Any welders out there? Need some tips. (1 Viewer)

[chapelno]

I'm a total amateur welder and self-taught through youtube, couple textbooks, and trial and error. I can get two pieces of metal to stick and with some grinding it'll look halfway decent. Need some help from the experts out there.

I keep getting these little craters in my welds, almost like air bubbles (pic attached) - what am I doing wrong here? Am I not aggressive enough with the filler? Tig welding using a Maxstar 200DX, 1/16" electrode, usually 3/32" filler. 20CFH Argon flow.

Another question: a lot of times at the end of the weld when I'm waiting for the post flow the weld will "grow" like those worms you had as a kid that filled out when you dropped them in water. You can kind of see it on the very lefthand side of the picture - it ends up leaving a 1/8" or so tit I have to grind off. What causes this and how do I get the weld to stay tidy at the end?

Thanks.

 

[bhmmapping]

Google "porosity"

I do not Tig weld but it doesn't look like you cleaned the base metal at all before welding. trying grinding down to shiny metal before welding and see if that helps. You might also want to check the gas flow and try turning it down a little bit.

 

[Tin basher]

x2 on the clean no grease oil rust paint or mill scale tig welding needs clean shiny metal
I use a small stainless wire brush after grinding just before i weld
im no expert still novice with tig
the brown soot were the weld goes to poo looks like contamination a# draft blew shield gas away
tungsten got b#dipped in puddle my favorite thing to do or c#unclean metal
the tits at the end of weld try backing off the heat slow and dont pull torch away hold it in same position as welding till post flow stops hope this helps

oh and do not use brake clean on anything you are going to weld it turns into i think chlorene gas or something that makes your eyes burn
and hard to breath

 

[alberta mac]

Patience, get comfortable , and go slower. Keep the filler rod end in the gas plume and let it drip into the weld puddle while circulating the torch movement minutely.
Looks like good technique so far.
Make sure the base metal is clean on both sides. When the tungsten is dull sharpen it.
Carefull not to overheat what you are welding.

Fitting : fit tack measure grind down tacks then weld.
Patience makes a good weld, if the weld looks like *%$# then it is not structural and will fail.

Cheers
Alberta Mac

 

[PAToyota]

x-whatever on what people are saying about cleaning the surface before welding.

As for the "tit" at the end, slowly taper off on the heat and raise the electrode in a small "swirling" motion as you come to the end of the weld. It keeps the shielding gas on the weld, but sort of "fuzzes out" the end of the weld and keeps it smooth. Sort of hard to describe without demonstrating.

 

[TRAIL TAILOR]

Porosity in a GTAW/TIG weld occurs as the result of one of more of the following.. 1) improper shielding gas coverage 2) the wrong filler metal or shielding gas 3) too much heat 4)dirty base material. I'd say you have the proper gas and flow rate.

However, like others have said.. your base metal looks dirty/scaled .. GTAW/TIG hates mill scale and contamination. Try using a tiger paw/disc to clean/shine up the material. Mill scale and contamination cannot always be removed by a 4" wire wheel. Also, check your hoses for leaks as well.

Looks like a possible increased heat input issue as well to the left of picture and/or a possible larger gap/fit-up that needed more filler and reduced travel speed.

Termination of a GTAW/TIG weld... can be done in many, many ways. I personally like to walk/lift the filler up and lightly wash the puddle to the edge of my weld while holding the torch with the gas flow on it for a second or two to help cool/shield my weld. IMO you are leaving the filler in place too long and not allowing the torch to keep the puddle hot enough, hence the raised anthill.

Take your time and practice, practice, practice... Not too shabby for your experience. Welding can be frustrating so, just relax and BREATH!!!

Good luck

J

 

[chapelno]

Thanks all. You're correct on the dirty metal - this was a prototype and I just wiped it down with alcohol. I'll take a grinder to the edges of the next one and keep at it.

Also, for any other beginners out there, I just ran across "The Metal School." They sell how-to videos on welding but offer up a few freebies on their youtube channel with some good advice on general fabrication. For example they get into how the metal stretches and pulls as it's heated and cooled from the weld and how to keep things square.

 

[Pin_Head]

I'll take a grinder to the edges of the next one and keep at it.

Don't forget to shine the back side of the joint. You will pick up slag and porosity from any part of dirty metal where the weld penetrates.

 

[spressomon]

chapelno,

This is another pretty good resource for us welding newbs...

http://www.weldingtipsandtricks.com/

 

[chapelno]

The prep was key.

 

[The Jade Bean]

The prep was key.

Purty!

-Daniel Kent

 

[Walton]

I have a lot of experience with this common problem. I have welded on quite a few guns for a blacksmith. The first gun I welded for him, I used 1/16th stainless rod, as you get no porosity like you are getting. It's nothing you are doing wrong. The problem I had was the gunsmith came back and said the gun would not take the bluing to the stainless. I then did some research, and found a Tripe Deoxide mild steel welding rod to Tig weld mild steel with. It works great with no porosity. Another great way to Tig light guage mild steel is with Silicon Bronze rod; it lays like butter with less heat.

 

[chapelno]

Good point Walton, I didn't even mention what type of filler I was using. So far I've only used ER70S-2 because that's what the local shop carries. I have some -6 to try when this stuff runs out, but I'll also take a look at the stuff you mentioned.

 

[Huis Clos]

By the looks of the picture you are pushing your bead.
1. Make sure your gun angle does not change through out the weld.
2. If you are welding indoors, the contamination looks as if your tungsten rod touched your metal, don't let it touch and you need to keep the tungsten rod, I believe a 1/4 inch sticking out of the cone, and keep the rod/cone close to the metal. You might have pulled away to far to cause the contamination.
3. Your beads are bunched up, they need to be overlapping each other by 35% to 50%, consistency is the key, either speed up, or lower the volts to match your speed.
4. Make sure you keep a point on your tungsten rod, when the rod contacts the welding surface, you have to re grind the point to get the contamination off the rod.
I hope this helps.

 

[Huis Clos]

Nice almost there, watch out for undercut on the sides, and keep a consistent pace you are speeding up when you start and slowing down at the end, stay calm in the beginning and watch the puddle form.
1. Undercut- either temperature too high or your pace is a little slow. Undercut is on the side of the beads, creating space between the metal you are working on.
Keep at it.

 

[Huis Clos]

Nice almost there, watch out for undercut on the sides, and keep a consistent pace you are speeding up when you start and slowing down at the end, stay calm in the beginning and watch the puddle form.
1. Undercut- either temperature too high or your pace is a little slow. Undercut is on the side of the beads, creating space between the bead and metal you are working on.
Keep at it.

 

[firestopper]

Make sure your tungsten is clean as well. Grinding in line with the wheel pointed up will give good results. If you "dip" in while welding, you'll need to regrind. Tig welding is very finicky as far as everything must be clean...everything.
good luck
ps. you will need to dedicate a grinding wheel for sharpening you tungsten and NEVER use that wheel for anything else as it will contaminate your tungsten the next go around.

 

[Rokntoy]

In tig there are 2 words! Clean and Shiney!

 

[neufab]

also try cleaning the filler rod use some red scotch brite and wipe with rag.you will end up with a dirty rag.

 

[landyNZ]

If you are new to TIG then most point have been covered.

Cleaning is key. Get a flapper disc for your grinder and get some acetone. Acetone applies twice as much if you are welding ali because the oxide layer on ali is a magnet for oils and waxes.
Second after cleaning is fitup. TIG generates the best looking welds with the least amount of cleanup of any process but the reason you don't see it in volume manufacturing environments is because the fitup needs to be excellent. MIG and arc are far more tolerant of imperfect fit, TIG is not. You need to invest the time fitting your pieces.
Move the torch around while you are waiting for the downslope current to peter out, as the current tapers the cooling of the metal will "wick" up into a molehill if you don't.
Your electrode stick out is related to the size of the cup you are running which in turn informs how much gas you need. I typically run 12lpm on a number 4 cup, that's 12 liters per minute, I'm metric. I use more if I am using a big gas lens to get my electrode into tight places.

Good luck welding and do go check out Jodies channel on youtube, he has a lot of sound advice and better arc shots than most.