Fuel Tank Failures: was installation method ever changed?

[snaponron1]

I am in the market for a used 21 Parker. The threads on fuel tank failures have me concerned however. Are tanks now Coated? Perhaps installed differently to avoid corrosion? If so what year were the changes implemented?

Thanks!

 

[warthog5]

Yes and No I'm speaking of all manufactures.....Most will never spend the extra to coat a tank....After all... It's a expense and their idea is it will be way out of warranty when it fails. Some companies have gone to plastic.

 

[Inshore Chaser]

I am in the market for a used 21 Parker. The threads on fuel tank failures have me concerned however. Are tanks now Coated? Perhaps installed differently to avoid corrosion? If so what year were the changes implemented?

Thanks!

Have a 2021 21 DV....tank is epoxy coated.

 

[Hammer79]

I have a 2018 21' DV CC, tank is also coated.

 

[Andy]

I am in the market for a used 21 Parker. The threads on fuel tank failures have me concerned however. Are tanks now Coated? Perhaps installed differently to avoid corrosion? If so what year were the changes implemented?

Thanks!

Here's an interesting article on marine fuel tanks. I know the article is 'headed' Diesel Fuel Tanks, but the tank information is universal.... Near the top of the article is information on epoxy coating of aluminum tanks, and why it may not be a great idea. Also, some interesting information on the expansion of poly-tanks further down in the article; expanding once fuel is added, and having to compensate for that....

https://www.passagemaker.com/technical/diesel-fuel-tank-design
Excerpt;

 

[warthog5]

If it's 60gal or below.... I stick with 1/8in.....Larger [like we have] I jump to 3/16in, while the original is 1/8in.

Provided it is exposed to circulating air.

Those ARE key words and the air does Not circulate in the bilges of these boats.
Instead, it is a damp , cool spot that changes daily with temp changes thruout the day.

It cam be made to have circulation, if you do what Kevin did to his.....When the boat is put up....Piehole covers are popped out and solar cover installed....But must be shielded from rain.

However....That part of the tank that is imbeded in foam and moisture has crept in will hold that moisture against the alum and defeat it's self healing properties.

Therefore.......the formula of 2 coats of Coal tar epoxy and glassing over the foam to keep ALL water out of foam has been the way to manage this.

 

[Togntime]

Does a profile need to be added to the tank before applying the coal tar epoxy?

 

[warthog5]

I think you mean Primer?

Here is how I do it...
Clean the tank with wax& Grease Remover, using 2 rag method.

2rag method = apply with one rag wetting surface....With outh rag Dry it BEFORE it evaporates....This lifts contaminates. Don't let liquid dry on it's own....Wipe it dry.

Next. Tape up openings in tank......Then 80gt on DA sander the whole tank.

Then W&G Remover again with 2 rags.

Use rolled small roller covers that are Epoxy friendly and the short foam style works well. West System epoxy has them.
Warning! Using roller covers from a typical box store will just give you a mess in about 3 to 5 min of exposier to epoxy.

Mixing Coal Tar Epoxy..
Typically it is 1 to 1 , however....I have seen some different formulas.

a power stir for Pt A and then another power stir...for Pt B

Mix 1 qt of material 16oz pt A = 16oz pt B......Stir it WELL Stir Time 2min.
1 of the #1 failures with any epoxies is failure to stir it enough.....

Pour Coal Tar in one of those small roller trays....and Go to work.
Well ventilated area....It stinks like Tar.

2 coats.

 

[Togntime]

Thanks! I meant surface profile like you're adding with DA.