brembo refurb, what did i do wrong?

[cupra-db]

Hi guys, ive tried spraying my brembos twice now, the first time the paint bubbled up, loads of tiny bubbles, i rubbed them down and now this has happened,

how do i repair it? and what have i done wrong? i still have to add decals and laquer so will this hide this effect? any help would be great as im gutted with the result, thanks guys

 

[UncleFester]

Looks like too many coats / first coat hasn't dried before you applied the next coat(s)
.

 

[andycupra]

too muich pant in one go/coat and or not waiting for previous coat to dry. (as unclefester has said)

What paint are you using?

Some paints you can also wait too long between coats interestingly. eg need to leave it 3 mins before seccond coat, but more than 3 hours then wait for 24..

Lots of thini coats of paint are always better than a few thick coats.
For some paints like hammerite if the coat is too thick it may never ever dry!

sand it down. then apply very thin coats and make sure you follow instructions regards timing.

 

[Muttley]

Looks like a variety of orange peel, caused by the paint not being able to self-level. Usually this is because the coat has been applied too lightly, or from too far away, or the previous coat has dried too much, or - well, spray painting has a lot of variables.

The advice given by Uncle Fester and andycupra is good: Can you tell us a little bit about how you applied the paint to the calipers - number of coats, drying time between coats, heaviness of each application, how far away you were spraying from, what kind of paint it is and so on?

Lacquer will not hide the problem, it will emphasise it. From the look of the finish, I'd guess you've sprayed on several heavy coats at fairly short intervals. If you're using a rattlecan, you need to either spray several light coats (not heavy enough to cover completely) giving the first coat enough time to level but not set, or slightly heavier coats but leaving it enough time to set, and rubbing down the set surface between each coat.

Some guidelines here

http://pc.dupont.com/dpc/en/US/html/visitor/s/trouble/PDSG_Home.html

 

[cupra-db]

hi guys, i used hammerite smooth in a rattlecan, the instructios say to aplly light even coats from 6 inchs away leaving 15mins between coats, i did this to the best of my knowledge apart from being further away than 6 inches, but i suspect my coats were too thick, however this peal effect was much worse after my first coat which was def my thinest coat? could temp be an issue as i did it in my shed, i should be shot instantly before being allowed near a spray can! so you would leave to dry rub down and start again?

 

[rallynut]

did you degrease them?

 

[cupra-db]

yes mate,

 

[Muttley]

Hammerite is a bit of a special case. It can take a very long time to set completely. I'd say your coats were too thick, a light coat should not completely obscure the underlying colour on the first application. The reason for multiple light coats is to let the solvent evaporate but still leave a liquid layer that the next coat can dissolve into and continue the levelling-up process as one coat.

It might be worth trying to take some Hammerite thinners to it to see if it will come off that way. I suspect that trying to rub it down will result in a lot of clogged sandpaper as the paint hasn't set.

But you need to get back to the metal, or to let the paint set (can be weeks with Hammerite) then rub down to a smooth finish. If you decide to let it set, you should be able to rub down the paint to a smooth finish then polish it up to a gloss without any further applications. You'll have to wait a long time, though.

 

[cupra-db]

I hate being so useless at this stuff, cant believe ive done this, so if i leave them and sand them down your saying it should still be a gloss finish and i can lacquer straight on them?

 

[Deleted member 12147]

The thing with the hammerite spray is that it is very runny/thin and very easy to get carried away with putting it on abit thicker. Use the techniques mentioned above and make sure they are completely dry and the paint has hardened before you put them back on. IMO I'd leave them at least 48 hours to dry.

 

[cupra-db]

Im so annoyed as they were fine but the backs needed a bit more cover and then this happened. Seriously gutted because i knoe ill **** it up again.

 

[20v roper]

Be alright mate, can you practice on another metallic surface beforehand to give you some confidence before redoing the brakes?

 

[Deleted member 12147]

Tbh once they are on the car with the wheels u can't see the backs so I would have left them if you had them ok the first time. As long as the part of the caliper that can be seen looks good nobody will ever know of any c*ckups u do on the rest of the caliper.

 

[cupra-db]

You your right. I just thought id try and do it rihht. Live and learn as they say. Would heat help the drying time do you think guys? Someone even suggested putting them in the oven after dinner? Lol. Thanks. Daz

 

[Deleted member 12147]

I used a heat gun to help but even then the paint was still soft 24hours afterwards. I suppose it depends on how many coats you apply, I nearly used a whole can on mine. Just press your finger nail in the paint to test if they are completely cured, if it leaves an indentation then they need to dry for longer.

 

[cupra-db]

Mine are leavin finger prints if i push.lol. Been 24-36hrs. Im gonna sit them on top of my rad.thanks

 

[UncleFester]

If you're going to speed dry them, you need a nice even heat over a period of time - short sharp bursts won't help.

Hammerite is an arse, it doesn't mix well with other paints and that includes lacquer.

I prefer ordinary paint that is designed to be used on metal - preparation of the surface to be painted is absolutely key and you MUST use products that are designed to work with each other.

 

[cupra-db]

So what would you recommend i do as i have to fit decals and i assume they will just fall off unless laquered on? Thanks for all the help guys. Been awesome on this. Daz

 

[ibiza_95]

if theyre fully stripped down id use thinners or paint stripper to remove thepaint and start again...

 

[UncleFester]

Decals as transfers go on before you spray the clear coat If you want them heat and weather proof Or you spray them as a template on top of the colour coat