Topic: Concern of gas tank fumes while sanding/painting?

[denward17]

I'm thinking of painting my gas tank this winter and had a thought of the fumes after the tank is empty.

What precautions should I take during the sanding/painting process with the empty tank if any?

[newday777]

Grinding and welding, yes to be worried. Sanding, not really.
Be sure to empty the tank fully, wipe out the excess with a clean rag on a mechanics finger stick, then leave the tank open to air out for a week/until no more fumes present.

[denward17]

Good idea, Thanks Stu.

[calj737]

Just fill it with soapy water, slosh it around well and dump it. Spray the interior with WD-40, 2 stroke mixture, a 1/4 cup of oil even. Gas fumes dissipate from volatility very quickly. After a day or two you could easily weld on that, and grind that tank. There's too little concentration in the air for a single spark to ignite a vapor...

[Don R]

  I was told by a painter don't paint all of the way up to the cap gasket on the neck. Fuel can seep under the edge of the paint and lift the paint lower where you can see it. I'd get a new gasket also.
  I've used the exhaust from my cleaned shop vac to blow the fumes out of a tank. Outside of course.
  Be sure to tape the opening well too, my painter sandblasted and got sand into my tank. I fought it for quite a while before finally getting it all out. I said @#$%&* er.

[denward17]

Good tips guys, Thanks

[MauiK3]

Leave the tank in the sun for a few hours

[seanbarney41]

Be aware that a gas tank must always normally be vented.  I once gave a tank to a pro painter friend of mine to put a clear coat over some old beautifully patinaed custom paint on a kz1000 tank.  I had cleaned the inside and dumped in around a cup of wd40 to protect the fresh metal.  I gave it to my friend sealed tightly with rubber stoppers.  He cleared it beautifully and put in his paint boothe so it could dry quickly in the heat cycle.  Neither of us predicted the outcome.  The heat cycle caused the wd40 to outgas enough that the pressure built up inside and distorted the tank to the point that is unrepairable.

[RAFster122s]

For smaller projects you can make CO2 with vinegar and baking soda, the CO2 is heavier than air, so you mix in in a tall jar and then pour the CO2 into what you need to displace...
Not the vinegar and baking soda mix/slurry, just the gas.
Would take quite a few mixes in a quart jar to displace 5 gallons of volume in a tank.

Exhaust from a car tailpipe vented into the tank with a hose could do the same thing...

[Bodi]

I do the blowing out with a shop vac as winter prep. Don't use suction ... the motor makes a lot of sparks.

[Floshenbarnical]

Fairly unrelated but I was using electrolysis to de-rust my gas tank. After a couple of hours, enough liquid had been used that it created a small headspace where some pure hydrogen had built up. I forgot to disconnect the battery charger first before removing the electrode for cleaning, and created a small spark that ignited the hydrogen in the headspace and blasted a quart of washing soda solution out of the gas cap hole directly into my face.

Quite a surprise, I'll tell you

[Don R]

 Mythbusters did a myth that a shop vac would turn into a jet engine if you vacuum up flammable materials. They weren't able to light one up but still didn't recommend trying it at home.
 I use a piece of copper tubing held on a shop vac hose to clean the bottom corner of the oil tank. A little brake clean helps get the sludge out of it.

[Geoff Hastings]

Myth busters obviously didn’t speak to me, I managed to convert my cylinder vac into a jet engine for about 1/2 a second before it blew to bits leaving my ears ringing. Admittedly the tank had only been empty for an hour or two, it was a moments lack of thought, the tank had leaves in the bottom and having emptied it I just looked around and spotted the vac sitting there. Anyway, I now blow my tanks clear with an airline and have welded them with no more explosions.

[Floshenbarnical]

Myth busters obviously didn’t speak to me, I managed to convert my cylinder vac into a jet engine for about 1/2 a second before it blew to bits leaving my ears ringing. Admittedly the tank had only been empty for an hour or two, it was a moments lack of thought, the tank had leaves in the bottom and having emptied it I just looked around and spotted the vac sitting there. Anyway, I now blow my tanks clear with an airline and have welded them with no more explosions.

Jesus, that'll wake you up

[BenelliSEI]

I know a tank painter who always washed tanks out with hot soapy water. He then wired them up on the back bumper of his MGB with the tailpipe up the fill hole. Ran the car for 5-10 minutes to warm and dry everything totally. He swore the carbon monoxide reduced the risk of any disasters and welded away. Never tried it, but it worked for him. He’s still alive.

[Don R]

 I watched a guy cut up a steel gas station gas tank, he used the exhaust from his truck piped into the tank to remove the oxygen so he could cut the tank. He didn't explode. I have experience tig welding pressure vessels, Argon will fill a tank just like a liquid, it's heavier than air, I used a leaf blower to pull the Argon out and monitored the oxygen levels with a meter.

[rotortiller]

Various cleaning methods are available, some create gas pressure and if the tank is sealed unattended this process can distort the tank shape. Even using vinegar can ruin a tank shape.

If you burn yourself down through stupidity, well that's natural selection at work.  Sparks and flammable gas are bad.

[willbird]

I know a tank painter who always washed tanks out with hot soapy water. He then wired them up on the back bumper of his MGB with the tailpipe up the fill hole. Ran the car for 5-10 minutes to warm and dry everything totally. He swore the carbon monoxide reduced the risk of any disasters and welded away. Never tried it, but it worked for him. He’s still alive.

CO is a flammable gas ?? The LEL is 12.5%.

Bill

[nvr2old]

If you rinsed out the inside of the tank with Acetone (specifically) it will clean your tank nicely and will leave absolutely no residue from the gas that was in it.  It dries  in seconds.  Done.  Acetone is available at most if not all hardware stores.

[Floshenbarnical]

If you rinsed out the inside of the tank with Acetone (specifically) it will clean your tank nicely and will leave absolutely no residue from the gas that was in it.  It dries  in seconds.  Done.  Acetone is available at most if not all hardware stores.

Will also delete a tank liner in seconds, which is brilliant if thats what you need to do

[calj737]

If you rinsed out the inside of the tank with Acetone (specifically) it will clean your tank nicely and will leave absolutely no residue from the gas that was in it.  It dries  in seconds.  Done.  Acetone is available at most if not all hardware stores.

Will also delete a tank liner in seconds, which is brilliant if thats what you need to do

That’s not true of many modern liners. They can be very resistant to chemical strippers. And Acetone is not that caustic to begin with.

[willbird]

If you rinsed out the inside of the tank with Acetone (specifically) it will clean your tank nicely and will leave absolutely no residue from the gas that was in it.  It dries  in seconds.  Done.  Acetone is available at most if not all hardware stores.

Will also delete a tank liner in seconds, which is brilliant if thats what you need to do

That’s not true of many modern liners. They can be very resistant to chemical strippers. And Acetone is not that caustic to begin with.

Over the years working in machine shops I had developed the idea that Acetone was a super solvent. But while digging into some project some RKI chimed in to point out that overall it is not really that. It is good at removing maybe he said "organic esters" but for many purposes Isopropyl alcohol is actually a better cleaner/degreaser. I seem to remember a Chemistry teacher saying one good attribute it has was not leaving any residue after evaporation.

Some paint equipment cleaners I looked at recently had both acetone and toluene in them.

[RAFster122s]

  I was told by a painter don't paint all of the way up to the cap gasket on the neck. Fuel can seep under the edge of the paint and lift the paint lower where you can see it. I'd get a new gasket also.
  I've used the exhaust from my cleaned shop vac to blow the fumes out of a tank. Outside of course.
  Be sure to tape the opening well too, my painter sandblasted and got sand into my tank. I fought it for quite a while before finally getting it all out. I said @#$%&* er.

Also, you should take an epoxy like JB Weld and paint a ring around the tank neck covering the paint to metal transition, this way fuel vapors don’t lift your beautiful expensive paint work wrinkling the paint abd working its way wider sometimes than just the neck. The epoxy seal that transition and the cap covers this so you won’t see that part unless filling the tank. I see lots of tanks painted all the way up and even on the sealing surface and think to myself, that is really not going to end well…