Marc Shaw

With the rear brake calipers off, I treated them to a full coat of red VHT paint (I know - the picture looks orange, but it isn't ), new high-temp decals, a coat of VHT clear coat, and new bleeder valves/caps.

The can of VHT paint says to bake at 400 F for an hour to increase the paint's chemical resistance (to brake fluid, for example).

Is that too hot to bake a caliper at with seals and pistons in place??

Thanks. Marc

Larry Herman

Usually you would bake stripped calipers and then install the seals, pistons & boots. If they are assembled like yours, I'd probably go a little cooler, like maybe 350 or so; just my feelings. As an aside, your calipers can certainly get up to that temperature during racing/track driving.

Marc Shaw

Thanks Larry - I did not rebuild them but rather just cleaned them up a bit.

I figured that they got that hot at the track but was not sure if 400 F was a little TOO hot.

I know Chris Walrod will bake the powder-coating he does with the caliper assembled but I do not remember what temp. he does it at (so what is safe).

Marc

Gus

I am no expert at this but - Before I would bake any rubber element at 400 or even 350 I would run a test on an old seal or dust cover to see what happened to it if you baked it at 350-400 for 1 hr. While calipers get hot - they do not sustain that amount of heat for along period of time. The rubber is likely to undergo damage or fatigue if you bake it for that long -
I had my calipers powder coated. I split them and removed all rubber parts before i baked them -
Run the test first you will make your own discovery-

Indycam

Why not pull the pistons and seals ? You could have a look see at all the parts , clean them up , bake the paint worry free and then put them back together with brand new seals or the old ones if they still look good and have beautifully greased pistons & seals .

Marc Shaw

Thanks all.

I found Chris Walrod's thread and he bakes the calipers at 385-400 F for 20 minutes with no harm done. I will do the same. It will not be as good as baking for an hour but it will do until the paint gets heat cycled by use.

Because I am installing front Big Reds this winter and rear Big Reds next winter so can't be bothered for just 1 season of use!

Marc

Indycam

Have you ever redone calipers before ?
I don't think I could install a set of calipers without pulling the pistons first . When ever I have set of them off , I always pull the pistons out to see whats going on inside .

MARC A. 964 C4

My $0.02... I only just noticed this... Not only has the UHT Red spray paint dried hard, proof to that was the fact that the clear coat (resin) spray did not eat into it and crinkle the surface, but obviously many hours if not days have passed before you actually took these photographs. If I’m right, follow this logic...
Not only has the UHT Red spray paint dried hard as a skin, but over it you have again created a skin even harder, with the clear coat (resin). My fear for your callipers is everything that has already been said by others but... If also... The under surfaces of paints/primers are still fresh /not cured because of the clear coating (resin) protective skin that as closed the micro pores of the UHT Red spray paint for breathing and curing... Then... With an extreme heat to the metal causing expansion you risk damaging the already hardened surfaces that are well and truly hard. The extreme heat to the still fresh /not cured interior paints/primers then withdraws the volume resulting in exterior surface micro movement/shattering... Either the entire UHT paint is baked while uncured or you allow it to cure under room/application temperatures... The clear-coat (resin) is neither UHT nor the decals... Too many IF’S for me Marc, considering such an already beautiful end result...

When I UHT Paint Marine Engines, the curing process is one or the other, but not the two at the same time... Never a clear-coat (resin)...

If not too late, follow the logic; allow them to continue as is... If baked in the oven, I hope it worked out... Maybe you have Lady Luck on your side, I hope so...

From here,
Marc...

PS... The domestic oven is made for Pizzas, not to cook like-new calipers...
Who knows, maybe this will be the newest trend at Rennlist Avenue and 964th Street...

MARC A. 964 C4

Hey Marc...
I know... "No news is good news". And perhaps my... "Better late than never", was in fact the truth of the matter. However, there were members that offered advice to your quandary, and I for one because of the... "Curiosity that brought me back", to your thread this morning, was surprised not to get the usual output from your DIY’S results for us to read and discover and learn from. (*) Perhaps the results are else where or were spoken about sooner, but I have not found them. Needless to say, I'm interested in Porsche restoration. And the new to me, North American products are of interest... So,...

"How in fact did the callipers come out in the end"...
Oven "cooked" or naturally "dried"...

Thanks for your input.
From here,
Marc...

PS. (*)The time zone differences of 6 to 9 hours, in my case puts me always on the outside looking in... I can only read the following morning what was "chatted", the night before. I always miss the, direct and in colour. Oh well, nothing new there...
"Life could be worse"...

BTW... Where's a photograph of your, Family Car... Would love to see it!!..

Marc Shaw

Hi Marc,

You have not missed anything as I have not done anything further yet (I had to go back to work ).

I did e-mail the decal maker to see what temperature his "high temperature" vinyl decals would withstand and I bought the largest toaster oven I could find (I doubt my wife would be uderstanding about using her oven).

I have been considering what you wrote (layer of clear coat over paint altering drying) so I am undecided about what I shall do yet. Even if I don't bake it, I can still use the toaster oven as I just ordered a powder coating machine too.

I'll let you know how it turns out.

Marc

MARC A. 964 C4

Hey Marc...
Thanks for posting an answer... It’s like the telephone when you say, "good-bye" to someone that has said "hello"...
Silly question... Why the email to check out the Porsche decals...
I assume you applied them to the red painted surface, and then clear coated over them for the protection that is needed... Even if only washing the car down, let alone severe heats from track / street use (or ovens?) the decals need more than the glue that sticks them in place to maintain them in place...

Sorry to go on and on about your painted callipers and decals, but that’s what I'm good at...

Painting / Restoration is right here, I can maybe help you Sir...
Engine rebuilds, etc... Sorry that’s further down 964th Street...

From here,
Marc...

PS... You do not have to post me an answer to this..."Silly question"...

Smokin

Marc. If your intention for using the clearcoat is to seal the decal... Why not just skip the decal? They make a Porsche stencil so after your paint cures you put the stencil on, mask the calipers and then use hi-temp spray paint to spray paint on the Porsche name. Then there is no need for the clearcoat.

kris

Marc, you can not just mention this without any further explanations Could you do the rims with that also?

Marc Shaw

Kris,

My little toaster oven will not fit rims - I was going to start with small parts and work my way up to fancy stuff. I'd have to get an old pizza oven to fit rims.

I have an old set of small-piston C2 rear calipers I think that I'll try to make look pretty, just for practice.

I'll have to run them through the new benchtop glass-bead/sand blaster first.

Marc

Marc Shaw

I baked my rotors today at 300 F for 35 minutes with no problems (I removed the bleeder valve covers as I was not sure of their temp. resistance).

Paint looks exactly the same and the decals are unchanged. Based on what the VHT can says, this will help with chemical resistance (ie. brake fluid).

I'll try just putting a decal in the oven tomorrow and see how it withstands hotter temps.

Marc