Malco FST2 Fin Straightening Tool

I initially tried a metal fin straightening tool from Lowe’s (also sold under different brands on Amazon), but it was a total disappointment. Within five minutes of use, it fell apart. The small wire pieces meant to straighten the fins kept getting misaligned, and it was clear that the metal pieces weren’t properly crimped. I returned it as defective and decided to do more research before trying another tool.I came across this new tool and watched a few YouTube tutorials, which was crucial. A tip I found helpful was to avoid forcing the fins. Instead, gently slide the tool up and down in both directions, taking your time. Be patient on damaged/bent fins and work from the edges toward the center, focusing on one section at a time rather than diving straight into the middle of the bent fins. If you encounter resistance, don’t push too hard as you might tear the fins. If the tool doesn’t go through in one direction, try approaching the fin from the opposite side. Sometimes a damaged fin can block your progress, but by alternating directions, you can straighten everything up to that damaged point.This tool worked much better for me, and with a little patience and technique, it got the job done without causing further damage to the unit.I attached a photo with before and after pictures. The before pictures are on top and the after pictures are on the bottom.

One of the combs (which is the one I needed) wasn’t straight and it seems like it had manufacturing plastic left over which without the bent would probably be a problem anyways.

I had an air conditioner (a/c) with mashed in fins that needed straightened. This tool enabled me to straighten them. Where the fins are mashed the hot exhaust air can’t escape.A few observations. The fins didn’t come out as straight as original, but straight enough to function properly. Also, it was a little more difficult than it appeared to align the tool teeth to the a/c fins. I had to gingerly adjust the position across the fins to get the tool teeth to align between the fins. If I inserted the tool before doing that, I would end up with more bent fins. Once the tool was inserted correctly, I had to pull straight down fairly hard to get it to straighten the fins.So that aspect was more delicate or intricate than I anticipated, but not difficult once I got up to speed with the tool nuances.This tool has four different tooth densities: 16, 18, 20, or 22 teeth per inch. From my experience it is essential that the tool tooth density matches the a/c fin density. If it doesn’t match, you can’t get the teeth inserted between the fins and I think you’re just going to mash in more fins. So having these tooth density options is good, it wasn’t too hard for me to count the fins per inch on my a/c to know which part of the tool to use. Still, I ended up putting Dymo labels on the outside of my a/c units identifying how many fins per inch. I don't want to have to count fins with a magnifying glass and a ruler again in the future if I can help it.This product is advertised as having a “resilient nylon comb” to avoid damaging the a/c aluminum fins, but I can’t help but think I might prefer a metal toothed comb. I think metal teeth, if they were thinner, might have been easier to insert and straighten more effectively.*** edited 7-10-24A year later I can't find my comb so I bought another, same product. I used the new one and some of the plastic comb teeth bent. Now for sure I wish I had a metal comb, but the Amazon descriptions of similar products are poor. Most don't indicate the material, even fewer indicate the teeth density. On many of the items the Amazon summary states "Recommended for hair, hair styling." I guess I'll make do.

Take your time with this. Have patience and it works just fine.Some deep punctures or badly damaged fins cannot be fixed.Great tool all in all

First of all - The gray-colored 'teeth' on the comb look like they're metallic in the product photo. They are plastic. It's not a ding against this tool, as I think this is necessary to minimize damage to coil fins, which are typically very thin and could be more easily damaged or destroyed by a metal comb.That said, the tool's plastic comb teeth are also subject to premature wear and damage if you are too aggressive in your combing efforts. I strongly suggest you try to pre-straighten bent ac coil fins first before attempting to comb them with this tool (more on that below). If you try and drag the tool through a section of fins that are severely deformed or crushed this tool will likely rip some of the fins and make the situation worse while also shortening the useful life of the tool.I have a Lennox exterior AC unit with coil fins that are very closely spaced, requiring use of the 20 or 24 teeth per inch options. During my initial attempt to use this tool, it was immediately obvious that the tool cannot straighten severely bent fins without risk of further damaging the fins or chewing away at the tools plastic comb teeth. To increase the effectiveness of the tool, you may need to pre-straighten the coil fins with a fine-edged tool of some sort. I used a single-sided razor blade covered with a layer of masking tape to avoid metal-to-metal contact. I meticulously picked, prodded, and slid the blade edge as needed to straighten some of the fins, creating just enough space between them to allow the tool's comb teeth to slide between them afterwards. Getting the tool's comb between the fins can require a gentle touch. I found that using a light combing pressure in the direction of the fins allows the tool teeth to gently find their way between the fins. If you use too much pressure and try to force the comb teeth into position, you may end up just smashing fins.Depending on the severity of your fin deformities, the process of pre-straightening and using the coil to dress up the fins can be very time consuming, but your overall degree of success and satisfaction is proportional to the level of patience and care you put into the process. If you skip the pre-straightening and attempt to force the tool through a section of fins that are too damaged, you can easily snag the tool and start ripping out the fins, leaving them shredded and/or damaging the tool. For my project, there were some small areas of coil fins that were simply too crushed to be straightened or repaired by any DIY method. I doubt even a professional AC repair tech could salvage them, but I was able to straighten and dress 95 percent of my bent coil fins that needed attention.Overall, I found this tool effective and easy to use. You just need to take your time, use it with care, and recognize it's limitations.