Newbie Question.

[Stu]

I am refinishing my bike and I've got a tank that has bare metal around the fuel fills where the paint lifted off.Am I better off sanding the whole tank down to bare metal or sand it smooth leaving the existing paint & prime it and if so should I prime the whole tank or just the bare metal?Thank you.

 

[rex]

Hey Stu welcome to the board

Let me ask a few Q's first.First is it factory paint?If it is,is a factory production bike like Harley or Honda or is it an aftermarket bike like Titan or Bourget?Try to describe the paint edge next to the steel like is the paint chipped or is it actually lifting off the steel or another substrate?

 

[Stu]

Thanks for the welcome Rex.The paint is not factory.It's a on a sport bob tank that I'd purchased from an aftermarket supplier,brought to my local HD dealer and they sent it out to a seperate shop.The finish is about 8 yrs. old.The edge of the paint is lifting from the metal,it started blistering a while back around one of the fuel fill openings,spread and after time the paint flaked off.Thanks in advance for your help...I've learned a ton from the posts on this board in just the past week.Glad I found it.

- Stu

 

[rex]

It sounds like they didn't seal the edge of the paint or it was thin and broke down over time.Another cause would be they didn't tape off around the opening to be able to seal it up and just sprayed it with the cap in the filler hole.This is still common practice and is a sign of a poor job to me because it's harder to seal that edge and is more prone to a beating by the gas nozzle.If you or someone else redoes it have the opening taped off about 1/16" back from the edge or to the edge of the rubber cap seal,then seal the edge with clear fingernail polish or catalized clear.The gas fumes have already done their damage so at least that area needs to be stripped and if it's a simple paintjob that area could be blended out and the whole tank recleared.

 

[Stu]

Thanks again.That will definately help and hopefully keep me from having the same problem a few more years down the road.

- Stu

 

[rex]

Let me throw you a a few tips quick.The 1/16" is a guess,I screw the cap down and see where the edge of the seal hits and tape off just a hair inside the edge so it's all paint outside.A good bung and seal won't seal on the top but on the radius of the hole.This way you can get a nice bead of sealer around the paint edge but none on the radius to worry about beating up with the filler.Do teh same on the crossover nipples and petcock bung too,tape them back so the paint goes up to the attachment and there's no steel showing then seal those edges too.It's a little extra work to measure but it beats touching up a short taping or cracking the paint screwing the petcock back on.

 

[rex]

Tinys makes a good point here I forgot,the left is usually the one to go on Softails.The cause is people don't realize a gas cap isn't always forever,and those damn ratchet caps are aweful.If you have a nice paintjob with a low side cap,get a set of non ratcheting ones so as the seal gets old and crushed you can crank down a little more on it.Then you can use full tank capacity without worrying.

 

[Tinys]

Rex is right on with the sealing of the paint, but there is a certain amount of responsibility that is placed upon the owner to help prevent this from happening. 90% of blistering is on the left tank on Harleys. This is caused by filling up the tank from the right side (high side) and leaving it parked. We all know that Harleys lean pretty good and the left tank cap is now submerged in gas. Even the best sealing job will breakdown under these conditions after time. I tell all my customers to fill your bike from the left side only!! This will prevent soaking and will make your paint last longer.