88 Bayliner Trophy 1710 - wet foam and ...?

[Woodonglass]

Well there's been a LOT of glass boat with Leaky tanks and I've never seen the gas eat thru the hull. Just not gunna happen. Just like the pour in foam, gasoline just won't affect it.

 

[Arawak]

If you mean to use glass to fill in the pits I would not do that. If anything use something like JB Weld or similar. If gas comes in contact with glass it will eat it up.

So, to be clear, my tank is NOT leaking, so whatever coating goes on it should not come into contact with fuel unless there is corrosion on the inside. There is no sign of this.

JB Weld is an epoxy. What I am considering is to use epoxy to glass a light cloth onto the tank. The cloth is there to add a little thickness and toughness to the coating. The pits would be filled with resin but the key point is that the exterior should not pit any further.

Years ago lots of car gas tanks were patched with fiberglass and lasted for years. This was before ethanol.... I know that there have been many reports of ethanol dissolving cured polyester resin, I'm guessing that this is what you experienced.

Epoxy (and vinylester) is much more resistant to ethanol than polyester. But in any case I run an older motor so I only put non-ethanol premium gas in. And again, I think I'll be unlucky to have gas come in contact with the epoxy anyway.

This is not an ideal repair and may be a bit of a gamble.... I'm aware of this. But if I get even five years before I have to pop the cap and replace the tank I'll consider that worth it. I'm really not willing to drop $500 on a new one right now.

 

[tpenfield]

My comments about an epoxy/glass laminate on an aluminum tank - for your consideration.

There does not seem to be a lot of experiences documented out on the Internet to draw from in terms of it working or not working.

My concern of an epoxy/glass laminate versus epoxy spot repairs/fills . . . The thermal expansion properties of the two laminated materials is probably quite different. It would seem that for a large area there could be separation of the laminate at the edges over time due to these different thermal properties. The separation of the laminate will then create a nice crevice for water (moisture) to collect and cause corrosion of the aluminum.

More theory than experiences to draw from as I have stated, but that would be my concern.

I would think that spot repairs (i.e. filling the pit areas with epoxy) would be preferable to a complete laminate due to the thermal properties

 

[alldodge]

Being 19 and in the service I had a gas tank leak,filled it with BJ and it held until I junked the car years later. As you mentioned this also was before ethanol.

 

[Arawak]

My concern of an epoxy/glass laminate versus epoxy spot repairs/fills . . . The thermal expansion properties of the two laminated materials is probably quite different. It would seem that for a large area there could be separation of the laminate at the edges over time due to these different thermal properties. The separation of the laminate will then create a nice crevice for water (moisture) to collect and cause corrosion of the aluminum.

More theory than experiences to draw from as I have stated, but that would be my concern.

Yep, I had the same thoughts and concerns. However, I dug out my college materials textbooks and did a little math. It seems the thermal expansion of aluminium over on operating range of -30C to 40C is about 0.2%, and the stretch before failure of epoxy is about 4%, glass i think about 7%. So even not accounting for the expansion of the epoxy/glass itself, I think the elasticity of the non-metal components should handle that. Much the same way that black paint on a sun-exposed metal surface does.

I would think that spot repairs (i.e. filling the pit areas with epoxy) would be preferable to a complete laminate due to the thermal properties

We differ here. As I see it, it's the same problem, whether I add glass or just use resin.

But as you point out, this is something that is perhaps not well understood in our domain. If I end up doing this, I'll have to make a point of reporting back how well it works. Or doesn't work

 

[Woodonglass]

Well being the Old Dumb Okie that I AM. And...a sucker for researching issues such as this, I spent some time last night "Googling" and found that the general consensus seems to be that epoxy coatings on aluminum are "If'y" at best The Cadillac produce seems to be West Systems "G-Flex" due to it's superior flexibility and bonding characteristics. Did not find any articles touting benefits of using cloth/fabric in the mix. Again just an Old Dumb Okies limited research so it's only worth what you Paid for it!!!

 

[Smtred]

Great thread Keep up the good work! Learned alot from this and hopefully more to come +1

 

[Arawak]

And...a sucker for researching issues such as this, I spent some time last night "Googling" and found that the general consensus seems to be that epoxy coatings on aluminum are "If'y" at best

That consensus could well reflect the facts. However, one could also do a bunch of googling and deduce that the general consensus is that lead acid batteries will discharge if stored on a concrete floor. I'm distrustful of common wisdom without solid evidence to support it. Seen way too many provably false things put out as fact and widely agreed to.

Pretty much every "paint" I have seen recommended for coating aluminium tanks is actually a two part epoxy. I've seen aluminum boats repaired with fiberglass and epoxy. So I think it is likely that with good preparation this could succeed.

But I'm fully prepared to be wrong if I go ahead with it. Wouldn't be the first time, or likely the last. :watermelon:

 

[jc55]

Since Jigngrub isn't here any more to "say it how it is", lol... If you insist on doing all of this work and willing to remove the cap and deck to replace the tank in 5 years to save $500 and don't plan to smoke, grill, or light a flare... My experienced opinion is this...

You must prep and condition the aluminum, new and especially used/corroded aluminum to epoxy coat. In addition to sanding. PPG ...
http://www.bapspaint.com/docs/psheets/PPG/Automotive/Deltron/P-226.pdf

You can research the particulars. Then shoot or roll a paintable epoxy paint. Laminating cloth onto a gas tank is silly and is going to cost more than a quart of paintable epoxy. Look into USC All Metal for filling properly cleaned and prepped metals.

Please don't be offended. I've been called out and straightened out on my build as well. Keep up the good work!

 

[Woodonglass]

Uhmmm..The "Googling" I did was mostly on "Project Experience". I don't take much stock on "Theory" either. So let me be a bit more precise. The stated "experiences" that aluminum boat builders and Tank builders and aircraft builders (that's what I did most of my "googling" on) stated that when the substrate was prepped properly the epoxy would hold up fairly well with the exception that it had NO UV protection and if exposed to the sun it would fail. This is easily handled with some type of additional coating. As long as the epoxy didn't come under heavy load or undue severe flexing it seemed to hold up fairly well but... they all seemed to think mechanical patches and or welding was the optimum method of repair. Again, this is just my findings and since I'm not a "Tinner" I cannot speak from "Experience". Just passing on what their stated "Experiences" were. Not their Theories!!! I've learned most of what I know from personal experience and the experiences of others. And...Like I ALWAYS say "It's your Boat and You are Free to do with it as you see fit!!!!"

 

[Arawak]

Since Jigngrub isn't here any more to "say it how it is", lol... If you insist on doing all of this work and willing to remove the cap and deck to replace the tank in 5 years to save $500 and don't plan to smoke, grill, or light a flare... My experienced opinion is this...

You must prep and condition the aluminum, new and especially used/corroded aluminum to epoxy coat. In addition to sanding. PPG ...
http://www.bapspaint.com/docs/psheets/PPG/Automotive/Deltron/P-226.pdf

You can research the particulars.

Cap and deck are one piece, see early posts on this thread. After the rubrail was removed it came off in about 20 minutes. It's not trivial, but the entire process is nothing I couldn't do in a weekend. As stated earlier, that's worth going 5 years not having to pay another $500 for a new tank to me.

And, with respect to the hyperbole about fire hazard I'll repeat yet again, that this tank is NOT leaking, and is generally in good condition. It will be going back into a sealed compartment that does not drain into the bilge. It the tank did for some reason develop leak, and the layer of glass developed a leak as well, the gas would not be going anywhere. Bilge water cannot get at the tank, nor can fuel get into the bilge.

I'm somewhat familiar with the particulars. I do spend some time on bateau.com following the work of Joel Shine and I'm familiar with how he does this. Like Wood, I google a lot, so I'm aware of the more commonly followed procedures on the hulltruth and other sites. Google Books are a handy resource too.

Laminating cloth onto a gas tank is silly and is going to cost more than a quart of paintable epoxy

Why is it silly? Possibly unnecessary but silly requires explanation.

I don't see how a quart of of epoxy paint will less than the pint of epoxy resin ($15 CAD) and cloth ($10 CAD) I already have. If you can put a quart of epoxy paint in my hands for $30 CAD then I'll certainly consider it. I also do not see what properties, other than perhaps increased elasticity, epoxy paint has that epoxy resin does not have. Some explanation of this would be appreciated.

Please don't be offended. I've been called out and straightened out on my build as well. Keep up the good work!

Nah, you'll have to work WAY harder than that to offend me. Call me a Javascript coder... now THAT will offend me

 

[jc55]

The reason I say that it would be silly is because after you've treated the aluminum and "faired" the area. In the event of a reoccurance of corrosion, You could potentially trap moisture between the layer of cloth and the tank as TP suggested. You WILL have moisture under your deck in the tank compartment(condensation). Having done some Cathodic testing and inspections in the Pipeline industry, and being an electrician, I really believe that these grounded tanks are affected by corrosion in the pecking order of the galvanic chart and act as sacrificial anodes to an extent.

My Steiger tank leaked this summer Arawak. I started smelling fumes more and more as the season progressed and thought it might have been my portable kicker tank. I have two 14 year old girls and a 12 year old son and had I grilled on the boat and something happened...I would never have forgiven myself. I have the isolated tank compartment, but it's still doesn't isolate the fumes. It's just that your comment kind of implies that if you have a leak at 5 years it'd be worth the wait.

So, I hear ya, it doesn't leak but for discussions sake, it's good for us to hash out these ideas and discuss all options and opinions. BTW, I have an old quart of PPG DP50LF I'd be more than happy so send you for free. Probably wouldn't use it for a high end paint job but it's probably good for a tank.

Thanks for being gracious and letting me weigh in!

 

[Arawak]

Ok, I see where you are coming from. Your point about no compartment being moisture free is well made. I don't know enough chemistry to have a useful opinion on the tank becoming a anodic, but it seems reasonable.

However, I don't believe that epoxy plus cloth is going to bond worse than epoxy. As you point out, preparation is going to be key, but that's true for epoxy paint or epoxy resin. Again... epoxy resin used as paint is not going to be much different than epoxy resin with glass stuck in it.

 

[Arawak]

So the transom is glassed over. This is unlike any transom I've ever done... it doesn't go across to the sides of the hull, so the tabbing is very different. I used 12oz 45/45 double bias 8" tape, and some 1708 I had leftover from a previous project. There's two layers of 12oz tabbing along the edges (12oz), followed by two layers of 1708, followed by a couple more layers of tabbing. The "pockets" have about 8 layers.... I think that's a key area to reinforce. The layers there alternate horizontal and vertical to give me more of a 0/45/90/135. The towing eyes get installed there too, so there will be a 1" plywood pad glassed over there as well.

All in all, I'm pretty happy. Definitely a lot better than what was there before. The entire transom has consumed about 3/4 gallons of epoxy. That includes bonding the first layer in, and the two subsequent layers, all the glassing, and also some filling I had to do in the pockets and behind where the "wings" start.

 

[Arawak]

To illustrate my use of weird words and to show how I've changed it from the original.

 

[alldodge]

Your doing some real nice work, I can only hope I can do as well

 

[nurseman]

That looks pretty solid! Nice work!

 

[Arawak]

Thanks guys... a lot of you set the bar pretty high, just trying not to let you down.

 

[tpenfield]

Nice progress. What is interesting (to me at least) is that there was recently posted, in another forum site, some pictures of a 'professionally done' transom and engine room stringer replacement. The work did not look as good as much of the restoration work we see here on the iBoats forum, your work included. :thumb:

 

[Arawak]

Thanks tp!