metal paint stripping w/ 4.5" disc grinder

[mslim]

I'm in the process of refurbing a vintage coke machine.

The metal frame that mounts the compressor in the bottom of the cabinet has been lightly rusted with the residue of what I guess to be coke syrup. I want to strip and paint the frame to preserve it.

What sort of stripping disc or flap wheel should I use on my disc grinder to strip the paint and rust off the frame before I repaint it? The original color seems to be similar to the Early Ford blue. If I use a spray can of decent engine paint should I prime the metal first?

 

[Farmall450]

Knotted wire cup wheel.

https://www.harborfreight.com/3-in-twisted-wire-cup-brush-60482.html

 

[OccupantRJ]

Powered wire brushes of assorted shapes and attack capabilities, used in various types of power tools. I prefer krinkled wire brushes as the knotted brushes are too stiff and grabby for me, and can hurt you in the wrong conditions. I refurb machines daily for a hobby and like keeping skin on my body parts. Wear a face shield and long sleeves. If the framework can be removed, other options such as abrasive blasting are available. If I blast, Sometimes I do not prime. After wire brushing, I do. I have on occasion used cold galvanizing spray for a primer, then scuff lightly with burgundy scotchbrite. Picture is of what I am working on now. I ain’t skeered!

 

[Stooge]

how thick is the frame metal that you are stripping? if its nice and thick, like 3/16, I'd feel fine gingerly using a crimped wire wheel, but if its a thinner material, I would more inclined to use a surface conditioning disc. I've been a big fan of these ones from Lehigh Valley Abrasive https://www.lehighvalleyabrasives.com/search.php?search_query=HL45NW-CRS+&Search= you need a separate hook & loop backing plate, but they work great and you can use them on sheet metal as well without having to worry too much that you are going to damage the metal.

the backing plate they sell didn't last long for me, (this one https://www.lehighvalleyabrasives.c...g-pad-for-hook-loop-discs-lva-hlbp45p-hlbp45p )
so I bought one from McMaster Carr that's been holding up well.

 

[Farmall450]

Powered wire brushes of assorted shapes and attack capabilities, used in various types of power tools. I prefer krinkled wire brushes as the knotted brushes are too stiff and grabby for me, and can hurt you in the wrong conditions. I refurb machines daily for a hobby and like keeping skin on my body parts. Wear a face shield and long sleeves. If the framework can be removed, other options such as abrasive blasting are available. If I blast, Sometimes I do not prime. After wire brushing, I do. I have on occasion used cold galvanizing spray for a primer, then scuff lightly with burgundy scotchbrite. Picture is of what I am working on now. I ain’t skeered!

Any power tool can hurt you -- that's especially true of those involving wire wheels. No need to be overly dramatic about it, though.

 

[M_George]

I'm in the process of refurbing a vintage coke machine.

The metal frame that mounts the compressor in the bottom of the cabinet has been lightly rusted with the residue of what I guess to be coke syrup. I want to strip and paint the frame to preserve it.

What sort of stripping disc or flap wheel should I use on my disc grinder to strip the paint and rust off the frame before I repaint it? The original color seems to be similar to the Early Ford blue. If I use a spray can of decent engine paint should I prime the metal first?

Can you post a thread with some of your projects. I would really like to see some of your work.

 

[whateg01]

I would see about removing the syrup via some sort of cleaner, like soaking in hot water and simple green. Then use one of the "conditioning" disks like Stooge suggested. Wire wheels can tear up the metal you are working on, especially if it's stamped sheetmetal.

Dave

 

[Mecha]

I agree with what most are saying wire wheel brushes work great. I prefer the brass kind though but sometimes steel is all you can find, does less marring of the metal your cleaning. Also scrape the big chunks first.

 

[Alaniho]

Clean & strip discs are the best for this, designed to strip paint but not damage surface underneath. Various examples below, 3m purple and Norton Blaze are the best but the cheap black ones are fine for one off jobs. Any good local welding dealer should have these.

https://www.amazon.com/s?k=clean+and+strip&ref=is_s

 

[Packard V8]

FWIW, I restore old cars and rebuild old engines. Getting the crusty rusty old stuff ready to work with is the most difficult part of the process. Stripping a metal frame with a grinder would be my last resort. Usually, one can have something like that sandblasted and powdercoated for a very reasonable cost.

If you want to paint it yourself, it would fit inside one of the larger blast cabinets and a few minutes would have it far better prepared for paint than a wire wheel on a 4.5" grinder.

jack vines

 

[tarbellb]

After going through dozens of these, both knotted wire and crimped wire, I can confidently say that the cheap HF ones are NOT a GOOD buy.

Had a project that required stripping paint/charcoal from hundreds of boards, buying the HF wheels resulted in lots of wires shooting into my workers clothing and quickly degrading to unusable. Ended up buying good ones and it was a world of difference.

Do yourself a favor and buy quality from the start, it will perform better and last much longer.

Recommend these-
Pferd
Weiler brand
https://www.ebay.com/itm/Lot-of-5-N...eel-Brush-Twist-Wire-4-Brush-Dia/122771085802

Made in Spain cups-
https://www.ebay.com/itm/Lot-of-5-N...eel-Brush-Twist-Wire-4-Brush-Dia/122771085802

 

[Farmall450]

I linked the HF b/c...surprisingly...I've had really good luck with several. I'm only speaking to the knotted cup I linked, not the type you linked. I'm not a fan of those except for certain crevices.