Paint Reacting/Filler Primer

[onc onc]

Well i just started going over some rusted and blistered seams that need doing after last years Rustoleum job on me van ( i was well chuffed with the finished job ) but however the rust has come through again, This time i am just doing the seams, as i have loads of paint left over and under stand that it should blend in ok BUT the problem im having now is i am using a Filler primer to go over where i have sanded and filled but it seems to be reacting to something and bubbling up, its HALFORDS filler primer and yellow in colour, its not doing it all over just in certain areas, Anyone else hed this problem

Cheers
Onkers

[jamesc76]

have you cleaned up properly before putting it on???? even the slightest silicone or grease will react, you need panel wipe first!

[onc onc]

Well i have rubbed it down to bare metal now and it is still lifting around the edges where i have feathered it back to the paint, im guessing its reacting to what ever is under the original paint

[ninja.turtle007]

Halfords filler primer is rubbish.

[onc onc]

I may have to agree with you there, does anyone know of a more sutable product that wont give me a load of grief,

[weldore]

could it be reacting to the rustoleum ?
i had this problem when i did mine a few years ago..the guy before had used hammerite and the acrylic undercoat i used reacted as did yours

[weldore]

oh..i ended up using barcoat as the primer

[onc onc]

could it be reacting to the rustoleum ?
i had this problem when i did mine a few years ago..the guy before had used hammerite and the acrylic undercoat i used reacted as did yours

I dont think its reacting to rustoleum, i did a patch further up the panel just to see and no reaction there, i,m starting to wonder what is underneath the topcoat because i have a feeling the van has had some spray work done around the area i,m trying repaint.

By the way what is barcoat.

[weldore]

barcoat is a ready to spray or brush on isolater.i think its alcahol based

http://www.qpaints.co.uk/barcoat-quick- ... er-1l.html" onclick="window.open(this.href);return false;

im no painter by the way...but when i did mine i wanted to see what the finish would be like after sanding, befor i put the rustoleum on.it was a doddle to spray on and showed up any problem areas,just like primer
someone with more experiance of painting might suggest a better method mind..tis just how i got round the problem..also make use of the vactan..i didnt and mine started to rust through after a winter too

oh and mine only reacted with the feathered edges

[bennwedge]

halfords paint is rubbish. ive had lots of problems in the past with it reacting badly . the only solution is to bury the stuff deep underground so that no one will ever find it and go to a proper car paint suppliers

[onc onc]

Thanks for all the help fellas , it looks like i shall have to treat it to a coat of barcoat to sort the problem, the Halfords primer has hit the bin


Cheers
Onkers

[New Kentish Campers]

Well i just started going over some rusted and blistered seams that need doing after last years Rustoleum job on me van ( i was well chuffed with the finished job ) but however the rust has come through again, This time i am just doing the seams, as i have loads of paint left over and under stand that it should blend in ok BUT the problem im having now is i am using a Filler primer to go over where i have sanded and filled but it seems to be reacting to something and bubbling up, its HALFORDS filler primer and yellow in colour, its not doing it all over just in certain areas, Anyone else hed this problem

Cheers
Onkers

This problem is known in the trade as 'pickling' Its almost always caused by there being too much thinner used in the paint mix [probably celluose] or, the wrong thinner used. Air dry paints use 2/3 types of thinner. A slow one when the air temperature is hot so that the thinner evaporates slower which avoids dry spots/low gloss in the paint film. A medium one for medium teperatures, obviously, and a fast one for when the air temp.is colder.

If the wrong thinner is used, and or, too much paint is being applied too quickly, the solvent in the thinner cannot do its job and wont evaporate, effectively sealing in some solvent.

Any new paint applied over the top, again an air dry product will contain similar solvent. This will soften what is underneath, and the two lots of solvent basically have an argument and gives the pickling effect. It will be even worse where the old paint has been sanded back into other layers of old paint - like the rings on a tree for instance so new solvent will attack these rings even more.

If it were me, then I'd sand back the new paint, etc again, and apply some brushed on 2 pack primer filler/surfacer [pay due attention to the H&S issues that come with this material] allow it to cure, and then prepare the new surface for the new paint topcoat. That usually does the trick.

Doug.

[bigherb]

Doug sums up your problem pretty well. Actually Halfords primers are pretty good and cover most substrates, but will react with previous incompatible solvents. People usually have a problem with them because they are apply it too thick, the paint skins over before the solvents evaporate which can show up six months later as crazing or solvent blows in the finished paintwork, like most paints you have to build the paint up in several thin coat with adequate drying time between each coat, you cant rush paint work.
One other option to your problem if you are using Rustoleum as the top coat is to use a synthetic coaching enamel primer which can be applied with a brush and then flatted smooth.

[onc onc]

I find that quite interesting about applying the primer to thick and spraying thinley to allow solvents in paint to evaporate, i seem to have sorted problem on said wing however i,m about to do nearside rear wing so i will try the small amount of spray i have left on that side and see what happens, i hopr its one of these and not one of these
Cheers
Onkers