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RE: [PSUBS-MAILIST] Sandblasting Information

Jim,
 
That helped allot, thanks.  I've done allot of sandblasting on metal and wood, and I've never at home had enough CFM to do the job like I wanted to. So I was maxing out my compressors. To get more CFM I made up a splitter so I could connect more then one compressor to the pot blaster. One compressor is oil less and the other not, but I could get three more smaller oil less compressors for under $500 and have 20 CFM at 90 PSI. I like to blast at 110 PSI. I don't see to much in the way of larger compressors that are oil less. I worked at a auto body place a while back and we used a big oil type compressor for the whole shop, even the painting. We used a Napa type truck oil filter and water separators more then 25' away from the compressor to get most of the condensation and oil out. 
 
I've been told MEK works great for removing any oils from sandblasted metals. If you handle the part with your bare hands after blasting, then you'll get some oils on it from that as well. I used MEK to final clean the K-250 mild steel view port cover rings before painting them. I need to find better quality chemical gloves. That MEK is nasty. I've used it to kill wasp nest and entire bald faced hornets hives at night. Just put some MEK in a glass and hold it up to the hole in the bottom of the hive. The hive will go nuts, and you'll be up on a ladder thinking, should I stay or should I got now. The cup will fill with bees in no time, and they will die as fast as the come out. Works supper fast. Wear protective clothing just in case.
 
I'm switching over to copper slag blasting media for a number of reasons; it's black and that works better when I get it in the checks of the manzinita I blast, so I don't need to remove it for visual reasons, like silica sand, it cuts faster, and it's better for your health. But it's good to know that if I need to, I can use silica sand for metal, and have no paint issues from it. Thanks Jim.


Regards,
Brent Hartwig


From: kocpnt@lakefield.net
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower Battery
Date: Tue, 7 Aug 2007 17:47:59 -0500

Hi Brent,
I cannot comment on most items that you mentioned in your humorous email. As an industrial painting contractor I can assure you that silica sand from sandblasting DOES NOT cause fisheyes. These are sometimes caused be silicone contamination. While it does sound similar it in totally unrelated to the blasting process. If the fisheyes are connected with the blasting process, it is almost always a result of oil contamination. Almost all compressors large enough to do sandblasting will emit some oil during normal operation. This is minimized in several ways
                                                1. Have a larger than essential air compressor - the higher percentage of capability is used - the worse this condition will be
                                                2. All screw type compressors and most piston compressors use an air/oil separator, if this separator is not in good condition it will add to this problem
                                                3. To do high quality blasting, it is best to use an aftercooler. Large compressors generate a great deal of heat and can carry a great deal of water because of
                                                   the temperature. This water carrys with microcopic amounts of oil. When the air leaves the nozzle pressure and temperature decrease quickly and the air
                                                   cannot hold the level of moisture that it was previously capable of holding. The result is what settles on your work.
I have oversimplified to conserve space, but I do hope that it helps.
 
Best Regards,
 
Jim Kocourek
 
 
----- Original Message -----
From: Brent Hartwig
To: personal_submersibles@psubs.org
Sent: Tuesday, August 07, 2007 12:50 PM
Subject: RE: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower Battery

Thanks Peter and Carsten,
 
That makes me want to do more test. What should I do next?   How deep can a PSUB go into a bubble bath before it melts?  Does yellow paint make one crazy? Will metal glue guns revolt if painted pink? Do goldfish in a fish bowl like being underwater in a submarine with a black interior? Will my sweetheart forgive me if I buy view ports instead of house windows? Can a Night Rider KITT car replica be made into an ambient submersible?
 
What am I going to do tonight, the same thing I do every night, try to take over the world. ; )'
 
So far the mower is just fine and started right up again this morning.
 
How would chlorine enter the cells? Like I used to say when I was commercially raising parrots. Nothing a gallon of bleach and a pressure washer can't fix.
 
Anyways I forgot to mention that the battery never got warm will doing this testing.
 
I did do a test on some acrylic scraps. If you wipe it with MEK, it will instantly craze the surface.
 
Also I just heard that sandblasting with silica sand gives painters trouble later with, what is called fisheyes (bubbles) in the paint, since the silica can permeate the metals surface.



Regards,
Brent Hartwig


From: peter@submarines.dk
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower Battery
Date: Tue, 7 Aug 2007 09:09:30 +0200

Hurrah !
 
 
Finally a person who understands the value of experimentation. No more worried grandma´s - batteries are not bombs initiated by seawater nor electric chairs ready to electrocute submariners.
 
- Do expect that if any chloride has entered the cells the lawnmower will be in trouble soon.
 
Best regards, and applause...
 
Peter Madsen
----- Original Message -----
From: Brent Hartwig
To: PSUBSorg
Sent: Tuesday, August 07, 2007 7:28 AM
Subject: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower Battery

Well Boys and Girls, I did some testing.
 
Ya I know that usually means vacate the area with or without your shorts, to another county. But it's to late, I already did it. One can talk about it for only so long before they get off there arss and get dirty. It's more fun to.
 
So I removed a fully charged 12 volt lawn mower battery, I could do with out until next week, if it blow up anyways, and I did some testing.  I then obtained a five gallon bucket, jumper cables, lots of protective clothing, and a full face shield, among other things. I then put the battery in an empty bucket and then put the end of the hose into it. Then I remotely filled the bucket with slightly hard freshwater, I don't remember what the PH of my water is. Nothing happened, or at least that's what I thought at first.  I then removed the water and battery from the bucket and attached jumper cables to it in the normal fashion. When striking the ends of the cables together I got the normal sparks. When I put them underwater there was some weak hydrogen production from the negative lead. Then when I touched the leads together underwater, I got the same basic spark as I did out of the water.
 
Then I went and found my old stash of aquarium stuff, and pulled out some Instant Ocean brand sea salt and mixed it in freshwater, until I got a specific gravity of 1.21, like most sea water. I then removed the freshwater from the bucket and added the saltwater for some more testing.  I tested the leads in the same way and got the same result, but with a bit more hydrogen production from the negative lead.
 
Next I added enough salt into the one gallon in the bucket to make three gallons of sea water, so I could completely submerge the battery. But before I added the water I mixed in the salt and tested the leads again. Now when I put the leads into the water on either side of the inside of the bucket, the negative lead produced allot more hydrogen. When I then touched the two leads under water there was a larger spark on the tangent surfaces and they tried to stick together. They didn't try to stick together in freshwater and not much in normal sea water.  Point is that if you take your sub to the Great Salt Lake in Utah be careful.
 
Now I added two more gallons of freshwater to the mix, to get a specific gravity of 1.21 again, and put in the battery remotely. Nothing much happened, just some hydrogen production from the negative pole. This was just a cheap normal battery, not a AGM sealed type. I then did some testing and then put my bare finger in the water. Nothing, not even a tingle. I then lowered the level of the water to about an inch over the top of the poles. Then did some more testing and then put my finger directly between the poles, nothing.
 
I then removed the salt water and refilled it with freshwater and did the same testing, nothing. I would say that the battery would of slowly discharged by producing hydrogen until spent.  No explosion when submerged in this way. The hydrogen in an enclosed space would be real bad news. You'll be safer in freshwater then salt since you'll have more time to get out before the hydrogen levels get to high. Still you better get out ASAP unless you can route the hydrogen into your AIP unit quickly. ; )'
 
Finally I reinstalled the battery in the mower and started the mower with no trouble. I learned allot from doing this, how about you? Just remember I'm a submarine half full kind of guy.
 
Here are my pictures of the submerged battery testing.
 
http://www.frappr.com/?a=viewphoto&id=4001713&pid=7357670
 

Regards,
Brent Hartwig
 
                   "Do or do not,        There is no try"
                                  
                                                                                  ~  Yoda

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