In defense of sandblasting model engines.

rsv1cox Tue Apr 10, 2018 11:49 am

Sandblasting, a catch-all term used to describe pressure blasting using various types of abrasive media. I have been doing it for the past 48 years.

I started out using play sand, cheap, plentiful, readily available, and it works well. I used it in an outside home-built scavenged cabinet always using a respirator. But I gave it up due to perceived health issues. Since, I have used "Soda", "Black Magic" (coal slag) and aluminum oxide in various grits and meshes settling years ago on the popular aluminum oxide.

Aluminum oxide (you may have brushed your teeth with it this morning) is an abrasive media available in various meshes and used for everything from cosmetic reconstruction to cleaning jewelry to you name it.

I would guess that I have used Aluminum oxide to clean/refinish over 50 model airplane engines and countless automobile parts and accessories. But I don't use it on moving mating surfaces pistons/connecting rods/combustion chambers.

Having over 75 Cox engines I have only found it necessary to media blast just two. Cox engines do not lend themselves to that procedure. But, it works great for almost all other common model engine types especially those with matte finishes.

I keep records of most engines that I have cleaned and found that on 8/10/15 I media blasted a Cox Babe Bee engine case, fuel tank, and back plate. I then ran it the same day with no noted (fuel tank leaks) issues.

Day before yesterday I media blasted this badly corroded Cox engine then polished the fuel tank spun on a drill press spindle using 400 grit wet/dry paper followed by a paste aluminum polish applied on a pad of 0000 steel wool. I polished the case using basically the same method minus the drill press. I only media blasted the back plate then painted with Krylon gold. As to fuel toleration we shall see. .

In defense of sandblasting model engines. Cox_mi16

In defense of sandblasting model engines. Cox_sb10

In defense of sandblasting model engines. Cox_fi10

Most people have never seen a sandblasting cabinet, unless they frequent Harbor Freight Smile

much less used one, but if interested regarding the procedure more information is available here:

http://www.kramerindustriesonline.com/finishing-guides/abrasive-blasting-guide.htm

Bottom line is - properly used media blasting is not going to hurt your Cox engine or it's fuel tank. But I see no reason to use it on any Cox engine or it's components unless it's as bad as the one I pictured, or if the back plate is as corroded as the one that new222 had to contend with.

I just hate to see anyone dissuaded from using this option if it is available.

Just my dollar and a quarters worth.

Marleysky Tue Apr 10, 2018 7:06 pm

I did not know that sandblasting was on Trial. It sure sounds like their lawyer, Robert T Alumibright Esq. ( distant cousin to Robt T Ironsides) is on the case and has provided a convincing defense for cleaning and polishing all them dirty little things you have. I’m positive the jury will return a verdict of “innocent “ on all charges and recommend that these methods be used whenever you need to take a bite out of grime!
Thank you, Your Honor.

I know I have an air hose, airgun and compressor, just no gravity feed bin or catch basins or cabinet for the abrasive or the abrasive.( unless I use kitty liter) It’s on my list of things to “set-up” when I find a project worthy of the time to put it all together. Seeing the success you’ve had on that Cox crankcase, I might just try it on a couple of really bad ones I have. cheers

NEW222 Tue Apr 10, 2018 8:38 pm

Thanks for taking the time to do your testing and procedures. It was really well done. It will be neat to see what others may post or show how they clean up their engines. I was personally impressed in the way the cat litter in the tumbler worked. This would probably be the cheapest alternative for those without a sandblaster or those with no place to do such, but nowhere near the quality or time taken to do as you had done. Next time, however, I will try it with blasting media (will look for aluminum oxide) and see how that works. If even not for a Cox engine. I am in process of hunting down my old hand held sandblasting gun that I used at work many years ago. I could not find it here at home, as I thought I sold it, but talked to my dad and he remembers seeing it around his garage somewhere. So I will keep watching this thread.

rsv1cox Wed Apr 11, 2018 7:53 am

NEW222 wrote:Thanks for taking the time to do your testing and procedures. It was really well done. It will be neat to see what others may post or show how they clean up their engines. I was personally impressed in the way the cat litter in the tumbler worked. This would probably be the cheapest alternative for those without a sandblaster or those with no place to do such, but nowhere near the quality or time taken to do as you had done. Next time, however, I will try it with blasting media (will look for aluminum oxide) and see how that works. If even not for a Cox engine. I am in process of hunting down my old hand held sandblasting gun that I used at work many years ago. I could not find it here at home, as I thought I sold it, but talked to my dad and he remembers seeing it around his garage somewhere. So I will keep watching this thread.

I have never tried kitty litter, probably most effective in a tumbler, but if it works in a media blaster I would like to know the results. Seems as it would clog the nozzle.

I have a Craftsman out door unit that I use for large items, but it make a mess as the media is not contained.

My first cabinet arrived crushed and was returned.

In defense of sandblasting model engines. Crushe10

The replacement worked much better. Smile

In defense of sandblasting model engines. Mgb_sa10

I use it for everything, even did a broken Wen Mac SNJ in it.

In defense of sandblasting model engines. Snj_sa10

The tail section was missing but balsa worked well as replacements.

In defense of sandblasting model engines. Mga_sn11

Even did a few of these.

In defense of sandblasting model engines. Rem_5513

In defense of sandblasting model engines. Rem_5512

And........Rene...Your calling me a L-A-W-Y-E-R?????????? Smile

Bob

GWILLIEFOX Wed Apr 11, 2018 9:15 am

NEW222 wrote:Thanks for taking the time to do your testing and procedures. It was really well done. It will be neat to see what others may post or show how they clean up their engines. I was personally impressed in the way the cat litter in the tumbler worked. This would probably be the cheapest alternative for those without a sandblaster or those with no place to do such, but nowhere near the quality or time taken to do as you had done. Next time, however, I will try it with blasting media (will look for aluminum oxide) and see how that works. If even not for a Cox engine. I am in process of hunting down my old hand held sandblasting gun that I used at work many years ago. I could not find it here at home, as I thought I sold it, but talked to my dad and he remembers seeing it around his garage somewhere. So I will keep watching this thread.

I missed the part about tumbling with kitty litter, where was it?

Marleysky Wed Apr 11, 2018 10:08 am

GWILLIEFOX wrote:
NEW222 wrote:Thanks for taking the time to do your testing and procedures. It was really well done. It will be neat to see what others may post or show how they clean up their engines. I was personally impressed in the way the cat litter in the tumbler worked. This would probably be the cheapest alternative for those without a sandblaster or those with no place to do such.

I missed the part about tumbling with kitty litter, where was it?

It may have started at this you tube video:

https://m.youtube.com/watch?v=DGT20ghWMZA

NEW222 Wed Apr 11, 2018 11:18 am

Oh Bob. Having a blasting cabinet like that would be nice to have. But, unfortunately, I would also then need a new big compressor to keep up with it, although those cabinets have come down in price.

NEW222 Wed Apr 11, 2018 11:27 am

Hey there Marleysky. Funny as you bring up that YouTube video. This is in fact the one that I got my inspiration to try my tumbler out in. I thought the same as others had about the noise of the sander running and also having to make some parts, when in fact, I remembered I had this tumbler laying around. The only difference is that the one in the video would have probably worked better as it did more of an 'agitating' motion at a quicker pace rather than a slow tumble.

GWILLIEFOX, if you were interested, the topic in which I used my rock tumbler to clean a backplate is here:

https://www.coxengineforum.com/t11768-babe-bee-restoration .

To summarize, I got a Babe Bee that had a badly corroded backplate (suspected water damage) that did not clean while soaking in the crockpot. With no sandblaster immediately available, I looked online for ideas, and took one as posted by Marleysky above and put my own 'spin' on it.

rsv1cox Wed Apr 11, 2018 12:07 pm

Marleysky wrote:
GWILLIEFOX wrote:
NEW222 wrote:Thanks for taking the time to do your testing and procedures. It was really well done. It will be neat to see what others may post or show how they clean up their engines. I was personally impressed in the way the cat litter in the tumbler worked. This would probably be the cheapest alternative for those without a sandblaster or those with no place to do such.

I missed the part about tumbling with kitty litter, where was it?

It may have started at this you tube video:

https://m.youtube.com/watch?v=DGT20ghWMZA

Nice. That fellow gets a 10 out of 10 for innovation. And, that kitty litter did a great job. I have little knowledge of kitty litter, but I think it's clay based. Might have to give that a tumbler try.

BTW - I powered that sand blaster with a little 5hp compressor (lower right in picture) before moving on to a larger unit. Still, it did the job.

Bob

Ken Cook Wed Apr 11, 2018 12:49 pm

Bob, while this isn't Cox related, I just have to ask. I'm a carpenter by trade and lately work has just piled up on us mandating long days and weekends. I always have sharpened my own tools such as chisels and plane irons. My Stanley #5 uses a chip breaker which attaches to the iron itself. When you remove the top cap this whole assembly comes off. I really needed it sharpened and I sent it out to a tool sharpening business down the street from me. I picked it up the other day in which it was taped and wrapped in newspaper. I paid and went home only to discover when I unwrapped it that the entire assembly was glass beaded prior to sharpening. I was pretty upset about that. While it has no bearing on the function of the assembly, I was wondering if there was a way to return the finish to it's prior appearance. Not to mention that my handprints on it already created rust in the outline of my fingerprints. I honed the back of the blade on my stone to remove the burr that should've been done from them sharpening it. While that polished the surface, it didn't offer the mirror like appearance it once had. I find it hard to believe that when you send a tool out for sharpening, it means more than just grinding it, one would think it means SHARPEN it. Having just received a very large plane from a deceased fellow carpenter, I'm glad I didn't send that assembly as well. Much of the Stanley UK parts are no longer available due to much of their current products being made in Mexico. Aside from buying used or Ebay parts planes, I just thought I would ask. Ken

rsv1cox Wed Apr 11, 2018 1:04 pm

Ken Cook wrote: Bob, while this isn't Cox related, I just have to ask. I'm a carpenter by trade and lately work has just piled up on us mandating long days and weekends. I always have sharpened my own tools such as chisels and plane irons. My Stanley #5 uses a chip breaker which attaches to the iron itself. When you remove the top cap this whole assembly comes off. I really needed it sharpened and I sent it out to a tool sharpening business down the street from me. I picked it up the other day in which it was taped and wrapped in newspaper. I paid and went home only to discover when I unwrapped it that the entire assembly was glass beaded prior to sharpening. I was pretty upset about that. While it has no bearing on the function of the assembly, I was wondering if there was a way to return the finish to it's prior appearance. Not to mention that my handprints on it already created rust in the outline of my fingerprints. I honed the back of the blade on my stone to remove the burr that should've been done from them sharpening it. While that polished the surface, it didn't offer the mirror like appearance it once had. I find it hard to believe that when you send a tool out for sharpening, it means more than just grinding it, one would think it means SHARPEN it. Having just received a very large plane from a deceased fellow carpenter, I'm glad I didn't send that assembly as well. Much of the Stanley UK parts are no longer available due to much of their current products being made in Mexico. Aside from buying used or Ebay parts planes, I just thought I would ask. Ken

That's a bummer Ken. I suspect they thought they were just being helpful.

So probably the glass beading resulted in a matte finish rather than the smooth shiny finish it once had. I have had good luck restoring finishes by using an electric buffer wheel with the correct for the metal type compound. Or, if it doesn't lend itself to that, fine 0000 steel wool and a polishing compound and a lot of elbow grease gives good results.

Generally after polishing, on ferrous metals I rub in a good quality oil, or treat with Howard Feed-N-Wax. A final buffing with a micro filament cloth helps too.

Not sure if any of this helps though.

Bob

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