stripping (blasting?) and repainting radiators

JeffM

Does anyone here have experience with getting steam radiators refinished? I've got 11 or 12 in my house and a few could use refinishing which I'm thinking about undertaking this summer while the heat is off (flaking paint, bubbles, too many layers hiding casting details, etc). What's the best process for removing existing paint (which I think is likely latex interior paint over older oil based stuff, but that's just an educated guess)? Should I pull them a couple at a time and take them for sandblasting? Any opinions on having someone paint them for me, or should I just do that myself (with a high-temp spray, I assume)?

Thorp Thomas

Powder Coat...

We have a local guy in our area that does powder coating. I take the radiators over to him, he sandblasts and then powder coats them. What an excellent job he does and the colors, if you can think it up he does it.



We use to haul them out back and sandblast them then shoot them  ourselves. The results were pretty good for a bunch of hacks. But then we  did a job for the powder coat guy and the rest is history.



The Exeter Brass Works made very ornate cast iron radiators that were very popular during the Victorian era. Lots of the elegant, stately homes in the area still have them today. These radiators command a very healthy price as they are getting harder and harder to find.



The Powder Coat guy charges me a $100 each radiator, but well worth it when you consider what each radiator is worth. We sell them at $150/section. The only down side is; handling them, it's like moving a piece of art. A very heavy piece of art!



BTW: The Exeter Brass Works is located in my backyard (1/4 mile away), but they don't make radiator there anymore.   

JeffM

perfect!

Thorp,

     I couldn't have asked for a more convenient reply! That's pretty close to me. I spoke to you on the phone a couple of weeks ago about doing a gas burner conversion for me, so maybe when you're out to look at the boiler to quote that we can talk about radiator refinishing too. Happy to know there's a resource close by! I've had a few bicycle frames that I've brazed together finished with powder coating, and love the durability.

     (Also - as promised, I'll give you a call in a couple of days to set up a time to look at the boiler). 

Jeff Matson

Bob Harper

RRP

Don't forget your RRP obligations. I would have a paper trail making him also responsible for compliance in his methods of handling and preparation. You are probably responsible for testing painted rads before you remove and handle them then disclose those test results to him.

Any form of paint or coating will act as insulation and reduce the effectiveness of a rad. Consider using a flat black matte finish where possible. Also, radiator covers are a bit of an oxymoron.

Thorp Thomas

Not ture...

No disrespect meant Bob, but you're way off base on that comment on color. Obviously you didn't read the report done at the Brookhaven Institute about 25 years ago on radiator performance. The test show color and surface texture have little or no effect on the performance.



I'm old enough to have design and install steam systems. Here's the rule of thumb on steam sizing that my father used; Do a room by room load calculation (IBR method) whatever that number was, double it then find a suitable radiator over that size that fits the application, calculate up the total load  add 35% for piping loss then double that number again for the boiler size.  Back in the good ole days bigger was always better. Keep in mind that since most all the boilers were coal fired back then you needed to get at least an eight hour burn. If the house got to hot you'd open the top sash of the double hung windows let the heat out and open the lower sash to let cool air in. My father's specialty was vacuum-steam systems with Timken rotary oil burners.  We were still installing them when I was an apprentice.



So, you got to be kidding me about whether the radiator would be marginal capacity for the application it's in today.   

ChrisJ

size

I would have to agree.  Every radiator in my house is around 50% too big for the room it is in.  Luckily everyroom is the same so the house heats evenly.  I seem to recall the only thing that mattered in paint was whether or not it had metallic pigment and even then I don't think it made too much of a difference.



I'm curious though how much of a difference powder coating would have.  Isn't it basically giving a plastic coating?

Hap_Hazzard

Powder coating vs. paint

Yes, powder coating is the same as giving it a plastic coating, but so is painting. The difference is that one is cured a 390° and the other cures while drying out at room temperature.



All of my radiators have been painted with interior house paint, and all of them are peeling badly. I haven't decided on whether to paint them or get them powder coated, but I'm definitely going to strip them bare first. If I can get them perfectly clean myself I might try painting them with Rust-Oleum High Heat. If not I'll have someone powder coat a few.



Powder coating shops are set up to do better surface prep than most of us can do, and they can apply the finish immediately, before the surface oxidizes, but if I decide to get them all powder coated, I'll still try to remove as much of the old paint as I can so it doesn't contaminate their blast media and chemical baths too much.

SWEI

Powder coating is about the best

finish you can get for both beauty and durability.  If done properly, it will outlast all of us.

Hap_Hazzard

If done properly...

Most of the people who do powder coating are professionals. Most of us don't have an oven big enough to put a radiator in and heat it up to 400° for ten minutes for starters. But I think the surface prep they do is a big part of why it's so durable. Most do-it-yourselfers don't have a clue about surface prep, and that's probably why so many paint jobs look like hell after a few years.



If you take the time to remove every trace of paint, rust and dirt, and the paint it immediately, with a paint designed for bare metal and high temperature, you could probably get decent results. Of course it still wouldn't look like a powder coat. I've been looking at what they offer, and some of those colors are gorgeous!

ChrisJ

sandblasting

Most people also don't own equipment to sandblast which, in my opinion is a must to remove the old paint.



I've sandblasted and painted one thing and I it was not the fun experience I had always expected. I was a dope and didn't wear much protection and did it outside of a friends shop with a huge compressor and sandblaster.



Can't wait to blast Monitor top #2..

Jean-David Beyer

Making me feel old.

My parents hat one almost like that. It was a GE and the gas was ammonia. They got it second hand to replace their ice box. That was a wood one and the ice man brought us a big block of ice every other day. We had to empty the bucket underneath every day and in summer, sometimes twice a day. It was not cold enough to keep ice cream in it, but we had that less than once a month because we could not afford it anyway.



The top of the GE was just about like your picture, but the coils were not enclosed as shown in your picture. So was my parents unit older or newer?



When the refrigerant leaked out, everyone knew it but me. I think my nasal sensitivity is below par. I do not notice a natural gas leak unless it is pretty severe.



When the top leaked all its ammonia, in around 1947, my parents managed to buy a new top, which was just a box with vents all around. I remember it cost $106, and my mother paid in cash. That one used sulfur dioxide as refrigerant. Weird that I remember that. It was a long time ago: 67 years.

Jean-David Beyer

Ours was like this.

http://www.railwayvillage.org/Resources/img0839.jpeg

ChrisJ

SO2

No domestic refrigerator has ever used ammonia other than absorption types (propane RV style).



The Monitor top you are speaking of used sulphur dioxide. To be exact 1927-1932 and 1935-1937 used sulphur dioxide and 1933-1934 which are the two years I have, used methyl formate.



If the coils were open, that was up until 1932. The replacement unit you are speaking of had a compressor, condenser and a fan enclosed under a square cover. I could be wrong but I had thought those were all R12. Chances are the original SO2 unit had a porcelain coated cast iron evaporator (freezer) which rotted due to a pinhole or chip in the porcelain. later on GE switched to stainless steel which doesn't have the problem.



If you want to talk about this more please shoot me an email. I really don't want to derail a threat.

Hap_Hazzard

It's a blast!

It takes a lot of compressor to keep up, but the most important thing is knowing all the details, like getting all the sand off when you're done and applying your coating immediately.



Sandblasting leaves an excellent surface for applying paint or powder, but if you don't remove that fine dust it leaves behind, you'll just be painting the dust.



That dust is also the reason you want to wear a particulate mask and goggles. That dust is really tiny fragments of shattered sand. When it gets into your respiratory tract, it gets trapped in the mucus that lines your respiratory passages, but unlike the other particles that your body eliminates, the sand is too heavy for the cilia to sweep upward and out of the respiratory tract, so they end up settling in your lungs, where the sharp edges constantly irritate, inflame and damage the alveoli, gradually reducing their ability to absorb oxygen. This chronic, debilitating condition is called silicosis.



If you think you've gotten away with sandblasting without protective equipment, you could be right, but we won't know for sure for 30 years. The symptoms usually show up 10 to 30 years after initial exposure. Then the next 10 to 30 years are rather unpleasant.

Rick_41

radiator paint

Many years ago I made the mistake of painting several radiators with regular interior paint,..still peeling. Then I used Derusto High heat spray paint on the others and they still look good.