Rocinante33
Contributing Partner
Hahaha!!!!
Fuel tank Inspection Port Design and Installation
- Thread starter Christian Williams
- Start date
Hahaha!!!!
907Juice
Continuously learning
Ha! Had a little alcohol last night... The gallow of a boat would be a scary place! I meant galley
907Juice
Continuously learning
Yeah, their well head was recessed in the ground about 6ft in a 4ft culvert pipe. Pretty sucky, that is the only reason I mentioned it.
Rocinante33
Contributing Partner
That was sucky. I'm sorry for them
markvone
Sustaining Member
Stainless steel inserts are a nice feature for aluminum tanks
Hi Christian,
The stainless inserts that Grant mentioned in reply #8 sound like a nice feature.
http://www.ezlok.com/inserts-for-metal/solid-threaded-inserts/stainless-steel
They will eliminate the worry of dissimilar metals with the ss machine screws threaded into the aluminum tank top, and also the need for Tef Gel. But it seems the diesel fuel on the threads may keep this corrosion at bay.
They also eliminate the thread wear issue, but you won't be opening the access very often.
The only negative I see is additional cost which is considerable at $3.21 each:
http://www.mscdirect.com/product/details/98759855?rItem=98759855
I think I would skip the inserts to start. It looks like you could re-drill larger holes later to add the inserts if you have the issues above. A 10-32 screw uses a 0.1495 bit in aluminum and the 3/8-16 external threads on the insert take a 0.3125
Just a thought,
Mark
Hi Christian,
The stainless inserts that Grant mentioned in reply #8 sound like a nice feature.
http://www.ezlok.com/inserts-for-metal/solid-threaded-inserts/stainless-steel
They will eliminate the worry of dissimilar metals with the ss machine screws threaded into the aluminum tank top, and also the need for Tef Gel. But it seems the diesel fuel on the threads may keep this corrosion at bay.
They also eliminate the thread wear issue, but you won't be opening the access very often.
The only negative I see is additional cost which is considerable at $3.21 each:
http://www.mscdirect.com/product/details/98759855?rItem=98759855
I think I would skip the inserts to start. It looks like you could re-drill larger holes later to add the inserts if you have the issues above. A 10-32 screw uses a 0.1495 bit in aluminum and the 3/8-16 external threads on the insert take a 0.3125
Just a thought,
Mark
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Tom Metzger
Sustaining Partner
If I was doing it, and wanted better threads, I would use self clinching nuts like these:
https://www.fastenal.com/products;j...oryl3:"602450 Self-Clinching Nuts"|~&pageno=2
Also available from McMaster Carr, etc.
https://www.fastenal.com/products;j...oryl3:"602450 Self-Clinching Nuts"|~&pageno=2
Also available from McMaster Carr, etc.
Navman
Member III
access port
Christian,
Must have searched 50 pages on the forum today and cannot find the template I was referring to. Did find one here, but it not nearly as nice looking as the "taco template". I did print out the temlate in full size and will look for it. I can scan it and send it to you. The directions and information that was included in the description of fabricating and installation is what really made this appear to be the best method. Will get back to you. My e-mail is dpmsail@yahoo.com.
http://www.threefools.org/velocity/P...ccessPlate.htm
Christian,
Must have searched 50 pages on the forum today and cannot find the template I was referring to. Did find one here, but it not nearly as nice looking as the "taco template". I did print out the temlate in full size and will look for it. I can scan it and send it to you. The directions and information that was included in the description of fabricating and installation is what really made this appear to be the best method. Will get back to you. My e-mail is dpmsail@yahoo.com.
http://www.threefools.org/velocity/P...ccessPlate.htm
Much appreciated, Navman. Please post the template here if you can, it would be a good addition to the thread.
the seam was then glassed over with 4" fiberglass tape by the factory--screwheads and all. A stick of gum to anybody who can deduce the reasoning behind that that tape.
I now believe the tank lid on these boats is to be considered structural.
On further demolition I found the lid was first glued to the supported shelf, with six biscuits. Then screwed down with 3" stainless screws. Then glassed over.
The quarterberth on the E381 is a double, providing a gap of nearly 4 feet athwartships near the CG. The other side of the boat (starboard) has the sink furniture, sturdily built. My guess is that Bruce King, or the builder, specified a no-flex assembly over the tank , which was accomplished by the belt/suspenders/corset and garter methods used. (...And the worker who put on the criminally sloppy fiberglass tape was drunk, or perhaps was taunting the carpenters who had crawled into that space to make perfect joiner work at the aft recesses, plug the trim, and varnish it perfectly).
Anyhow, point taken: I'll make the new lid structurally secure.
the seam was then glassed over with 4" fiberglass tape by the factory--screwheads and all. A stick of gum to anybody who can deduce the reasoning behind that that tape.
I now believe the tank lid on these boats is to be considered structural.
On further demolition I found the lid was first glued to the supported shelf, with six biscuits. Then screwed down with 3" stainless screws. Then glassed over.
The quarterberth on the E381 is a double, providing a gap of nearly 4 feet athwartships near the CG. The other side of the boat (starboard) has the sink furniture, sturdily built. My guess is that Bruce King, or the builder, specified a no-flex assembly over the tank , which was accomplished by the belt/suspenders/corset and garter methods used. (...And the worker who put on the criminally sloppy fiberglass tape was drunk, or perhaps was taunting the carpenters who had crawled into that space to make perfect joiner work at the aft recesses, plug the trim, and varnish it perfectly).
Anyhow, point taken: I'll make the new lid structurally secure.
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Navman
Member III
fuel tank access port
Christian,
FOUND IT!
(see #31 below)
The taco reference comes from the fact that the interior metal gasket is able to be inserted into the tank by folding it like a taco. They said the gasket fit was tight enough around the screws that the screws would not fall out, I guess you could drill and tap also. The method of fastening is up to the maker, but I thought the design was worth copying. It is the method I am going to employ.
Good Luck! Keep me posted please.
Christian,
FOUND IT!
(see #31 below)
The taco reference comes from the fact that the interior metal gasket is able to be inserted into the tank by folding it like a taco. They said the gasket fit was tight enough around the screws that the screws would not fall out, I guess you could drill and tap also. The method of fastening is up to the maker, but I thought the design was worth copying. It is the method I am going to employ.
Good Luck! Keep me posted please.
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Self-clinching nuts. Never heard of them. Very promising idea. But--how in the world do they work? Ahh....
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Tom Metzger
Sustaining Partner
These work really well, but with 3/16" of aluminum I'd just use sheet metal screws. It wouldn't happen, but if I stripped the sheet metal screws then I would use the self-clinching nuts.
Back several incarnations ago I used them when making cabinets for prototype electronics. They preferred weld nuts for production runs, but I liked these. I think this was well before you met Ted.
Tom,
Fastenal, the manufacturer, says an arbor press is needed to install the self-clinching nuts.
(Although nobody I could find at Fastenal has any actual knowledge of self-clinching nuts, even though they manufacture about 12 kinds of them.)
Any comment?
I found this statement on a random forum, which needs further confirmation:
So, received the SS Self-clinching Nuts and installed one after enlarging the stripped hole to the recommended .250 diameter. Used a plastic soda bottle cap held to the inside of the fuel tank under the hole with a thin strip of sticky tape to catch any shavings as I drilled the hole out. I did the same thing to hold the repair nut in place while I tightened a tiny C-clamp as tight as I could with a pair of pliers to set the nut into the hole. The repair came out excellent and with SS threads, will probably never strip out again. I would have to say this is definitely the best way possible to repair a stripped fuel sender screw hole in a aluminum fuel tank.
__________________
Dave B in Windsor, Kalifornya
1984 Skipjack 20 "Finatic" - 1995 Proline 190
Fastenal, the manufacturer, says an arbor press is needed to install the self-clinching nuts.
(Although nobody I could find at Fastenal has any actual knowledge of self-clinching nuts, even though they manufacture about 12 kinds of them.)
Any comment?
I found this statement on a random forum, which needs further confirmation:
So, received the SS Self-clinching Nuts and installed one after enlarging the stripped hole to the recommended .250 diameter. Used a plastic soda bottle cap held to the inside of the fuel tank under the hole with a thin strip of sticky tape to catch any shavings as I drilled the hole out. I did the same thing to hold the repair nut in place while I tightened a tiny C-clamp as tight as I could with a pair of pliers to set the nut into the hole. The repair came out excellent and with SS threads, will probably never strip out again. I would have to say this is definitely the best way possible to repair a stripped fuel sender screw hole in a aluminum fuel tank.
__________________
Dave B in Windsor, Kalifornya
1984 Skipjack 20 "Finatic" - 1995 Proline 190
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Tom Metzger
Sustaining Partner
I don't think Fastenal actually manufactures anything. They are just a wholesaler, or jobber, which explains why they know little about what they sell. The nuts are designed for harder metals which is where the arbor is really needed.
In aluminum I would just start the installation with a screw from the top side and tighten it as much as possible without striping the head or threads. Then, if that is not set enough for you I would use vice grips to finish the job. My common vice grips are offset enough to get in there.
There are no forces involved trying to make these nuts come out of the aluminum so I suspect you are over thinking the project. Also, I see no big downside to a nut falling into the tank. Reach in and pick it up.
Unless you are using a backing ring as Mark suggests I would use sheet metal screws. Second choice would be tapping threads in the tank. 3/16" aluminum would take 6 threads with 32 thds/inch screws.
If you are using the backing ring the self clinching nuts go on the ring so no problem using a press if you want. A hammer would also do the job. I've used both, but at the time I think the arbor press was a new invention.
Tank manufacturers really don't like sheet metal screws for this. My sheet metal guy, who is making the 3 1/8th alum cover plates, doesn't like the whole idea of this project. Hence, the $200 bolted taco, or DIY version.
Screwing down the covers will work, but it's a custom amatur job best approached with lots of overthinking.
A dirty tank in a gale means a filter change. Leaking inspection ports in a gale, well, I'd rather have a dirty filter.
I have all the fuel out now, through the sender port. Lots of junk visible in there, so I don;t really have much choice.
Screwing down the covers will work, but it's a custom amatur job best approached with lots of overthinking.
A dirty tank in a gale means a filter change. Leaking inspection ports in a gale, well, I'd rather have a dirty filter.
I have all the fuel out now, through the sender port. Lots of junk visible in there, so I don;t really have much choice.
Tom Metzger
Sustaining Partner
I assume your sheet metal guy has never been to sea on a small boat. Why doesn't he like inspection ports? Obviously, a tank with no openings is less likely to leak, but...
He thinks there are too many variables. He doesn't like screws for this application. He says metal flexes and that can change things. He says 3/32s is "pretty thin" for a 50-gallon tank, and he isn't a fan of tapping it.
He's been in n business many years in Santa Monica (Rich metals, on Colorado AVe) and forms all sorts of sheet metal, but is also willing to taking on small projects from sculptures to antique rain gutter restoration.
But no, he doesn't have a sailboat.
Many of these repairs, even different boat yards would have different opinions. We're on our own, as usual. Sorting advice.
He's been in n business many years in Santa Monica (Rich metals, on Colorado AVe) and forms all sorts of sheet metal, but is also willing to taking on small projects from sculptures to antique rain gutter restoration.
But no, he doesn't have a sailboat.
Many of these repairs, even different boat yards would have different opinions. We're on our own, as usual. Sorting advice.
Tom Metzger
Sustaining Partner
I agree, however originally you said:
I would tap 3/16" which would provide 6 threads when using #8 or #10-32 machine screws.
Sorry, typo. It's 3/16, which is what I told Rich. The plates will be 1/8. And yes, I plan to tap it.
Rocinante33
Contributing Partner
Christian,
I can think of two good options for you (and for myself since I'm in a similar situation.
1. With the same aluminum you use for your inspection plate cover, cut 4 strips of 3/4 to 1" wide, long enough to function as backing plates around the edge of the hole. Clean very diligently around the under edge of the hole (with mineral spirits or perhaps even acetone). Affix the strips under the edge with epoxy like J-B Weld. Drill and tap your holes to mount your cover through the double layer of aluminum and you have double the threads of your single layer tank.
2. Use nutserts which can be installed into sheet aluminum fairly easily. Installation is much like a pop rivet. They are available in either aluminum or stainless steel.
I can think of two good options for you (and for myself since I'm in a similar situation.
1. With the same aluminum you use for your inspection plate cover, cut 4 strips of 3/4 to 1" wide, long enough to function as backing plates around the edge of the hole. Clean very diligently around the under edge of the hole (with mineral spirits or perhaps even acetone). Affix the strips under the edge with epoxy like J-B Weld. Drill and tap your holes to mount your cover through the double layer of aluminum and you have double the threads of your single layer tank.
2. Use nutserts which can be installed into sheet aluminum fairly easily. Installation is much like a pop rivet. They are available in either aluminum or stainless steel.