Need Help From Welding Experts.

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flyboy01

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I have a few questions, it has been about 15 years since I last used to weld, it seems that I forgot everything I knew about welding.

I recently bought a small Lincoln 110v welder, I am usung pure C02 with it. The issue I am having seems to be dirty Welds when I was welding up some 1/4 holes, the smaller holes looked fine, but the beads are sticking up to far, I have to do a lot of grinding to get them flat. I have the regultaor set on 30psi for the C02, which was recommender my Lincoln tech support.

What is a good pressure?

Why are my welds so tall?

Why all the soot?

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100_0551.jpg
 
The soot is from the paint burning. I did not like welding with CO2 so I went with a 75/25 argon/CO2 mix.

Chuck
 
There was no paint on the bottom row of welds. What is the difference in weld quality between C02 and 75/25 mix?
 
you have grind that bubbled paint off anyway right?? so you might as well make sure its real clean before you weld. Fill the holes in just like your putting on a panel, a bunch of little spot welds. I would start at the top of the hole with a spot, let it cool, hit the edge of the 1st spot with another, let it cool, and keep repeating until its filled in.If your welder is set too cold it will build up too much and if its too hot it will blow away the edge of the hole. Also if you can clean off the back side of the holes as well, sometimes there is undercoating on the back side and it melts and runs down into you welds and will mess you up,,hope this helps,,good luck
 
You should sand around the holes at least 2 inches front and back. Make sure you are using the correct wire with the Co2. As far as build up goes you need to turn down your feed speed. Your feeding to much wire and it's stacking up. It's best to use a backer when welding in dead holes. They have spoons made of copper for this, the weld doesn't stick to it but it allows the arc to continue and still penetrate the steel. I would suggest getting some practice metal and perfect it before working on the final piece. Try different setting for your heat with the same wire speed, and vice-versa. With shielding gas cleanliness is very very important, along with making sure you aren't in a wind storm.
 
I'm no expert, but maybe I could give you some tips. 30 psi is way much unless, as stated before, your are welding in windy conditions. 20 psi is all I use. Like chuck said, use a 75/25 mix of CO2/Argon. You are using solid core wire right? For sheet metal, use .024" wire with the apropriate tip. I weld hot and fast so I dont burn through but get good penetration. The metal must be absolutley clean, no exceptions. OK, maybe "weld through" primer is the exception.

This takes a lot of practice, so use some scrap metal of the same gauge to practice on. I've been welding for 26 years and it doesn't happen overnight. I move the tip in a semi-circular pattern for butt and lap welds, outward spiral (like filling an ice cream cone) for rosette welds (what you're doing). Heat and feed speed are key.

Good luck and keep practing. Soon enough, you'll get a feel for the weld puddle and whether you are penetrating or not. Metal flows grasshopper, go with the flow. Nothing cooler than melting metal (as long as it's not inside your engine! LOL!). :thumbup:
 
i would go with 25/75 also ... make sure u got the polaity right on ur leads if u was using flux core u have to switch them around ,check ur owners manual
 
The deal with 75/25 is it creates a much cleaner weld. All of the welding shops around the area use 75/25. We at the shop use Weld Kleen, and flux core wire also. Hardly any lil dingle berrys or anything of the sorts(if so knock it off with your fingernail), also provides a cleaner weld and doesnt oxidize/rust (guessing thats the right word) as fast as if you didnt. This isnt a bad idea on sheet metal either.

We dont do sheetmetal work and I havent tried recently but I agree with ramcharger on filling the holes. I build railings and stairs at the shop and sometimes when I weld in the step panels I have a blonde moment and burn through, I fix it the same way as he tells you. Just the opposite as if you are trying to cut a nice 1/2 or 3/4 inch hole with a torch, you would start from the center and work out moving with both hands and weaving like your drunk so-to-speak, but doing it backwards when welding.

Lincoln welders I know some of them have a chart where the wire goes that tells you the best voltage and wire speed to weld a particular thickness and type of metal. This is helpful to a point, but I never have had exactly or sometimes even close to those specs. So try it out on some scrap metal if you have any!
 
75/25 is also a cooler weld then streight co2... that helps with sheetmetal.
 
is it 75 argon and 25 co2... or 75 co2 and 25 argon that your recomending?
 
I weld cages, frame connectors and such things like that...I use straight co2...I don't have sooty welds that look like that unless the bottle has been forgotten to be turned on...LOL..Can you hear gas coming out of the tip when you trigger the gun?...Did you change polarity of your machine and install the shield on the end of your gun when you went to straight wire...As they mentioned before, 30 psi is way to much...I use 14 psi (inside shop) outside will be greater in wind...And the .024 wire IMO is the way to go for small welds. Do not hold the gun away from the weld, tip needs to be close enough to receive the gas on the weld...Practice on scrap...Should sound like bacon frying..Not popping and snorting...I had a mig 100, was 1 of the best welders I ever used...I have the mig 170 now...It is a great welder also... Good luck at figuring it out !...Lee
 
Another thing to consider is the wire stick-out. It should be 1/4 inch max from the end of the contact tip, the closer, the better. snip the end of the wire every time you stop. It sounds like a pain, but it's worth it. The front and back of the panel must be bare metal,and don't forget to clean out the hole too! I like 75 argon 25 co2 mix, it has less penetration and is smoother than straight co2. Co2 is for penetration and it's a lot cheaper than the 75/25. The copper spoon is a great idea as well as some heat barrier putty or gel. DON'T weld in one spot ( 1-2 seconds max ) or you will warp the crap out of it! (on flat side panels). gas flow should be 15-20 cfm max.make sure to clean the spatter out of the nozzle often. Also practise on some scrap before you commit .I've been a welder over 25 years now, and this is what I teach to new guys just starting out! Good luck; and keep us posted on how you make out! Tom.
 
Arrgh! I forgot to mention that I meant "20 cfm", not "20 psi". Darnut just reminded me. Make sure you have a gauge that reads output in cfm, not psi.
 
OK here are all my answers

I have the Handy Mig, which a slight step down from the 100. It was a christams gift, and all I have ever used it on is exhaust and sheetmetal.

lcn-k2185-1.jpg



Yes I am using .024 tip and mig wire. Came with the welder from Lincoln.

I am using the 100% c02 because I already had a bottle with regulator.

I did use copper behind the holes, otherwise I would have never been able to close them.

I turned up the wire speed because it was popping rather than sizzling.

Yes I did switch the polarity.

Lincoln recommended 20 psi, but I turned it up to 30 because even though I was in a garage, there was a breeze outside and I thought some of the gas might be going out the back of the hole. DO you set the pressure on the gauge or with the trigger depressed (flowing)?

For the rest of the holes, I will go ahead and sand back farther. Unfortunately I cant get to the back of most of the holes to sand the back.

I appreciate all the advice. I guess I need to practice more, but its hard to know what changes are doing to the work when you are not sure what you are doing. I wish I could take a quick 1/2 day class or something like that.
 
I'm going to read this again when I get another chance to pull out the welder I have... All I did was make a mess last time I checked it out.
 
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