Best Primer for Sandblasted Aluminium

[LukLagun]

For the last few years been using local powder coated to powder-coated brake callipers that I have been refurbishing as a hobby. As you know powder coating is a quite thick coating and is not always perfect ( spider webs under the clear coat/ gassing pitting holes/ edges not always fully covered or small particles of dust stuck in front ) and waiting time for each set is around 7days and sometimes 14 days if I'm not happy with the finish ( pin holes/ cracked powder).

So I'm looking to start spraying them with proper high temp paints and looking for the best primer to use on bare usually sandblasted aluminium. Had a look through eBay and there are lots available. I'm not sure which would be best for my needs. Also sometimes some callipers need pitting or damaged areas filled to be smooth only for a nice look not for main repairs is there anything like high heat filler or something else that I could use for filling uneven spots???
Thank you for any advice !

 

[Erie Fred]

Isn't there a home "alodine" kit or something ?
Might do that quickly after blast, and then paint over it.

 

[Blobber]

7-14 days to set?? powder coat is done/finished after it comes out of the oven

 

[Dcal]

I don't know of a proper high temp high build primer.
Most I've seen are pretty thin, like the hight temp paint.
It also depends on how hot they are going to get.
Epoxies are great for aluminium but don't like temps above 90 or 100 degrees which I'd say is too low for front brakes.

Ceramic coating (Cerakote) might be an option.
I've a couple of calipers I intend to try it out on shortly, but I know it won't cover any defects.

@. has had great results with it on calipers.

 

[LukLagun]

7-14 days to set?? powder coat is done/finished after it comes out of the oven.

By set i mean to do a set of callipers. If the finish is ok then I get them back once are out of the oven. But sometimes they had to redo them and that takes another 5-7 days.
And there are always minor imperfections plus I'm using alloy plugs and if they don't remove them for acid dipping and washing then i have to spend another 2h cleaning them out

 

[LukLagun]

I don't know of a proper high temp high build primer.
Most I've seen are pretty thin, like the hight temp paint.
It also depends on how hot they are going to get.
Epoxies are great for aluminium but don't like temps above 90 or 100 degrees which I'd say is too low for front brakes.

Ceramic coating (Cerakote) might be an option.
I've a couple of calipers I intend to try it out on shortly, but I know it won't cover any defects.

@. has had great results with it on calipers.

I have found some on ebay etch primer for aluminium that can take up to 250degress so I'm guessing that should be fine for my needs they also sell top coat paints that can take up to 220degress.
I have seen a few done in cerakote but as nothames mentioned it will not cover imperfection and you are restricted with colours.

 

[LukLagun]

Cerakote looks great on flattish aluminium callipers, it doesn't look so good on cast steel ones. This is h series red (oven baked). The c series which comes in spray cans is also good for callipers and is air cure. It is a thin coating. I don't like thick costings on callipers as it can interfere with the pads etc.
Here's some I did for a customer
View attachment 394674

View attachment 394675

Same here pal as over time thick coating on pads guides will restrict their movement and will cause uneven pad wear.
I usually mark the spots i want masking and I use alloy plugs for masking pistons inserts.
Going to do my own 6pot & 4pot calipers for my van as i can't get matching colour in powder.
Gets quite frustrating when u have to explaining to customers why they need to wait another week

 

[marlinspike]

Buzzweld do a high build etch primer which might cover some imperfections but don't mention the temperature rating.

High Build Etch Primer - Black - Aerosol

Highbuild etching primer in Black. Excellent adheson, build and spray characteristics

www.buzzweld.co.uk

 

[500e]

Aludine is a good start to pacify the surface.
Not that expensive and goes a long way + simple & quick to use