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Tue Feb 18, 2014 1:40 pm

I've cleaned ans sealed 3 tanks using the same product "KBS" coatings Tank Sealer. The tank I did last week peeled inside. I spent 3 hours fishing out all the debris. After I sealed the tank I went to install it and heard stuff rattling around in there. I cleaned it and out came rust particles. WTF? I just sealed it 4 days before. Well I went to the manufacturers website and found out that moisture and cold temperatures cause it to peel and not bond. I had washed it , but maybe it wasn't completely dry. That is the key, no humidity in the tank. I knew something was funny when I poured the product in the tank and turned it all around to cote it and no residual poured out. Usually I have half of it back that I use to paint the exterior of the tank. While pulling the peeled seal out of the tank I determined it went off as soon as I poured it in the tank. It was 3/4" thick on the bottom and thin as paper on top. I rotated the tank around for 20 minutes and tried to pour out the residual, but nothing came out?? "DRY BEFORE SEALING" I screwed mine up because I misunderstood the severity of moisture or humidity while sealing. Hope this helps.

Wed Feb 19, 2014 6:42 am

Shit, wish I would have read this thread yesterday...just ordered POR-15 tank sealer kit last night. Now I'm having considerable doubt. Looks like I'm out $80.99.

Wed Feb 19, 2014 6:54 am

oscarsnapkin wrote: Shit, wish I would have read this thread yesterday...just ordered POR-15 tank sealer kit last night. Now I'm having considerable doubt. Looks like I'm out $80.99.

Or just shipping! Send it back. Or keep it and test your luck. Some swear by it.

Call the vendor, maybe it hasn't shipped yet.

Wed Feb 19, 2014 8:52 am

oscarsnapkin wrote: Shit, wish I would have read this thread yesterday...just ordered POR-15 tank sealer kit last night. Now I'm having considerable doubt. Looks like I'm out $80.99.

I've used it with no issues. Preparation and sticking to the instructions are key. You definitely can't just throw the stuff on.

You're in PA, I'd be waiting for some warm humid weather or doing this in a heated garage (70F).

Wed Sep 07, 2016 6:55 pm

First, sorry to resurrect this thread for the 2nd time...

raygreenwood.... Thanks for the detailed explanations. They've been very helpful in gaining an understanding the foundation of this process. I have a question that I'm thinking you can answer.

I found this crap in my fuel filter this past weekend (see pic below) so I'll be tackling this job this weekend. I plan to do a muriatic acid wash after getting whatever loose stuff I can out of the tank. I DO NOT plan to seal the tank as long as I don't have any holes and such.

I've seen a few posts around saying to use Ospho or similar on the post-muriatic flash rust, coat with ATF then re-install and fill with gas. My question is does the iron phosphate coating the Ospho creates stay put or does the fuel wash it away? If it washes away is there a benefit to using it or could I just acid wash, rinse, ATF coat, and reinstall?

Thanks for any help you have to offer.

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Wed Sep 07, 2016 11:04 pm

Take your tank to a radiator shop and have it boiled out. That should remove all traces of rust etc. I would not coat the inside with any "kit" I am a HUGE fan of POR 15 products. But would not even think about using their gas tank sealing kit. Waaaaaay too many things that can go wrong. In the original VW bulletins they recommended using mineral oil after a "sloshing" of the tank. Which is just another way of saying an extreme cleaning. Keep your tank full of gas....do not introduce things that will break away
And eff up your injectors etc.

Wed Sep 07, 2016 11:19 pm

bus68us wrote: First, sorry to resurrect this thread for the 2nd time...

I plan to do a muriatic acid wash after getting whatever loose stuff I can out of the tank. I DO NOT plan to seal the tank as long as I don't have any holes and such.

Post some pics of the inside of your tank after removal.

Its hard to tell from the pic of the fuel filter whether your tank is a good candidate for a sealing product.

Wed Sep 07, 2016 11:21 pm

bus68us wrote: First, sorry to resurrect this thread for the 2nd time...

Dude, absolutely no reason to apologize, you did the right thing. If you started a new thread, you surely would be lambasted and receive some intense scorn. (Honestly, I have no reason to complain, I've created a couple post topics that were already covered and didn't get blasted for it.) :lol:

But seriously, in the Bay forum, have no shame about digging up these old threads, it refreshes them for those of us who didn't get a chance to see them the first time around, or never "bookmarked" them for future ref.

Thu Sep 08, 2016 7:35 am

It the tank is making brown crap like that it'll need some sort of acid wash to get clean, the sealer is a bad idea unless the acid turns pits into pin holes. The Phosphoric isn't a must afterwards but the bare metal left from the muriatic flash rusts in seconds, partially from being bare and likely also due to acid residue. I've never tried a rinse with a strong base (TSP?, baking soda?) to neutralize the muriatic completely but it may slow the flash somewhat. The phosphoric adds that permanent grey coating which takes days to flash rust in most cases, gas is a great solvent and can leave areas of the tank washed clean when sitting after use, in most cases it's a moisture free environment in there but if you get some bad gas and you park it a while moisture can condense on the upper exposed areas, the grey film helps keep it clean in situations like that. A final rinse with the methanol to dry it out really helps as well followed by forced drying with a shop vac in reverse (blow mode), then the ATF.

Someone recently posted that you can get phosphoric acid at a hydroponics store for a fraction of the price of Ospho or Rust mort, not sure if it's buffered the same way as the specific metal treatment products but it's worth a look.

Sun Sep 18, 2016 6:03 pm

Here's what my tank looks like after 2 muriatic acid washes of 1 hour each and a phosphoric acid wash. Did I do something wrong or is it supposed to get flash rust after ospho?

Sun Sep 18, 2016 6:11 pm

acid, rinse, heavy 2-stroke mix or gas/ATF

no flash rust

Sun Sep 18, 2016 6:18 pm

bus68us wrote: Here's what my tank looks like after 2 muriatic acid washes of 1 hour each and a phosphoric acid wash. Did I do something wrong or is it supposed to get flash rust after ospho?
Did you immediately follow with water, then methanol and then a fast air dry?

Sun Sep 18, 2016 6:23 pm

Immediate rinse with water then air dry with shop vac in reverse

Sun Sep 18, 2016 6:36 pm

Hmmm...., mine all come out like Skills' tank, is the Phosphoric you are using the generic stuff from the hydroponic store?, or name brand Ospho or Rust mort?, the generic stuff may not be buffered.
I like to follow the water with the methanol or alcohol to pick up the last of the water and dry faster, odd that's happening since you aren't in a high humidity area.

In the end a little orange is way better than what was in there previously, one or two fuel filters will take care of that, most of it will pass right through without an issue.

Sun Sep 18, 2016 6:41 pm

It's hydroponic store stuff. The tank had less flash rust after the muriatic. That's my concern. Thinking of putting ATF in there and just rolling with it. Thoughts?

Sun Sep 18, 2016 6:54 pm

Man, I've been through the tank seal bit, with my shovelhead 5 gallon gas tanks. Trying to be a good little gear head I thought I was doing something good to my project. Flaked off mostly the tops and floated around in the gas like a bunch of leaves, What? But no problem until I ran the tank low and it all sat packed around my filter. Fill it up again and it's dancing around in there again not causing problems, still, I abandoned the tanks to be garage wall art. Even more disappointing was the tanks had some great art put in them. I think that a motorcycle tank really never gets full and when in the sun the heat is just too extreem for the coat to adhere.....

In a bus,the tank doesn't have direct exposure so the sun isn't an issue, but I'd never trust it again. I see these products on shelves at auto and adventure sport dealers and I just want to take my arm and sweep the shelves, knowing what this stuff costs a person. A sucker gets sold hear and there I guess. I begged my Dad not to do this to his 37 Chevy tank. His tank looked galvanized or something, like the day it was made, skipped the coat and has had no problems.

I'm for getting new tank, keeping it full of premium with filters you can watch periodically and replace if needed. I'm rebuilding a type 4 motor now and I won't take chances with the quality of fuel I'm putting into it.

Sorry, I'm new here, haven't introduced myself yet, but I'm just gonna jump in.

Sun Sep 18, 2016 7:13 pm

bus68us wrote: It's hydroponic store stuff. The tank had less flash rust after the muriatic. That's my concern. Thinking of putting ATF in there and just rolling with it. Thoughts?
Like I said, better than what used to be in there. You can try scrootching most it off with a length of chain in there and a good shake if you wish.

Sun Sep 18, 2016 7:17 pm

Alright. 2nd phosphoric treatment... It ate up that flash rust. Used a lighter rinse and it's WAY better. Guess I just rinsed for too long (like 30 mins) the first time. We have really hard water here in AZ. Can that effect this sort of thing??

Sun Sep 18, 2016 7:18 pm

^^^^

agree. just hit it with muriatic again. it will burn off in a nano second and follow up with a 2 stroke mix. after the drain, I like to hit it with the air hose to blow out the water, but the reality is the water will kind of mix with the fuel anyway.

you can drain the 2 stroke and decant the water out of it and toss it back in there. keep going till the gas is water free.

Sun Sep 18, 2016 7:23 pm

bus68us wrote: Guess I just rinsed for too long (like 30 mins) the first time.
Could be part of the problem, I've always just given it a quick slosh and out it goes, water + bare metal never ends well.

I like Skills' idea on the oil rinse and floating off the water too.