Thinking to Invest in my First Air Abrasive

[Huntonia]

Hello all, (I do hope I've gotten this in the correct category) I'm considering trying to invest in an air abrasive setup for fossil prep. Mainly looking to find something that will be capable of some light matrix removal in tight spaces. I already have a functional air compressor and I find these kits online for cheap. My questions are simply, are these cheap pens functional for prep? And will the aluminum oxide they come with be safe for fossils? 

Thanks for all of your help and guidance!

 

[Fossildude19]

3 hours ago, Huntonia said:

Hello all, (I do hope I've gotten this in the correct category) I'm considering trying to invest in an air abrasive setup for fossil prep. Mainly looking to find something that will be capable of some light matrix removal in tight spaces. I already have a functional air compressor and I find these kits online for cheap. My questions are simply, are these cheap pens functional for prep? And will the aluminum oxide they come with be safe for fossils? 

Thanks for all of your help and guidance!

  

 

 

This looks nearly identical to the Harbor Freight one that I own. 

It is OK for occasional prep. Many people have had issues with trying to get it to work. 

Mine works well, but, I don't do a ton of preparation. 

 

It is a pain to refill the hopper every 5 minutes or so, but it is cheap, so there are trade-offs.

If you are doing a lot of prep, you may want to wait and save up for a more professional unit. 

Keep an eye on auction sites and used item sites like Craig's List or Let Go.  You might be able to find one for a bit less money. 

 

Let us know what you decide. 

 

Some examples of my work.

 

 

[Ptychodus04]

4 hours ago, Huntonia said:

And will the aluminum oxide they come with be safe for fossils? 

Al2O3 is too hard for most fossils. You want something softer like baking soda or dolomite.

[RJB]

What Ptychodus04 said.   and the best of luck.  You have chosen a really neato hobbie.

 

RB

[Fossildude19]

4 hours ago, Huntonia said:

 And will the aluminum oxide they come with be safe for fossils? 

Sorry, I missed this part of the question. 

As Kris said - it is much too hard for most fossils. 

I use dolomite and regular, over the counter baking soda. (not the kind for laundry) 

Dolomite I get from a pottery supply house on line. 

 

 

[Malcolmt]

This is a great starter unit . The main issue is that it is only rated for 55 PSI and will not let you abrade reliably.at lower pressures(<15PSI). It is very susceptible to clogging unless you have very dry air but it is easy to clear the clog with an air blower. Depending on the pressure you use the little tank must be filled every 2 to 5 minutes, but that is not a big deal as it takes all of 30 seconds. Eventually there is a little brass part at the bottom of the tank that has tiny holes in it that will wear out. But if you get to that point you will be ready for the next step up , a dental unit or a Vaniman. See my post somewhere about using the Paasche with dispensing needles to make it more precise. Aluminum oxide is far too abrasive for fossil work unless you are at extremely low pressures and have a very precise abrasion unit that allows you to introduce literally particles in the air stream. I never use more than a 10% aluminum oxide in dolomite for anything.

 

Here is a pic of this unit with a a Dispensing needle attached. There are also completely metal ones but I find these plastic ones are easier to attach with the tiniest dot of cyanoacrylate. A dispensing needle will last 5 to 10 hours before it burns through. On this Paasche unit the gage of dispensing needles that work reasonably are 18 and 20.Smaller gages than that do not work well on the Paasche and larger ones are in my opinion too unprecise for fossil work. Even though I have high end professional equipment I still have 2 of these that always have aluminum oxide / dolomite mix and silicon carbide /dolomite mix so I can just quickly remove a stubborn bit without having to empty out a tank on my COMCO unit. FYI I use dispensing needles to make nozzles for my air abrasion as you can get needle lengths of 1/2 in to 2 inches so it makes for some very customized nozzles. At 30 and 32 (.008inch) gage they are finer than any commercial nozzle. Oh and did I mention...they are dirt cheap on online..

 

[jpc]

Thanks for this update, malcolm.  I really like the idea of having this thing laying around with harder powder to use occasionally as needed.   

[Huntonia]

Thanks so much for the help and replies everyone! I'm very excited to take this next step up with my prepping. If I could pick your brains just a little more, I've found a few of these for very affordable prices, that seem to have a second more precise nozzle on the opposing end. 

The one I showed above advertised that the moisture filter was in this area, so I'm curious if the secondary tip is effective, or if it might impede the function of the device as a whole? 

[Malcolmt]

Thats not a second tip its a needle valve that controls the paint flow on an AIRBRUSH... That is not an abrasive unit

[Huntonia]

21 minutes ago, Malcolmt said:

Thats not a second tip its a needle valve that controls the paint flow on an AIRBRUSH... That is not an abrasive unit

 my bad. Still extremely new to prep, and air tools especially. Thanks for bearing with me in this process.

[Malcolmt]

57 minutes ago, Huntonia said:

 my bad. Still extremely new to prep, and air tools especially. Thanks for bearing with me in this process.

Not a problem..I only know that because I have one bought over 35 years ago that I now use as an air blower to clear away dust. Paasche was originally known for making very good air brushes (although that model is not one of them)

[hadrosauridae]

9 hours ago, Fossildude19 said:

Sorry, I missed this part of the question. 

As Kris said - it is much too hard for most fossils. 

I use dolomite and regular, over the counter baking soda. (not the kind for laundry) 

Dolomite I get from a pottery supply house on line. 

 

 

does this need to be sifted?

[jpc]

I sift 

I use a No 30 or so soil sieve.  These things are about 50 bucks new, but maybe found cheaper on our favorite auction site.  

[Malcolmt]

The dolomite from Pottery supply house labelled 4013 does not need to be sifted as virtually all of it fits through a 120 mesh sieve and about 80% fits through a 320 mesh sieve. Thee one they sell called Dolocron clogs too much

[Huntonia]

45 minutes ago, Malcolmt said:

Not a problem..I only know that because I have one bought over 35 years ago that I now use as an air blower to clear away dust. Paasche was originally known for making very good air brushes (although that model is not one of them)

One certainly does learn a lot from experience, and what a wonderful tool the forum is to connect some with decades of experience to other (like me) who are new to the field! I plan to make some purchases in the very near future and begin starting my setup! 

I found one of your old posts and it looks like your prep area isn't particularly large as far as square footage. Are you able to keep the debris and dust from prepping within this area? Due to the climate here prepping outside would be pretty much put of the question.

[FossilNerd]

11 hours ago, Fossildude19 said:

Many people have had issues with trying to get it to work. 

 

 Nice work Tim!  

 

I have one of the Harbor Freight versions as well, but I'm one of the unlucky people that have issues with it. The button sticks and causes the valve to stay open so the thing tends to stay slightly on all the time. It did this out of the box. It also clogs a lot. All of that, coupled with the frequent refills of the tank, leave me fiddling with the thing and trying to get it to half way work more than actually using it. When I can get it to work correctly it certainly does the job, but mine just isn't worth the hassle. I'm saving for something different.

 

That being said, I think the Harbor Frieght version is cheap enough to give it a try. It obviously can work based on Tim's prep jobs, but being a cheap unit, quality control probably isn't the best. I think that I very likely got a dud, but for the price I don't regret buying it. It worked enough to make me realize I want one (that works) for prepping!

 

Of course, If I tried it out as soon as I bought it, I could have returned it for another, and maybe got a better one, but mine sat on the shelf for a month or more before I was able to give it a go and realized it was sketchy. Maybe I'll just go buy a second one since they aren't expensive. 

[Malcolmt]

Huntonia, .......That's a really old picture where the area was used for rough scribing and hand dental tools  with just a shopvac hose to suck the chips and dust.....The blue you can barely see on the left hand side of the pic you showed was a dental air abrasion unit similar to a Vaniman........ Here is a more current look at my setup but it is still relegated to a corner of my laundry room. The compressed air is piped in from the garage and the suction after a cyclone and a heavy duty shopvac with a drywall bag and a hepa air filter is vented to the outside...Not a lot of workspace in my area  but that box will let me do very large plates. Each of those panes is 11 * 14 inches

 

Hmm........now that I look at it this pic is probably 12 months ago...should really take a new one

[Malcolmt]

I have 2 of the Paasche units they are both about 10 years old at least and they still work and have not had issues that were not solveable. I suspect they are a bit better quality than the Chinese Harbor freight clone

 

[Huntonia]

I ordered the air abrasive, it should arrive fairly soon. However with the humidity in my area rising very rapidly I don't think I'll really be able to use it until spring or summer. On the plus side that gives me more time to save up and spring for a few other odds and ins. My goal is to have a functional abrasive setup by this summer. I figure with an abrasive and the tools I already have I should be able to prep most trilobites without issue. 

[jpc]

11 minutes ago, Huntonia said:

I ordered the air abrasive, it should arrive fairly soon. However with the humidity in my area rising very rapidly I don't think I'll really be able to use it until spring or summer. On the plus side that gives me more time to save up and spring for a few other odds and ins. My goal is to have a functional abrasive setup by this summer. I figure with an abrasive and the tools I already have I should be able to prep most trilobites without issue. 

To deal with humidity, you can get a couple of air driers set up  in your compressed air lines.  I have one where the air leaves the compressor and one before the air gets to my tools.  Granted I livein dry Wyoming, but it should be do-able in Oregon, too.  Might have to dry do more maintenance there.  

[Malcolmt]

Best time to prep is in the winter..very little humidity in the air

[Huntonia]

Well I'm not sure about other areas in Oregon but at least where I am it tends to rain quite a lot during the winter, it's 88% humidity outside right now and it tends to continue raining heavily through March. By June it's usually pretty dry around here. 

[Kane]

Have you considered getting a water trap between the abrader and the compressor as @jpc recommends? They are pretty cheap and available at your local hardware store. You can also bake your media by spreading it out on an oven tray and set at 200F for 20 minutes, sift and put in an airtight container until you need to reload the cup. The baking will remove any residual moisture in your blast media, helping you to "keep your powder dry." Just make sure everything is sealed -- the west coast is notoriously damp, and curls the pages on books!

[Huntonia]

4 minutes ago, Kane said:

Have you considered getting a water trap between the abrader and the compressor as @jpc recommends? They are pretty cheap and available at your local hardware store. You can also bake your media by spreading it out on an oven tray and set at 200F for 20 minutes, sift and put in an airtight container until you need to reload the cup. The baking will remove any residual moisture in your blast media, helping you to "keep your powder dry." Just make sure everything is sealed -- the west coast is notoriously damp, and curls the pages on books!

Good idea with the baking! Would I need a specific size of sifter?

[Kane]

Just now, Huntonia said:

Good idea with the baking! Would I need a specific size of sifter?

I don't have a sifter, so I just break things down with a fork.  @Malcolmt could probably recommend one. If it's dolomite, I know it is 40 micron because of my source, but baking soda... not so much. But I've never really had any problem with straight baking, fork, and seal in a container.