click photo to enlarge

Perhaps the most important but relatively boring components of a liquid cooled computer system is the radiator. All the sexy parts extract the heat from your hot CPU and other chips and put that heat into the water. But the radiator is what eventually gets that heat out of your system. Also being rather bulky and ugly, it can be quite challenging to install a radiator so your system still looks great and not like the engine compartment of your old car.

After a long search I finally selected HW Labs' newest product, the Black Ice Xtreme II radiator. This radiator is specifically designed for computer watercooling rather than automobiles. It is relatively thin and sized perfectly to fit two 120mm fans, and has excellent heat transfer and water flow characteristics.

This Xtreme II comes with what should have been a very nice shiny black painted surface. However I was quite disappointed to learn that the paint on mine flaked off very easily in places. Apparently either no primer was applied or the metal was not properly prepared before factory painting. Well, I had to do something about that, and I'm glad I did now because I really love the new modified look I obtained (see photo at the above-right).

Barb replacement

The Xtreme II comes with two half-inch manufactured barb connectors which are angled perpendicular to the main plane. For my purposes though I needed one of the barb connectors to come straight out rather than at it's 90-degree angle. So I modified it, as the before and after photos below show.

click photo to enlarge

click photo to enlarge

When modifying an expensive radiator (or even a cheap automotive heater core) there is really only one main concern: don't introduce any leaks. That being said, it should be obvious that the fins and tubes that run through them are delicate and prone to puncture; so care is also needed when handling it. In fact while handling it I wrapped the main body with thick paper and bubble wrap.

Parts list:

The first step is to remove the unwanted barb and to open up a hole where the new barb will be placed. A simple hacksaw took care of the old barb easily. However opening up the hole for the new barb took some effort (since I didn't have access to professional tools). Using standard drill bits I created a hole as large as I could, being very careful not to drill into the delicate tubules inside. Also I kept the angle horizontal so that shavings would not fall down into those tubes resulting in clogs. With hand files I was finally able to open up the hole large enough so the new barb would just screw into the opening. Then with sandpaper I removed all paint from around the areas where I would be soldering.

Radiator with barb removed and hole created Closeup of inside radiator inlet chamber

Although my hole was fairly tight it obviously was nowhere close to being watertight. Furthermore the thin metal at that area is not really strong enough to withstand the mechanical forces the barb may impose on it. Solder would solve the leak issue, and using a pipe nut would solve the mechanical one. The following photo shows the barb in place just before soldering.

Radiator with new barb fitted before soldering Another view of fitted barb

Soldering the joint is fairly straight-forward if you've ever done any copper plumbing. But for the novice I have a few tips. First you must insure that all the metal parts are clean, sandpaper and steel wool are good ideas. Mount the radiator in something that will hold it solidly and away from anything that could catch fire. Also it is a good idea to wrap a damp old rag around the base of the chamber to keep it cool (you don't want to end up unsoldering any other parts of the radiator resulting in leaks). Apply solder flux/resin to all the surfaces where you'll be soldering. Finally remember the main rule of soldering, use your torch to heat the metal parts, and not the solder. When the parts get hot enough you can just touch the solder to the metal and it will instantly melt and be drawn into the crevices. The following photo shows my finished soldered joint.

Radiator with new barb soldered in place

The remaining part of the job is to plug the hole left by the old barb. For that I took a hex plug and filed and sanded it round so it would just fit snuggly into the old hole (without falling all the way inside). Then I cleaned the parts and soldered it in place. After letting the parts cool, and cleaning off any remaining resin, I performed leak testing.

Painting and polishing

At this point I had performed all the mechanical modifications. But the radiator looked like it had been through a war battle; paint was flaked off or scratched and the solder joint looked unfinished.

I sanded down the endcaps to remove all the old paint. The thin metal was a little too deformed or complex to polish, so I decided to paint those parts. But the thick brass sides were in good enough shape to polish to a mirror finish. This took a lot of work. Although the factory paint flaked off in some spots almost by just breathing on it, removing all the paint was very difficult as where it did stick it was bonded to the metal very tightly. It took a lot of sanding through a wide selection of grit sizes.

Finally I had all the paint off everything except the inner tubules and fins. I wanted to leave those black and definitely did not want to damage them. I prepared some rectangular masks out of painter's masking paper and taped them down over the fin area on both sides. I then proceeded to polish the two long sides. To do that I sanded it using progressively finer sandpaper, all the way to 2000 grit. Then I applied metal polish and did a lot of rubbing. The result was so shiny that it actually looks just like a mirror with a slightly yellowish tint.

I then masked off the polished sides and prepared to paint the two endcaps. Note that I also masked off the barbs too where the hose would touch. If you use ordinary paint, you'd first need to apply primer. However I wanted a very shiny metalic look so I purchased some special automotive paint at a local auto parts store. Specifically I chose Dupli-Color Metalcast Annodized Blue (Part# MC-201). This paint is designed to apply right on top of bare metal if it is clean. The result is slightly translucent which gives a true metalic look, simulating professional annodized finishes. That stuff has nasty fumes though, so you'll definitely need to wear a respirator. Here is a final photo showing a closeup of the new barb after the paint finish:

Radiator with new barb after painting