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MG TD TF 1500 - Sealing an old petrol tank

Hi Guys

I know this has been talked about before and I have read all the post's. But still a little unsure as how to proceed.

My TF tank has stood empty for over 30 years. Today I as part of the restoration I decided to clean it prior to sealing it.

First I used a safe rust remover which I think was probably a waste of time as I later discovered it needs to be fully immersed for days if not weeks! It got 2 hrs...

Next I used a product called tank clean. This I used combined with 10 sharp stones. I rigged up the tank with brackets on the side and was able to spin it between 2 chairs.
This worked well and I continued for about 2 hrs also.

After emptying the tank and retrieving the 10 stones I power washed it and dried it with a hair dryer...

At this point I was going to proceed with the tank seal but I thought I would get some advice first.

I have looked at the pictures online of the inside of the tank and have seen the row of baffles. This was brought home to me when I partly filled the tank with water and tipped it to empty it and there was quite a delay before the water came out.

Although I have a double batch of seal I think I may still have problems covering all of the inside.

After all of the cleaning I took a couple of pictures with my phone and it still looks quite rusty inside.

Any thoughts on how to proceed.

Thanks Darryl

D Lamb

Still pretty rusty!

D Lamb

The products

D Lamb

The set up

D Lamb

More rust even after cleaning....

D Lamb

Opposite the sender unit...not as rusty

D Lamb

Best way to prep it is with phosphoric acid to take away the rust. Leave for 24h. Then drain and rinse and dry as fast as possible with compressed air. Then coat the inside following the manufacturers instructions. If you turn it every which way at different speeds, including slowly and for as long as possible, you will cover every surface. It is surprising how little material it takes to do it.
Dave H
Dave Hill

I like the set up, but you also need to turn it end over end.
Dave H
Dave Hill

Thanks Dave for the advice.

I need to work out where to buy phosphoric acid in large quantity.....

I had to do the end over end manually....tiring on the old arms.
D Lamb

You can get it from ebay.
Dave H
Dave Hill

Looks like a fair amount of rust down at the bottom. I forget if it is welded or what all down there at the seam. Problem with the slosh type seals is they require so much prep. The 2 part ethanol proof epoxy seals are a bit more tricky to work with getting distributed all around inside, but I think easier to prep the tank. The epoxy kind claim to stick better with a bit of rough surface and rust. Clean out is with solvent like acetone and along the lines of your 10 rocks to knock away any loose rust. 10 years later my original tank is still sealed up well and no problems with the Caswell.
S Cole

To remove rust you need acid and phosphoric is best. Some clean nuts and bolts in there to rattle around and knock lumps off the rust are a good idea (not stones unless you know they are definitely not alkaline). Its difficult to vigorously shake something that size, but you can churn it round. After rinsing with water, a final rinse with acetone has a single useful purpose and that is to remove remnants of water (any hydrocarbons should have been removed as a first step).
Dave H
Dave Hill

Add 3 gals of white vinegar and two boxes of 5/16 the nuts from your local hardware store. Leave in tank for up to 3-4 days slosh the nits side to side end to end over and over repeatedly every few hours let the vinegar rest on each of the four sides several hours at a time. Agitate often. Dump the vinegar and rust. Respect this several cycles until the rust is gone. Rinse tank with water and force dry with a blow dryer in the sender hole and cap open Then you can use the sealed. I used RedKote. I bought a gallon and dump three qts in sloshing it every way to Sunday and drained off the excess back into the can for reuse on other projects. Then continue to roll the tank around to ensure any small excess doesn't pool up as heavy Amounts won't cure properly. Read the label. Then force dry again with a blower on low heat. I used a dog grooming blower with the hose stuffed into the sender hole. Tank is ready when fumes are no longer present. Usually in a few days. Cinegar is also an acid but less corrosive. If you get vinegar on the paint rinse it off immediately. It also wouldn't hurt to apply a good paste wax on the paint before hand to protect it as well. Worked well for me but it was a two week process at home. In warmer weather. Took three application of the vinegar to clean out almost a quart of solids and about a quart of the RedKote Don't skimp on either as you want good coverage.
W. A. Chasser

Darryl,
As above but I have never heard of using chairs but I have heard of the version with a cement mixer.
Here's a video
https://www.youtube.com/watch?v=kPBcjw3ppLg

Once set up, go down to the pub and by the time you are sober again the tank is clean.
Regards
Declan
Declan Burns

Thanks guys.

The pub sounds like a good idea after the frustrating day yesterday Declan.

Thanks Dave and W.A. for the suggestions of white vinegar or phosphoric acid. Not sure where to get either of these in large quantities. Would one be quicker/better than the other?

I believe coca cola contains phosphoric acid. Is it worth a try or not strong enough.

Ps the wife's hair dryer worked great but I got an ear full when she discovered.....

D Lamb

You wouldn't want to do that with a petrol tank that has had petrol in it recently!!
I always use phosphoric for derusting. Its an acid so care is needed, though much safer than any of the other mineral acids. If you use it wear rubber gloves and safety glasses. To dilute, add acid to water and never the other way round. About 30% is strong enough. This is what is used to derust in industry. You can get it delivered if you buy from ebay.
I've never used white vinegar for the job, but basically its dilute acetic acid. No doubt will do something as various people have said it works. Requires less in the way of safety precautions, but still take care.
Going down the pub is always a good plan!
Dave H
Dave Hill

A tank filled with white vinegar purchased at the local grocer will produce shinny metal in a few days..I did not slosh mine..no need.
Inside looked like new metal (pitted, but shinny). No haz-mat to dispose of afterward either..no gloves, no toxic fumes.
Regards, Tom
tm peterson

Darryl

I like your chair idea to slosh the tank. Simple and easy to do. I wish I thought of that. I did mine with someone helping me to agitate back and forth. When I needed more work, I did it myself. It was heavy but it finished the job.

I bought the fuel tank sealer kit from Hirsch Auto http://www.hirschauto.com/Gas-Tank-Sealer-_-Repair/products/4/ which worked okay but I needed more than the pint to get the tank completely clean.

I checked archives and got myself some phosphoric acid from a local hardware store. Worked well and I did use the Hirsch Auto tank sealer from what I'm told holds up to ethanol. I bought an additional gallon to go along with my quart from the kit to get the best coverage.

This is my set up to get the tank completely dry before adding the sealer. Nice high volume of air to make sure everything is nice and dry.

I've been following your restoration on your TF. Looking great! I really like how you preserved the gold paint on the Gold Seal engine.

Best

Frank

MG TF 1414



Frank Cronin

Hi Darryl,

This info is absolutely vital. If you use a tank sealer do not uses anything with threads to blank off any openings. The sealer is more efficient than thread lock and you have real problems removing any bolts or screws.
I used tank sealer for the tank in my M Type and blanked off the outles with some scrap brass unions. They locked solid.

Jan T

J Targosz

I used the cleaning vinegar, bought from a local grocery store on Bill's tank this summer. It was a first for me but I would certainly do it again. About 3 gallons soaked with it on it;s back and some nuts and bolts added for an occasional agitation. Dumped and repeated with it on it's front side.

L E D LaVerne

To the local car wash after dumping followed by about 4 hr's of blow drying with the shop vacumm. Later coated. Not a great picture but the inside metal looked ;like new when finished.

L E D LaVerne

Has anyone tried Evaporust or similar product? That stuff is amazing, and I don't see why it wouldn't work well in a tank. George
George Butz

Jan I had no problems with the threads. I made sure my screws came out of the sender mounting holes first and capped it off again after inspecting my old sender. It was bad so I removed the float and reinstalled it knowing it was going to be scrapped. One could make a suitable seal by wrapping a gallon ziplock bag round the unit and reinserting the sender leaving the open part of the baggy outside the tank and screwing it back into place. Or make a plate to cover the hole with a fresh gasket and a piece of plastic between the gasket and tank so as to save the fresh gasket. I simply sloshed the sealant after prep and immediately pulled the screws from the old sender, and removed the sender while opening the cap once I was confident any residual sealant had not pooled in the tank.


Also, I cleaned out the old cork gasket at the cap and installed a new one to insure a seal at the cap before beginning the vinegar wash. Make sure you immediately wipe off any of the sloshing vinegar and or the sealant should it contact the paint It should be noted that my old sender was bad so I wasn't concerned with it should the prep ruin it. Vinegar can be bought in gallon containers at your local grocery store. And as noted is safe to dispose of down the utility sink. Don't do it in the house though as your wife definately won't appreciate the rust in her beautifully clean sinks. I dumped mine in a five gallon bucket so I could see how much scale was removed. My tank hand been laid up for 40 plus years and though it looked clean when looking down from the cap. I was amazed how much junk had been removed. If you are repainting the tank then then you need not be worried so much about residue getting in the paint but if your plan is to save the existing paint then the extra care steps are needed i.e. A good paste wax, to act as a barrier and rinsing off the vinegar and sealant that may come in contact with the painted surfaces. It's a bit time consuming but the results are worth every step as a DIY project.

Best of luck

Bill Chasser
TD-4834
W. A. Chasser

FYI, WalMart sells gallon jugs of 'Cleaning Vinegar'. Bud
Bud Krueger

Great advice guys thanks.

Yes Jan I took note of your warning thanks.

Dave I got a heating system flush in the hardware store that contains phosphoric acid so giving this a try for a couple of days with my chairs... No petrol in it for the last 30 years.

Think I might finish it off with some vinegar LaVerne if the acid hasn't cleaned it up perfectly.

Thanks Frank for the vote of confidence, it's appreciated.

I will let you know how it all goes.


D Lamb

Fill the tank with molasses and leave stand for a week, all rust will be gone. Going to take some effort to remove the residuals though so not sure of viability on enclosed surfaces.
G Evans

Darryl. I looked up the recipe for that Protex descaler and it certainly contains phosphoric acid in the right concentration, and a surfactant, plus something else that I couldn't identify exactly but I believe to be a biocide. Use gloves and safety goggles and prevent skin contact or breathing any fumes.
Dave H
Dave Hill

Thanks funny taste off my fingers this morning....

I added a bit of water so not sure how good it will work.

Picked up 4 5ltr tubs of distilled vinegar which I believe is also white vinegar. Only €12 from a wholesaler. I am going to get this tank cleaned if it kills me.

Watch this space :)
D Lamb

Inside of the tank looking a lot better after 2 days of being agitated with phosphoric acid and 30 nuts.

Now planning to do the same with distilled/white vinegar.

D Lamb

That's more like it!
Dave H
Dave Hill

Thanks Dave very satisfying.....
D Lamb

Looking better. You getting closer
W. A. Chasser

Cheers Bill....just realised there is an optimum quantity of liquid to nuts and 10 litres is too much. Should have read your post earlier more carefully as 3 litres is perfect to allow the nuts to do their business.
D Lamb

After a day of vinegar and nuts being slashed around the tank I changed the vinegar and this is what came out.

You would be mistaken for believing I was using malt vinegar!!

Bearing in mind this is after tank clean and phosphoric acid.

D Lamb

After a week and 3 changes of white/vinegar the inside of the tank is looking much better but not perfect. I have one more 5 ltr container of vinegar in it now with nuts and going to concentrate on the side to side motion. Long process.

D Lamb

This thread was discussed between 26/11/2016 and 04/12/2016

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