mill-scale removal

[bigtiller]

I have a weld table with all the mill-scale removed from the tabletop. It looks like it was wiped off, as there are no sanding scratches. How was it done?

What can I use to keep it from rusting in my unheated shed that won't collect dust and dirt, and maybe even prevent weld splatter from sticking?

I don't know why the pic is sideways.

 

[bigdeano]

You can buy steel in that condition, I believe it's called pickled. I think they use acid to remove the scale. I bought some once to make a hyd tank. You could use car wax to keep it from rusting. I've never tried it though.

 

[Thats Hot]

If you use the table a lot you will not see to much rust. I use WD-40 on my table top every 3 or 4 months. If you get splatter on it.... just use a flopeeee disc on it, just enough to remove the splatter.

 

[dstig1]

Could be cold rolled, perhaps?

 

[rswyan]

Mill scale - which is present on hot (not cold) rolled steel - can be removed by soaking (immersing) in regular vinegar and then using a Scotchbrite pad, wire brush, and/or steel wool. Could take 24 to 48 hours depending on heavy the scale is.

After soaking and scrubbing, rinse in a water/baking soda solution to neutralize the acid and then dry immediately to prevent flash rusting.

 

[Mark @ Everlast]

The likely treatment you have is probably "Pickled and oiled"

 

[kennyd]

The likely treatment you have is probably "Pickled and oiled"

Yes, I agree. Its known to most steel suppliers as "HRPO" for Hot Rolled, Pickled and Oiled.

 

[bigtiller]

Does it have to be immersed? for that long of time? the table top is 3'x5'x1/2". That would require a big cake pan.

 

[Big Barn]

Nice table, bigtiller. Is that a Forney welder behind the table in your pic?

Terry

 

[bigtiller]

Nice table, bigtiller. Is that a Forney welder behind the table in your pic?

Terry

Yes it is. I bought it and the Victor torch beside it, at a garage sale in the early 90's. I couldn't guess how old they are but they are pretty tuff because they have always been in an unheated shed.

 

[Big Barn]

Yes it is. I bought it and the Victor torch beside it, at a garage sale in the early 90's. I couldn't guess how old they are but they are pretty tuff because they have always been in an unheated shed.

My dad bought a Forney welder from the Snap On truck in the mid 1960's for the farm.
Just finished a restoration on it. Redoing the faceplate alone cost more than the original purchase price of the welder.
Terry

Edit. No idea why pic is now sideways

 

[rswyan]

Does it have to be immersed?

Yes ... any metal that is in proximity of the air/vinegar interface will rust in fairly short order. Not only that but, there is probably some type of convection or circulation that occurs, when the part is immersed.

I've seen bubbles form doing descaling but where you really get them is with derusting ... I've had a "rust foam" an inch or two thick form on the surface of the liquid when doing really rusty parts.

I'd guess as the reaction occurs the acidity gets spent ... so you'd want some way for the vinegar whose acidity hasn't been spent to replace that which has.

for that long of time?

That's been my experience.

the table top is 3'x5'x1/2". That would require a big cake pan.

Yup ...

 

[Egon]

Acids such as phosphoric react with rust and form a light coating on steel. It gets to the inter granular rust which cannot be seen with just the eye alone.

Some paints will do this as well as seal of the iron from air.

 

[CNC Dan]

Does it have to be immersed? for that long of time? the table top is 3'x5'x1/2". That would require a big cake pan.

Cover with plastic to keep it from drying, after applying acid.

You will need several treatments.

 

[Mark @ Everlast]

If you treat the top, I have found that rust will be kept in check if you spray some anti spatter spray onto a rag, and burnish it in. It'll help prevent spatter sticking, make it easier to "dust off" and give it a nice sheen. Reapply after use, or ever 6 months or so...just keep rubbing it in, don't make it slimy with it. It'll act just like a polish. I've been using it for about 8 years now. Works very well.

 

[bigtiller]

I've heard some about that stuff but i never tried it. It's on my shopping list now.