Cleaning RMS Motor Hardware...

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bronicabill

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In the past when flying AeroTech RMS motor systems, I used vinegar to clean up the inside of the casings. That was 15+ years ago!

Now that I'm back flying them again, I remember reading something a year or so ago about alternative cleaning chemicals that work well, but I cannot remember what they were.

What do you guys/gals use to clean up motor hardware after use?

Thanks in advance!
 
Sink full of water with dish detergent, fine steel wool, and tube brushes. I very rarely have to use stronger solvents.
 
Baby wipes at the field when its still warm after firing. Then warm soapy water at home with a nylon bristle brush. If that still doesn't do it, a short soak in SimpleGreen followed by warm soapy water and brush.
 
Yep, clean as above.

Do ensure that the Delay residue is removed from the forward enclosure. Very important on the 18/20 case but important on the others as well.
If this builds up then the Delay's O-ring doesn't seal and ejection change goes off way too early.
 
I used to use vinegar until I noticed on some of my AT forward closures that it was removing the black anodizing. So now I just use a sink full of hot, soapy water (Dawn dish detergent). After a soaking of 10 minutes or so, I put a few drops of Dawn on a long, plastic-bristled toothbrush (or the gun-cleaning equivalent) and scrub the case interiors, the delay chamber, and all threads and o-ring touching surfaces. Dawn cuts through the Super Lube quickly. I use a good bit of that synthetic grease when I assemble, as it keeps the soot and carbon from sticking.
 
I read somewhere that the residue was acetic. I don't know as much about chemistry as I should, but something that is a base would be logical choice as a solvent. Sometimes acid/base reactions leave a residue, so who knows? Best to follow manufacturer's recommendations.
 
I read somewhere that the residue was acetic. I don't know as much about chemistry as I should, but something that is a base would be logical choice as a solvent. Sometimes acid/base reactions leave a residue, so who knows? Best to follow manufacturer's recommendations.
Mixing an acid and a base produces water and a salt. That’s likely the residue.

Acids tend to attack metals but bases usually don’t. You should be pretty safe with a basic cleaner, so long as you’re careful about disposing of the salt products and following the cleaner’s warnings, if any.
 
Acid is easier on aluminum than alkalines. I've always used a short( 1/2 hour or less) soak in vinegar for hard to remove residue and then dishwashing detergent and a good rinse. Vinegar works great, is cheap, no need to use any other solvents. Vinegar was recommended by Dr. Rocket.

I used to use vinegar until I noticed on some of my AT forward closures that it was removing the black anodizing.

The vinegar is not removing it, the firing of the motor is what is removing it. Normal wear!!
 
A school group that was out at HARA this weekend brought a couple bulk bottles of acetone for case cleaning in between flights.

I'll admit that was a new one for me
 
The vinegar is not removing it, the firing of the motor is what is removing it. Normal wear!!

1633995599581.png

I don't think this is normal wear and tear.

And I can't categorically say that the vinegar soaks I to subjected my AeroTech hardware to in my early rocketry days were the root cause of this ugly damage to the anodizing of these forward closures (a 29/40-120 and a 24/40). But when I stopped using vinegar soaking in favor of plain ol' hot water and detergent only, my hardware no longer exhibited the damage.

Perhaps it was substandard anodizing. But none of my other AeroTech hardware, especially the HP stuff I've since flown many, many more times than these guys over the years, WITHOUT vinegar soaking, ever repeated the offense.

As always, YMMV.
 
I'm sure there are others that know better but in general, aluminum safe in most mild acids due to the surface oxide layer. If that oxide layer is missing due to a scratch or chemical damage, then soaking in an acid like vinegar can cause pitting.
 
I would admit if you soak the things forever in vinegar and expect to have them clean themselves I could see problems like pictured. A few minutes to 30 minutes and rinsing them good isn't going to hurt them. Those pictured do look bad. Normal wear is losing some of the anodizing inside the delay and ejection charge wells. I use vinegar on my rails also, they soak a lot longer than motor parts, no problems with them.
 
I'm sure there are others that know better but in general, aluminum safe in most mild acids due to the surface oxide layer. If that oxide layer is missing due to a scratch or chemical damage, then soaking in an acid like vinegar can cause pitting.
Good point, I hadn’t considered the surface layer. Oops!
 
I found 100% Limonene (orange peel extract) the best, but it can be pricey depending on the source.
 
A school group that was out at HARA this weekend brought a couple bulk bottles of acetone for case cleaning in between flights.

I'll admit that was a new one for me
I missed seeing what they were cleaning with, but they did have a bunch of rockets! Nice kids too! I put them in touch with this forum, so hopefully we'll see them hanging out here before long.
 
Oh, forgot to mention... I did try gun cleaning solvents and brushes, and it works well. Hoppe's #9 on the grime and let it sit a while, brush it back off, then spray away the residue with Gun Scrubber.

My wife and daughter hate the smell of Hoppe's #9, but I think it should be made into a men's cologne! 🤣
 
How do you clean the end of the delay well? I haven't found a stiff brush with bristles on the tip.

Ed's Red gun cleaner works well to get carbon off.
 
How do you clean the end of the delay well? I haven't found a stiff brush with bristles on the tip.

Ed's Red gun cleaner works well to get carbon off.
Usually it wipes clean with a baby wipe stretched over my finger tip right after the flight. That’s really the key; get it while the residue is fresh and it wipes right out.
 
How do you clean the end of the delay well? I haven't found a stiff brush with bristles on the tip.

Ed's Red gun cleaner works well to get carbon off.
On the 29 and 24mm delay chambers too small for scrubbing with the tooth- or gun-cleaning brush I use on larger hardware, I've found that a disposable bamboo chopstick from Asian carryout works well as a cleaning tool. The stick's small, sharp-sided point gets down into the delay chamber's corner to break up the charred residue. Ditto for the black powder well and touch hole.
 
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