VHT flameproof coating - again...

Post by **wibble_puppy** » Sun May 04, 2008 7:42 pm

hi guys,

still trying to work out how to cure this flameproof Very High Temperature coating I've used on my brake drums and exhaust manifold.

For those unacquainted with the saga, these coatings are sprayed on like paint, but then have to be cured by baking, at specific, progressively higher temperatures, until they achieve their (expensive) solvent etc resistant properties.

The thing is, the highest temperature they have to be cured at is well higher than a domestic oven (1000 degrees F

)

So someone, somewhere, must know of the correct way to bake these things! The manifold is less of an issue as I can cure it in situ by running the engine. The brake drums however are a problem. Theoretically they could be cured in situ as well, by braking hard lol. However the coating is very vulnerable until baked - it just rubs off like a powder - and I have to work on the brakes and the suspension after I put them back on the van, so they will get knocked and scratched etc. The work on the van is all being held up by this one link in the chain.

Any ideas?

Enquiries about potters' kilns have borne no fruit at all - no one round here wants to risk putting these things in their kiln in case they give off fumes etc while they are curing and affect subsequent firings of pots.

I'm thinking of resorting to a barbecue and hoping that I can get the highest temperature by sheer luck.

Thought I might ring round some local garages and see whether they have used them and if so how they have done the baking.

Help!

wibble

ps sorry to start a whole new thread but I can't find the old one

Post by **aupickup** » Sun May 04, 2008 9:32 pm

TRY A STEEL FOUNDRY IN SHEFFEILD

Post by **MikeNash** » Sun May 04, 2008 11:13 pm

Wonder if a blacksmith could help. Could they go in their forge, or over it? I expect the two around here would give it go - at your risk of course.
Pehaps a torch inside the drums? MikeN.

Post by **moggydriver62** » Mon May 05, 2008 2:29 am

Be carefull with heating ,brake drums,they may warp.

Post by **MikeNash** » Mon May 05, 2008 8:37 am

Yeah, even heating is essential. Can you put each drum over an open gas burner like a cooker ring to get even heating? A camping stove might do it. (Get it outside!) If done with a steadily, not too high and raised slowly it should be heated evenly.
The difficulty would be to know the temperature reached. A thermocouple attached would be the ideal solution, but can you tell from the appearance of the paint when its been properly "cooked"? Can anyone lend you a remote reading infrared thermometer?
A long time ago & far away I used "temperature sensitive paints", and if you bung that into google it comes up with loads, but not much help on buying them from your local stores. Anyone else know about this stuff? MikeN.

Post by **aupickup** » Mon May 05, 2008 9:30 am

simpler to use another kind of paint

Post by **bmcecosse** » Mon May 05, 2008 10:05 am

Absolutely - 1000 deg paint on a Minor ! The exhaust manifold won't get anything like that and the brakes - well, no chance. Why paint these things anyway??

Post by **aupickup** » Mon May 05, 2008 12:24 pm

exacxtly bm why indeed

Post by **MikeNash** » Mon May 05, 2008 1:18 pm

Corr! Wot a bunch of old fogies! I've painted by 9" Wolselys BRIGHT RED so people will notice! (Just got fit them now - 3 years so far.) Be of good cheer, WP.

Post by **wibble_puppy** » Mon May 05, 2008 1:26 pm

hi guys,

aupickup, bmcecosse - too late, I have sprayed the brake drums and manifold already. Why? To protect them, avoid rust (for which I personally have a bit of a dislike, it rubs off on my white velvet evening dresses) and hopefully to prolong their life. Oh, and also the brake drums are black, to help radiate = dissipate the heat generated by braking, therefore optimising the performance of the brakes. Hey, I might have been wrong. I'll live with that.

MikeNash, you have put your finger on exactly why I am scratching my head over this (just a leeetle admixture of metaphors there, move along now, nowt to see here

). Heat sources aren't all that hard to come by, it's knowing how hot the pieces have got which is the problem.

moggydriver62, you've also hit a relevant nail on the head

I guess, worst case scenario, I can't bake the paint sufficiently and it rubs off and I've wasted some dosh. But I feel it's worth ferretting away at the problem a little bit more before I give up

Thanks for all your replies, please keep the suggestions coming!

wibble xx

Post by **aupickup** » Mon May 05, 2008 1:37 pm

hammerite is good for brake drums, as the brakes dont get that hot

Post by **ASL642** » Mon May 05, 2008 8:03 pm

I painted my brake drums red hammerite as they show through the alloys!

Post by **ASL642** » Mon May 05, 2008 8:08 pm

Just a thought - would a blow torch help - gentle turning all the time?

Post by **minor_hickup** » Mon May 05, 2008 8:58 pm

Or just a high power heat gun, I don't know what 1,000 o F is in C. Perhaps if you have an upright and hub to hand you could put it in a vice with the drum on and turn it as you heat to achieve the even heating. Personally I'd buy some caliper paint, bake it in the oven and know I've saved the special paint for more suitable cause in the future.

Post by **bigginger** » Mon May 05, 2008 9:20 pm

minor_hickup wrote: I don't know what 1,000 o F is in C

537.78 C...
a

Post by **alex_holden** » Mon May 05, 2008 10:03 pm

I used a big propane blowtorch to cure the high temperature paint on my Riley drums, however I wish I hadn't bothered as it is flaking off after a few months stored indoors. Smoothrite seems to work better for brake drums.

Post by **callyspoy** » Mon May 05, 2008 10:31 pm

erm, can you buy caliper paint in standard shops? factors halfords rtc? ive only ever seen VHT sorta stuff. but i will b painting the calipers on the mog very soon...

Post by **ASL642** » Mon May 05, 2008 10:54 pm

Just how do you do that BG? I recon you swallowed the Encyclopaedia Britannica at birth! It would take me all my time to turn on the calculator!!

Post by **polo2k** » Mon May 05, 2008 11:10 pm

Has anyone ever tried BBQ paint?
Never really thought of it before.
As a reference point, a soldering irom gets to 300 Deg C so 600 shouldnt be too hard to get to.

Also, I dont mean to throw a cat amongst the pigeons or upset anyone (If I do then I apologise in advance)
While its nice to have them immaculate, they are brake drums. They are illusive little buggers and not often the main point of consideration on a car. As long as they are black(or what ever color you want) and not peeling, does it matter about the finish on them?
Like I said, I respect the kind of guys who can jack a car up and put mirrors beneath, but isnt this hobby mostly about enjoying the car
(I shouldn`t think that Sir alec Issigonis payed much attention to the astetics of the brakes)

Please be gentle on me, im just trying to settle into the community and find my feet.

:):D

Post by **alex_holden** » Tue May 06, 2008 7:56 am

polo2k wrote:Has anyone ever tried BBQ paint?

Yes, that's the stuff I used. I don't recommend it.