The Stovebolt Site Forums The Shop Area General Truck Talk Gas Tank Venting

C’mon-
Did anyone here think I was condoning or considering that “procedure”?
I must have been a bit to dry when I said I would “probably would not use..” that method.

Sarcasm guys , sarcasm.
Didn’t anyone find the close-up of the torch duct taped to the long pole funny? I sure did.

I thought it was hilarious.

Nobody on this site is dumb enough to believe that to be an appropriate method of prepping a fuel tank before welding.

Ski and Otto, I get your points on sarcasm and hilarity and I can enjoy that perspective. My initial reaction was, boy is this guy an idiot!
I didn't make any assumptions (yes I know where that goes) that this was being suggested as condoned or an appropriate method by either of you. My point was to clearly indicate that the method shown is not condoned or recommended in any way/shape/form by our community (Moderator doing his job here). You gotta remember there are a lot of non-members that come and view/read/use information from our site and I think the Big Kahuna (John Milliman) would agree that primary consideration be given to showing/demonstrating "Safety First" work practices throughout Stovebolt.

I think the video and subsequent chit/chat would better fit in the Greasy Spoon. That being said, back to the topic at hand. I'm interested in hearing/seeing more on Waveski's fuel tank repair.

Since that tank is "new" of unknown origin. I`d look into a NEW replacement that you know where its from. The one you have might have generic defects in the welds. You sure don`t want to take it out again.

Here’s my assessment of the tank in question:
The seam looks as though it was welded by a vey methodical robot.
The failed connection looks like it was soldered by a low payed worker with insufficient training.

See photos –- the resemblance to the images from a recent thread on a similar topic is striking.

My inclination is to get that connection repaired to a proper standard and reinstall. That is not a final decision; I have only begun to consider my options in terms of repair method and source.
Input on repair methods would be welcome. I have not ruled out welding - pros , cons?

Addendum:
Looking at the failure images posted by Otto , and considering my similar situation, I am inclined to think that this sort of thing is not all that rare. That’s why I’m tentatively planning to repair what I have rather than spending money to get a shiny new example of a flawed truck part.
Who knows how many substandard solder joints are out there? As long as they don’t leak they’re fine- so long as they are not subjected to a mechanical strain.

Also addendum:
That idiot video is not of any importance; it’s just a Darwin Award Trainee thing I came across while researching cleaning & purging gas tanks, good for a quick laugh.

I would agree that the joint failure on your tank looks remarkably like Otto's tank failure. I think in his thread another member suggested the best suggested repair method would be to take to a local radiator repair shop as they would most likely be able to properly repair:

A lot of "radiator shops" haven't soldered anything in a long time- - - -all the radiators they work on are made of aluminum with plastic tanks, rubber O rings, and crimped seams.
Jerry

What about welding it back on?
That would be secure; it would surely stay put for my duration. Hard to service later but I don’t care too much about that.

Yep, Wavesi, that is most certainly the same brand tank I have, Spectra. Broken flange aside, the tank is very good quality, otherwise.

I'm going to do a little googling to see if I can find out if this is a problem that's made it to the internet complaint department. I'm also going to see the problem affects other Spectra models or just AD trucks.

Interesting coincidence that we both had that same experience in such a short time. Like you said earlier - it took very little force to separate those 2 pieces, very little resistance.
If I had a high value finished project with that tank in I’d be none too happy knowing of that flaw.

You got that right Wave. I had about 15gal of fuel in the tank when I attempted to open the drain plug after shutting the petcock. Bink!! off it snapped.

Gas flooded the floorboard of the truck interior and started pouring out over the door sill onto the running board, etc.

I eas under the truck swapping out plastic containers to catch the fuel pouring out the hole.

10 gallons ended up in buckets and whatnot. Five gallons disappeared into the floor mat, garage floor, wicked up by the sole plate of the wall...

What a mess!

This on the web....You get what you pay for.

Spectra had problems with spot welds failing after the tank was installed.

Otto -
I’m sorry to hear that your Exxon Valdez incident was worse than mine, much worse in fact. I’m guessing I lost a quart or two into the cab before I succeeded in wrestling the tank out of the truck. The big difference in the 2 scenarios is that I had already made preparations to remove the tank; the straps were removed and there were only a couple gallons in the tank. I was preset to minimize a spill , even though I wasn’t expecting it. When I realized what was happening I resorted to the oldest trick in the book - I stuck my finger in the hole. Then we lifted the tank out.

I’ll wind up throwing away some carpet , but that’s minor because it was a free leftover from a local installer, and I can use the smelly carpet sections as templates.
You must have a significant detox situation on your hands. And elsewhere.

Regarding the tank flaws , was there supposed to be a link posted with that?

Ya but other than the loss of a full tank of fuel, no real damage was done. It isn't exactly a 100 point show winner.

It is a real aggravation, though. Do I really want a new tank? What if the welding problem hasn't been fixed? I'll see where this goes but I may take it over to the radiator shop and have them fix it.

So , if your truck ready was a show winner you’d have60k or more in it - and you’d have a real problem on your hands right now , a very costly problem.

Life is good with a “driver” ; yours looks pretty much original, mine is a rattle can special.

I agree with your call to work with what you already have. Get that mating of parts properly repaired the you know what you have. I trust the shop will pressure test the tank for you?

Yes, they'll do a proper job. I've been taking radiators to them for over 20 years. They even fixed the aluminum/plastic radiator on the '95 F-150 for me for free - just had to tweak the crimped band around the header tank.

Anyway I'll go over the situation with them to make sure they check everything else on the tank, not just the outlet.

I am going to talk with Spectra to find out exactly what they've done to address this problem.

Please let us know what means of repair the shop chooses. It sounds though like you have a good reputable resource there - and that’s not to be taken for granted these days. People possessing such skills are a dying breed.

I’m still considering welding for my tank. I also plan to learn more about brazing before deciding. I do not know what the advantages of soldering are, other than the ease of later removal. As previously stated I don’t care too much about ease of removal.

Waveski, the problem with welding is that you'll have to remove all traces of the lead solder (or whatever they used) which would contaminate a weld. The other issue with welding is that you run the danger of blowing holes in the thin metal of the tank. It takes some skill to get a good weld joint on thin metal. Silver solder is a better solution than just 50/50 lead-tin solder. It's an alloy that has no lead, but yet melts at low temperature like 50/50 does, so can be done with an old school soldering iron (a block of copper on a with a handle heated by a torch or furnace) on thin metal or a propane torch. I'd recommend Bridgit Lead Free Solder. You should be able to find that at a plumbing supply house. I've used it with good results. It flows nicely and forms a strong joint. Be sure to clean the joint beforehand, whatever method you use.

Kevin,

I have no experience welding and only some experience soldering. I've sweated copper pipes with a torch and repaired sending unit and carburetor floats with a soldering iron.

The soldering iron is an electric model with interchangeable tips. It has a 20watt and 40watt setting.

Is this the type of soldering iron you would use to repair this flange? How do you clean off both mating surfaces? Emery cloth? Wire wheel??

When I remove solder for reusing copper pipes I get my thick leather gloves over cheaper cotton cloves
Then I heat the pipe until all the solder is liquid and I wipe the pipe off with my gloved hand
I use a propane torch on max when doing this
The gloves get a bit hot but not bad if you wait between pipes
There is a slick of solder left behind but when doing pipes that’s not an issue
On your gas tank I would use the exhaust of a vacuum cleaner going into the hole to vent it for a while first
Then I would heat that solder up until it’s very liquid using Oxy-propane and wipe it all off
You dont have to worry about the traces of lead if you are going to braise the new connection
But if you plan to tig or mig then yes you do need to worry about contamination and sand the final lead off before welding
For this situation I recommend braising it on with the Oxy-propane or oxy-acetalyne for strength.
Just a propane torch might not get you hot enough for this large heat sink tank
Electric will never work on a large surface area like this tank you will loose too much heat and make another cold joint.
-s

So what I'm getting from you is that the basic electric soldering iron won't work nor will a MAP gas bottle torch used for sweating pipes.

Taking it to a radiator shop seems like the best plan.

40 watts isn't near enough heat to do the job.

Map gas setup might be just enough if you are inside a garage and you max it out
I haven’t used that kind of setup but seen it used and this job would probably be near the limit of that tool.
-s

MAP burns hotter than propane, so it *might* work. I would start by asking the radiator shop for a quote. They have the right tools and their price could be low enough to make it not worth doing yourself.

Ya, I'm not going to experiment on the gas tank. Radiator shop is the choice unless I get satisfaction from Spectra.

If you are not comfortable wit soldering definitely get a quote,
But, Let’s get some facts in order

50/50 solder melts at 350f, 95/5 melts at 464, that’s the range we are in here.
Propane torch is 3600f, mapp is 3700f, oxy/ acetylene 6000f, any of the 3 will solder, oxy/ac will be my last choice to solder.
Soldering is defined as below 840f, brazing is above 840f. All 3 will braze, it just takes Longer with lower heat…

Heating the parts, brushing flux on, melting solder on it and wiping it off to leave a bonded layer is referred to as “pretinning”, a good practice for both parts for this application.
I would expect that pretinning both parts and then putting a puddle on the tank to set the heated bung on to melt in would be the method of choice. Heat/ torch control is everything and not burning the flux or parts (will contaminate the joint). The tank being thin sheet metal will heat and blacken very quickly, no so for the bung. (If the tank was stainless that is a whole different level and I don’t think you should even try solder, different flux etc, I would probably weld on a SS bung)
Choice of solder and flux is yours, Nokorode flux is old school tried and true, 50/50 solder (lead-tin)is softest and bridges gaps best, 95/5 (tin-antimony) is strongest but harder to bridge gaps, and you are closer to the burn temp of the flux. There are choices in between, I used a lot of Bridgit lead free because it was at hand, 50/50 is not weak and common in the tin shops, but I am out of trades for a while.

I'm comfortable with soldering copper plumbing but I've never done anything more complicated than that. Using a soldering iron on carb floats and electrical connections is the only automotive use I've made of my limited soldering skills.

Again , I am early in the decision making process.
I understand the risks of welding sheet metal. The only reason I’m even keeping welding on the table is because I thought it might be possible to weld the 2 steel plates together while avoiding the sheet stock.
Pictured is the plate on the bottom of my tank.

Could be I’m barking up the wrong tree.
We’ll see.

Propane is plenty hot enough to do that job. It can get sheet metal red hot. I would NOT use Oxy-Propane or Oxy-Acetylene. We also used to use an Air-Acetylene torch, because it was quicker, and we were in a production scenario. Waveski, your joint looks worse than Otto's. That dark center section looks like it never got solder to it.

As klhanson said, if it was originally soft soldered, you will have to remove the old filler 100% before you can weld or braze it. From Ottos first pic, it looks like his was brazed. You can re-braze it if that was the original. Brazing is just like soldering only at a little higher heat for the chosen filler. Sil-Fos brazing rod is available in different silver content and is pretty forgiving, you just need a flux designed for steel, or use silver solder with steel flux. If it was mine, I wouldn't use solder just due to the type of joint, it isn't well supported, I would braze it.

Like I said earlier, it is interesting and a bit troubling to wonder how many more bad joints are out in circulation.
Spectra sells a lot of tanks.

Yes. And If they decide to send me a new tank, I'm not sure if I should be happy about that. Is there a way to test the weld before use? Try to pry it off?

Thought occurred to me, can you just use a tank outlet/ bulkhead fitting, available in 3/8” size, just need to get a fuel comparable washer for the seal.
https://www.discounthydraulichose.com/mm5/graphics/00000001/00397-06-PNG.png

How would you install that?

With a new unit think it would be a solder joint - hopefully a good and proper one. You would need to hear from a representative that Spectra is fully aware of the bad run of solder joints and has taken definitive measures to correct that manufacturing flaw. (Sounds like yours was just going to eventually fall off while driving…)

My search efforts , brief though they were, yielded nothing about widespread reports of failure or any statements from the company.

As to testing, short of high tech stuff like magnaflux(?) I know of no meaningful way of testing. How much prying is too much? I sure don’t know.

About Hanks’ bulkhead fitting, it looks as though there is a toothy washer that prevents the inner part from spinning.
I don’t know how a person could get those threads started inside a tank though.

A better design for the tank would be to have a thicker plate in place of the one pictured above. That plate would be securely welded or brazed to the tank (brazing would allow for the plate to be brass?) , and would have a standard sized and threaded opening into which a fitting could be inserted and turned. That attachment , specific to the application of the tank, could be soldered or bedded with Permatex -
Bing bang boom , done.
The two flat surfaces soldered together make no sense to me , and are obviously prone to failure.

Ya, that's why I asked how it would be installed. It would be perfect to install it during fabrication and then weld it on both sides.

I don't understand the two thin plate method, either.

FedEx just delivered a new fuel tank from Auto City Classic for my '56 Coupe de Ville. It has an outlet bung that's welded on the inside of the tank.

I'm paranoid about fuel tank connections now!

This is what I thought of, I guess you cannot get your arm down inside.

Only if you're anorexic or 7 years old.