Welding Tips and Tricks

I don't know if there is a term for welds on aluminum showing on the back side but trying to see how to minimize it!
Example aluminum boat, every weld on the side ribs showing on the outside of hull?
Some boats you can't even see it and some you can feel !
I have a boat right now that looks like crap because of all the lines on the sides where welds bleed through
.100 aluminum. But I have had boats that you can't see anything?
Are they somehow sanding it out? I want to build one from .125 aluminum and want to not have every weld show outside!
I am not a professional welder but have been working with a spool gun a bunch the last few months
I might also buy a tig but what technique works best?
Can you even sand out the marks? Thanks

You should be able to sand it out, just keep an eye for cracks on the edges of the weld. This happened because you were probably running a little too hot for the material thickness. With your spool gun you could cut your voltage back by a volt or two and see a decent difference. Another thing, whatever technique you are using you could just move a little quicker thus not keeping the heat in one spot for any longer than neccessary.
Ultimately I would reccomend that you get a TIG machine (make sure it has an AC option[you said you aren't a professional welder so I don't know how much you do or don't know, sorry if it seems condescending]) which would allow you to have more precise control over how much heat is going in and not melting through.

What you are talking about is called "burn through". It is what happens when you get a full penetration weld. I work at a plant that builds petroleum tankers for truckers to haul gas to the local convenience stores. When they weld the baffles from the inside, if they get too hot, then you get a burn-through. It blisters the outside.

You can sand them down and metal finish them to match the outside with a DA sander. Or you can weld them from the outside-in, where the burn through won;t be seen. Just remember-metal has grain, just like wood. After you sand with a DA sander-use the same grit sandpaper to sand with the grain. That will put the grain lines back in the metal. Your repair work will be less obvious then.

Fishbum wrote:I don't know if there is a term for welds on aluminum showing on the back side but trying to see how to minimize it!
Example aluminum boat, every weld on the side ribs showing on the outside of hull?
Some boats you can't even see it and some you can feel !
I have a boat right now that looks like crap because of all the lines on the sides where welds bleed through
.100 aluminum. But I have had boats that you can't see anything?
Are they somehow sanding it out? I want to build one from .125 aluminum and want to not have every weld show outside!
I am not a professional welder but have been working with a spool gun a bunch the last few months
I might also buy a tig but what technique works best?
Can you even sand out the marks? Thanks

Even without burnthrough, on alumininum you want to see clearly from the back exactly where the weld is. If the weld is not visible at all, you have poor penetration. It's the nature of aluminum... The amount the metal shrinks as it goes from molten to solid, combined with it's flexibility, is what causes this. If you're getting blistering or sagging on the back side, you're getting too hot, but if not, they can be sanded out, or they can be carefully planned for in the design and spaced so evenly as to be attractive in the finished product.

Steve S

'Stang wrote:What you are talking about is called "burn through". It is what happens when you get a full penetration weld. I work at a plant that builds petroleum tankers for truckers to haul gas to the local convenience stores. When they weld the baffles from the inside, if they get too hot, then you get a burn-through. It blisters the outside.

You can sand them down and metal finish them to match the outside with a DA sander. Or you can weld them from the outside-in, where the burn through won;t be seen. Just remember-metal has grain, just like wood. After you sand with a DA sander-use the same grit sandpaper to sand with the grain. That will put the grain lines back in the metal. Your repair work will be less obvious then.

'Stang, I just now noticed your location...

I don't suppose you work at Polar in Springfield?

Just curious. That area is my old stomping grounds. I use to ride trials bikes at Chadwick, and had a favorite campsite east of Ava in booger county...

Steve S

Otto Nobedder wrote:

'Stang wrote:What you are talking about is called "burn through". It is what happens when you get a full penetration weld. I work at a plant that builds petroleum tankers for truckers to haul gas to the local convenience stores. When they weld the baffles from the inside, if they get too hot, then you get a burn-through. It blisters the outside.

You can sand them down and metal finish them to match the outside with a DA sander. Or you can weld them from the outside-in, where the burn through won;t be seen. Just remember-metal has grain, just like wood. After you sand with a DA sander-use the same grit sandpaper to sand with the grain. That will put the grain lines back in the metal. Your repair work will be less obvious then.

'Stang, I just now noticed your location...

I don't suppose you work at Polar in Springfield?

Just curious. That area is my old stomping grounds. I use to ride trials bikes at Chadwick, and had a favorite campsite east of Ava in booger county...

Steve S

Hey Steve!

Sorry for the late response. Been putting in a lot of hours this week. Yeah! I work for Polar. Hired on there out of welding school. Pretty good place to work. We're Union now, so, not a lot of bs from management. And, I used to ride at Chadwick. 250 Ducati. Lot's of fun. Remember O'Neill Cycle? Dave is a long time buddy. Him and his buddies cut most of the early trails in Chadwick.

'Stang wrote:What you are talking about is called "burn through". It is what happens when you get a full penetration weld. I work at a plant that builds petroleum tankers for truckers to haul gas to the local convenience stores. When they weld the baffles from the inside, if they get too hot, then you get a burn-through. It blisters the outside.

You can sand them down and metal finish them to match the outside with a DA sander. Or you can weld them from the outside-in, where the burn through won;t be seen. Just remember-metal has grain, just like wood. After you sand with a DA sander-use the same grit sandpaper to sand with the grain. That will put the grain lines back in the metal. Your repair work will be less obvious then.

I should have previewed this post!!! Got off work, then had a glass of the Irish! Lol. What I meant was he could weld his project from the outside. You can't weld the baffles on a tanker from the outside! My bad! Sorry if there was any confusion.

'Stang wrote:
Hey Steve!

Sorry for the late response. Been putting in a lot of hours this week. Yeah! I work for Polar. Hired on there out of welding school. Pretty good place to work. We're Union now, so, not a lot of bs from management. And, I used to ride at Chadwick. 250 Ducati. Lot's of fun. Remember O'Neill Cycle? Dave is a long time buddy. Him and his buddies cut most of the early trails in Chadwick.

I'd have to say, it's a good thing you're union, now...

When I looked at polar as a place to work, they weren't union at that time (25 years ago) and I didn't like the culture. They were, at the time, some of the best money in Springfield, and probably still are for a welder, especially since you've gone union. 25 years ago, though, I didn't have the skills.

Steve

Otto Nobedder wrote:

'Stang wrote:
Hey Steve!

Sorry for the late response. Been putting in a lot of hours this week. Yeah! I work for Polar. Hired on there out of welding school. Pretty good place to work. We're Union now, so, not a lot of bs from management. And, I used to ride at Chadwick. 250 Ducati. Lot's of fun. Remember O'Neill Cycle? Dave is a long time buddy. Him and his buddies cut most of the early trails in Chadwick.

I'd have to say, it's a good thing you're union, now...

When I looked at polar as a place to work, they weren't union at that time (25 years ago) and I didn't like the culture. They were, at the time, some of the best money in Springfield, and probably still are for a welder, especially since you've gone union. 25 years ago, though, I didn't have the skills.

Steve

I didn't either! I'm an old truck driver. Spent 18 years running from one coast to the other. Got tired of that life. I went back to school at my local community college at 51 years old. Did a double major in welding and machinist. Lot of long hours, but I laid my resume down, along with my copies of four semesters on the President's List for carrying a 4.0 gpa. They hired me on the spot. Lol. Hard to find a good job around here, especially at my age. Just turned 58.

'Stang,

I think we've efficiently hi-jacked this topic, but since it's your topic...

Good work for a tradesman was so hard to find in Springfield when I left... I was saved by that massive ice storm in January of '07. I was working, but dead broke. CU had locked out my gas and killed the electricity. I pirated the water because it wasn't locked out. I had a great opportunity in IA, but no money. I did have electrical skills, and a supervisor friend of mine at CU told me that, despite the mayor's exhoration to have all electrical work done by a licensed electrician, CU was waiving that requirement... If the tech turning on the power was comfortable with the work, it was Okay... So I made $300 each (on average) to reattach weatherheads and rewire peoples' service connections. I made about $3K in ten days, and fled Missouri for a $2K/week job in Iowa.

I love southern Missouri, and would return in a heartbeat if I could find a job like I have now.

Steve S