Penetration

[Thrashsmith]

Hi folks, sorry to ask a question that I'm sure has been asked many times before, I promise I have searched this forum and have watched many videos to find the answer but haven't had any joy...

How do you know that you are getting good penetration whilst arc welding? All I've come across so far are videos/pictures of people running beads then turning the metal over and accessing whether there's been sufficient penetration or not, but no explanation on how to tell whilst you're in the process.

If you have a link to an existing thread where this is discussed or a video that explains it then I'd really appreciate it.

I'm now cowering away like Quasimodo...please don't chuck rotten eggs at me all at once!

 

[chunkolini]

I did see a mate check for penetration while Mig welding.
The idiot, while welding popped a finger down the other side of the weld to feel for it.
Plonker, I would not recommend this technique.
He is Belgian though.

 

[Badger1bear]

After you have run your practice welds lay into it with a BFH, if it doesn't break then your doing good

 

[Thrashsmith]

BFH? I'm guessing that's Big "Flipping" Hammer?

The practice fillet welds I did on some 6mm mild steel plate withstood a good deal of BF&I with a hammer (brute force and ignorance) so if that's the acid test I guess I'm on the right path.

Sounds like your mate is a character from "In Bruges" chunkolini.
http://www.imdb.co.uk/title/tt0780536/

 

[slim_boy_fat]

BFH? I'm guessing that's Big "Flipping" Hammer?......

Close.......

 

[KemppiFrog]

Huh. The Belgian connection might have been Poirot. Except that is translated as leeks around here.....

More to the point, do a weld, then cut across it with the angle grinder and check how deep the weld is on the joint. Beats the cremated finger test
KF

 

[desmo11225]

Testing your welds

At college we were always testing welds, we made a simple weld breaker, a machinist will machine a slot about 20 mm wide to a depth of 50mm or so in a chuncky piece of bar about 150 mm long, weld a length of round 30mm diameter 300 mm long, so you can slide a length of tube about 1.8 cm for good leverage cut a notch in your sample weld and pull it over quietly in your vice.
Use gentle pressure so you do'nt ruin your vice Stanley/Record Vices are only Cast Iron so take care but a lot better than a club hammer.
A few trial tests and you'll soon get the hang of it.
desmo11225

 

[mybuttssplit]

It's more about experience if unread your question correctly. I know when in putting a root in how much pen Iv got by the feel of it and more so, the length of weld laid down.
I.e you lay a flat run down on a plate with a 2.5mm rod and get 100mm of weld in length. Then you put a root in, you WON'T get 100mm in length on a root as much of the weld will be laid down on the inside. So you can get a rough idea judging it by that. If that makes sense? Experience will teach you how much penetration you have got

 

[arceyered]

0nion

When welding the root looking at the weld pool you can see the slit of the prep face and the little onion shaped hole as the rod is burning in to the prep.
If the slit closes and the hole disappears you have lost penetration stop and grind out prep then start again "we used to use a thin cutting disc and grind untill it started to turn blue not grind right through".
If the onion or slit opens to much you burn through if this happens I used to push the rod in and back of for a split secound then carry on, don't pull the rod off.
You can also feel good pen, to me it used to feel like when you put two magnets pole to pole that spongy feeeling on the end of the rod.
Well thats the way I did It hope it helps