Sand blasting media for heavy paint/filler?

I would avoid using sand for a number of reasons, silicosis being an important one. Besides, sand is not particularly aggressive IMO.

I'd be tempted to try "Black Magnum":

I've never used Black Magnum, but I've been curious about it ever since I first saw an Ebay listing for the stuff a while back: it looks like good stuff.

Here is a description of Black Magnum from another distributor's web site:

[quote] Coal Slag product that is very angular and contains less than 1% free silica. Black Magnum is available in coarse to extra fine sizes. The hardness of this material makes it very resistant to material breakdown.

Advantages:

- Does not react with coatings so there is less coating failure

- Does not draw moisture

- After-job cleanup is fast and easy

- Low free silica content [/quote]

The only reason I haven't bought some yet is because I bought a fairly large supply of aluminum oxide before I came across the Black Magnum listing.

If you get some of this, let us know how you like it.

- Michael

Maybe the most effortless way to remove paint and fillers is with high heat. A propane torch (or almost any flame) will soften and blister it almost instantly. One needs to avoid breathing the stink, it's most likely very nasty fumes.

An improvised scraper will get thru deep coatings quickly with the aid of heat.

A solvent scrub of the stripped areas should be adequate for refinishing.

Media blasting soft materials is generally slow as the impact of the grit seems to be reduced by soft materials.

WB .............

Im not concerned about silicosis at this point..I have a 36" x 48" Trico blast cabinet with the dust collector and Im using it outdoors

Im looking for something with some mass to it. If I had enough steel shot Id try that..but...

These are heavy cast iron castings with the typical shellac type filler under it.

Ill check locally for the Black Magnum stuff..as Ive got several other projects that will need something gnarly to blast down to clean metal.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Yes, you mentioned you had a blast cabinet in your original post. But even blast cabinets leak dust. However, since you're outside, probably not too much of a concern. You can always wear a respirator.

Consolidated Stripping (the company I linked to in my earlier post) sells Black magnum on Ebay:

Just $13.95 for 10 lbs, with free US shipping. They also sell 50 lbs bags on Ebay. You can choose from several grit sizes, including 6/12 which has got to be like pea gravel!

But if that's not heavy enough for you, they also sell steel shot blasting media:

$15.95 for 10 lbs, again with free UPS shipping. (50 lbs bags also available.)

Disclaimer: I have no interest in this company, and in fact, I've never done business with them. But they seem to have some good products at a decent price.

- Michael

D'oh! Damn...And I didnt even think about using heat....blush..and I have an electric paint stripper in the truck for bearing heating..and a bunch of various torches of all types.

Blush..... thanks for for the kick start.

Gunner

Gunner I worked at a Sandblasting shop for almost 10 years and trust me if you get Sandblasting Sand there is not any silica in it anymore, that has long since been removed for health reasons. However if your serious about the blasting and want something that will last a long time look at aluminium oxide. You can re-use this for a long time. Most local Blasting shops can get it for you. We use to use "old" glass bead to polish aluminium and car rims. Also if you really want to take something down one layer at a time use baking soda. Last point is to make sure the pressure is not very high, keep it around 90-100 psi otherwise you just crush your media into powder and it's no good to reuse.

There's some pretty interesting media available at your local Abrasive Emporium. I got some stuff a while back that looked like small stars with a hole in the center. Very dense stuff, 2 bags took two trips to the truck, $12 total cost. Cuts like a buzzsaw. Wears out tips pretty quick too.

- - Rex Burkheimer WM Automotive Fort Worth TX

Gunner wrote:

Why remove all the filler? All this baloney about "gotta get down to bare metal" I now think is pointless. If the stuff hangs on there like glue, just PAINT OVER IT.

I learned this when I redid my Walker Turner band saw. I insisted on every square millimeter of cast iron being clean and then I painted it. Sure, it looked great. Now it's usually covered with chips, who cares?

GWE

I actually have about 50 lbs of aluminum oxide..but its very very very fine stuff. Talcum powder fine. Polishes well, but only polishes the paint.

Ill check locally..or try the heat trick this time around. Id much rather blast than heat and strip then fiddle with the detail stuff.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

i find aluminum oxide doesn't last very long when blasting glass. i get better longevity using silicon carbide, and it's sharper too.

Simply because the edges dont feather very well. They seem to crumble leaving ledges rather than a smooth blend.

I was going for "One nice looking machine in the shop" on this one. Shrug..Ill likely give up shortly and simply spray it as is.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Stick with your plan, and do this one right. You will be glad of it.

Rex

Gunner Just contact a local Sandblaster and see what they have. There are hundreds of different media for different applications. As far as aluminium oxide goes this also comes in different grits so get something a little more course.

My opion on stripping the machine is do it right, I have a few "OLD" machines, welders etc. that I stripped, replaced older wires and had powder coated. I've had more than a few people want to buy them from me for their shops. Honestly for some of us I take as much pride in my work as I do in a clean shop. After each project I cleanup and then start the next one. A clean shop is a happy shop. Also I find that people that borrow my shop respect my tools more when I take care of them.

BUT JUST MY OPINION

Use coal slag, Black Beauty, Black Magnum, etc.. Should cost between 8 and

12 dollars per 40 pound bag depending on quantity. I blasted a very corroded dump body last summer down to white metal. It stings a little bit when it bounces back on you, so wear a suit and use a shield for your face.

I understand - but my restored 1930 Delta drill press that I painted in 'cover the Earth" Machine Green has held up nicely over 40 years. The original coat was failing and the machine would have likely rusted to death in the salt leaden air of the old house we lived in.

Martin

What he said. I used to strip old machines back. Then I decided it was a waste of time seeing as how I bought them to cut metal, not be museum pieces, and any new paint job was gonna get damaged anyway. Now I just clean off old caked oil, grease etc and put them into service.

PDW

As an alternative to coal slag and a big compressor/sandblaster, you might try a needle scaler. It should chip the filler out pretty well.