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Welding question - filling craters or voids in visible welds

Mdub

Mdub

NAXJA Forum User
Location
Gilbert, AZ
All, I am in the process of manufacturing my own bumper. Using 3/16" steel sheet, 220V Lincoln Mig with 75%/25% CO2/Argon. The welds I'm laying down are structurally sound with good penetration. However, on the welds that will be visible I am grinding them down to look pretty. Every here and there, there are little craters or voids in the welds. What, other than slapping more weld on that area can be used to fill those voids prior to prime/paint? I was thinking about using Bondo, but my guess is that there is a product that is out there specifically for this. I found one such product from 3M called Scotch-Weld, but you have to cure it at 250F and my wife will have kittens if I try to put this bumper in her oven. Any help would be appreciated.
 
Mdub said:
All, I am in the process of manufacturing my own bumper. Using 3/16" steel sheet, 220V Lincoln Mig with 75%/25% CO2/Argon. The welds I'm laying down are structurally sound with good penetration. However, on the welds that will be visible I am grinding them down to look pretty. Every here and there, there are little craters or voids in the welds. What, other than slapping more weld on that area can be used to fill those voids prior to prime/paint? I was thinking about using Bondo, but my guess is that there is a product that is out there specifically for this. I found one such product from 3M called Scotch-Weld, but you have to cure it at 250F and my wife will have kittens if I try to put this bumper in her oven. Any help would be appreciated.
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JB Weld? just like bondo but harder.
 
GrimmJeeper said:
JB Weld? just like bondo but harder.
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Yep, that's definitely on my list, but think there is some weld putty type stuff out there especially for this.
 
I keep a can of Hammerite primer, I leave the lid off until it gets thick and a can of Hammerite thiner around in case it gets too thick. Stuff can take awhile to dry when it's thick, but is on there to stay. If you warm it a little (use a lamp) it will set faster.
I've been using Hammerite water based (latex I guess) flat black lately, I have had some good results on tow hooks and axles with it. Schools still out on how it takes and holds a top coat of enamel or whatever though. The water based black Hammerite dries fast. I think it is going to be my next preservative/primer after welds. I'm going to retire the old lead based stuff I've used for 40 years.
 
if you are grinding your welds and finding porosity they are not "structurally sound with good penetration" they should be solid thur and thru with no air pockets sounds like you not getting enough gas to cover you weld pool. you welding outside? a little breeze will take that shielding gas right away. are you grinding the metal before you weld or just trying to weld thru the mill scale and such.
 
If you have "low spots" in a bead, which isn't that unusual, fill with weld and re-grind.

--ron
 
There is a metal filled bondo type product that I use for the final pass. It is a high enough temp product that I can actually powder coat over it.
 
Captain Ron said:
If you have "low spots" in a bead, which isn't that unusual, fill with weld and re-grind.

--ron
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This is all I do when dealing with low spots.
Your going to grind and paint anyway, its fast and you have what you need right there.....
 
bj-666 said:
if you are grinding your welds and finding porosity they are not "structurally sound with good penetration" they should be solid thur and thru with no air pockets sounds like you not getting enough gas to cover you weld pool. you welding outside? a little breeze will take that shielding gas right away. are you grinding the metal before you weld or just trying to weld thru the mill scale and such.[/quote]

X2 your welds should be SOLID all the way through!!
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ColoradoRaptor said:
bj-666 said:
if you are grinding your welds and finding porosity they are not "structurally sound with good penetration" they should be solid thur and thru with no air pockets sounds like you not getting enough gas to cover you weld pool. you welding outside? a little breeze will take that shielding gas right away. are you grinding the metal before you weld or just trying to weld thru the mill scale and such.[/quote]

X2 your welds should be SOLID all the way through!!
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Just because...

Look dude, 99% of you guys are flux core whores welding scaled material. You all have voids and porosity, you just havn't ground though it to see it.

Fill it and move on. If you want real welds, this ain't the place to find them. Understand?

:D

--ron
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Captain Ron said:
ColoradoRaptor said:
Just because...

Look dude, 99% of you guys are flux core whores welding scaled material. You all have voids and porosity, you just havn't ground though it to see it.

Fill it and move on. If you want real welds, this ain't the place to find them. Understand?

:D

--ron
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Damn.......Not all of us here are shadetree welders using flux core to get by!!:gee: My welds are SOLID!! Thanks for the input though!!:looney:
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