Topic: BUBBLES IN THE TANK PAINT = HOLES IN THE TANK?

[34barab]

Bike is CB750K3, Flake Sunrise Orange, with original tank.  PO lined it with POR 15, but I now suspect he lined over rust.  After having the bike a month or so, my mechanic found pieces of the liner "floating" in the fuel (I saw them), which was causing running issues.  He tried to tumble out the liner with gravel for about a week, but couldn't get it all out.  So he removed what he could of the POR 15 and then Kreemed over the entire tank (Fall of 2016).  No fuel issues since then.

Bike's been sitting, covered with a Mexican blanket in a heated dry garage since Spring 2019, when it was last ridden Didn't see any bubbles in the paint then, but noticed them a few days ago. Right now tank is off the bike.

Could the bubbles be rust-through?  What's my next step?  If there is no rust-through, I want to remove both the Kreem and the POR 15 and start over.  I can repaint the tank if necessary, but I'd rather not have to.

The goal is to use the tank back on the bike.  I have a spare I can use until the original is ready. 

[jlh3rd]

por 15 is designed to go over rust. It's a good product, but like any coating the prep is crucial. por 15 stops the rusting process....so....like most of these stories, i'll bet the application wasn't done properly.
Relining your tank isn't gonna fix those rust bubbles, and if those are from the inside, which is my guess, you've got a lot of 'em. I've never seen a stock honda tank rust like that from the outside.
So, i'd say you have a restoration process ahead, if that's even feasible with that many bubbles.

[69cb750]

The ones on the side are either rust through or surface rust that was painted over.
If you want to know try to push a needle through.
The top ones are either surface rust or debris that came from paint gun.

[carnivorous chicken]

Kreem is not a good product, POR 15 is much better (but as jlh notes it has to be done properly).

But if you've lined the tank properly, it should stop further deterioration if it's from the inside.

[Tomshep]

The tank may be the original but is the paint? That looks like paint reacting with rusty metal underneath but just minor pitting on the outer surface of the metal, not rotting through.

[Stev-o]

That tank is toast [I have one similar].  Either use as is or look for a replacement.

[34barab]

Responses are a bit disheartening, but not that surprising.  Is it feasible/worth restoring?  If so, what steps are involved?

Strip liners?
Strip paint?
Fix holes? (did find a dripping leak at right front bottom of tank this morning)
Reline tank?
Repaint tank?

Please note I can probably remove liners if I someone tells me how to do it.  Thanks

[MCRider]

Yeah that tank is toast. Not saying you can't restore it, but it would be a job.

I had one full of pinholes and had these guys restore it. Kinda pricey, but at the time I wanted to do it.

http://www.gas-tank.com/

Nice to know about them anyway. Its been 4-5 years since it was done, no leaks.

You can see my paint job in my avatar or my build thread. Several coats of clear and metal flake, airbrush flames and wolf's head. Got a lot on money wrapped up in that tank.   

[calj737]

I don't believe the bubbles are from interior rust, more than likely they are the paint layers reacting to an incompatible surfacing product. "Bondo" is not all the same. And some surface fillers off-gas for a while before they cure and are paint ready. Especially if a sealer was not used prior to paint.

Modern paints are "systems" designed to work with each other in layers. Mixing types is not a recipe for durability.

If you plan to store a tank, always do so completely empty and dry. Heck, even drop some dessicant into it (large stable chunks easily retrieved) to absorb any condensation that may form during storage. Leaving the cap open is best so evaporation can occur if the storage environment fluctuates in temperatures and humidity.

Strip that tank to bare metal, and start over. Use a chemical stripper to cause the least amount of surface stress. And tell your buddy who filled it with gravel to get a clue.... Gravel will damage the metal and can itself cause pinholes if the surface is the least bit damaged in integrity.

[seanbarney41]

To me, the only time it is worth while to line a tank, is to save some original paint.  Unfortunately, the necessary prep is usually so rigorous that the o.g. paint is lost anyway, or the liner is gonna fail.  Lots of clean, solid used tanks still out there if you are gonna repaint.  Hell, there are even brand new reproductions available now from yamiya.

[carnivorous chicken]

One thing that's missing is whether the spots are getting worse or staying the same. Why not run it for now, keep an eye on it, and wait and see? 

[jlh3rd]

Responses are a bit disheartening, but not that surprising.  Is it feasible/worth restoring?  If so, what steps are involved?

Strip liners?
Strip paint?
Fix holes? (did find a dripping leak at right front bottom of tank this morning)
Reline tank?
Repaint tank?

Please note I can probably remove liners if I someone tells me how to do it.  Thanks

well...are you trying to save an original, maybe unrestored bike?....repairing then repaint makes it a restoration....but just the tank.......but then you will have to repaint the side covers at the same time with equal layers of paint or they will probably  not match the tank. Its a translucent candy color paint that gets darker every time you spay another layer........you can see where this is going......
The time and money is yours, basically just about anything can be repaired though.

[jlh3rd]

To me, the only time it is worth while to line a tank, is to save some original paint.  Unfortunately, the necessary prep is usually so rigorous that the o.g. paint is lost anyway, or the liner is gonna fail.  Lots of clean, solid used tanks still out there if you are gonna repaint.  Hell, there are even brand new reproductions available now from yamiya.

+1

[Jerry Rxman Griffin aka MuthaF'er]

Kreem is not a good product, POR 15 is much better (but as jlh notes it has to be done properly).

But if you've lined the tank properly, it should stop further deterioration if it's from the inside.

Kreem is a fine product if done properly. Mine has lasted over 30 years.

The way I see it is to use your tank as it is if not leaking or you will need to go full pop and strip the tank inside and out hoping for the best and hopefully not be disappointed. Poke a hole and you WILL have to do some extensive repairing. Only time would tell.

[seanbarney41]

Kreem is not a good product, POR 15 is much better (but as jlh notes it has to be done properly).

But if you've lined the tank properly, it should stop further deterioration if it's from the inside.

Kreem is a fine product if done properly. Mine has lasted over 30 years.

The way I see it is to use your tank as it is if not leaking or you will need to go full pop and strip the tank inside and out hoping for the best and hopefully not be disappointed. Poke a hole and you WILL have to do some extensive repairing. Only time would tell.

Jerry, how long has it been since you filled up at the pump and went for a ride?

[754]

The fact that it's on top, to me indicates, it coming from the outside.
 Dennis aka Old Scrambler  lost the paint in that manner to a nice tank. It was parked beside I think tractor tire chemicals, and it ruined his paint to .. similar.
 What is near the bike ? Is it heating and cooling a lot in there ?

[34barab]

This morning I found two pinholes underneath just rearward of the right mount that were visibly leaking.  I plan to use my spare tank for now.  It has a crease/dent on one side (see second pic), otherwise nice condition and spotless inside.  Can this type of dent be banged out using the long, thin dent removal rods sold on Amazon?

[carnivorous chicken]

Kreem is not a good product...

This morning I found two pinholes underneath just rearward of the right mount that were visibly leaking.

Well there ya go...

Liners are supposed to stop pinhole leaks, and they can if done correctly. I've used POR15 and Redkote, Caswell's has a good rep, but most people don't like kreem.

If you wanna try to line it (again), at least Kreem is easy to get out. If you're carefull you can do so without damaging the original paint, but it takes a lot of care.

[jlh3rd]

This morning I found two pinholes underneath just rearward of the right mount that were visibly leaking.  I plan to use my spare tank for now.  It has a crease/dent on one side (see second pic), otherwise nice condition and spotless inside.  Can this type of dent be banged out using the long, thin dent removal rods sold on Amazon?

yep.....if you know how to do it....if not, there's places that can do it. And the place i used sells the tools, the patented tank holder, and instructions.
     That tank looks  to me like an original painted tank. I've never seen a honda tank do that from the outside. 

[34barab]

The fact that it's on top, to me indicates, it coming from the outside.
 Dennis aka Old Scrambler  lost the paint in that manner to a nice tank. It was parked beside I think tractor tire chemicals, and it ruined his paint to .. similar.
 What is near the bike ? Is it heating and cooling a lot in there ?

Bike has been garaged since 2016.  No direct heat source, but it is heated by having ceiling and two walls integral to the house.  Temps range from 50 F to 90 F.  Two car width, with bench on one side, this bike on other.  Only chemical exposure has been fuel, and the usual carb cleaning chemicals on the opposite side.

[34barab]

This morning I found two pinholes underneath just rearward of the right mount that were visibly leaking.  I plan to use my spare tank for now.  It has a crease/dent on one side (see second pic), otherwise nice condition and spotless inside.  Can this type of dent be banged out using the long, thin dent removal rods sold on Amazon?

yep.....if you know how to do it....if not, there's places that can do it. And the place i used sells the tools, the patented tank holder, and instructions.
     That tank looks  to me like an original painted tank. I've never seen a honda tank do that from the outside.

I’m in NJ and I see you’re in PA - who did you use for your tank?

[Don R]

The fact that it's on top, to me indicates, it coming from the outside.
 Dennis aka Old Scrambler  lost the paint in that manner to a nice tank. It was parked beside I think tractor tire chemicals, and it ruined his paint to .. similar.
 What is near the bike ? Is it heating and cooling a lot in there ?

 I looked at a 750 that had been parked next to a tractor tire leaking chloride on a gravel floor. That bike was way more gone than any 750 I ever saw. I gave parts to the guy that ended up with it. That tank was missing it's entire side.

[754]

That is what ate Old Scramblers paint, still runnable , he caught it in time....same sort of damage.

[spotty]

the tank i got off terry with the zzr had the same bubbling across the top and sides and when i rubbed it back it was just bubbles in the paint, no rust spots underneath. as far as i know that was factory paint and a lot newer than this bike

as for the feckin' great holes in the underneath of the tank....well that was a different matter

[jlh3rd]

This morning I found two pinholes underneath just rearward of the right mount that were visibly leaking.  I plan to use my spare tank for now.  It has a crease/dent on one side (see second pic), otherwise nice condition and spotless inside.  Can this type of dent be banged out using the long, thin dent removal rods sold on Amazon?

yep.....if you know how to do it....if not, there's places that can do it. And the place i used sells the tools, the patented tank holder, and instructions.
     That tank looks  to me like an original painted tank. I've never seen a honda tank do that from the outside.

I’m in NJ and I see you’re in PA - who did you use for your tank?

dent dynamics, santa rosa, Ca., Daniel gromm.......I just went to the timonium bike show and there is someone in N.J. that bought and took lessons from gromm and now has his own business.....ill try to recall his name......CA. is a long way.......