress is often concentrated away from the weld). That doesn't mean it is a good weld. A poorly designed or executed weld that fails somewhere else is still a failed weld. At least, that's what the instructor said. ;)

[David Einhorn]

The previous comments have given good advise. A good way to tell is to destroy your first couple of welds because layers that appear to be welded could possibly be stuck together by the flux but not really and completely welded.

[wooginator]

Thanks for the advice everyone. I only actually welded one side of the bend before I decided that I probably shouldn't proceed until my didymium glasses arrive, lest I damage my eyes. In future, for this sort of weld is it better to get the two sides close to each other but not touching, heat them up, apply the flux and then pound them together, or get them completely flush so that there's only a slight depression between them and apply the flux then? (For the moment I'm sticking to fagot welds since I'm just learning and those seem easiest).

[Frosty]

There's not much I can add to what's already been said. However, ( there's always a however or but eh?) Didymium glasses are of really limited use to forge work. They're intended to filter the sodium yellow that's so intense in glass torch work and unless there's something really odd going on there shouldn't be any sodium in your forge or iron to make that color yellow.

Most fluxes will be yellow in the fire but nowhere as intense, a pair of low number tinted glasses is usually plenty unless you're sensitive to light. Don't worry about UV. If your forge is getting hot enough to emit UV your neighbors would be complaining and the NSA would be visiting to find out what's showing up so strongly on satellite images. Seriously, IR can damage your retinas but that's easy to avoid by not staring into the forge, just take regular looks.

The other thing I usually show folk how to forge weld with flat bar stock around 1/4" x 1" up to 3/16" x 1 1/2". Being flat makes it easier to clean, the flux stays put and they're a lot less likely to shear sideways even under a too heavy blow flat stock doesn't need the soak time and it's more likely to heat evenly.

That's me though.

Frosty the Lucky

[wooginator]

Thanks for the info about didymium but I already ordered 'em. Heh. A blacksmithing book I bought a little while back says to use them, so I figured I should after keeping an eye on the steel + flux in my forge left me seeing spots. They'll probably do the trick, even if they're overkill.

[MattBower]

Didymium got to be all the rage a while back, but I'm not sure how. It bugs me that some places still sell didymium glasses specifically for forge welding. They DO NOT filter IR, which is the type of damaging light that a forge is going to produce, AT ALL, unless they've had IR protection added separately. At least that's what these guys say: http://www.sundanceglass.com/didymiumsr.htm

[wooginator]

Hm. So...are they going to help at all? And, for that matter, absent protective glasses of any sort (if those don't do any good) is forge welding going to hurt my eyes?

[MattBower]

They have no protective value for IR, which is what your forge puts off.

There seems to be evidence that long-term exposure to IR can cause cataracts, and that blacksmiths, glassworkers, and others who work around very hot fires and materials, suffer higher rates of cataracts as a result. Someone suggested not staring into the fire, and that's good advice. Shade 3 welding lenses provide good (complete?) protection, but they'll make it hard to see what's going on in the forge -- and the rest of the shop -- and especially to judge colors.

[wooginator]

So there aren't any ordinary sunglasses-style glasses that protect against IR?

[MattBower]

Ordinary sunglasses? I don't know. But you can buy clip-on shade 3 lenses from the link I provided above.

[bajajoaquin]

UVEX makes safety glasses that block out IR. If you do a search, I think I posted a part number, but I don't recall. You can also go to their website and download their product brochure. Or search Amazon.com. I got mine for something like $15.

I wear them for forge welding, but clear lenses for regular forge work.

[pkrankow]

So there aren't any ordinary sunglasses-style glasses that protect against IR?

"Some" but no. Any lens or glass blocks some IR, in fact this is why oil lamps have the shape of glass they tend to. However, some of a whole lot is still enough to do damage to your eyes. This is simply because the lenses are not tinted to specifically block IR wavelengths and the material simply reflects a portion of the IR. The greenhouse effect of your house warming up in the afternoon sun as the low angle light from the sun is streaming in is the "some" that passes, although in a different situation.

Phil

[MattBower]

Here are the Google Shopping results for "IR safety glasses":

http://www.google.com/search?q=ir+safety+glasses&hl=en&rlz=1I7GGLL_en&prmd=ivns&source=univ&tbm=shop&tbo=u&sa=X&ei=n7cdTrjYFY7fgQfKqKz4CQ&ved=0CIABEK0E&biw=1024&bih=536

Some are very inexpensive. Caveat emptor.