is it normal for there to be an ugly gray weld under the surface weld on the inside of the pipe? i've been trying to get a nice surface weld but its unattainable without getting full penetration and getting that ugly weld on the inside..

I was wondering "do all welds that are non-purged look like that on the inside?" and doesnt it take a fraction of an inch on the ID on a full bead around the pipe? its like 1/16" all around on the inside and its ugly caca gray.

i'll get pics later tonight, but is it normal and does that full penetration ugliness affect the integrity of the weld? or is it purely cosmetic? i know its contamination because the inside is not shielded but does it really matter?

sorry if i repeated myself 100x in the post but i cant seem to get my point across.

 

Stainless or mild steel.

Ideally any pipe weld should be backpurged. Stainless it's needs to be done otherwise you get carbide precipitation on the backside.

 

so what color is it on the inside?

 

it usually looks like normal stainless. sometimes it has a little color.

 

i was kiddin because he said it was ugly gray about 1023 times in the post

 

actuallllly.. i said it was caca gray.

 

will this carbide precipitation affect the strength of the weld?

 

Yes, it will affect strength, for instance if its on an exhaust manifold,
within a few months it will start cracking, its always best to cap the
ends and purge the inside with argon at about 5 psi, thats what I do,
and usually you will get perfect beads on the inside.

 

For a manifold, no.
You should still shield it one way or another.

 

i think u mean 5 cfm. also block all your holes and poke a few little holes in each to create even gas flow to the weld.

i use like 20 cfm, u dont wana create pressure in the manifold.