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Fuel Tank Removal CD-25
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Tue Sep 20, 2022 8:27 pm    Post subject: Reply with quote

Quote:
ine wire brush will get into these pits and make them clean enough to assure good bonding with the G Flex. You are not really removing any aluminum, just the oxide on the surface with the fine wire brus


Got it. I'll do that tomorrow before starting the application of the G/Flex.

Quote:
The rubber has to be in direct contact with the aluminum, and the carbon in the rubber (or any compound) is what is the conductor to cause the damage to the aluminum. If your spacers are containing rubber / carbon then there is a chance that you will have problems under the strips. This comes primarily from David Pasco, but is repeated by many knowledgable boat builders. Often graphite is added to materials to make them black. It is a complicated issue, for example with neoprene, does it contain carbon or not. Pure neoprene should not..but.


Ok. I think I understand now. I did find out today that the spacers are rubber. I think I should be able to reuse them once I get the G/Flex on. And they'll have the 4000 uv between them and that. Colby
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Tue Sep 20, 2022 9:03 pm    Post subject: Reply with quote

Pascoe's recommendation is to use fiberglass or similar material for the battens. See:Pascoe on fuel tank installation.

Quote:
As shown in the illustration below, you are going to set the tank on top of 1/4" strips of plastic about 2" wide and spaced about every 12". Its best to place the strips transversly to the length of the tank. We recommend Haysite or any of the fiber reinforced plastic sheet. The strips should be cut to a length exactly 1/4" shorter than the width of the tank. We don't want the strips sticking out the sides and collecting water.


I don't agree 100 % with what Pascoe says about the tank platform or that bare aluminum will not corrode. It depends on the alloy of aluminum. Also epoxy is the only resin I will use to seal plywood. That is from experience dating back to the late 50's.

_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Wed Sep 21, 2022 8:52 pm    Post subject: Reply with quote

Well that wasn't exactly what I expected.... I was thinking that the G/Flex 650 would be more of an epoxy paint. It was actually pretty much just like any other clear epoxy as for consistency and application. I had purchased the kit that comes with two 16oz bottles. (One Resin, one hardener.) I used the entire quart on the bottom and sides of the tank. I would have been hard pressed to have enough to do the top if I had wanted to. I used a paint brush to apply it. (Following directions of G/Flex, cutting half the bristles off, so to make the brush only half as long.) I did put it on thicker on the bottom.


Here's another close up of the tank pitts. I did use a wire brush before applying the epoxy, to clean them out a little better.




Here is the tank after the Epoxy was applied. It's a clear epoxy, which made it that much harder to see where I had already been as I applied it.




I'll let the epoxy cure over night, as it reaches a workable cure in 7-10 hours. (I finished applying it around noon, and won't be working anymore on the tank until a good 20 hours later). Tomorrow then I'll use 4000uv to attach the spacers back on. And plan to reinstall the tank into the boat on Friday.

Today I also finished cleaning up the old caulking around where the cockpit floor sets back in, so basically the boat is ready for everything to go back in it. I continued to work on the steps, and should be able to finish them up tomorrow as well. I removed a lot of the old spray foam and rotten core that was in them, and just poured fiberglass resin back into the voids. Kind of messy as the tape I placed around some of the edges, while I poured the resin in the other edges, didn't seal so well. So there will be some extra fiberglass inside them strengthening the corners! Mr. Green I still need to clean the caulking off the cockpit floor before it goes back in. I'm still looking at having everything back together this weekend. Colby
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Sat Sep 24, 2022 8:29 pm    Post subject: Reply with quote

I got the spacer strips glued on two days ago, and got the tank back in the boat yesterday. I used what was left of my small tube of 4000uv, and ran out after just two of the spacers. I ended up going to a local marina and bought a tiny tube of 5200. (That was all they had in white.) I used that and finished putting on the spacers. (And as luck would have it, my order of 7 10oz cartridges of the white 4000 UV arrived shortly after I returned from the local marina... )





I had my neighbor help me lift the fuel tank back over the side of the boat and into the bilge. I placed a strap around each end of the tank so we could lift the tank with those to position it better once we dropped it in the bilge. I didn't want to loosen the spacing strips that were glued on with 5200, since that was a slow cure, as I slid the tank into position. The deck cutout is actually just a little less in width than the tank. So you have to drop one end of the tank in first, then slide it under the deck cutout, before dropping the rest of the tank into the bilge. Then slide it back to center it. The hardest part of reinstalling the tank, was getting the 2" fuel fill hose back on. I had already purchased new hose and installed it to the fill caps. The stuff is pretty stiff and doesn't bend in a short radius very well. Today I finished coating the stop blocks (used to keep the tank from moving aft) with resin, and then fiberglassed them into the bilge just behind the tank. Tomorrow I'll install the floor back in.

The next few photos are of the fuel tank installed back in the boat, and a closeup of the fill hose connection on each side.






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ssobol



Joined: 27 Oct 2012
Posts: 3361
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
PostPosted: Sun Sep 25, 2022 10:48 am    Post subject: Reply with quote

Heat gun on the hoses helps quite a bit. Don't want to use it if there are gas fumes about though.
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Sun Sep 25, 2022 8:15 pm    Post subject: Reply with quote

The job is mostly done. Tomorrow I'll clean up the caulking (some ridges left from pulling the tape), and finish installing the side boxes. In the first photo below you can see where I taped around the area that will get caulked. I used painters tape, and then used 4000UV to caulk around the entire floor and steps. I did not fill the entire void around the cockpit floor, but rather just put enough caulking to seal the floor. After caulking the floor, I pre-positioned the steps to insure I didn't need to sand or shape them anymore after repairing them with fiberglass. Everything looked good, so I reinstalled the metal brackets on the steps, that hold them in the boat. Then I placed them back in the boat and taped the floor and sides just outside of where I'd caulk the steps in. I also taped the steps before placing a bead of caulk around the edges of the step. Then carefully I placed the steps in position, attached the brackets to the sides of the cockpit, and finished caulking around the corners. Colby





Mostly finished



Last edited by colbysmith on Sun Sep 25, 2022 8:20 pm; edited 1 time in total
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Sun Sep 25, 2022 8:17 pm    Post subject: Reply with quote

Quote:
Heat gun on the hoses helps quite a bit. Don't want to use it if there are gas fumes about though.


Wish I would of thought of that then. Surprised (The tank was completely dry inside, and I had cleared all the vapors out...I had used my shop vac with the hose placed in the outflow, and then attached it to one of the two tank fill fittings. Ran it for a while until no more gas smell!) Colby
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MannyBridge



Joined: 30 Aug 2017
Posts: 12
City/Region: Nanaimo
State or Province: BC
C-Dory Year: 2006
C-Dory Model: 25 Cruiser
Vessel Name: C-Star
PostPosted: Mon Sep 26, 2022 10:36 am    Post subject: Reply with quote

Thank you for documenting your work so well.! This is something that I will likely need to do soon.
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Mon Sep 26, 2022 12:33 pm    Post subject: Reply with quote

Great job. Posting the photos really helps other folks. Also note that Colby has double clamped the fuel hoses properly. Although most of use the spiral perforated band hose clamps, there are better ones. Although the bands are 316 stainless steel, the worm gear or worm gear case may not be. Also the "T" bar type are better:



All hose clamps should be 316 SS, not 304 (which many are). There is also a Pinch type of hose clamp with ears. I have not used those on boats, because they are not reusable and can be difficult to remove. A fitting which may need to be changed, such as a water pump, is often has quick release fittings, so that the hose does not need to be reclamped with each change of the pump. I also use quick connect electrical fittings on the fresh water pump. (they always seem to go out when the wife is in the shower!).


A couple of other tricks in getting tight fitting hoses on a hose barb or other fitting is to heat a container of water and dip the end of the hose into the water to heat it evenly. Put a small amount of liquid soap around the lip of the fitting the hose is being clamped to before pushing the warmed hose over it.

In fittings which seem to leak or pull off no matter what you do, is to coat the outside of the fitting with Permatex "Form-A_Gasket #2, non hardening". (If dealing with gasoline hoses, the #3 Aviation is even better.) This will remain pliable, but seal the hose to the fitting. (Wear gloves, the Permagasket takes a lot of solvents and scrubbing to get all off your skin.)

One point, however in case someone does not know the risks:
Quote:
..I had used my shop vac with the hose placed in the outflow, and then attached it to one of the two tank fill fittings. Ran it for a while until no more gas smell!) Colby


If there any residual fumes, a shop vac is not ignition protected. There a few cases where a shop vac ignited "fumes", with disastrous results.
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Mon Sep 26, 2022 12:46 pm    Post subject: Reply with quote

Quote:
If there any residual fumes, a shop vac is not ignition protected. There a few cases where a shop vac ignited "fumes", with disastrous results.


I thought about that later. However I did have the shop vac a good distance from the open fill connector on the other side of the tank, and while everything was in the garage, the big garage door was open. The tank was completely empty of fuel, but still had fumes, so I understand. Not making excuses or lite of gas fumes, but how many of us have our propane grills on our boats, near the fuel tank vents? (If they are on the cockpit of the boat somewhere, they are near the fuel vent...)

Regarding the hose clamps, I probably should have replaced them. Too late now, but except one, they all appeared in pretty good shape, and all were SS 316. I did replace one, that broke as I was (likely over) tightening it. I agree those T-bar type would have been an improved replacement. I learn as I accomplish feats. Learned quite a bit while doing this job, and still learning for next time, which hopefully won't need to happen! Smile Colby
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ssobol



Joined: 27 Oct 2012
Posts: 3361
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
PostPosted: Tue Sep 27, 2022 1:30 am    Post subject: Reply with quote

Yes, a shop vac is not ignition protected. However, if it is in "blow" mode and the motor is sufficiently removed from the source of potential fumes, I don't see this as a problem. Using the shop vac in "suck" mode is a different story.
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Fri Feb 23, 2024 5:15 pm    Post subject: Reply with quote

Well, hopefully this time will be a charm. I thought I had the water leakage stopped. And actually, for a good year I did. However, last October while cruising the Cumberland River we had a couple of days of downpour. Woke up the next morning, only to step into water as I crawled out of the V-Berth... Evil or Very Mad Plan was to just keep towels under the step where it was apparently coming in. (Appeared to be coming in from under the shower stall again.) That and using a long stick to place a lot of caulk (3M 4000UV) in that area. However, I had done that before, and not really a cure since unable to really get in there to insure complete coverage! Anyway, mid 50's for temps here in Wisconsin in the middle of February, so decided to pull everything up again. Steps, floor, fuel tank... Looks like the area behind the head has some stress cracks, and a groove where my initial fiberglass ran out during cure.







The rest of the fiberglass work seemed pretty solid. So this time I just put in a thick layer of 3M 4000UV along that seam and over the stress cracks.







Replaced the fuel tank and finally the floor. Temps cooled off today, and we're heading out west for a few weeks, so I'll reseal it when we get home.



Really hoping that's the last time I have to pull the steps, floor and tank. Colby
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thataway



Joined: 02 Nov 2003
Posts: 20778
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Sat Feb 24, 2024 10:47 am    Post subject: Reply with quote

Thanks for bringing us up to date. I should have been more insistent when you did the first repair.

Quote:
The only thing I would have done different would have been to use fiberglass tape and epoxy, mainly because this gives a better secondary bond. The boats all should have had mat, tape (cloth) mat/tape done before the gas tank was put in. Some do. All should have the mat/ tape on the cabin side. (I suspect that some don't all of the way around the hull part of this bulkhead,


The other item I did not mention, since you were past that point in the "repair"--is to run a fillet along the seam, so that the glass mat/cloth does not have to make a right angle turn--an item which often fails, and did so here. Also I like to make this type of repair with epoxy because of better bond adherence. Here is an article from "Epoxy Works" on fillets.

Mat has very little structural strength. It is used to smooth out rovings, and surfaces, plus filler giving strength to a repair where there is some form of "cloth"--either woven, or bundled fibers.

The article above treats fillets as a bond alone, but that is not adequate for a bond in a structural bulkhead--there traditionally it would be several layers of cloth and mat if an initial build with polyester. In this case I would try and find some fiberglass mat which is compatible with epoxy (the usual mat uses a binder which is soluble in styrene, and the polyester uses styrene, so the binder is dissolved. Not so with epoxy.)

I hate to say this Colby, but the "cure" you have done here will not be permanent--and has a very good chance of failing, since there is no structural strength here with a sealant. When you do the repair for the last time (who knows how long that will be), please use a grinder to give a good surface bond of at least 3" on each side of the fillet (bottom of boat and bulkhead) Put strips of at the very least 2 layers of at least 6 Oz cloth (one overlapping 2" on the bulkhead and boat bottom, and the second 3" overlapping on both bulkhead and bottom. We are going to be doing surgery on my Caracal Cat, and we will be using 1708 and epoxy for the fillets (I can no longer do the work--so a very good fiberglass technician will be doing the actual work). I will be documenting us of fillets, and proper bulkhead construction.

At the bottom of this photo album page is a series of photos from my album on making a fillet.

Here is the final demo fillet.

[url][/url]
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colbysmith



Joined: 02 Oct 2011
Posts: 4523
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
PostPosted: Sat Feb 24, 2024 10:57 am    Post subject: Reply with quote

Time will tell. 4000 is flexible and I did grind some along that trouble spot. Odd that it’s just in that one area and not along the entire seam. If it doesn’t hold up it’s going to be a more major project that will need to be accomplished during the summer or in warmer climate…
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