View Full Version : help me make a RADIATOR

06-22-2005, 02:11 PM
i've been doing some work around the house -- some new plumbing recently, and adding some more heating elements -- hot water radiators.

took a drive out to a fancy schmancy home decor shop ... that also sells radiators. http://bbs.homeshopmachinist.net//smile.gif

touring the cast iron and aluminum radiator elements the salesman made a pitch for the "hottest thing" (he found that funny)..

he proceeded to show me a "fancy" radiator that was about 1.5' wide x 8' tall. it was made up of 8 vertical 3/4" pipes about 2" apart. it had two cross-tubes.. one that the top and one at the bottom, which connected all the vertical tubing.

looked like the vertical tubes were brazed onto the larger horizontal ones. the top tube had a welded fitting on one side for hot water, and was capped on the other side.

the lower tube had another fitting welded on, the return, with the other side capped.

he proceeded to tell me that it was *GENUINE* *POWDER COATED* *TOOLSTEEL* .. with the same voice one would use if it were hand carved out of a single piece of marble.

the kicker? $750.

the first thing i thought was "uhm.. tool steel?"

second thing i thought: "i could make that for $50"

obviously these things can't be terribly efficient (if they work at all). but they sure look neat.

i'm wondering, if i made this giant manifold out of regular steel pipe.. and painted it with two part epoxy.. will the insides rust themselves out?

oh, and has anyone EVER seen toolsteel in the form of structural iron? like 2" sch40 pipe?
thats gotta be bogus ... right, guys? ... guys?


06-22-2005, 02:25 PM
I don't know a lot about hot water heating systems. If it would meet pressure and corrosion requirements I would make it from copper pipe. It seems to me that if copper pipe is good enough for your hot water it should be good enough for your, well, hot water.

06-22-2005, 03:00 PM
*GENUINE* *POWDER COATED* *TOOLSTEEL* ? probably just crome-moly tube.

the copper (as posted by evan) sound like the best plan,looks nice and is easy to work with.

The thought of a radiator bursting hot water in the living room does not sound like fun.

maybe $750 is not a bad price for a tested tryed and true part.

06-22-2005, 03:17 PM
Seems to me that you'd want to heat the cold air close to the floor rather than the warm air close to the ceiling. Having a tall radiator may look "cool", but it cannot be as efficient as one with most of the surface area close to the floor.

The idea of a radiator is to get as much heat out of the water as you can before it goes back to the water heater. You do that by putting the radiator near the floor in the coolest part of the room. That makes the room more comfortable and the entire system more efficient.


[This message has been edited by winchman (edited 06-22-2005).]

3 Phase Lightbulb
06-22-2005, 03:26 PM
My house is heated with a modern forced hot water system. The system is filled with anti-freeze that helps prevent corrosion and I think has some other thermal properties that perform better than hot water. I think you can use the same type of anti-freeze I have in all forced hot water systems.

I actually like the look of copper pipe myself. I recently made some drawer handles for some large drawers out of polished alum and polished 3/4" copper pipe.. If you make your radiator out of stainless and copper all polished would look great. The polished aluminum and copper look really great:





06-22-2005, 03:39 PM
adrian, nice work on the handles. that last photo almost looks like a computer rendering.

how would you go about welding (water tight) a copper-SS joint?

going by the price, i bet the artsy radiator was stainless. but why powdercoat stainless? (it was blue/grey -- "gunmetal")

it didnt appear efficient, not because of the height (tho good point), but it didn't appear to serpentine. that is, hot water could take the shortest path through the first tube and not even really circulate through the others.

maybe it was powdercoated to hide welds in the horizontal pipes -- where they might be 'capped' in the middle to force the water to snake through the whole radiator?

i think i'll make one out of copper for starters. bet it won't take much 1" flexible copper to hit $750. http://bbs.homeshopmachinist.net//smile.gif


3 Phase Lightbulb
06-22-2005, 03:50 PM
<font face="Verdana, Arial" size="2">Originally posted by knucklehead:

how would you go about welding (water tight) a copper-SS joint?

I said it would look nice-- I didn't say I could make it http://bbs.homeshopmachinist.net//smile.gif

Actually, I would make it completely functional out of polished copper pipe, but use stainless to hide the copper elbows, or use polished steel/aluminum for a support frame. I just like the look of polished copper with pollished alum/stainless.


06-22-2005, 03:51 PM
you can't weld copper to SS. By and large you can't weld dissimilar materials. You'd have to braze the copper to the SS, but I think that would probably work fine, barring any galvanic corrosion problems.


06-22-2005, 03:52 PM
I would use copper. Put it near the floor. Use plumbing solder. Put little fins on it to transfer heat.

For a workshop, I've thought about running hot water through some old car radiators or a small outside central air conditioning unit with a nice looking vented cover over them. Then hook it up to a homemade solar collector.

Maybe some day. http://bbs.homeshopmachinist.net//smile.gif

[This message has been edited by pgmrdan (edited 06-22-2005).]

06-22-2005, 04:17 PM
Here's my few cents worth from a heating system service tech.
You guys seem to have a few common misconceptions about H/W heating. I commonly work on 100 yr old piping & radiator systems. Cast iron was used because it was cheap, had high thermal conductivity & mass. Systems operate at 140 to 160 F & some are even still gravity circulation. (No pump).
Corrosion isn't much of an issue since it is a closed system & no oxyegen permiable (ie. poly-butylene piping (grey plastic)) was used. Allmost all the systems are ferrous...
Newer systems may use baseboard radiation, copper piping, pumps, etc. Also closed systems with little corrosion problems. Operate these at 160-180 F. difference in temp. across the radiation should be 5-10 deg. F and in no case have a return water temp. This will result in condensation & corrosion of the boiler....
Stainless steel would be an unwise choice for a radiator, due to its lower thermal conductivity compared to copper or cast iron.
Pressure resistance isn't much of a problem since these systems usually operate at less than 30 psig.
Building a radiator out of copper & brass fittings is possible if you can solder & cut pipe (hey we're supposed to know how to run lathes, so that should be easy.) I've even seen some nice designs, but most people usually buy used iron rads from a demolition or install baseboard or radiant floor systems.
I hope that gives you some ideas. Any more questions, E me.

06-22-2005, 04:20 PM
Forgot to edit my few cents worth. Return water temp. should never be below 140 F, is what I meant...

3 Phase Lightbulb
06-22-2005, 04:42 PM

Thanks for the info.. I've been looking for a good book that would completely cover my heating system so I can completely maintain and repair it myself in the future. I was wondering if you could either point me to a good book that answers my questions, or maybe you could help answer them? Recently, I've wanted to know the following about my heating system:

I have an Oil system with forced hot water (anti-freeze) in it now.

#1: After I do a yearly tune up: Clean up the system, replace the nozzle, replace the filter, etc. etc. How do I test to make sure I have the air intake slider set for best efficiency? Is there a trick I can do, or is there a special sensor I can buy to help me measure my Air/Fuel mixture in real time?

#2: My system has four separate zones. Each zone has it's pump, it's own air bleed valve, and what look like Flow-regulators. I had to replace the air tank because the bladder leaked and it wouldn't hold a charge so i ended up closing all 4 flow-regulators, then unscrewing the tank and replacing it with another one... Afterwords I realized that maybe my 4 zones are not balanced anymore because I closed each of the 4 flow-regulators without counting how many turns each one was open... So my question is, do I need to balance the flow? If so, how do I balance it? I'm thinking that maybe I should balance the system based on the return water temp? (IF it's coming back too hot, decrease the rate of flow? Or if it's coming back too cold, increase the rate of flow? if so, is 140F the target for balancing? How do you measure the temp? Any special therm that wraps around the return?)

#3: Should I clean anything from the combustion chamber when I'm doing my yearly tuneups? I see a lot of orange powder inside of the chamber and I've just left it in there so I'm wondering if it's suggested to clean out anything that's loose inside of the chamber or just leave it alone and just inspect the lining for problems.



06-22-2005, 05:36 PM
Hey Adrian,

My boiler works with wood. I light a fire and when the water is warm enough 160°C it starts to circulate. When it drops down to 140°C it shuts off. When the wate temps reaches 180°C then the fire shuts off.

#1. Get someone to adjust the burner. Cheap money to sleep well at night. Don't forget to clean the Chimney.

#2 Open all zones at the same time. See which ones are the last to return warm fluid. Restrict the other until they all return warm fluid at approximately the same time.

#3. Clean and inspect. Things can never be too clean. A shop vac is great for this kind of work. Use every filter you can on it. Soot is really bad for the lungs. I know as an ex chimney sweep


My boiler has copper pipe 3/4" to 1/2" in the rads. Some of my rads are exactly how Dicks described them. Not hard to make.

Rob http://bbs.homeshopmachinist.net//smile.gif

3 Phase Lightbulb
06-22-2005, 06:07 PM
<font face="Verdana, Arial" size="2">Originally posted by spkrman15:
Get someone to adjust the burner. Cheap money to sleep well at night.</font>

It's not a money thing. I'd sleep even better knowing I don't have to rely on someone else.
I don't mind paying someone. What bothers me, is not knowing how to do it myself. I keep running into road blocks trying to get the information.

Now, as for pumping my own ceptic tank. Yea, I'll sleep better knowing I can just pay someone to pump it for me. http://bbs.homeshopmachinist.net//smile.gif


06-22-2005, 06:21 PM

You may find some useful information on these pages. (http://oee.nrcan.gc.ca/Publications/infosource/Pub/home/heating_with_oil_chapter2.cfm?PrintView=N&Text=N)

06-22-2005, 08:14 PM
The World Trade Center twin towers were built using structural sized tool steel columns.
It might require a special order, but hey if you've got the cash there's always somebody willing to make what you want.


3 Phase Lightbulb
06-22-2005, 09:07 PM
<font face="Verdana, Arial" size="2">Originally posted by Evan:

You may find some useful information on these pages. (http://oee.nrcan.gc.ca/Publications/infosource/Pub/home/heating_with_oil_chapter2.cfm?PrintView=N&Text=N)</font>

That's the kind of information I've been able to find.

I'm looking for servicing guides with diagnostic sequences and such. Basically the kind of information available to service technicians.


06-22-2005, 09:24 PM
Do you have TIG capability or know some one who does?If so copper tig welds like a dream,just use copper wire for filler metal.You could also soft solder it together.

When you connect it to the supply use a dielectric union(pipe union where one side is copper,the other is galvanized iron seperated by a teflon gasket and bushing) to prevent galvanic action.

If I were designing it,I would use a 2" tube for the headers and 20-30 1/2" tubes for the transfer tubes.Like said above more surface area means more efficiency.Hope this helps.

06-22-2005, 09:43 PM
i guess most of you folks have modern central air heating and cooling. my house is about 100 years old and has hot water baseboard heat. it is all copper. my wife and i added a second zone, and all we did was cut the pipe and solder in the new lines. as for pressure, i believe the pressure relief on our system is set around 30 psi as Rick said. the water pressure at my parents' house is about 80 psi. i'm talking cold water from the city water supply. so i'd think if copper can handle that, it can handle 30 psi 180F hot water heat.

i'd say you could make the crazy radiator from copper with no problem.

andy b.

06-23-2005, 01:39 AM
You can use black iron pipe, It will not rust out if you treat the water and keep the tank full, pipes rust when oxygen gets in the water. I you actually want light rust film to devolop on the insides of the pipe to create a barrier(magatite layer). Go the the library and get a book on boilers.

Michael Az
06-23-2005, 11:56 AM
I'm courious if you couldn't use ionized water for the system. Wouldn't that prevent rust?

06-23-2005, 12:10 PM
<font face="Verdana, Arial" size="2">Originally posted by tattoomike68:
*GENUINE* *POWDER COATED* *TOOLSTEEL* ? probably just crome-moly tube.</font>

Aw c'mon. Go all the way. Make it outta billet.

06-23-2005, 12:16 PM
<font face="Verdana, Arial" size="2">Originally posted by jburstein:
you can't weld copper to SS. By and large you can't weld dissimilar materials. You'd have to braze the copper to the SS, but I think that would probably work fine, barring any galvanic corrosion problems.


While that's mostly true, I read once about a fascinating process called "explosive welding". I don't recall all of the details (maybe 3phase or somebody could straighten me out), but I believe it was used to "weld" a (special) metal liner into a tank made of some other (strong) metal. The idea was basically if you whack the metals together really, really hard and evenly, the molecules in the two metals will interlock somehow.

Like I said, fascinating, but kinda OT. I doubt it'll help for Tony.


J Tiers
06-23-2005, 04:32 PM
That "fancy" radiator sounds like the regular old crummy "factory and warehouse radiator". I wouldn't pay $5 for it, particularly with that powder coat "insulation" on it.

A real one, as you probably are aware, has lots of surface area, done in the CI sections. Each may have 2 to 7 vertical channels cast into it.

We have hot water, and I grew up with it. I think its far better than steam or hot air.

Having had experience with copper pipe connected to iron/steel, I would NOT allow it. When the new boiler was put in, I made them use all iron pipe, and when they protested, I wouldn't listen.

I've seen too much local corrosion due to galvanic stuff. Might be that I was worrying too much, but I expect that system to last another 70 years if no yahoo screws it up (not that I will be too interested then).

06-23-2005, 09:01 PM
<font face="Verdana, Arial" size="2">Originally posted by Wirecutter:
Aw c'mon. Go all the way. Make it outta billet.</font>

Hahaha,I knew somebody was going to hang that one on! http://bbs.homeshopmachinist.net//biggrin.gif

06-24-2005, 01:35 AM
Just build it, and billet to the government.

Billet, yeah. With enough time any one of us could machine up a heat exchanger with lots of fins inside and out.
Hey, how about lost foam casting these things out of melted 'tool aluminum'. Just use cheap foam since it's supposed to give a poor surface finish. Just the thing for extra surface area. This could be a fun hot-wire foam cutting project, followed by the foundry work.