Garden Folly

October 8, 2012
Jay and his brother Dave decided to build a folly to support a wisteria vine in the garden. It’s going to be a dome-shaped structure about 8 feet in diameter and 8 feet high, made of rebar with decorative scrollwork. Jay bent the S-shaped scrolls from 3/8-inch rebar with a plywood jig. Using 52-inch lengths of rebar, he first bent one end into a spiral around the jig.

Once the first spiral was bent, he reversed the piece and bent the other end in the opposite direction. To make the folly took a total of 28 of these.

The folly will consist of two pairs of arches crossing at a right angle. Each arch is made from a 20-foot length of 1/2-inch rebar, with an 8-foot length stretching across the bottom. Once Jay had bent a few scrolls, Dave started welding the arches together while Jay continued to bend.

Each of the two sections has 10 scrolls and about 50 double-sided welds. By late afternoon both sections were fully assembled, but not joined together yet.

October 9, 2012
After aligning the two halves and clamping them together at the top, Jay welded the intersections to anchor them together. Then we put cross braces along the bottom to join the ends of the arches into a square base. He welded 2 more scrolls into each space between the arches to fill in the dome shape.

We used the tractor to move it from the driveway into the main garden just south of the house. It may take the wisteria vine a year or two to cover it, as this is an American wisteria that won’t get as large as the Asian species.

Here’s a close-up of the scrollwork joining the arches, and a view looking up from the bottom.

How I Made a 4th Axis Harmonic Drive

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After finishing my Modular CNC Controller I built this 4th axis attachment for my CNC router and my milling machine. This will let me machine parts such as gears, and carve 3D patterns wrapped around cylindrical shapes. In the Part 1 video I build the main drivetrain components, using a harmonic drive gearbox to get precise angular positioning and high torque with low backlash.

In the Part 2 video I weld and machine the steel enclosure, install the harmonic drive system, and try it out.

In this video I apply Powder Coating to the housing.

Documentation

The Harmonic Drive web site has detailed information about the style of gearbox that I used. The Catalog link on that page provides detailed documentation about this family of ultra-low-backlash gearboxes.

I bought the 3-jaw front-mounting self centering lathe chuck from Shars. Any similar chuck should work, provided that it can be mounted from the front.

I bought my stepper motor on Ebay after quite a bit of searching to find one with the specs I wanted, including the 8mm output shaft to fit the coupling on my particular gearbox. Here is a link to a similar Nema 23 stepper motor on Amazon.com, but with the more common 1/4″ output shaft.

Building with Surface Mount Devices

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Building circuits using surface-mount devices (SMDs) is not as difficult as some people think, and it gives you a lot more flexibility than youhave when working only with through-hole components. You can create your own commercial-quality SMD-based custom printed circuit boards and assemble them at home, in small batches and and at relatively low cost. Here’s a photo showing part of a board that I designed and built myself, as a learning project:

This is a short getting-started guide with links to some of the equipment and resources that I have found useful.

Custom Circuit Boards

If you only want to solder components onto PC boards manufactured by others, you can skip ahead to the assembly sections below. But it is surprisingly easy andinexpensive to create your own PC boards from scratch.Back in my ill-spent youth, making custom circuit boards meant applying “resist” ink or film to blank copper-clad PC board material and then etchingit with ferric chloride, then drilling all the holes by hand. The results were usable but crude and it was tedious, messy, and the quality was very low. These days it is very affordable to haveprofessional-quality PC boards fabricated in small batches.

The PCB Shopper web site provides instant comparison shoppingamong many different vendors that produce custom PC boards in small batches – just enter the parameters of your board and it gives instant pricingfrom a dozen or more vendors. Boards are most economical in sizes up to 100mm (about 4 inches) square, and the price goes up rapidly if you exceed that size.You also don’t save much by ordering fewer than 10 identical boards at a time, and even if you only want one board it’s just as well to have extras in case of damage and to share with friends. One can get a batch of ten 100x100mm double-sided PC boards for around $20 total ($2 per board), including shipping! The only catch is that the inexpensive ones come from China and have alead time of several weeks unless you pay extra for expedited shipping. I used Seeed Studio for my first order and the board quality was very good, butyou can read reviews of specific vendors on PCB Shopper. Based on the reviews and prices I will probably use Elecrow in the future.

Most of the services offer the option to also create a stencil with your board order. The stencil makes it easier to apply solder paste (see below) by doing the whole boardat once, instead of dispensing it onto individual pads one at a time. It’s worth the cost if you’re going to build up more than a few boards, but for just one or two small boardsit’s easy enough to apply the paste by hand or with an air-powered dispenser as described below.

Circuit Board Design Software

In order to have PC boards fabricated, you need to provide digital files describing the various layers of the board. This is relatively easy and the softwareis free. One of the most popular commercial pacakges is Eagle CAD, which is available in a free version that supports boards up to 100mm x 80mm.An advantage of Eagle CAD is that because it is a verypopular commercial package, it can be much easier to find component libraries for it and some vendors like SparkFunand AdaFruit provide freely-downloadable schematics and board layouts for some of their products in Eagle format. Another popular option is the open-source KiCad software, which is completely free with no restrictions on board size. That can be a bigadvantage if you want to make larger boards, but it may be more challenging to find component libraries and sample projects for KiCad than it is for Eagle.

Regardless of which CAD package you use, the workflow is basically the same. First you create a circuit diagram for your project.Then you create a board layout, placing the components and routing traces for all the connections. The CAD packages have auto-routing capabilitythat will automate much of the work in routing the board, but it’s not always successful so some manual routing is practically inevitable. Once the board islaid out, you export it to a set of files in a standard format called Gerber. Most of thePC board fabricators require a ZIP file containing the Gerber files describing the board. Basically you just upload the ZIP file, payyour money, and wait a few weeks for the boards to arrive. It really is that simple.

Optics

Some SMDs are extremely small, as are the leads on many larger packages. One accessory that I have found indispensible for close work is the Optivisor Headband Magnifier, with the OptiLoupe for really close work plus an LED Light Attachment.I only started using the OptiVisor recently, and I use it for so many different things that I wonder how I got along for so many years without it.

Another really handy optical tool is a USB Microscope like this one:

It’s great for inspecting circuit boards and also for capturing digital images of them. Here’s a close up of the board shown above, taken with this USBmicroscope and showing somejumpers that I had to add because I got two of the signal lines swapped when I laid out the circuit:

Click the image above to see a full-resolution version exactly as it was captured from the USB microscope.

Solder Paste

You can use either Lead Free Solder Paste or Leaded Solder Paste, which melts at a lower temperature but contains lead so must be handled more carefully due to the potential toxicity. Essentially all modern SMD components aredesigned for the higher temperatures of lead-free solder so I prefer to keep things lead-free. It’s also helpful to get a tube of Flux Paste.You don’t need it if you’re using solder paste because it includes flux, but if you need to solder or rework any components with an iron and wire solder thenapplying paste flux really helps.

You can apply solder paste directly from the tube it comes in, using the dispensing needle that comes with the tube, but it doesn’t work very well. At the very leaseconsider getting a Dispensing Needle Assortment because the needles that come with the solder paste tubes are much too big and will deposit big globs of solder. The smaller needles can be bent slightlyin order to give you a more convenient angle for dispensing onto the pads. Another big help, which is not a necessity but really speeds up the process, is a Solder Paste Dispenser thatuses timed pulses of air pressure to deposit a controlled amount of solder on each pad. It comes with a syringe but it’s too big for solder paste, so I alsogot a 10cc Syringe Adapter thatconnects directly to the 10cc tubes that the solder paste and flux are supplied in. The automatic dispenser takes some practice but it’s worth it.

Pick And Place

For picking up and placing SMD components, a quality Tweezer Set is a necessity.I also use a Vacuum Pickup Station tohelp pick and place small components faster. It’s not a necessity – tweezers will work – but it does speed up the process when you have lots of SMDs to place.

Hot Air Soldering

You can solder SMDs with a conventional soldering iron, and there are many tutorial videos out on the Internet showing how to do it. But I find it MUCH easierto use a Hot Air Soldering Station and they are very affordable. Once you’ve tried hot air you won’t want to go back to using an iron on SMDs.There are also many tutorial videos showing how to solder with a hot air station. It’s pretty simple – just heat gently until the solder melts. My hot air station alsohas a conventional soldering iron so it does double duty, and I also findit really handy for applying heat in tight spaces such as when using heat shrink tubing inside an enclosure.

Reflow Oven

Commercial circuit board assembly is done using large reflow ovens that heat the circuit board and SMD components to melt the solder paste over the whole board at once.You can get a small Reflow Oven that is suitable foruse at home, and quite affordable. You can certainly solder up an entire board using just a hot air station, but the reflow oven makes it go a lot faster. If you do get one of these reflow ovens, be sure to read the T-962 Reflow Oven Improvements published by United Engineering.Many thanks to these folks for publishing these modifications! The oven comes from the factory with masking tape inside that can get very stinky during operation,so if you do nothing else you should replace it with this Kapton Tape as described on the United Engineering page.They also provide a cold junction modification that improves the oven’s ability to accurately regulate temperatures, as well as a complete firmware replacementthat is much better than the firmware from the manufacturer. I made all these modifications in less than a day and my oven has worked very well.

Summary

You can get started working with SMDs pretty cheaply. A good way to get started is to try assembling a kit that uses SMDs. You can do it with just a soldering ironbut I recommend the Hot Air Soldering Stationdescribed above because it is so versatile and relatively affordable. There aren’ta lot of electronic kits that use SMD components that aren’t pre-soldered, but here’s one that I found and it helped me get started in expanding my soldering capabilityto include surface-mount components, plus it’s just a cool little portable oscilloscope for not much money:

DSO 138 DIY KIT 13804K

Note that this kit comes in two different versions, one with all the SMDs pre-soldered and this one that has them unsoldered so you can use it to practiceSMD soldering techniques. The included instructions are very good, and after I assembled mine carefully following the instructions it worked perfectly the first time I powered it up.It took a few hours to solder all the components but you get plenty of practice with the smaller SMDs such as resistors and capacitors, plus a couple ofsimpler (larger-leaded) ICs. The fine-pitched MCU integrated circuit comes pre-soldered but that’s the only part that is.

Build a Drone

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In this video series I show the design and construction of a quadcopter drone that will carry a stabilized camera platform for shooting aerial video. Part 1 covers all the main components and shows how I calculated the expected performance using xcopterCalc from ecalc.ch in order to optimize the design.

Part 2 shows the construction of the drone, setup of the CC3D flight controller using LibrePilot software, and first flight tests.

Part 3 shows construction of the stabilized camera platform, and aerial video from the first test flight.

Part 4 shows an upgrade to use the SP Racing F3 flight controller with CleanFlight software, communicating live flight data to the On Screen Display, and a new lightweight FPV payload section.

Performance Data

Here are PDF files showing the predicted performance data for my original design using 2300KV motors, and for the revised design with 1900KV motors and larger propellers:

eCalc_F330A.pdf

eCalc_F330B.pdf

Parts List

Here are the components I’m using for this build:

F330 Multicopter Frame

(2) QAV2206-1900KV Brushless Motor CW

(2) QAV2206-1900KV Brushless Motor CCW

Turnigy Slowfly Propeller 8×3.8 Black CW, 4pcs

Turnigy Slowfly Propeller 8×3.8 Black CCW, 4pcs

(4) ZTW Spider Series 18A OPTO Multi-Rotor ESC 2~4S

HobbyKing™ Micro Battery Eliminator Circuit 5V/1A

Multistar High Capacity 5200mAh 3S 10C Multi-Rotor Lipo Pack

CC3D Flight Controller

2-axis Smart GoPro Brushless Gimbal

Turnigy Action Camera

ImmersionRC 600MW 5.8 GHz A/V Transmitter

Micro Minim OSD

Seriously Pro Racing F3 Flight Controller

Fat Shark FPV Camera (this is a newer version of the one I’m using)

Fat Shark FPV Transmitter

EACHINE ProDVR FPV Recorder

Software

I use LibrePilot software for the flight controller, which you can download at http://www.librepilot.org/.

3D Printable Parts

Here’s an STL file of the 3D printed cover for the flight controller and receiver, and the new baseplates I designed, so if you have access to a 3D printer you can print them yourself:

FPVPlate.stl

ReceiverCover.stl

Baseplate.stl

Dragon Sculpture

I made this plasma-cut and welded steel dragon sculpture for Liz’s birthday. It is based on a Tyrannosaurus Rex model with added wings and horns.

Plans

The design is based on this Instructables post by kaptaink_cg, and a big thank-you to him for posting it! He has graciously published the plans under the creative commons license so I have copied the PDF files here and I have added my own drawing for the wings and horns that I designed. You are free to download and use these plans as you wish under the terms of the creative commons license.

T-RexTemplates

T-RexGuide

DragonWingAndHorn

I used Adobe Reader to print these, and in the print dialog I specified 30% scale for the T-Rex templates so that each page would fit on an 8.5×11″ sheet of paper. The DragonWingAndHorn drawing is already sized for 8.5×11″ paper when printed at 100% scale.

CNC Router Improvements & Spindle Conversion

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This video shows some improvements I’ve made to my CNC router, including the base and enclosure, an inexpensive micro-adjustable leveling system, beefing up the structure of the bed and gantry, improved dust collection, and conversion from the original router motor to a water-cooled spindle with a VFD controlled by the CNC controller I built.

Resources

I used a 2.2KW Water Cooled Spindle Motor and VFD Kit from amazon.com.

Here is a 3D model file for the dust hood that attaches to the spindle as shown in the video. This should fit any spindle with an 80mm diameter. I printed it in PLA filament using my 3D printer:

DustHood.stl

Modular CNC Controller

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I built this modular CNC controller to run a variety of different machines in my shop. My first application is to replace the old controller on my CNC Shark router but I wanted the flexibility to reuse the same hardware on different machines, so I came up with a standard connector layout that will let me swap the controller and power supply for different needs. Initially I’m using the DDCSV1.1 Control Panel but I could someday replace it with a different standalone controller or an Ethernet SmoothStepper and Mach3 or Mach4 software.

The second video covers details of wiring and configuration of the CNC controller.

DDCSV1.1 Control Panel Documentation

Here is the DDCSV1.1 User Manual that contains a wealth of information about this panel, including details of wiring and operation.

Construction Details

Here are links to most of the parts that I bought on Amazon.com:

  1. DDCS 4 Axis Control System
  2. KL-5056 20-50VDC 5.6A Digital Bipolar Stepper Motor Driver – 32 bit DSP Based
  3. BUD Industries AC-405 Aluminum Chassis, 7″ Length x 7″ Width x 2″ Height, Natural Finish
  4. 2P5T 2 Poles 5 Position Rotary Switch
  5. Ferrule Crimp Tool Kit
  6. Remington Industries 18UL1007STRKIT UL1007 18 AWG Gauge Stranded Hook-Up Wire Kit
  7. Connectors Pro DB37 Female D-Sub Solder Type Connector, 10-PK
  8. D-Sub Hex Head Screw with Nut 4-40UNC
  9. 400W 36V Switch Power supply, DC power S-400-36 11A
  10. URBEST Inlet Module Plug 5A Fuse Switch Male Power Socket 10A 250V 3 Pin IEC320 C14
  11. US 3 Pins Power Socket Plug Black AC 125V 15A
  12. Blue Sea Systems Push Button Reset-Only CLB Circuit Breakers with Quick Connect Terminals
  13. uxcell DB25 25 Pin Female to Male Solder Type Adapter Connectors 5 Pair
  14. 12mm 5 Pin Aviation Connector Male Female

I laid out the openings in the aluminum case for the pendant and cut out the front panel using my Dewalt scroll saw. The end panel couldn’t be cut on the scroll saw so I used a nibbling tool to make the openings for the USB and DB37 connectors. I also added aluminum L channels on the back of the case in order to mount the control panel:

The wiring was pretty straightforward but there were a lot of connections, and because most of them used screw terminals I used crimp ferrules on the wire ends. This was the first time I had used crimp ferrules and they worked great, much more secure and neat looking than bare wire ends.

The signal wiring is all 22-AWG stranded wire, and here’s the pinout that I used on the DB37 connector:

I couldn’t find an off-the-shelf enclosure of the size that I wanted for the power supply module so I made my own from aluminum sheet using my ShopFox box and pan brake and plate shear. I ran the AC power from the switched inlet to a 10A circuit breaker, and then to the two power supplies. I also added an AC outlet to run the cooling pump for my 2.2KW water cooled spindle. On the 36V 11A supply for the stepper motors, I added a 22,000 microfarad capacitor to help absorb the current spikes from the stepper drivers.

The output current of the stepper drivers is configured using DIP switches and I have them set for 2.8A output current, which is the rating of the stepper motors in my CNC router. I could have used a larger power supply and drivers that would be sufficient to run the larger 6A stepper motors I plan to use on the milling machine, so that a single power unit could run either machine. But that would require changing the DIP switches when moving it between machines, which is inconvenient and error-prone so I chose to dedicate this power unit to running medium-size steppers and to build a separate one for the mill. I could still use this power unit on another machine such as my metal lathe, as long as I use stepper motors with similar current requirements.

I set the stepper drivers for 1/16 microstepping, and the CNC Shark HD router’s X-Y lead screws have multi-start threads with a lead of 0.5 inch or 12.7 mm per rotation. So with 200-step stepper motors, the pulses per millimeter are calculated as 200 * 16 / 12.7 = 251.969. This number must be entered into the settings page on the CNC controller. The Z-axis lead screw has a finer lead of 0.25 inch or 6.35 mm per rotation so its setting is 503.937 pulses/mm.

Software

I use AutoDesk Fusion 360 to model 3D parts and to generate CNC toolpaths using its CAM capability. AutoDesk makes this software available FREE to hobbyists and it’s very powerful. It has a steep learning curve but there are lots of tutorials available for it. I initially started using Fusion 360 with the original controller for my CNC Shark router, but unfortunately it lacked a post-processor to generate compatible G-code so I wrote my own post-processor for it and the resulting G-code works with the original CNC Shark controller as well as the DDCSV1.1 control panel that I’m using now. To use this post-processor with Fusion 360, follow these steps:

  1. Right-click on this link and save the target file to a directory of your choice, and rename the file with a .cps extension. The post processor is written JavaScript and it includes an open-source license that lets you use and copy it freely, but entirely at your own risk.
  2. In Fusion 360 select the CAM workspace, create a milling operation and generate a toolpath from it. You can find online help on CAM if you don’t know how to get that far.
  3. Once your toolpath is generated, select it and either right-click to select the Post Process menu, or select the Post Process button on the toolbar at the top. Again you can find online help on post-processing if you need it.
  4. In the Post Process dialog, next to ‘Post’, click the drop-down and select ‘Choose from library…’. On the left side under ‘My Posts’ select ‘Local’ (it may already be selected), and up above click the ‘Import’ icon. Browse for the .cps file that you saved in the step above, and press Open. You should only have to do this once – thereafter it should show up as an available post when you select the My Posts / Local item on the left.
  5. Pressing the Post button will generate G-code that should work on the DDCSV1.1 controller, as well as on the original CNC Shark controller.
  6. Transfer the resulting G-code file to the controller and run it. I strongly recommend “cutting air” at first, to test the G-code before performing actual machining with it. My usual technique is to raise the Z axis well above the part and then zero it out, so that I can test the code without actually cutting anything until I believe it’s correct.

Coolant Control
The latest revision of this post-processor supports the M8/M9 output, which will be activated while running any toolpath with any Coolant setting other than ‘Disabled’. This output can be used to control a coolant pump for liquid cooling, an air valve for air blast cooling, a vacuum for dust removal etc. It has limited current capacity so an external relay is required for controlling any high-current loads. Please refer to your DDCS controller manual for documentation of the M8/M9 output.

You may email me at Jay (at) BrainRight (dot) com with reports of any problems or requests for enhancements to this Fusion 360 post-processor, but I provide it at no charge with no guarantee of any kind and I may or may not respond to requests for changes.

4th Axis Engraving a Micrometer Dial

This project is the first real test of the new Modular CNC Controller and 4th Axis Assembly that I built. I used themto engrave a micrometer dial to make an adjustable carriage stop for my metal lathe, which is based on a YouTube video by Tubalcain. Here’s how the finished part looks:

The first video shows how I modeled the part and created engraving toolpaths using AutoDesk Fusion 360:

The second video shows the machining of the dial using the toolpaths generated in Part 1:

I ran into some difficulties during the machining, one of which was that my cheap stepper motor drivers were not able to keep up with the pulse rate coming from the DDCSV1.1 control panel. Upgrading them to higher-end drivers solved the problem, and the specific ones I’m using are the KL-5056 from Automation Technology:

This driver supports a power supply up to 50V and can deliver up to 5.6A of current, which is more than I need for the steppers I’m using at the moment, but I also plan to use these drivers someday to run my milling machine where I’ll need bigger stepper motors. I have the drivers set at 2.7A for the smaller stepper motors that I’m using on the CNC Shark router and the 4th axis. I noticed that in addition to solving the problem I was having with lost steps on the Z axis, the improved drivers also gave noticably smoother motion and less noise.

Aquaponics

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Aquaponics is a combination of aquaculture (raising fish) and hydroponics (growing plants without soil). The wastes from the fish are broken down by bacteria living in the growing medium, and converted into a form that can be used by the plants.

Integrated Vertical Tube System
Here’s a drawing and a photo of the integrated vertical tube aquaponics system we built. The photo shows the tubes in the planting/harvesting position; normally they are rotated 180 degrees so that the openings face the window.

I made the drawing using SketchUp, a great free 3-D drawing program. If you have SketchUp and want my drawing file you can download it by clicking here.

To make the grow tubes, I cut slots across with a hack saw and then heated the plastic with a heat gun to soften it. Once it was soft I pushed in a tapered wooden plug to hold it open until the plastic hardened again. I did this outside because the PVC gives off some fumes when you heat it. The second photo below shows a close up of one of the openings after the tube was filled with pea gravel.

The PVC caps on the bottom of the tubes have slots cut around the edges with a table saw, so that any water that might drip out around the plants can just run down the outside of the tube and through the slots. Otherwise the cap would seal against the funnel and the water could not drain. Normally the water flows down through the tube and out the holes I drilled in the bottom of the cap.

The photo below shows the top of the system, with the flow control valves that regulate the flow of water to each tube. These were necessary in order to balance the flow because without them, most of the water runs into the tube closest to the pump. Note that the tubing is black in order to prevent algae from growing inside it, but after a while it will still develop a film inside from beneficial bacteria that break down the fish wastes. We found that it was necessary to clear the tubes out now and then, by closing all but one valve and turning the pump off and on. The sudden surge of water when the pump starts is enough to clean the accumulated biofilm that adheres to the inside of the tubing.

April 3, 2007  We got fish today! They are about 3″ long and cost us $3 apiece. Their first meal was a small handful of earthworms, which they ate eagerly. I think the one in the bottom picture is burping.

Here’s my new experimental setup to permit multiple fish to each establish a breeding territory in one tank:

5-2-2007  Here’s our first harvest of lettuce, which totaled a whopping 9 grams (0.3 ounces)! The lettuce is a red variety so the color is normal for this type.

6-3-2007: We’ve had quite a few salads now and the plants are doing great. The spinach is spindly but the basil, upland cress and lettuce are thriving.

8-14-2007 We’ve got babies! We hadn’t looked closely for a while so we were surprised to see about 50 little tilapia in the tank today and they’re already over 1 cm long. The water isn’t normally this cloudy but we just cleaned the tank so it’s all stirred up.

The adults are doing well too, and they’ve grown quite a bit.

9-3-2007: The first group of babies have grown to about 1″ long, and we now have a second brood of little ones. The adults pretty much ignore them but the larger babies will “thin out” the smaller ones for us. It’s survival of the fittest in this tank!

Epilog: We shut down this project in the spring of 2008, in preparation for moving to Michigan. We ate the largest of the fish, which weighed in at about 10 ounces – not quite market size but enough for a taste anyway, and it was pretty tasty.In retrospect we wouldn’t undertake any serious fish-raising project without first developing a food source, as purchasing fish food getsrather pricey plus there’s no control over its contents. We’d also use a tank that’s easier to clean!

Fixing Insulation Problems

Using our new Thermal Imaging camera we were able to see some significant problems in the insulation of our exterior walls. The cellulose insulation was specified to be installed to a so-called “dense-pack” density, which compresses the material enough that it will not settle. But alas our contractor did not do it as specified, and in the 3 years since it was installed there has been significant settling in the walls. We had just a vague sense that the house was not retaining heat as well as it originally did, until we used a Thermal Imaging camera to make the problems visible.

Once we could see where the problems were, Jay had to crawl through the attic to the tops of the exterior walls and stuff more insulation down into them by hand. It was a very Dirty Job and not practical to photograph, but now that it’s done we can clearly see the difference in the infrared images. We can also tell the difference inside, where the bedrooms stay one or two degrees warmer than they did before with similar outside temperatures.

In the series of photos below, each set of three pictures shows a shot of an exterior wall area taken with a regular digital camera, followed by thermal images taken before and after fixing the insulation. The pictures are not framed exactly the same in each set since they were taken at different times, but in each case they show the same general area. The indicated absolute temperatures of the surfaces are not significant because we didn’t calibrate the camera for absolute temperatures, and the colors are not very significant either; what matters is the huge reduction in the temperature variation before and after. It’s plain to see where the walls had no insulation at all, and that filling them up made a big difference.

Visible Image

Thermal Image – Before

Thermal Image – After

In the very last photo above, you can see some cooler areas shown in blue along the corners of the walls. It is normal for surfaces to be slightly cooler in the corners because there is less interior air circulation there, but the significantly colder spot at the lower right of the photo cannot be explained simply by reduced air circulation. It is most likely a small gap remaining in the insulation, or perhaps a thermal bridge where the inner wall framing is tied to the exterior walls in a few places. It’s not a major concern because, although it is a couple of degrees cooler there, the area is so small that its heat loss is not significant.

Since the original insulation had 3 years to settle and the newly added insulation is packed in pretty tightly, there is a good chance that no further settling will occur. But since we decided to invest in the thermal camera we can re-check it every year to make sure no new problems arise. So far we’ve only done the walls in the main house, and the exterior walls in the cottage section also show some significant insulation settling that we’ll need to fix before next winter: