Sanding large metal construction beam ?

[threesixright]

Is there a humidity problem that needs to be addressed?

I don't think its a humidity issue. The beams where new installed, but before the roof was on (they first build the 2nd floor) it was fully open for over ½ year due to many delays. And obviously -Murphy came for a cup of joe  [eek] -  and we where hit with a terrible rainy season, hence the rust 

To cap it will be the last solution. For aesthetic reasons, we wanted to keep the beam the beam. The horizontal one will be painted in same color als the window frames and the pole we want to keep metal look. Well that would be the plan [tongue]

I found a "copy" of the renovator, I think I will give that a try.

Thanks you all for the help!!

 

[kmickey]

I don’t know where you are, but chances are there’s a service similar to this nearby. When you calculate man-hours, their rates are very reasonable.https://www.laserflux.com/en/soluti...gsdienst-is-een-zeer-toegankelijke-oplossing/

 

[leakyroof]

Is there a humidity problem that needs to be addressed?

I don't think its a humidity issue. The beams where new installed, but before the roof was on (they first build the 2nd floor) it was fully open for over ½ year due to many delays. And obviously -Murphy came for a cup of joe  [eek] -  and we where hit with a terrible rainy season, hence the rust 

To cap it will be the last solution. For aesthetic reasons, we wanted to keep the beam the beam. The horizontal one will be painted in same color als the window frames and the pole we want to keep metal look. Well that would be the plan [tongue]

I found a "copy" of the renovator, I think I will give that a try.

Thanks you all for the help!!

  post a picture or two of how it worked out for you and the tool you bought to do the job.  Thanks

 

[Sparktrician]

With regard to sandblasting. What would be the best media to use for this?

If you use glass beads, it will take forever and you'll get a "soft" texture.  If you use sand, it will be quick and you'll get rid of rust more quickly.  If you use a grit, it will cut the rust down very quickly and you'll leave the steel with a good bit of "tooth" to help adhere the next finish.  In any case, you'll want to curtain off the area and prepare for shoveling out the used grit and removed rust and paint.

 

[Cheese]

With regard to sandblasting. What would be the best media to use for this?

Just to echo Sparky's talking points, bead blasting, whether plastic or glass is more of a surface treatment. It will softly texture a surface and will be typically used on wood, plastic or aluminum or sometimes stainless. The look's the thing.  [big grin]

For what you're undertaking, you need to grit/sand blast the surface to remove the rust. The grit/sand comes in various abrasive levels. The real issue you face is partitioning off the blast area from the rest of the house. This is some really dirty work and the sand blasting material will work its way through every nook & cranny. I can't stress enough the need to fully and completely cordon off the area because you will be shoveling the blast media out of the blast area in shovels full.  You will probably go through several hundred pounds of blast media.

If you go down this path, consider adding a large 24"-36" exhaust fan to the cordoned off area to draw off the fines. That way most of the fine stuff has been exhausted outside the house and you just have to shovel up the big stuff.

 

[AlexThePalex]

In the body shop we had a mobile sandblaster like the one below, though ours was twice as big. It is a blaster and vacuum in one. All the sand you blast is immediately sucked up at the source and put back in the container to be re-used. Loss of material is very low. There really is no need to think you'll go through hundreds of pounds of the stuff, or fill up the basement with a sand storm. These things can be rented.

[attachimg=1]
https://www.nederman.com/en/pws-catalog/p/industrial-vacuum-cleaner/dust-free-blasting-unit-sb-750#
https://sapigmbh.com/en/produkte/pr-50-injector-vacuum-dust-free/

 

[Nardo]

Go here: https://www.hmgpaint.com/PDF/knowledge-base/KNB0026.pdf

It's called "Swedish Standard" for metal prep.

Short version - need to clean it - get all the mill scale off, wipe it down. 

Ventilate and use low odor paint thinner or wash with simple green.

Scrape off loose stuff in 3 directions

Wire brush in 3 directions

Clean again

Paint with Rustoleum rusty metal primer

Top coat

you can use POR15 or Rust Bullet but you don't need to. 

Anything you use to machine sander or wire will make shiny polished spots and the primer and paint won't stick to that.  If you do use a grinder then def go with a 36 grit flap disc

If you get shiny spots then you will have acid wash to get a tooth on the surface for a primer to bond to...

Main thing is to get it really clean and oil free then clean again after

Oh - use a new wire brush or you will just spread around grease and oil