Etching welds

[BrokenBiker]

Any rough and ready methods for etching welds to see penetration?

More for my own curiosity than anything, be nice to cut, Polish and etching a few joints just to see how well they have penetrated on thicker stuff

 

[E T]

HG rust remover.

 

[BrokenBiker]

HG rust remover.

that seems simple enough, thanks...just a case of applying then wiping off after some time?

 

[E T]

Yes, but polish the surface first. The finer the polish the beter the results.

 

[BrokenBiker]

Yes, but polish the surface first. The finer the polish the beter the results.

no problem, i can falt it off with a 120 grit on the belt grinder then use my little 3" DA with various grits. ive got everything from 240-5000 i think

 

[E T]

Linky to an earlier thread.

Post in thread 'Acid Etch Test'

May 10, 2024

HG rust remover works great for etching mild steel welds.

• E T

• 

 

[BrokenBiker]

ah cool, thats way more defined than i was expecting. thats exactly what im after, thanks

 

[hotponyshoes]

If it's just for curiosity on how much penetration there is, then any acid will work eventually.
Cut and polish first. The more shiny you polish it the weaker the acid you'll get away with using.
Any household acid will do something. You might just have to zoom in with a camera and wave a torch around to see it.

Or, weld the piece, cut and polish. Then dump a load more weld a few mm away from the edge to heat up the piece. You'll see the depth as the polished edge starts to change colour.

Or, just weld stuff like I do.
Then when you cut it apart, it's easy to see how deep the weld has gone by the bubble holes and bits of slag

 

[BrokenBiker]

If it's just for curiosity on how much penetration there is, then any acid will work eventually.
Cut and polish first. The more shiny you polish it the weaker the acid you'll get away with using.
Any household acid will do something. You might just have to zoom in with a camera and wave a torch around to see it.

Or, weld the piece, cut and polish. Then dump a load more weld a few mm away from the edge to heat up the piece. You'll see the depth as the polished edge starts to change colour.

Or, just weld stuff like I do.
Then when you cut it apart, it's easy to see how deep the weld has gone by the bubble holes and bits of slag

blowtorch could be used to show the different colours maybe?

 

[hotponyshoes]

blowtorch could be used to show the different colours maybe?

Yea, anything that heats it up.
Eventually it all goes the same colour (or oxidises) so heating the material rather than blowing the torch directly over thenpokised edge gives you more time to observe.
You can purge the weld area with argon from the torch to buy a bit more tiem as well.

I've seen some pretty cool demos with induction heaters where they take it to the changing temp of one material then hold it there to show off the level of control of the heater.
There was a blacksmiths show with some damascus steel with the pattern of a rose worked into it. Only visible when the heater was set to a certain power level

 

[BrokenBiker]

Ill have a go tomorrow, cut and Polish some of the welds i did earlier and flats the torch along the back side of the material and see if i can see anything