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What do you guys paint new cast iron drums with?
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I use black semi gloss rattle can rustoleum -
Good deal, I will get a few cans tomorrow. Thanks, I was hoping not to get out the spray gun and mix up some expensive stuff.Comment
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If you live in a mountainous terrain or are an aggressive driver then braking can get the drums pretty hot. Some paints will blister. You may want to use hi-temp black barbecue or stove paint. Last set of brakes I did started with a wash of Ospho over the fresh metal followed by Rustoleum 'High Heat' paint.Comment
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I have also used black brake caliper paint. Bad part is it takes forever and a day to dry. Rod"Much of the social history of the Western world, over the past three decades, has been a history of replacing what worked with what sounded good." Thomas SowellComment
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I use the Rustoleum high temp black. Before I spray them I clean them with acetone and let dry for about fifteen minutes and then spray on thin coat. Just enough to cover them and they will last a long time.Comment
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Painting brake drums reduces the drums ability to dissipate heat...Comment
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Actually this is not exactly true on two levels.Originally posted by CM2 View Post
First, as Bill mentioned, rust. Aside from ugly the rust is porous and full of trapped air, making it an effective thermal blanket.
The paint will provide slower thermal transmission than metal so a thin coat is recommended, as it has little insulating value. If you put gobs, layers and layers on then, of course, you will see some reduction in energy transfer, but still likely less than you will get through red rust.
Second, if you use black paint it will both absorb and radiate thermal energy differently than a reflective machined new drum. Here's what happens (warning- physics geek at keyboard!):
When photons strike a surface they either are reflected or absorbed. Everyone pretty much understands that a black surface will absorb heat faster than a reflective one. Infrared photons are very good at knocking electrons to a higher energy state.
OK, that is the opposite of brake drums- they are already hot and need to dissipate heat. Substances that easily send electrons to higher energy states when they absorb energy are also better at EMITTING infrared photons when the material drops electrons to a lower energy state (cools off). Shiny reflective metal, as well as white paint, do a much poorer job of losing heat by emitting photons than black substances. Ever wonder why all engine radiators are painted black? Try white and see if it cools as well.
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Given the porosity of rust and its roughened surface basically expanding the area needing to be cooled Id say rust is a better cooling media than the smooth paint job....millions of truck and car drums cant be wrong..given the braking dynamics in a model A I'll surrender at this point,odds are if the drums get hot enough to burn off the paint that's the least of your worries.. -
On my scooter, when passing by a BLACK Van, very little reflected HEAT. When passing by a WHITE Van, WAY MORE reflected heat.
Dad Sweating
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Just replaced my front drums and had them powder painted red to match the rear drums and wheels. Original powder paint was applied in 1998 and except for some chips on the radius rods, everything looks like new.Comment
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Most of the factory photos show gloss enamel on the drums, etc. We have rocky mountain fronts and standard rears that perform well with the rattle can enamel. We also found that the $1 variety gloss black cheapo from Home Depot gives just enough coverage, and the flat back same stuff is fine for radiators. They are thin enough to allow for touch up without heavy build up.Comment
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I need to have some original-style drums turned. What is the minimum wall thickness before I should not use the drums any longer?07-22-2019, 09:26 AM -
Today I went and retrieved the two cast brake drums and backing plates first thing I did was use one of my 12" Vernier calipers and the drums are 12" so i guess their off a 32 to 34 so can you put them on a 31? I called Brattons, Snyders and Smith and jones none of them had 12" shoes....10-12-2020, 03:58 PM -
I am doing the brakes on my ‘30 Tudor. I believe the rear drums are steel. They measured out at 11.021 and the thickness measurement at .132. They are quite smooth with no grooves. I think they are good to go as is. Do you think I should have them machined to make them perfect? Can steel drums be machined safely? The front drums are cast iron with about 12,000 miles on them. Very little wear. I...03-20-2021, 02:43 PM -
When were reproduction cast iron drums introduced? The key word being reproduction. I have some cast iron drums on my A but they are not as well machined as those currently available from vendors. Decades ago it was the late 31's from Ford that were highly sought after. I'm assuming because nothing else was available. I'm trying to date the drums I have. Here's pictures of a current drum and...04-02-2018, 04:50 PM -
Hi, A friend of mine Just gave me a bunch of model a parts and there are two 31 cast drums they are very nice shape they were used on a trailer for eons for around two different farms. I am wondering if anyone is using this type of drum and is it worth changing out my steel drums for these cast drums. I have webbed lining from snyders on my car. Thank you10-11-2020, 09:40 PM
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Good morning guys. Still working on my rolling chassis and now looking at the rear brake drum/ hub assemblies. I know that I should be buying new units with cast drums, but that is just not going to happen at this time. The existing pressed drums look like new, but the hubs look like they have never seen grease. I would like to switch the usable drums to a better set of hubs. I speculate that...05-20-2021, 06:37 AM -
Could someone explain to me why I would want cast iron drums on my car over steel drums? Also, I know I will get many different answers but if my generator is working fine, what is the advantage of replacing it with an Alternator? Thanks Hugh12-02-2018, 10:28 PM -
I have an ammco 4000 brake lathe,
resurfacing / truing the front drums is no problem as the 1" arbor and standard race adapters work beautiful. The issue is the rear drums as the 1" arbor will not slide through the end of the hub because it has a 3/4" opening. After doing a little research i found that ammco sells an 11/16th" arbor which comes with all needed accy's. This...07-06-2017, 07:54 AM -
We have my wife's family's 29 Tudor. It's stock-ish and I don't know what all may or may not have been done, but stopping is always my first stop on old cars. My intent is to leave it with the mechanical brakes. We do intend to drive it at least a couple times a month and tour our general area as time permits. It may well have cast drums already when her great uncle restored it 25 years ago, I don't...05-25-2021, 10:38 AM
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I have been helping a club member with a brake problem on his 30 Coupe. When we got around to miking the brake drums, we were shocked on how thin they were. All the drum were steel(not cast iron). The front miked out around .105" and the rears were both about .060". The low end of the spec is .120". I don't know how he was able to get his coupe to stop at all. VERY UNSAFE. We are now...11-02-2018, 07:24 PM
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