Author Topic: Air bubble in tank paint mean hole in tank? (Read 6986 times)

BollarNPS · « **on:** July 24, 2015, 05:13:23 PM »

I have been cleaning the inside of my tank out to get rid of the rust. Finally got it looking brand new and went to get some denatured alcohol to put in to assist with getting rid of water. I then put gas in the tank and swashed it around to coat the metal with gas. I then noticed an air bubble in the paint that i do not believe was not there before. I can push on the bubble but it then returns to size. Thought about poking a needle hole in the bubble to get rid of it. Before doing so i thought i would see what you guys thought. Thoughts??

Bodi · « **Reply #1 on:** July 24, 2015, 05:24:18 PM »

I have to say that's a hole in the tank. Can't think of anything else that would make a bubble like that.

BollarNPS · « **Reply #2 on:** July 24, 2015, 05:28:59 PM »

well shoot. so i either need a new tank or to have the tank lined? Any suggestions on which tank liner just incase a new tank is to expensive.

Don R · « **Reply #3 on:** July 24, 2015, 05:30:22 PM »

This not be good kimosabe. There was a thread recently for liners, maybe someone can provide a link.

Powderman · « **Reply #4 on:** July 24, 2015, 05:41:40 PM »

And a repaint. I would strip it clean and weld up any holes you find before sealing and painting.

triple · « **Reply #5 on:** July 24, 2015, 05:43:34 PM »

I think most commercial liners are quite good now days.

I recall a product " POR 15 " being of good value. I think this is what I used on a Norton tank approx. 15 years ago and no issues since.

Cant recall where I got it from but it did come out of the states

BollarNPS · « **Reply #6 on:** July 24, 2015, 05:51:43 PM »

yeah i mean heck there is only one way to learn how to do something. Im not super good at welding but i could use some practice. I was planning on stripping and painting tank anyways. How do i weld the tank though? Do i cut a small area out and put a larger piece that will cover the hole i cut on the inside then weld that. Just curious on how to weld and not leave a sheet metal sized bump.

flybox1 · « **Reply #7 on:** July 24, 2015, 06:02:17 PM »

Best to take it to a pro, and practice on a scrap tank.

BollarNPS · « **Reply #8 on:** July 24, 2015, 06:06:24 PM »

yeah im not gonna try to weld my tank. Ill probably just seal it.

flybox1 · « **Reply #9 on:** July 24, 2015, 06:10:14 PM »

Take some beer to a radiator shop

triple · « **Reply #10 on:** July 24, 2015, 10:58:58 PM »

On rusty ( ing ) tanks you may well be better off with the tank lining method.
Od tanks which show rust holes normally have surface rust elsewhere in the tank. If you don't neutralise and seal it you may find small parts of rust end up in your carbs..... you know where this will take you..

All tank lining kits I have used in the past come with a cleaning and rust neutralising solution and then the 2 part sealer.

Just welding the existing hole may lead to other holes opening up a little further down the path only to destroy your new paint job and then to do it all over again...

calj737 · « **Reply #11 on:** July 25, 2015, 06:21:59 AM »

There's no need to strip the paint if you only line the tank. And, that bubble is easily caused by a pinhole, which a lining of the tank will fix.

If you plan to strip the paint, do it now, then line the tank while stripped. Lining and protecting paint is VERY difficult. Besides, once you strip the paint (your picture shows a rattle can spray job) you may be surprised to find how much is "hiding" under there. A recent endeavor as an example...

Johnie · « **Reply #12 on:** July 25, 2015, 07:03:16 AM »

Not good...been there with my red KO. Ended up having it painted 3 times to get it right. I think the etching from the liner prep and the sanding by the painter just got the tank to thin. Pin holes showed up just south of the gas cap. The last time I had the liner removed and the top of the tank silver soldered. New liner installed and all is well. I could have bought a different tank, but since the bike was my first 750 I wanted to keep all the parts on it that it was born with. Good luck with it.

Cougars750F0 · « **Reply #13 on:** July 25, 2015, 08:39:26 AM »

You mentioned that you cleaned out the rust did you use Ospho or another product that kills the rust? If not the rust could come back and grow between the liner and paint. if you are going to repaint don't sand it off but instead strip the paint off sanding can thin the metal down. I've had good results with Aircraft brand paint remover. I agree with calj737 remove the paint first so you can see if there are any other issues that you need to address before you line the tank this is a common problem I have had to get another fuel tank after I removed the paint you never know what you'd find. Make sure you you use a paint that will handle gas spills after all that work

Good luck with your project.

nvr2old · « **Reply #14 on:** July 25, 2015, 09:35:09 AM »

If it were my tank, I would strip it to bare metal, tig weld the pin hole, grind it smooth and then line the tank. If the liner doesn't adhere perfectly, you'll have the same problem popping up again unless it's welded. Real simple to have a quick spot weld done.

BollarNPS · « **Reply #15 on:** July 25, 2015, 09:45:51 AM »

I'm going to remove paint first with aircraft removal stuff. Then I'll see what it cost to have it welded as I don't want to blow my head up. Then I guess I'll try the caswell. Thanks everyone

calj737 · « **Reply #16 on:** July 25, 2015, 10:49:09 AM »

With Caswell, pinholes cover/fill completely so you can skip the welding. But to weld it up is a better fix before the liner.

Tews19 · « **Reply #17 on:** July 25, 2015, 10:56:08 AM »

Quote from: calj737 on July 25, 2015, 10:49:09 AM

With Caswell, pinholes cover/fill completely so you can skip the welding. But to weld it up is a better fix before the liner.

Very true. My 550 F tank has around 30 pinholes on both sides. Sealed it with Caswell and not one issue since.

BollarNPS · « **Reply #18 on:** July 25, 2015, 11:00:06 AM »

I've read a lot of negative reviews with liner caswell having the least amount. Is it really that easy to mess up or are these people just not following directions?

Tews19 · « **Reply #19 on:** July 25, 2015, 11:10:30 AM »

Quote from: BollarNPS on July 25, 2015, 11:00:06 AM

I've read a lot of negative reviews with liner caswell having the least amount. Is it really that easy to mess up or are these people just not following directions?

Follow directions. My tank was as dry as one could be from the factory. Mix and pour. Than keep turning until all sides are covered. Let sit than use. I was so nervous I went to my buddies to do it. He is an older fellow who mixed it and poured it in. It's that simple. Best 40 or 50 bucks one may spend on a tank.

calj737 · « **Reply #20 on:** July 25, 2015, 12:12:36 PM »

Just like paint, prep is the key. De-rust, dehydrate, then pour in. Tumble slowly and completely (remove petcock) and let cure. I prefer to cut into 2 batches, focusing on underside of top first, then bottom with second batch. Allows me to control the coverage a little better. I apply second batch after an overnight cure.

przjohn · « **Reply #21 on:** July 25, 2015, 12:46:17 PM »

Another vote for the Caswell Kit. Never had a problem with the stuff. I am also in the camp of repaint and line it.

Muckinfuss · « **Reply #22 on:** July 26, 2015, 02:03:45 PM »

metal water and gas tanks of all sizes and metals have been getting repaired just fine with either silver or bronze braze for close to a hundred years. easy to 'flatten' when done prior to paint also. using acid for these tank cleanings is a real risk since acid doesn't discriminate between rust and ok metal. you are far better off using a reformer that only attacks rust and follow up with a corrosion inhibitor.....no more flash rust to mess with your tank liner. my second choice would be electrolysis followed up with a dose of reformer and then the inhibitor. And then you can use the PQR 15 that is sold in just about every auto supply in the US for cheap money.

Short shins · « **Reply #23 on:** July 27, 2015, 12:54:22 AM »

Sadly a bubble in the paint means a hole..

in my case the previous "restorer" rather than fix the problem just lined the tank, slapped a layer of bondo and some paint. looked nice and worked well until I noticed some paint lifting and then it escalated to a slight weep of fuel

Whole Right hand side...I think the liner and paint was holding it together

I had a go at fixing it with some epoxy Tank repair kit didn't really work. Needs stripping out welding/soldering and a repaint,
or I just buy a "new" tank from Wobbly..

Sorted!

lrutt · « **Reply #24 on:** July 27, 2015, 05:13:00 AM »

check the rest of the inside of the tank. If there is a lot of other rust then lining is probably your only option. If it's localized though. I'd suggest gently dimpling in the tank in that area, sanding down to bare metal, and soldering over that hole, you can then touch up with bondo to smooth it out.

I really hate liners as it seems it always a matter of if not when they decide to separate and fail.

Powderman · « **Reply #25 on:** July 27, 2015, 07:15:36 AM »

Quote from: lrutt on July 27, 2015, 05:13:00 AM

check the rest of the inside of the tank. If there is a lot of other rust then lining is probably your only option. If it's localized though. I'd suggest gently dimpling in the tank in that area, sanding down to bare metal, and soldering over that hole, you can then touch up with bondo to smooth it out.

I really hate liners as it seems it always a matter of if not when they decide to separate and fail.

Don't you mean "When and not if"?

calj737 · « **Reply #26 on:** July 27, 2015, 08:31:30 AM »

The same can easily be said of bare metal tanks, Powderman. If you don't like liners, don't use them. Equal parts of rivers have them and are pleased with their results to those with stories of failed liners.

Impossible to determine how/when "failed liners from POs" we're installed. And, if they last 10 years or more, that's pretty dang reliable for 40+ year old bikes that would otherwise rust into ruins without some protection.

754 · « **Reply #27 on:** July 27, 2015, 08:49:53 AM »

Try to get a bore scope in there and see the really condition... If it's only a few holes, I would probably just try to fix them.. Rather than liner..

nvr2old · « **Reply #28 on:** July 27, 2015, 09:41:12 AM »

Another alternative is to take the tank to a radiator repair business. They can clean the inside beautifully, repair the pin holes and pressure test it for you, too. I've done that several times with good success. It will ruin the paint, however, but if it's going to be stripped and re-done anyway..might be a good choice.

Powderman · « **Reply #29 on:** July 27, 2015, 09:57:15 AM »

Quote from: calj737 on July 27, 2015, 08:31:30 AM

The same can easily be said of bare metal tanks, Powderman. If you don't like liners, don't use them. Equal parts of rivers have them and are pleased with their results to those with stories of failed liners.

Impossible to determine how/when "failed liners from POs" we're installed. And, if they last 10 years or more, that's pretty dang reliable for 40+ year old bikes that would otherwise rust into ruins without some protection.

I don't have an opinion one way or the other towards liners. I was merely asking if what the poster posted was what he meant. In most cases the saying is used when something fails more often than not. Did he really mean "if and not when"? It just didn't sound right to me.

lrutt · « **Reply #30 on:** July 27, 2015, 10:00:43 AM »

Quote from: Powderman on July 27, 2015, 07:15:36 AM

Quote from: lrutt on July 27, 2015, 05:13:00 AM
check the rest of the inside of the tank. If there is a lot of other rust then lining is probably your only option. If it's localized though. I'd suggest gently dimpling in the tank in that area, sanding down to bare metal, and soldering over that hole, you can then touch up with bondo to smooth it out.

I really hate liners as it seems it always a matter of if not when they decide to separate and fail.
Don't you mean "When and not if"?

Yup, that's what I meant. Brain fart on my part

calj737 · « **Reply #31 on:** July 27, 2015, 10:34:56 AM »

I see your point, Powderman, but reversing the semantics changes the probability. Stated as you re-stated it, its an indication it will fail, not if it will fail. Probable versus possible.

I can tell right now, I'm soaking a tank for SohRon with 4.5 gallons of acetone on a tank lined with Caswell. Its not even budging it. I'll have to drain it and step up to MEK to evacuate the tank of the liner. If Caswell can sit for over 24 filed with Acetone and not weaken, dissolve or separate, then its pretty darn tough by me. You can refer to his thread as to the "why he lined it" and how it has now 2 layers in it.

754 · « **Reply #32 on:** July 27, 2015, 11:19:43 AM »

How old ng does lining a tank take.. I think maybe an hour or two.?
And cost.. 25 -50.00 or more?
Just wondering...it's seems guys on here like lining a tank..In some humans do areas, it may be almost always needed.
Just bringing it up as I once offered to sell a 400-4 tank on here at one time..appeared to be NOS, but some shelfwear dents..If. Wanted 160.00 I think. Probably PDR fixable with stock paint.
And then, a few guys came on and said way too much get a used one for for less on ebay, and then line it..
And I was thinking.. Who in their right mind would rather have a used tank with a liner, than a tank that may never had seen gas.... To save 50 or 80 bucks...

BollarNPS · « **Reply #33 on:** August 18, 2015, 07:08:21 PM »

The tank is currently full of gas and i was planning on tackling this challenge this weekend. I noticed though that the air bubbles went away. Is there a chance that this could of been caused by something other than a pin hole. Im just trying to be hopefull here. Thanks.

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Author Topic: Air bubble in tank paint mean hole in tank? (Read 6986 times)