Zip Line Challenge

My spousal unit, who actually writes this blog, is an author and illustrator of books for kids. She ran across this website for aspiring engineers, and thought it would be interesting to some of my readers. DiscoverE (formerly the National Engineers Week Foundation) helps to unite, mobilize, and support engineering and technology volunteer communities. They hope to increase the collaborative footprint in K-12 education and celebrate with the public as it discovers the value of engineering education and careers.

zipline

I was especially intrigued by their Zip Line Challenge for kids. It’s actually a model that challenges kids to transport a ping-pong ball down a zip line from start to finish in 4 seconds or less. The activity discusses many of the considerations when designing and building a zip line. I’ve uploaded the PDF so you can download it from here, or you can get it from the website listed above. There are a lot of other creative engineering related activities there, all free to download and use in your classroom, home, summer camp, whatever.

Check it out: zip-line-challenge_091316

One of these years I hope to finish my zip line. All is ready, but now the brush has grown up so much I have to hire a tree climber to clear the 420 foot long pathway.

ZipLanding

View from the zip line tower to the landing 420 feet down the hill.

Thanks for stopping by! Be sure to check out our bridge book if you’re thinking about a DIY suspension bridge. Here is the link: Building a Small Cable Suspension Bridge with the Cable Locking System.

And if you’re curious about Robin Koontz’s books, look her up on Amazon as well: Books by Robin Koontz

Images, diagrams, and text copyright 2013-2017 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Marston Mat Mudway

Marston Mats, aka perforated steel planking (PSP), were developed by the U.S. before World War II. The idea was to quickly build temporary runways and landing strips. They were first used at Camp Mackall airfield near Marston, North Carolina, in the U.S.

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A Curtiss P-40 Warhawk on a Marston Mat runway at Milne Bay, Papua New Guinea in September, 1942. – public domain

marstonmat

 

I honestly don’t remember where or when I acquired four of these heavy metal planks, probably saw them advertised somewhere. I know I didn’t pay much for them. The idea at the time was to see about using them for my bridge deck. I wasn’t able to acquire any more at the time, so opted for the wood deck you see in the photos. One of these days I’ll replace that deck with something metal. I like that the perforations would let air flow through so the bridge would not be as vulnerable to high wind gusts.

Meanwhile during our rainy season, areas where we like to walk get more than a little muddy. The small creeks flood and send water everywhere. I’m always digging ditches to try to control the flow somewhat, but this particular area is low, so it’s always a mucky mess.

mats
So I installed some 2×10 planks I had as well as the four Marston Mats. Nothing much to it, other than first setting out short cross members for everything to rest on. While you could just toss the planks into the mud, raising them up a bit makes them more effective, and you can get them level to some extent. I screwed down the wooden planks, but the mats were heavy enough to be stable without reinforcement.

jeepmud
When finished with the project, we noticed that Jeep the dog appreciated the wooden planks, but not so much the mats. He proved the point that the Marston Mats would not be the best material for a bridge, assuming you want to allow your four legged friends to come across with you. We’ll be watching for other options.

Thanks for stopping by! Be sure to check out our suspension bridge book. Here is the link:

Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2013-2016 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Habitat for Pond Turtles: Turtle Sofas!

There’s a stream that runs through our property and into Wildcat Creek, close to where our bridge resides. Though the stream is officially nameless, we’ve always called it Phillips Creek, because it ran through the Phillip’s place; Belle’s Creek, because our neighbor’s dog loved to play in it; and Penn Creek, so named by the ODFW who showed up (without notice) to count fish one day. Whatever the name, the stream tended to cause flooding in the pasture in winter, so we put in a pond. How that was done is a blog for another day.

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buddy

At first the pond dried out in summer, but once the beavers noticed it, they routed more of Phillips Creek so that it flowed into the pond year-round. We installed a bigger culvert along with a fence to keep the beavers from clogging it up, and had ourselves a nice pond we called Buddy’s Lake, after our beloved Swamp Puppy, Buddy.

We had seen pond turtles in various wetland areas on our property, but were amazed at how fast they discovered Buddy’s Lake. They first appeared on a log that we’d left out, sunning themselves in the spring chill. When that log began to sink, as logs are often prone to do, we decide to make turtle sofas.

turtlemom-baby

Previously we milled up a few logs for various projects and had kept the sides for benches or whatever. So why not a turtle sofa? And to keep our sofas from sinking, we screwed on strips of rigid insulation we also had left over after building our house. The material isn’t toxic for the watershed.

turtlesofa11After launching the first sofa, we noticed that it tended to hang out close to the shore where a turtle might feel vulnerable to land animals, especially the two-legged variety.

turtlesofa12

This turtle is game to try anything new!

So we tied an anchor to a rope attached to the sofa and tossed it out so the log would float more in the middle. We also roped the sofa to a tree on shore so we could haul it back in if need be. And, we added measuring sticks as a fun way to see how big the turtles were. A full grown pond turtle gets to be 6-7 inches long.

turtlesofa9

Jeep, Buddy’s predecessor, wonders why we threw such a big stick for him to fetch.

windjammers

We added windjammers to a couple of sofas to help stabilize them. Probably not necessary unless you have beavers who like to knock them over and use for their dam.

turtlesofa1

This is a turtle favorite, probably because of the moss that has grown on it. Without the foam underneath, this old log would have sunk by now.

turtlebunch

Six is not a crowd!

We’ve seen up to nine pond turtles at once on Buddy’s Lake. We’re happy that our turtle sofas are a preferred place for them to hang out. Or do whatever it is turtles do.

turtlelovecard

Floating Mantel Shelf

cherry treesOur house has posts, beams, and siding made from Douglas fir milled on our property. I decided to employ another kind of wood for a fireplace mantel. Bitter cherry, also called Oregon cherry (Prunus emarginata) is a native tree that popped up in our woods when it was replanted in 1988. I wondered what the grain and color would look like when it was milled. It has an interesting bark, that much I knew.

So I picked a tree I liked and thinned the woods by one cherry tree. I parked it in the barn to dry for about five months, then had it milled to about a five foot 5-1/2″x7″ with bark edge on the 7″ width. mantle-sawmill

As control against splitting, I scored slices on one side in varying depths, the deepest being the middle cut over the tree center at about 1-1/2″ deep. Then I primed the sawn sides and left it to dry, standing up, for about 3 more months.

frontgrain-joint
I was hoping to preserve the bark, so cutting and fitting the corners was tricky. I sanded down the precautionary slices (which were on the bottom) and cut the pieces. I sanded, splined and glued it all together, then applied a clear finish. The bark is threatening to peel, but underneath looks pretty cool so I really don’t care.

barkless

de-barked Oregon cherry

I used a bracket system to install the 35+ pound mantel. I hollowed out two slot holes at 9/16″ depth on the backside that corresponded with metal brackets that screwed to the wall studs.
wallbrackets

Metal straps, which were recessed so that the mantel would fit flush with the wall, were screwed across the hole slots. Taping their location on the mantel top,  I could line them up with the marked brackets.

backconnection

finetune
hammer

A bit of hammering with someone else holding on, and the mantel was up.

finish2

I have 3″ metal posts that I had intended to install on either side, not for support just for looks, but for now we’re seeing if we like just having a floating mantel. Eventually there will be a wall sculpture underneath. I’m just waiting for my spousal unit to come up with something…
finish

Thanks for stopping by! Be sure to check out our bridge book if you’re thinking about a DIY suspension bridge. Here is the link: Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2016 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Metal and Wood Computer Desk – DIY

Marvin-DeskLegsI’m not crazy about much of anything we can buy in today’s furniture market, at least in my price range. It’s all badly designed and sloppily made using cheap materials, including a lot of plastic. I feel that even a practical piece of furniture such as a computer desk can be well designed and interesting to look at. And it’s not all that difficult or expensive to make it yourself.

I bought a length of 1-1/2″ square metal tubing (wall thickness roughly 1/16″) and enough steel angle to build a nice, sturdy structure that could hold up a heavy wooden top. I cut and bent the angle steel so that it formed a three-sided structure, allowing for a chair to fit underneath.
tablestructure2
I made wooden feet from some ipe (that’s a hardwood) that I had. I cut out blocks, then cut a little off each of the four sides of each block so that they fit snugly inside the metal tubing, leaving about 1/2″ for a foot. A nice look and a way to protect the floor.

tablefeet

For the top, I had several 2″ thick slabs of rough-sawn wood that I got from a local sawmill last summer. I knew the seller well and got a great price on some beautiful big leaf maple as well as Lebanon cedar he’d cut down in someone’s yard. The slabs had been drying for about ten months and looked good. I decided to use the cedar for this project.

tablestructure6

The tricky part was picking out the part of the cedar I wanted to use for the table. It wouldn’t be deep enough so a second piece would have to be glued to the first and they’d want to match or at least, go well together.

top-cut

finishtable-2A lot of cutting and sanding later, I had pieces that worked. I splined and glued the pieces, removed the bark, then finished with clear Sitkens stain, one of my favorite finish products. I also added holes for the computer cords, etc.

finishtable

I added more angle steel to hold a shelf for the keyboard, and my new computer desk was ready to use.

MarvinOfficeYou won’t find this at Ikea, or anywhere else for that matter. It’s not a design everyone will love, but suits me. That’s the beauty of building your own stuff.

I didn’t include a lot of detailed instructions here, as most of it is self-explanatory. Please ask questions if you have any about this project or any others included on this blog.

And thanks for stopping by! Be sure to check out our bridge book if you’re thinking about a DIY suspension bridge. Here is the link: Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2016 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

 

How to build a house in six minutes.

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My spousal unit compiled photos from the five years it took us to build our little retirement house near Walton, Oregon. There is a lot more to the story but she is too lazy to update it. It is fun to see the bones of the structure and the slow but sure evolution of our house. We referred to the entire process as the What Year is it? of the However Long it Takes Plan. We moved in last August and are still working on the interior finish. Notice how much of the wood was home-milled. A few Douglas fir trees blew over in a storm several years ago, and now they are a house.

Thanks for stopping by! Be sure to check out our bridge book if you’re thinking about a DIY suspension bridge. Here is the link: Building a Small Cable Suspension Bridge with the Cable Locking System

Images, diagrams, and text copyright 2016 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.

Wildlife Shelters

Birdhouse I’ve built a lot of bird houses over the years, following one basic design and using cedar when I have it, and only varying the size a bit. The box is easy to make and installs with a screw on the inside back and one into the bottom of the back. I hinge the front with a bent nail or other metal device, making the house simple to hang as well as clean out in the winter. I have these all around the garden and on posts throughout the pasture. Cavity dwelling birds are for the most part insect eaters. Nice to have around in the summertime!

nestboxThis is an illustration from my spousal unit’s book The Complete Backyard Nature Activity Book which has a few other designs for houses and feeders as well.

I’ve also built a number of houses for our duck pond and have had wood ducks, hooded mergansers, and the occasional screech owl make use of them. A wooden hinge on the back of the box attaches to a rope or cable around the tree (run inside hose or plastic pipe). I loosen the rope/cable up every few years as the tree grows.

These larger boxes are pre-loaded with wood chips as ducks and owls don’t bring in nesting material other than their own feathers. I also add a piece of hardware cloth to the entry so the little ducklings can climb out easily.

I built a larger, deeper box especially for the flying squirrels that kept trying to live inside the roof vents of my old house. I blocked entry to their caves, then I figured I owed them an alternative. It SquirrelBoxStuffworked well, both for flying squirrels, Douglas squirrels, and chipmunks. A honeybee swarm also took it over the year I was selling the house. I let my bee-keeping neighbor take it away and when he convinced the bees to move into one of his structures, I got the box back and hung it at our new place.

We’ve had fun knocking first then sticking a camera inside a box to snap a photo. We like to see if it’s being or has been used, and several times we’ve found someone at home. Here are a few photos for your amusement. If you have questions just give me a shout. Meanwhile let’s do what we can to enhance what’s left of the wild areas so these critters can keep on keepin’ on.

Pictured: Hooded merganser, box interior with eggs, wood duck hen and baby, wood duck hen about to bite the camera, tree swallow babies, screech owl and baby.

merganserduckbox-interior

duckies

duckbox

SwallowBebes OwlsMarch

Images, diagrams, and text copyright 2016 by Marvin Denmark unless otherwise noted. Please do not copy and post my content anywhere without my permission. Thank you.