the fluoroelastomer caper

This is really for the deep DIYs amongst us and it's a bit long winded - but it's about IMCO important stuff:

338 is having her OB well totally altered. Serious thought has been given to using the space on either side of the hole for builtin, and twice the capacity, tanks. Finding info on 'home' building gas tanks is practically non-existent. There are any number of talking heads that tell you not to do it, there is no comparative information. For some, this represents a challenge. 338 is very close to having a couple of quarter tanks builtin.

It is generally conceded that vinylester, an epoxy modified polyester, is best for modern modified gasolines. I haven't experienced it yet - literature suggests the stuff is finikky as to moisture & temperature and set failures are not uncommon. It's probably best for broad layups rather that small intensive tank laminations.

My epoxy retailer suggests using his extrahard epoxy for my tanks, pointing out that the HarleyDavidson crowd use it for sloshing their hoggtanks - with no complaints. All fix-leak sloshes are epoxy, I think. Stopping to catch one's breath is, for me, one of epoxy's best attributes I can remember the intense paranoia with poly as it would suddenly gel mid-stroke.

Another concern with gasoline is what rubber to use for gaskets and rings. This led me to the McMaster Carr online catalog where I got edjucated as to what materials are generally available. There is a single expensive rubber standout called Viton (by Dupont Dow.)

That took me to the Minnesota Rubber site for further study on rubber polymers. And confirmation that flurocarbon (FKM) is the only synthetic rubber product for gasoline application. I don't know what the choices are at yer local autoparts store but modern gasoline mixtures eats most rubber, and most epoxy, befor lunch.

Paul Oman at epoxyproducts,com says it turns epoxy into jelly. 338 can get some real nice tanks with epoxy and matt started. Then I could line the inside with extra-hard or vinylester & matt...What else is there....? my brain's been halfmast of late.

Type in "fluroelastomer liquid". Of course, what else...? Email the first likely hit - explain my need and application - and fill out the 'company' form. Half na hour later get a phonecall. After 10 minutes of cirling we discover that PL6032 may be the perfect solution for my application. And the perfect solution (no pun intended) for sealing all sorts of tired and leaking fuel tanks. We talking here of a coating that bonds to nearly everything and is IMPERVIOUS to gas, ozone sunlight UV salt spray oil gasoline hydrolic fluids bases hydrocarbon solvents and acids. Used in industry but never the retail marine market. He thinks my lining my tanks with his stuff is a great idea! It is pricey, but it's a coating. Has to be shipped hazmat. I'm getting some miniature free samples. Turns out I've been talking with the owner of the company!

The DupontDow site for Viton cautions against compeditors saying things like "as good as.." or "contains similar.." www.pelseal.com uses the genuine ingredient (but as yet untested in my case or so far as I went with the conversation on inplace used tanks.) Anybody want a salesman job - be a boat show booth gypsy? Man, this looks so good to me! ...........Input please

Right now can't see the down side. Shore like to hear yer opinions.....

Fuels, such as gasoline, are scarry stuff to me. Why not go with ss tanks? Then all you would need is that special synthetic rubber for gaskets and fuel lines. Plastic is probably cheaper, but . .

Ebb,
Don't no nothing about no Viton , but I have used 50 or 60 gallons of vinylester resin on small projects with no surprises. It is easier to work than epoxy if you think and plan ahead . You need good measurements on the catalysts and only mix small batches unless you have help that knows of what they do.
A project can be completed in hours that would take days in epoxy .

It seems to me that there is a catalysed pourable , spreadable 'rubber' that can be used as a tank liner. I don't have the name available , but I'll ask .

hey Admiral, sorry to have missed yer soiree. Congrats on the win!
Think I'm more scared of the welds in ss especially if the tanks are form fitted into that space. We expect that stern area there to be continually doused in salt water, no? How would I keep the water out of the pockets? Wonder how much 316 passiated would cost for two tanks? Who would do the job? Also feeling very poor at the moment after being robbed by govmint forces.

Mike, I should try the vinylester out. Agreed. You sound skeptical about this new liner stuff. I'm going to test the sample, not quite sure how yet. He's also sending a miniature aerosol to try.

I am interested in these rubber coatings as I would think they are the only way to go to protect the plastic from degradation. And I do realize that most everyone is happy with their Tempo and I'm probably blowing in the wind.

How well does vinylester do with gasoline - long term? What's the life expectency = of plastic OR the ss? How come more of you aren't tearing yer little ship apart so you can get yourself in trouble too???:rolleyes:

Stainless welds, hmm. What do they do for automotive tanks? There are racing "fuel cell" tanks for old Mustangs and NASCAR racers that look pretty impressive. Maybe they are lined like the old WWII combat aircraft tanks that were claimed to be self sealing? Then there are the tanks used in hydroplane racing and other fast water sports. What do they use. I think there is more to research here . . .:) :confused: :mad:

what I might ask the Pelseal guy is:
Suppose you took a steel auto tank and coated it inside and out, what would happen in the briney, how long til corrosion set in, etc? And up the metal tank scale.
In the original conversation I didn't think to ask if the stuff was so good inside why not outside?

The Pelseal "bonds" to aluminum, ss, copper, brass, concrete glass, ceramics, Viton (ie, itself) and other elastomers. It comes as a coating, adhesive, sealant and caulk. Comes in colors including white, and can be color matched! One year shelf life.

2-part pot life of 4 to 8 hours, heat accelerates the cure. Almost too good to be true. Quart kit goes for $150. The catylist is solvent based so it has to ship hazmaat.

But the reat question is:
How long does it last in the tank?

Ok for the gas. Now, How About a Sealer For Potable Water Tanks ?

not mary, but me again as my login doen't work right still...

i can answer bill's question on the fuel cells, having made good money in motorsports for a few years...haven't been involved for over 10, but i can give some general info.

old-style fuel cells were neoprene bladders contained in welded aluminum boxes with the lids flange-bolted on...the bladders also had a bolt-flange to mount the filler area, and were jammed full of open cell neoprene-ish "anti-surge" foam to prevent impact explosion as well as undesirable sloshing.

the newer plastic cells are rotary molded plastic just like a gas can is made from, no liner...still have the foam in them, of course. at least in my time, some sanctioning bodies still required that these be mounted in an aluminum outer shell.

the foam is available, by itself on a plate, from any of the cell manufacturers...prevetning the fuel from hammering around in the tanks is helpful to boat handling, too...

one last bit. many silicone automotive products are FUEL-RESISTANT. NONE are suitable for constant exposure to gasoline. there is only ONE sealant which is impervious, and that is loctite/permatex 'hylomar gasket adhesive'. gasoline proof...totally. kinda spendy, but worth every dollar...you need MEK to get the stuff off your fingies in uncured form, though. we won't talk about cured, because it never totall does...stays flexible so the seal won't break.

best,
dave whyte

just incidently adding a few thoughts here, Dave,
and this is from the amatuer side of the perspective - I don't know a damn thing about this rubber stuff outside of what I'm finding out on the monitor here.
"Silicone is not reccomended for ketones (MEK) and most petroleum oils." I read into that: gasolines. If I was looking for gasket material I would tend away from silicone.

Neoprene is a "mid performance" (Dupont Dow) synthetic rubber. Neoprene, Hypolon, EPDM and Viton seem to be related synthetic rubbers each with more resistence to or, shall we say, are more friendly to, modern gasolines. These rubbers all are made into diaphrams, hose, tubing, seals and gaskets.

Manufactuers are in a scizo world of providing a product that has durability, resistance and obsolescence. There is also, I'd guess, some kind of legal color to the word 'resistant.' Like the use of the words fuel-resistant rather than fuel-proof. (EG, is your new hatch water-resistant or water-proof?) Synthetic rubbers have different attributes - none of them are evidently 100% proof against gasoline.

That great gasket mastic is gas/heat/compression set durable But isn't the gasket itself? The headgasket is probably Viton - it has the highest rated properties for rubber in a gasoline engine environment - that I can find, anyway. Neoprene, epdm, silicone notwithstanding. Viton has the best list of resistances overall. Longevity equals length of resistance.

I know, I know it's a huge leap of faith to put one's trust in a new product. Hell, frustrated and exhausted and dollar challenged, I do want to put my hopes in one last paint-on panacea. I just want to protect the tanks as long as I can from the ravages of EPA influenced gasoline.:D

Ebb,
Check out the products from Devcon,

www.devcon.com

Several look good for your apps;
ARL6000
VE9200 series and 9300 series

There may be more , that was a quick glance at their site.

These are commercial tank liners and containment field liners ( to prevent or lessen toxic spills)
I have used a lot of Devcon products and I am very happy with all I have tried.
They even sent me 2 cases of samples to play with .

Captains Courageous...........
That intank anti-surge foam sounds great. Is the stuff rigid or compressible? Be great if it was soft, then it could be replaced or removed thru the inspection plate. Positioning the hard baffle plates in the new tanks so that access to every corner thru the clean-out/inspection port is impossible, I think. A sponge sounds real good.

Love those exotic coatings. I've spent too much time on the internet coming up with 2-dollar words for 2-bit products, chin high b.s. for last resort coatings! Devcon, with a simular quick scan on my part, has some epoxy coatings for 'harsh chemicals' ('highly cross linked oxirane polymer' sounds sexy) but gasoline is not mentioned. Will have to talk with a rep. The elastomerics and vinylesters sound good for water storage but the magic word 'potable' is missing. So is gas. There is a new catch word for me: INERT. Want a coating that won't leach out chemicals into longterm water storage - or break down the container or lining in long term gas storage. GLASS

Take a look at Simco. www.simcocoatings.com. Simkote-2004 Water based Tank Coating. They say it's good for potable water tanks (probably the five million gallon variety.) This coating is not for fuel, they have a huge list of coatings for every kind of industrial use. I'll call 'em. Problem is that low life citizens have much difficulty getting something that looks good from these giants - if they have govmint contracts, forget it, you can't afford it.

I'll stick with the Viton paint-on, for the moment, for the gas. But the potable water tank coating is even more of a needle in a haystack. There is an inert coating that lays down glass (silane?) but I can't find the download on that. When I find it, I'll get back. I'm amazed how many of us are interested in this.:rolleyes: :rolleyes:

first, AAAAHHHHHRRRRGGGGHHH!!!!!

if i can't get my login to work right and keep using mary's forever i'm gonna have to wear a dress!

the anti-surge foam is indeed flexy, open-cell stuff...that's how it gets in and out, all right. whatever it's made of, it's some stout stuff...racing gasoline is a special breed, has all manner of high VOC "aromatic" hydrocarbon compounds the like of which we do not want to even look at the MSDS for...stuff the EPA would never allow in pump gas...so, the foam is pretty stout...holds to methanol, which is the true test of anything, as well as nitro. fairly inexpensive, if i remember right. (now isn't THAT amazing!)

a word on cutting....don't pretend it's cushion foam and use an electric carving knife...makes tiny powder that you will woe forever. don't even think about it...same goes for the bandsaw or whatever else seems tempting. the best way is with a hotwire cutter, which is easily made with a chunk of plywood of whatever size is suitable for your needs, a couple of nails--or some drill rod--or allthread (all depends on how big you need to cut it), the heaviest guage plain(not wound) guitar string you can find at friendly music store (usually .022, .024 if you luck out...they're only a couple bucks, so make your life easy and get a few), a pair of ignition ballast resistors connected in series, a chunk of asbestos gasket material (which is still readily available...they now claim it has no asbestos in it-ha!-and call it hi-temp packing material, usually found in anchor brand....this keeps the ballast resistors from smoking hell out of the plywood), and a 12-volt battery. looks kinda like a little wood football field with goalposts. oh---back up the first piece of wood with another underneath so there is NO WAY of putting a dead short across the posts. a switch is nice too, this thing gets hot FAST and will smoke the wire if you leave it sitting around too long with power to it. i made mine with allthread, which made dealing with the guitar string easier and also allowed me to set the height if i wanted to (pair of nuts and fender washers on each post). works great and leaves no debris. even so, i used to wash in water and thoroughly dry, then blow out with air just to be sure. sounds like a pain, but it's really not that big a hassle.

i think there was discussion sometime ago on the triton group about the water tanks, and the evils of drinking out of fiberglass, and the super-special epoxy based liner ook, and...
it's somewhere in the M-I-R on the NTA site, too, I think.
personally, i think epoxy is pretty inert stuff overall, and i'm not too worried about drinking out of it...my keel tank will be an e-glass job, and my bow tank happens to be 'glass already, which i shall keep...don't like fiberglass-flavored oatmeal, though...an inexpensive activated-charcoal filter takes the taste(and hopefully most of the alleged nasty business) right out, in my experience. if my liver spontaneously explodes into green fluff someday, i'll know i was wrong.

cheers,
dave

got lost around the ignition blastors wired in series. Stuff sounds more friable than flexible. Won't a heated bread knife do? How long does it last submersed in jetfuel? I guess in the sport car field it doesn't matter as it is shorterm city and oodles of money.
Maybe the sponge is made from the miracle fiber hemp, but it's probably plastic. Can we melt it down and coat the gas tank with it? The inventor with the liquid Viton, still sounds pretty good!

Another epoxy company has emailed me saying, there is no epoxy approved for food or potable water storage. Tho it is a fact that Europe does have approved systems, and that the Feds are being nortoriosly slow to approve epoxy here. How would anyone keep it straight: there are 10s of thousands of combinations of these plastics, they're everywhere, new ones every week, nobody can nail it down long enough even to test it.

For water storage, since elastic or soft plastics have loose organic molecules that leach into our food and water and turn into imitation estrogen in our body, I will stay away from them, even if a hypolon or urethane coating turns up. They can't be called inert. What causes hull blisters in polyesters are chemicals that didn't make it into hardening event, some of them are definitely carcinogens, cobalt, eg. By extension, I look real suspicious at ANY two part mix. Epoxy included, 100% solids. I won't work with the adulterated stuff. Don't like the word Leach. Trusting the Dupont Dow's is a leap of a too long lost faith.

The only stuff that hasn't gotten any bad press apropos food and water (that doesn't mean there won't be a revelation) or gasoline so far are the wonder polymers polyethylene and polypropylene. Next week they'll market some version that we can fabricated in the home shop and all this coating stuff will be very very moot.

The more you guys talk about these chemical elixirs, the more I love Monel and stainless steel . . .:cool:

hoi! wudenjunoit, just found this site,
it is a paint on monel product, called

Phelonomer Monelobalm.

Once you put in the gas, it's always full, never have to fill it again

Dave, some quotes from wandering into some high-performance auto racing sites, early this morning:
"Hylomar is a polyester polyol-based compound that turns from a gel into flexible putty...Originally developed by Rolls Royce for aerospace...impervious to oil, gasoline, glycol and other engine fluids, is oxygen sensor safe and performs at consistent temps up to 600 F" There is also a "solvent-free environmentally friendly" version. They have "a new range of 18 high performance aneorobic adhesives and H. 532 an alkoxy curing RTV silicone sealant" "Hylomar (also makes?) "a polyurethane based gasket-jointing compound that contains polyesters & silica":confused:

I guess the product(s) are made in England and dist. by Permatex. It's a highly specialized field, auto racing, not unlike small airplane flying - with technical language and knowledge I can't begin to digest - but one can appreciate and be really impressed while the eyes glaze over.

Impossibly complex these goops, gaskets, plastics and synthetics.

Epoxy still comes up as the "last resort" universal coating for both gas tanks and water. 100% solids, very hard, read brittle, novolac systems. I think I'll use an extra hard lamination for the gas tank and later consider adding the expensive liquid viton. I'm waiting on one last resort poly fabricator to get back to me on the water tanks. If that doesn't pan out, I'll probably lam the tanks up in place under the V-berths (have to cut out the top, which I wanted to avoid) and use expensive epoxy with some hard coats at the end to avoid vapors in the enclosed space of the boat. 'Neverending epoxy goo...' Check out Epoxy Systems Product #2 at www.epoxy.com
:cool: