trouble with paint

[new to this]

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ive been trying to paint my header tank,but the paint keeps reacting,the tank is alloy ,so used etch primer first,then primer a lot of primer to fill the marks from the grinder,let it dry about 2 hours, then sprayed the top coat on,it came out with little spot holes every where,rubbed it down again,resprayed again but still reacting, any ideas ?

dave

[wilf]

Possible silicon contamination?

[new to this]

Possible silicon contamination?

wilf

how would you get silicon contamination ?

dave

[Ian Durrant]

Silicone contamination usually gives you fish eyes. That looks more like one layer of paint reacting with another from the pictures. silicon contamination can happen really easily, especially if you have been using silicon spray like "back to black" nearby, it seems to drift in the air and get on everything.

[dasadrew]

I think the statement of "etch primer first, then a lot of primer, then let dry 2 hours" might be a clue.

That sounds mighty ambitious. Even after a very light mist coat of 2-pack primer I'd let it dry overnight. If you need to apply a lot of primer, then you should allow each thin coat to thoroughly dry before applying the next coat. Build up the primer thickness very gradually. If you're not using 2-pack primer, then add a lot of time to the above recommendations!

[Jeff]

What paint are you using?

Looks like you have put it on too thick or too heavy.

Let it dry a day or two, rub it down with 600 - 800 wet and apply thinner lighter coats.

I don't think there is silicone there or wax.

More lighter coats are better than fewer heavy coats.

Jeff.

[new to this]

What paint are you using?

Looks like you have put it on too thick or too heavy.

Let it dry a day or two, rub it down with 600 - 800 wet and apply thinner lighter coats.

I don't think there is silicone there or wax.

More lighter coats are better than fewer heavy coats.

Jeff.

jeff

do you think i would have to start again take it back to metal

dave

[new to this]

Silicone contamination usually gives you fish eyes. That looks more like one layer of paint reacting with another from the pictures. silicon contamination can happen really easily, especially if you have been using silicon spray like "back to black" nearby, it seems to drift in the air and get on everything.

ian

what does fish eyes look like ?

dave

[new to this]

thanks drew

[Jeff]

Fish eyes are small little circles which normally show there is wax or a contaminant of a sort which you have not got.

It's only a small piece so I would take it back to ally and start again but in between etch primer and primer and top coat, flatten back with wet paper and degrease with petrol. I used to use meths until a sprayer told me to use petrol and it's fine.

Looking at the pics I would guess you have put too much on too quick.

What paint are you using?

Jeff.

[new to this]

Fish eyes are small little circles which normally show there is wax or a contaminant of a sort which you have not got.

It's only a small piece so I would take it back to ally and start again but in between etch primer and primer and top coat, flatten back with wet paper and degrease with petrol. I used to use meths until a sprayer told me to use petrol and it's fine.

Looking at the pics I would guess you have put too much on too quick.

What paint are you using?

Jeff.

jeff

2k in a spray tin

thanks dave

[jakesmig]

Looks like a thinners reaction to me, perhaps too heavy an application of the top coat. try using more sparing coats and build up slowly.
John.

[73stagman]

typical solvent reaction by the look of it. You hav eused a proper etch primer for Alloy? probably you have but then by loading the primer onto the top you have more than likely trapped solvent in the layers of paint.
As others have said you need to let it dry out more before laying on the following coats. You can try to heat the headers slightly to flash them off quicker which will drive out the thinners / solvents but dont get them too hot or it will all come off again.
To recover the job you just need to flat right back until there are no signs of the solvent reaction. you might get back to bare metal but if you go carefully you should get back to where you put the paint on to heavy. By the way when you are painting, as you spray on the coats let each one flash off fully before laying on any more ; very light coats is the way to go. If you get a run or think its taking too long to get good coverage dont try to put more paint on .... go away leave it to dry and then flat off and go again after that.