Air eraser, proper pressure?

[Tom Todd]

I have bought an air eraser from Harbor Freight.  I have a small compressor.  I intend to use baking soda to remove paint from some Atlas flat cars.  So what pressure should I use on the compressor?  I have talked to several folks I know and have been told anywhere from 90  psi to 6 psi.  What is the wisdom from the Railwire a$$hats?
Tom

[u18b]

I'll speak up.

It partially depends on where you live- seriously.

I live on the Gulf Coast of NW Florida where the humidity is very high.
And no matter how hard I tried, I could not get good results with baking soda.  Even baking it beforehand to get it as dry as possible.
And I even used Nitrogen as an air source which is as dry as it gets.
Thus since so many other said how they got great results, I could only conclude that ambient humidity makes a huge difference.
Maybe if you live in a dry area you won't have problems like I did.

I started getting far far superior results when I just broke down and bought a big box of aluminum oxide off ebay.
Never regretted it.
About 25 pounds of #220 very fine has lasted me years.  And I no longer have problems.
I air erase at maybe 18-25 pounds max (sorry, been a while).

Like this:
https://www.ebay.com/itm/ALUMINUM-OXIDE-220-Very-Fine-25-lbs-Sand-Blast-Cabinet-BLASTING-MEDIA/254577110047?hash=item3b45fa6c1f:g:RkcAAMXQnYJQ95Nt

You can get finer, but it is more expensive.

By the way, what convinced me was the air erase oxide the Harbor freight used to sell.   That's what converted me.
Then they quit carrying it at my store-- so I just went all-in on the big box.

You can also get glass beads.

I suggest you go ahead and try the baking soda.
If you get lots of clogs no matter how hard you try...... you know what to do.

[Tom Todd]

Thanks Ron

I live on Washington State where it is damp for a good part of the year. I have a sweatshirt that sarcastically says “Olympia Washington  Slight chance of rain.”

I think I will try the grit you suggested.

Tom

[u18b]

Oh, by the way.  A practical matter.

I bought white.
but I have no reclamation process.   I just do it in the driveway.   But white sand is everywhere.

So if I had it to do over again, I'd buy brown so it blends in with the dirt  in my yard better.  haha.

It wasn't so bad at my old house, because I had a sandy driveway.
But not sure how it's going to go over at my new house with white everywhere.

[woodone]

If you can open up the holes in the stand pipe within the eraser you can get soda to flow. I don’t recall how big the holes need to be. I read this on a painting forum some time ago. I would check to see if you can get a spare stand pipe to experiment with.Open the holes a little at a time until you get flow. And your air supply must be dry!

[peteski]

What is the advantage (except for low cost) of using baking soda instead of Al Ox as blasting medium?  I seldom use my blasting gun, and I never even consider using anything but Al Ox in it.

[Steveruger45]

It just has a much milder abrasive impact on the item being cleaned/stripped.   They use it a lot on glass fiber for that reason and is even ok on wood and not cause surface damage.

[woodone]

Lots of paint people say that soda is a good media for cleaning brass. Very fine and will not heat or distort the brass.
Auto restorers use soda to remove paint from metal for restoration. Does not remove metal, only the paint and or body fillers.

[Chris333]

Soda blasting a real car is not enough to make paint stick. The grit is too fine and the metal will be too smooth. It might take the paint off, but you will need to sand the metal before any body work or paint.

[peteski]

Interesting.  Thanks!

[Chris333]

I have idea if it scales down though.

[woodone]

Chris,
I know of two auto restorers that use soda for paint stripping. I have seen in person the work done. What I saw was has soon has they soda blasted they shot primer on the body parts, otherwise the metal would show rust starting to form. So I think that sanding was not needed. Maybe later the primer was sanded, but I was not around to see all of the steps before the finish coat.
For us train people I think the soda will work for us to apply paint.

[Chris333]

I remember watching Fantomworks where a guy came in with a convertible VW that had just been restored, but the paint was bubbling and peeling. They figured out is was from it first being soda blasted. It was this car: https://fantomworks.com/project/1966-vw-beetle/

I used black beauty coal slag to blast my car, but that was just to get the paint off. Before epoxy priming I sanded the whole thing down with 60-80 grit. Any paint, primer, or filler needs tooth to stick too.

I dunno that is what I did.



For brass models I use that fine grit the Harbor Freight sells. As for pressure well I just turn it up till it works    Using the HF gun as well and it clogs a lot and likes to be full.

[wcfn100]

  Using the HF gun as well and it clogs a lot and likes to be full.

The Paasche is the same way.

Jason

[u18b]

For brass models I use that fine grit the Harbor Freight sells. As for pressure well I just turn it up till it works    Using the HF gun as well and it clogs a lot and likes to be full.

I confirm Jason's post.  I have both the Harbor Freight and the Paasche and they are clones of each other.

I'm glad you mentioned fullness- because that's my experience as well.  These guns like the well to be full and perform best at that level.  What performance drop too low, I open it up and add more oxide.

By the way... this was the ONLY way I could get any results with baking soda in my Gulf Coast climate.  With the well full and pressure about 50-60 psi (which is high).  And even then it was constant frustration.