smoke box temperatures

[fergusonjim]

Please can anyone tell me what temperatures to expect for the smoke box of a 3 1/2" gauge loco. The smoke box is supposed to be painted in black gloss. The highest temperature rating for gloss paint that I can find is 120 degrees C. A high temp satin finish paint is good for 600 deg.
Your comments would be appreciated.
Jim

[chris vine]

Hi Jim,

Reeves do a smoke box black paint. I have not used it myself though.

There are a load of paints made for stoves etc. Forrest is a good make range is called stovebright. Not sure they do a gloss though.

I have never had much success with the exhaust manifold paints, they don't seem to come up very black, certainly are not gloss at all and are not always very tough wearing.

I found Precision paints black gloss is ok up to around 200C from memory. I tested it in the oven. It has withstood my 7.25" gauge smoke box, but this has not run on a continuous circuit where it could get hotter....

Chris.

[mott]

Hi Jim, I was at a talk recently by the owner of Precision Paints. He said to use black gloss on the smoke box and over 3 or 4 steamings it would let down to the duller finish usually found on smoke boxes. Mott

[ron]

Have you checked out Barby paint from the likes of B&Q, I tried it on a ST 504 boiler side panels, it is glossy but it eventually peeled, can't remember what temp it was supposed to withstand but I don't think the smoke box of a loco would be anywhere near as high a temp as the 504 panels.
Agree with Chris, exhaust manifold paint doesn't stay black, ends up a sort of mid grey, which looks OK on an exhaust manifold but not much good for a loco.
Ron

[teakfreak]

I've tried aerosol barbecue paint from B&Qon my 4" traction engine smokebox and it lasted two steamings at most . At the moment I've stopped repainting it to allow all the current stuff to burn off before trying again with something like the 600 deg. woodburner paint. Does this need a special primer or does it go straight onto bare metal?

[chris vine]

Hi,

The stovebright stuff is best with their high temp primer. The only thing I could never get straight with their tech help desk was how it would be on brass. It is not designed for that so you would have to experiment. (for brass I would certainly grit blast it first)

C

[teakfreak]

Thanks for the info - I'll try again after a few more steamings!

[gilesengineer]

For smokeboxes I use the aerosol black Smoothrite (of hammerite fame). I've used this on two locos now, and it has been faultless over five years or so and couontless steamings. It hasn't peeled or discoloured, and was very easy to spray on.......

[charles]

wood burner paint is put straight on to the bare metal it does not liftof or burn of as for painting on brass one requires a good etch primer the type that is used in the aircraft industry
one can sand blast the surface first but be verry carefull doing that belive it or not all those fine particles will distort some pannel surfaces what it does is stretch the surface and tends to bow the metal but if you are carefull and do it lightly you should be ok i have seen a lot of modles that have been spoilt by badly prepared surfaces and incorect procedures chipped paint is the bigest problem using a good etch primer helps to stop this problem especialy on aliminum ,,brass it is best sprayed on lightly 2 coats thinly then your top coats can go directely on top of the etch primer

[JohnP]

I borrowed an infra red camera from work and measured the chimney of my Sweet Pea at over 170°C. That was just sitting on blocks with the blower on, rather than working hard.

Cheers

JohnP

[albertsell]

Hello Jim,
On my traction engines I use BBQ type black spray paint, I find the only way the paint stays on is to paint onto spotless clean bare metal (steel) as thin a coat as is possible to cover.
Bye Albert

[freddo]

Jim

200 C is probably expected in a smoke box.

A good buddy of mine (with whom I am currently staying in transit on my way west), Dr John, tells me his Simplex ran for many hundreds of hours with car engine black gloss on the smoke box, with no problems.

Freddo (currently in MY)

[Chris Kelland]

Hi Jim,

Pop down to your local car shop and get some Sperex exhaust paint which is in spray cans or some motorcycle cylinder black which is a spirit based paint both seem to work well though I prefer the cylinder black.


Chris.

[ausdan]

I have had good success using VHT brand in Aus (used on the space shuttle)

www.speco.com.au/vht_engine.html