Welding Tips and Tricks

Ok, I'm faced with a 250mm long overhead butt weld on a T beam lintel with a 10mm flange thickness. The web has already been welded. I know the routine but the unknown quantity is that brickwork has already been built on top. Not my doing. So, 85 amps for the root, 105 for the hot pass and 95 to 100 for the capping. BUT will the brickwork effect amperage? My rods are Kobe 52U 7016 which I believe are pretty much the equivalent of your 7018's.

i havn't done it, but any insulation on the back side of a weld will require slightly less amps. how much less i have no idea. just like a chill bar means you increase amps.
i would recommend practice first.
tho a concern might be about the brick cracking with the heat. typically avoid welding on concrete as it can blow bits out but not sure with brick.

the 7016 is a little different to the 7018. no iron powder in the flux so a 16 is less amps than an 18 as its slightly smaller rod.

gnabgib wrote:Ok, I'm faced with a 250mm long overhead butt weld on a T beam lintel with a 10mm flange thickness. The web has already been welded. I know the routine but the unknown quantity is that brickwork has already been built on top. Not my doing. So, 85 amps for the root, 105 for the hot pass and 95 to 100 for the capping. BUT will the brickwork effect amperage? My rods are Kobe 52U 7016 which I believe are pretty much the equivalent of your 7018's.

There are many types of 7016 and there are many types of 7018.
Most 7016 are perfect for open root on DCEN but open root with most 7018 is not that easy.
7016 and 7018 are certainly not equivalent in my book. The two things they have in common are the tensile strength and the low-hydrogen properties.

Regarding the brickwork. If they are solid concrete building blocks they might crack from the heat unless they are made from heat resistant concrete. If they are regular house bricks which are much more porous they wil probably survive.
Just do a test to make sure and to find out what amps to use before you make the final weld.

tweake wrote:i havn't done it, but any insulation on the back side of a weld will require slightly less amps. how much less i have no idea. just like a chill bar means you increase amps.
i would recommend practice first.
tho a concern might be about the brick cracking with the heat. typically avoid welding on concrete as it can blow bits out but not sure with brick.

the 7016 is a little different to the 7018. no iron powder in the flux so a 16 is less amps than an 18 as its slightly smaller rod.

Masonry? Hmm I was thinking opposite, would absorb heat, but you could be right there.
Test, yes, although in this case on the actual piece.
Bricks don't hold moisture the way concrete does.
Did get around to looking at the details. Thicker flux on the 7018's, 7016's have the addition of Potassium salts.

gnabgib wrote: Did get around to looking at the details. Thicker flux on the 7018's, 7016's have the addition of Potassium salts.

i think both have are potassium based, but every manufacture has their own mix and a lot of the other things they put in influences how it runs. i have a list somewhere of the common ones.
keep in mind there is a lot of leeway in the specs especially AWS.

E T wrote:

gnabgib wrote:Ok, I'm faced with a 250mm long overhead butt weld on a T beam lintel with a 10mm flange thickness. The web has already been welded. I know the routine but the unknown quantity is that brickwork has already been built on top. Not my doing. So, 85 amps for the root, 105 for the hot pass and 95 to 100 for the capping. BUT will the brickwork effect amperage? My rods are Kobe 52U 7016 which I believe are pretty much the equivalent of your 7018's.

There are many types of 7016 and there are many types of 7018.
Most 7016 are perfect for open root on DCEN but open root with most 7018 is not that easy.
7016 and 7018 are certainly not equivalent in my book. The two things they have in common are the tensile strength and the low-hydrogen properties.

Regarding the brickwork. If they are solid concrete building blocks they might crack from the heat unless they are made from heat resistant concrete. If they are regular house bricks which are much more porous they wil probably survive.
Just do a test to make sure and to find out what amps to use before you make the final weld.

Yes, different, but almost interchangeable and I simplified it seeing that everyone in the US seems to use the 7018's but 7016's are never mentioned.
And yes solid common bricks.

tweake wrote:

gnabgib wrote: i think both have are potassium based, but every manufacture has their own mix and a lot of the other things they put in influences how it runs. i have a list somewhere of the common ones.
keep in mind there is a lot of leeway in the specs especially AWS.

I really like the 7016's especially these Kobe rods. Now wonder if Jody would ever do anything with 7016's? They seem almost nonexistent in the US.

gnabgib wrote: I really like the 7016's especially these Kobe rods. Now wonder if Jody would ever do anything with 7016's? They seem almost nonexistent in the US.

who knows. probably would if he could find some.

i've got 7016 because i can get it in small packs. a bit hard to for me to find 7018 in small enough packs.
i did read a bit about it being used for root passes. it would be interesting to see how thats done.

tweake wrote:

gnabgib wrote: I really like the 7016's especially these Kobe rods. Now wonder if Jody would ever do anything with 7016's? They seem almost nonexistent in the US.

who knows. probably would if he could find some.

i've got 7016 because i can get it in small packs. a bit hard to for me to find 7018 in small enough packs.
i did read a bit about it being used for root passes. it would be interesting to see how thats done.

He must have been looking in. Just watched his video on 7016's and I finally understand what they are used for so will now more open to the use of 7018's.
Also welded the beam and my initial estimates re amperage were way out, using 142amps for the capping, so maybe the web and brickwork were absorbing more heat than I expected.

The difference between the 7018 and 7016 electrodes is the flux coating of the rods. According to the AWS smaw electrode description, 70 is the tensile strength, 1 is the position which the electrode will run, the final number is the composition of the flux coating on the electrode.

7016 has no iron powder in the flux. There for, less metal deposits... Slower welds but more controllable weld pool. But that said, you will be able to do perfectly well with either with practice.