Re: [PSUBS-MAILIST] Pitting Rust against Voids

["James Frankland" <james@guernseysubmarine.com>]

Hi Vance/Brent.

Just reading your posts on the pitting.  Vance, when you did your overlay repairs, did you grind it smooth afterwards, or just leave the weld beads on?

I've just got one little area about an inch square on mine where i overdid it a bit with the grinder.  I probably went down half a millimeter by accident.
Im tempted to put a few runs over it.  Not sure if it needs it though.

regards
James


----- Original Message -----
From: vbra676539@aol.com [mailto:vbra676539@aol.com]
To: personal_submersibles@psubs.org
Sent: Wed, 28 Jan 2009 20:30:01 -0500
Subject: Re: [PSUBS-MAILIST] Pitting Rust against Voids

Brent.

Both our subs were factory built, maybe even the same year. It sounds like yours had bigger QC problems than mine, as the welds are good all the way around down here in Florida. Mind you, mine was built twice, so to speak. It started off as a K250, which explains the rolled angle iron frames instead of T-frames. It was purchased and returned to George for upgrades, including a three hp aft thruster (which weighs well over 100 pounds!!!!). He also?chopped the acrylic hatch rig off and added a 4 port steel conning tower and steel hatch, too, plus battery pods. The sub has definitely been through the mill a couple of times.

I'm ditching the old thrusters in favor of Minn-Kota 101s, one aft on a pivot and two on a common shaft?just forward of the pressure hull and under the MBT. Taking a lesson from Carsten, I'm going to try them on and off only, without electronic motor controls. That gives me three speeds forward and reverse, and the only worry I have is that even one of those things will be too fast when operating near the bottom. We'll see.

One of the other problems would be that main ballast shell mating area on the hull where you had problems. I hate that, so I'm building two tanks to fit underneath the present shells, which will serve as streamlining and impact protection only.? Each tank will have a six inch diameter extension for the bottom opening and one of my pneumatic poppets on top. This one is sort of a testbed for what I want to do with the next one, so we'll see how it all works out.

As far as the pitting is concerned, well, lesson learned. It's all better now. I plan to keep it that way.

Vance


-----Original Message-----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: PSUBSorg <personal_submersibles@psubs.org>
Sent: Wed, 28 Jan 2009 6:43 pm
Subject: [PSUBS-MAILIST] Pitting Rust against Voids



Nothing to it Vance,?? ;)'

Do you think my sub warranty is void yet??? Sounds like you sub was in much worse shape then mine.? I have a few relatively small void and rust pitting areas I'll need to weld up.? Most the bottom area is in great shape, except the area on the tube that had the lead plates next to it.? Those will have to be completely over layed. Most of that are is not deeply pitted, but the is a few deep spots.? I feel much better about what I need to do on mine after hearing your tale.?

At first I was scared that the bottom on the interior was badly pitted before I cleaned the sub for the first time, since it was really rough down there. But as it turns out they installed a type of truck bed liner coating that looks like it protected that lower hull area very well. There is only a couple of small void areas just above that coating.? My internal rolled angle iron ribs are in great shape, other then then need to be blasted and painted.


http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/Aft%20Head%20Voids


Here you can see the biggest pitting area on the top of the aft head, that was under the FRP MBT.? They didn't use any primer in that area and it needed it.? Also there are some small voids, that? were in the heads when they were manufactured, that should of been welded over.?

http://cid-5085d10eb6afe47c.skydrive.live.com/self.aspx/Aft%20Head%20Voids/DSCN7812.JPG


Here is a picture of the kind of voids that I found next to the head weld beads from to much power used.? I copper slag blasted a test area.? I couldn't at first figure out why the "paint" that was in the voids wouldn't blast out after dwelling on that area for some time.? What I figured out, was that some one was trying to hide the voids before painting and filled them with a type of rubber caulking.? Pretty cool right.

http://cid-5085d10eb6afe47c.skydrive.live.com/self.aspx/Aft%20Head%20Voids/DSCN7806.JPG


Regards,
Szybowski




To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Side Thruster Removal on K-250 #118
Date: Tue, 27 Jan 2009 21:15:22 -0500
From: vbra676539@aol.com

Brent,

I sympathize. The same thing happened to my K350 and we burned better than thirty pounds of rod putting in overlays to get the wall thickness on the hull cylinder back to something safe. I had some deep pits (although small in cross section). Two areas were down to about .125". We used acoustic reflective thickness measuring in a 1" grid pattern to map all that out, and ended up throwing our hands in the air and overlaying very nearly all of the bilge from the aft ellipse (which was okay) forward for almost two feet! Plus there were?a handful of small spots forward of that. We even had to do some buildup on the ring stiffeners in a few places. Man, you talk about putting some hours in behind a welding hood!!! I'm here to tell you, that was a job.

Now I'm rebuilding the main ballast supports, and I've still got to add a couple of penetrators. All that and be ready for sandblast and paint by the end of February. Nothing to it, right?

Vance


-----Original Message-----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: PSUBSorg <personal_submersibles@psubs.org>
Sent: Tue, 27 Jan 2009 6:54 pm
Subject: RE: [PSUBS-MAILIST] Side Thruster Removal on K-250 #118




Hi? Frank,

The sub has been painted a couple of times, and so I'm not sure what exactly they did.? I think the original paint is still there, since it doesn't look like the sub has ever been sanded or sand blasted.? All the little weld splatter is still there, of which would of been very easy for them to sand off.? From the looks of it, I would guess they only did stick welding on the sub, and did it very quickly.? There is some voids next to some of the weld beads that look like they used to much power for those welds, and then didn't make another bead to clean it up. I plan to TIG those voids up. ? I have some pictures in regards to this I'll post in a bit.

I've sanded some test areas, and there is a pretty good gray primer at the base that is still protecting most of the exterior.? I don't see any of that primer on the interior, so I think they skipped that coat in there.? Most the rust on the sub is from it being left outside for the last 10 plus years, and allowing water to get in thru a open hatch and not draining it.? I cleaned up the mud, loose paint, and water about a year before I acquired the sub and drilled a .25" hole at the bottom of each ribbed section, so it would at least drain, and not deteriorate as fast as it was if it stayed there longer.?

The worst rust pitting is were the lead slabs were attached,since they didn't put any spacers between the lead and the painted metal.? That area couldn't breath and dry out easily.? So I might need to replace the main steel vertical panels on both skids, as well as the lower horizontal strip, with SS.


Regards,
Szybowski




From: ShellyDalg@aol.com
Date: Thu, 22 Jan 2009 14:58:27 -0500
Subject: Re: [PSUBS-MAILIST] Side Thruster Removal on K-250 #118
To: personal_submersibles@psubs.org


Hi Brent. Good pics. What type of paint was used on George's subs? I see where the rust has gotten pretty bad in some spots, and I wonder if it's caused by simple lack of maintenance, or not enough protection in the first place. Heavy zinc paint stands up well if maintained properly. Where two components are bolted together, there are several solutions to prevent rust. Delrin disks, bushings inside the bolt holes, judicious painting of all exposed parts, stainless, anodes, and lots of other ideas/methods are easy solutions.

I designed my sub so I can dis-assemble it quickly and easily for maintenance/repair. I should be able to strip it down to the bare hull and re-assemble it in a day, with minimal tools. That way I will be able to get it clean after dives, and touch-up any paint that needs it, without having to sit in the shop for a week. I like the idea of putting plastic/nylon bushings in the bolt holes. Stainless bolts and nylon/stainless washers, so the potential for rust is lessened. There are some places where I'll be using brass bolts with stainless nuts, and some places where I'll use lead bolts with stainless nuts. I have some parts that need to be very strong, and others that are designed to break-away if needed. Brass fasteners are good in some spots because they may need to be drilled out for removal. Here's a quick sketch of one place where it's needed.

Because the fairing covers the mounting tab, I'll be welding a stainless nut onto the bottom of the tab. The brass bolt head can be cut/ground off if need be to remove the fairing. The nylon bushing keeps the different metals from corroding together, and once the brass bolt head is gone, the bushing and fairing can be lifted off. Then some vise grips will pull out the brass bolt, or if needed, drill out the bolt because it's soft. This of course will only be necessary if I don't maintain that particular connection and allow it to get crusty.

http://www.frappr.com/?a=viewphoto&id=1578526&pid=10804946&myphotos=1

Spare bushings, washers, brass bolts, etc are just a few things to carry along in the field for repairs/maintenance. I want to be able to repair this thing with a minimum of tools when I'm out some where remote. Frank D.

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