Welding, Metal-Ready and Rust

[Jimmy240Z]

As I continue to replace the floorpans, etc. on my 240Z, I have two more questions. First, I have some areas in the back area around the seatbelt anchors where I can't seem to get down to clean metal. Someone told me I could treat it with metal ready and weld the pans to this area. Another person told me I should be using flux-core to weld wher there is the leftover rust. So I guess, the real questions are Metal-Ready Flux Core or not?

[John Coffey]

Rust and dirt are bad things when it comes to welding. You need to physically clean the rust and dirt out of the area you're going to weld. Try:

1. Wrapping sandpaper around a flat blade screw driver.

2. Use sanding rolls like these: http://www.mcmaster.com/#sanding-rolls/=b2r45g

3. Small wire wheels.

4. Media or sand blasting.

And you're much better off using MIG welding then flux core welding.

Edited February 17, 2011 by John Coffey

[Jimmy240Z]

What about the Metal-Ready?

[John Coffey]

As I said, "Physically remove" the rust and dirt. Save the brews and potions for paint prep.

[cozye]

You should be able to get most of that with a wire wheel on the end of a drill. They make a few different sizes to get into various spots.

[grantf]

Also after cleaning, hit it with some weld through primer, It helps prevent youre welds from rusting in the future.

[esmit208]

JIM

The same area will have to be worked on, on my rig. I am sandblasting but I am doing the entire car. As stated before wire wheels will clean it up nicely. If you don't remove it you will see it again. Nice job on the floor removal though. Keep at it.

[EScanlon]

Metal Ready and most other Metal Prep solutions are just mild acid washes that will only affect the rust molecules they can come in contact with... i.e. surfaces and other porous areas. Stronger acids are available, but then it gets very touchy as to how, and where to use, and how to neutralize the acid. Leave the stronger acids to the experts.

For welding to be done properly, you need as clean a metal as possible... free of coatings, paint, corrosion (rust) and other items. The use of Flux or Gas while welding is to help the weld stay in a given area and penetrate properly. Poor condition steel (rusted, painted, etc.) will not yield a strong weld if it even allows the electrode to spark.

While a wire wheel will do a fairly good job or brushing it off, you want to grind, or sandblast off the bulk of the rust before you just rely on the wire brush.

As John Coffey said, REMOVE the rust, then weld, then apply the solutions.

FWIW

E

Edited February 19, 2011 by EScanlon

[Jimmy240Z]

I have a question for esmit208, saw your post about the sandblasting. Curious as to how you are actually doing the sandblasting. Saw the blaster I think you posted from HF but how about containment, reclaiming the blast media, etc.?

[EScanlon]

Look at these, this is one idea:

http://www.classiczcars.com/photopost/showphoto.php?photo=9215&ppuser=1490

http://www.classiczcars.com/photopost/showphoto.php?photo=9216&ppuser=1490

http://www.classiczcars.com/photopost/showphoto.php?photo=9217&ppuser=1490

E

[Jimmy240Z]

Thanks alot, how do you clean up and dispose of the paint and blast media? how long does a tank full of media last? Sorry for all the questions, just trying to learn about the process. Again, thanks for sharing the pictures.

[Logan's 240Z]

Stay away from flux core wire,unless your welding a plow out in a field somewhere.Mig weld with a gas bottle argon/co2 mixture.Clean metal with wire wheel or tiger wheel,consentrate on weld penatration,adjust current/wires speed as needed.shell blast after welding is done,then primer and paint.It's that simple.....As far as blasting I've got the luxury of working at a place that has a 10x20 blasting room.Free use anytime I want.Hope I didn't make anyone jealous.Rog