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Best way to cut corrugated plastic?

On the day after the elections, I collected a bunch of corrugated plastic political signs that were going to be recycled. My plan is to turn them into a small geodesic dome, similar Nasa’s Hi-Seas dome for my daughter to conduct scientific missions in the backyard.Is the easiest way to cut these signs into the necessary triangles with a razor and a straight edge? Can I use a circular saw or skill saw to cut them faster or cut multiples at once?

Question by Erfunden  


Out of curiosity, can rubber coatings make cardboard more durable and waterproof?

I am talking about corrugated cardboard boxes as well as pieces of corrugated cardboard. 

Question by coolcarl89    |  last reply


Where can I buy corrugated platic sheets (Coroplast?)

Hi. I recently was working on an art project and realized the material I desperately needed (after many others failed) was clear corrugated plastic sheeting. Apparently the main manufacturer is Coroplast. I looked around and only could find places selling large quantities. And I mean LARGE, more for structural projects than craft ones. I'm just trying to find a place where I could get a few sheet of clear 24" x 24" sheets. Does anyone out there have any suggestions?

Topic by scsherman    |  last reply


Is corrugated plastic (the type commonly used for signs) a good covering for a greenhouse?

I'm in the planning phase of a greenhouse next spring and I'm wondering if the corrugated plastic that you usually see election signs made of would be good for a greenhouse covering. Has anybody tried this? If so, could you post your results? Here's some information I've come up with already: 1) Corrugated plastic is relatively cheap as dirt compared to glass and corrugated polycarbonate panels marketed under "Palruf" and "Suntuf". 2) There is a greenhouse covering marketed as "Solexx" that appears to be nothing more than corrugated plastic and is claimed to be superior to glass and polycarbonate panels. It's also very very expensive. 3) Solexx panels are claimed to diffuse the light coming into the greenhouse. This is supposed to be better for the plants than direct light from glass or polycarbonate. Below is an excerpt from the Solexx website: "How does light diffusion affect plant growth? Plants create food from light so the type of light they receive is important. Plants exposed to direct light (no diffusion) produce a majority of their food from the top leaves facing the sun. The select leaves absorbing the sun energy do most of the work while the shaded leaves do very little. Direct light also creates excessive heat which causes plant stress. When a plant is immersed in diffused light, all the leaves can photosynthesize resulting in more food production and healthier, fuller plant development. In addition, the upper leaves of the plant receive less intense light which means they will not suffer from plant stress caused by sun burn and excessive transpiration. " Again ,if anyone has tried using corrugated plastic as a covering for a greenhouse could you please share your results? If anyone has their own comment or prediction please share it. If not, I plan on conducting an experiment to test the performance of different greenhouse materials on plant growth. I may have to use artificial light instead of sunlight however, since the growing season here is coming to an end.

Question by EcoMotive    |  last reply



Material settings for Full Spectrum "hobby laser 40W 5th gen + cardboard?

Hi-I am new to the Full Spectrum "hobby laser 40W 5th gen"--I have a bunch of 123dMake projects to laser-cut in single-ply corrugated cardboard and cant seem to get the right settings for power, speed, and current (top burns, bottom not cut through, etc)--Anyone out there have any "approximate" settings that have worked with single-ply corrugated and that machine? I am grateful for any tips and suggestions! thanKS.

Question by ge5    |  last reply


Cardboard Chairs

Check out these finalists in a cardboard chair competition. Only corrugated cardboard (preferably reused) and glue could be used as materials. The entry below is particularly cool as it only uses one shape for all the cutouts and it can be flipped for a different angle.Link via Core77

Topic by fungus amungus    |  last reply


samurai costume-recycled materials

The armour(body, arms, legs, skirts) are made of cardboard boxes with one side peeled off to reveal corrugation...origami helmet was made of old calendar...with scissors, watercolor, tape, stapler and and ounce of creativity and patience of course voila!!! winning costume!!

Topic by joto2    |  last reply


How do I preserve a cardboard box so that it will last as a storage container for the tool that came in it?

The box interior has a shaped cutout (also cardboard) to hold the tool in place so the blade is protected. The box is non-corrugated cylinder board.  I need to preserve both the interior and exterior

Question by REFFI    |  last reply


How thick should concrete be to keep it strong, non-brittle?

Also, will concrete stick to strong corrugated cardboard, steel, aluminum, plastic? How can you get concrete to take a particular shape (and dry in that particular shape) without it becoming messy and uneven?  These questions are for a sculpture project that I am working on.

Question by coolcarl89    |  last reply


Quick and dirty parabolic dish solar concentrator design!

I do not have one.       I was hoping YOU could help me make a quick choice!   Basically I want to go to the store, buy an 8 by 4 corugated plastic sheet, cut it in petals, stick aluminum kitchen  foil to it (as few wrinkles as possible) and have as rigid a parabolic HALF dish as possible.   Then I mount it in my equatorial mount frame and test it. http://www.youtube.com/watch?v=5OqG2LesnSo   It gets a bit harder because the dish is not exactly a half. Some extends a bit past the center of the dish. Here are some of the issues and choices.  Do you cut along the corrugations or across them? Do you do petals radiating out from the center  or is it better to do the thing with cones? Like in the picture in the link http://solarcookers.ning.com/photo/cone-size-of-the-4-cones-solar-1?context=latest Cones might have a problem due to the corrugations not being in line with the shape that I make. so it might warp in strange ways. Is there an alternative to the corrugated sign plastic sheet? BUT they might work because I can guesstimate a not perfectly round dish more easily than with petals.. I think that something with a focus about 6 inches wide would be sufficient for me. It has to be rigid and light as can be too.   What can I use as umbrella splines to make it keep its shape? Thoughts and suggestions would be greatly appreciated. I might have a day off tomorrow so get those suggestions in quick as you can! Thanks Brian

Topic by gaiatechnician    |  last reply


Full Spectrum Laser help

Hi-I am new to the Full Spectrum "hobby laser 40W 5th gen"--I have a bunch of 123dMake projects to laser-cut in cardboard and cant seem to get the right settings for power, speed, and current (top burns, bottom not cut through, etc)--Anyone out there have any "approximate" settings that have worked with single-ply corrugated and that machine? I am grateful for any tips and suggestions! thanKS.

Topic by ge5    |  last reply


How to scale papercraft and where to print? Answered

We are planning to do several models from Star Wars as Halloween Costumes. I have a papercraft model of an AT-ST, Darth Vaders Tie Fighter, and an Xwing. And potentially a millenium Falcon. These are currently 1/16" models.  Our plan is to scale them up to about 6 feet to use as a pattern then put them over cardboard or corrugated board. What is the best/cheapest way to achieve this? I have them in a locked .pbo file and in pdf

Question by jhendershott    |  last reply


Help with costume

I'm making a costume that looks like this- This is actually my profile image. I have lots of corrugated carboard (but no large pieces yet-just medium sized boxes), thin cardboard, foamboard, and a sheet or two of lexan/plexiglass (for the green spikes), and I think I can get some fiberglass, resin, and some bondo. Does anybody have any advice on bending, cutting, dying(lexan-all I've got is clear) the cardboard, foamboard, or lexan? I've also never worked with fiberglass before-all I've heard is that it's a mess. Any tips? If anyone can help me with the head, antenna, armor, or especially the chest, I'd greatly apreciate it.

Topic by MattGyver92    |  last reply


Model Railway Exhib-Conservatory of Flowers-Mini Landmarks made of Recycled Materials

There is going to be a Model Railway Exhibition at the Conservatory of Flower in San Francisco's Golden Gate Park. They turned one of the wings into the largest fantasy Model Railroad layout. Landmarks of San Francisco have been built out of Recycled/Repurposed Materials and placed around the layout. It looks really cool.The Conservatory of Flowers is Recycled Acetate File Folder Tabs, Corrugated Plastic and Chess Pieces for Finials. The Chinatown Gate is out of Mah Jongg Tiles and Dice, Portals of the Past is from Cassette Tapes, the TransAmerica Pyramid had 6000 Computer keys, and Coit Tower has Rulers and Yardsticks. There are more buildings also.November 20, 2008 - April 19, 2009Golden Gate Express ExhibitionThere is a video at the link and you can read a news story about it.Model Railway-Conservatory of FlowersPhotosSan Francisco Chronicle

Topic by SFHandyman  


Solar reflector mounted on part of an office chair, might give people some ideas.

Http://www.youtube.com/watch?v=VhpwOD2gZLA is a video that shows a solar reflector that I made from mylar and an 8 by 4 sheet of corrugated plastic. I approximated a parabolic dish by cutting it to  make cones. I used bamboo to make it more sturdy. (Still needs more bamboo). It is on a stand made from an old office chair.  I intend to line up the mount properly and put it on equatorial mount but that will take a while. It might be weeks before I have time to test the thing so here it is for now.   I am slow at the experiment stuff. The dish started last september! And it took me that long to figure out how to keep the shape resonably tight. So here it is at this moment. It will change a lot before it is finished but no reason not to show the current state of the project. Brian

Topic by gaiatechnician    |  last reply


Model Railway Exhib - Conservatory of Flowers - Mini SF Landmarks made of Recycled Materials

There is going to be a Model Railway Exhibition at the Conservatory of Flower in San Francisco's Golden Gate Park. They turned one of the wings into the largest fantasy Model Railroad layout. Landmarks of San Francisco have been built out of Recycled/Repurposed Materials and placed around the layout. It looks really cool.The Conservatory of Flowers is Recycled Acetate File Folder Tabs, Corrugated Plastic and Chess Pieces for Finials. The Chinatown Gate is out of Mah Jongg Tiles and Dice, Portals of the Past is from Cassette Tapes, the TransAmerica Pyramid had 6000 Computer keys, and Coit Tower has Rulers and Yardsticks. There are more buildings also.November 20, 2008 - April 19, 2009Golden Gate Express ExhibitionThere is a video at the link and you can read a news story about it.Model Railway-Conservatory of FlowersPhotosSan Francisco Chronicle

Topic by SFHandyman    |  last reply


could 12 strips of pvc angle trim be used to make a light but fairly rigid box frame?

I need to make a prop, the base of which is essentially an open upside down box of around 75cm x 75cm x 75cm. i was going to use a large cardboard box but it needs to be able to pack down as flat as possible for transportation and needs to be able to survive potential rain. i'm thinking i could drill a hole in both faces of each end of 12 strips of pvc angle trim (the stuff used around windows and doors), bolt it all together as a frame and attach corrugated plastic panels as the box faces. do you think the resulting box would be rigid enough to survive a few accidental knocks and kicks without collapsing? i'm not intending to add any load to the box other than a few blocks of carved foam for panel decoration.

Topic by ambientvoid    |  last reply


Solar cells in series sum voltage and current?

I am very confused! I built a 10-cell panel (laid out on corrugated plastic for testing). They were rated at 1.8W and .5V. In the sun, putting the volt meter on a SINGLE cell yields about .55 V and 136mA. This is the same for every one I tested, on the panel and individual cells. What the heck? Shouldn't they be about 3.6A? So I soldered 10 in series and put the leads across the final terminals- sure enough I get about 5.5 volts! But I also get about .96A. And current is negative. WHAT THE HECK?! Am I understanding it wrong? I have to be. I thought putting cells in series adds voltage but current is going to be the same as whichever cell is producing the least. Somehow I'm going from .55V/ea to 5.5V/panel. and 136A/ea to .96A/panel. 10 cells. Should have had an 18W panel. Each cell should be giving me 3.6A. "This should be fairly simple" I thought.

Topic by Phoenix17    |  last reply


Battery Powered Programmable LED Sign

Hi all! I am working on building a sign to hold up at a concert I'm going to in a couple months, and I really want it to stand out!  To preface: I am very technically inclined but know very little about powering LEDs (have only done basic diode and battery combos) and have zero programming experience, but am a quick study.  What I am looking for is a solution that can be mounted on a 20x30" corrugated plastic panel, and run via battery pack with enough juice to last a 4+ hour concert. I know that one can easily buy battery powered LED strips, which I'd mount in an array on the plastic, but I'd really like to ideally be able to control the lights colors and show different bits of text, possibly via an iOS app.  I know this might sound quite ambitious but as my dad always likes to say, go big or go home! Anyone have any ideas where I can get started? Thanks in advance :) 

Topic by bitterfame    |  last reply


Sugru Build Night at MakeICT in Kansas

MakeICT participated in their first Instructables Build Night in July by making stuff with Sugru!  It turned out to be a lot of fun.  A couple people showed up with ideas.  A couple more people showed up without ideas, but they were quickly inspired by suggestions.  One guy who was at our space for the first time had used Sugru before and was willing to share best practices.  Sugru seems like a useful tool to keep around the makerspace, so thanks to Instructables for introducing it to us! Here are some of the Sugru projects our members worked on: Eyeglass repair by forming new nose pads DIY multimeter tweezer probes A universal tripod mount that works with any phone or tablet A mustache - for those times when you need to quickly disguise yourself We also had a member repairing a table-top gaming piece by forming a new base out of Sugru.  Another member used Sugru and recycled pieces of corrugated plastic (yard signs) to prototype a homeless shelter. Thanks to the Instructables team for the help in organizing these build nights! We look forward to participating in more.

Topic by makeict    |  last reply


I am home.

My dear friends, Its been quite some time since I was last seen here, more than 6 months I guess. I see today I missed lot many contests, missed the winnings of many of my lovely friends & followers, missed their awesome instructables and their awesomeness. I received emails from you, asking me about my well being. Thank you so much for your concerns. I missed instructbale so much but  all I can say that the only thing which kept me away from it were life priorities.  Now I am back home and I am not going anywhere. During this period, few things happened, which I feel I must share with all of you. Hope you will like it, and please forgive me for the fact that I kept it away from you. Here they are: http://www.kwikdeko.com/blog/diy-boring-mats-to-an-exciting-decor/ www.kwikdeko.com/blog/ignored-cartons-to-corrugated-art/ www.kwikdeko.com/blog/do-not-throw-your-junk-bottles http://handmade-jewelry-club.com/2013/11/featured-diy-beach-inspired-jewelries.html You are awesome. Thanks

Topic by Tarun Upadhyaya    |  last reply


1/2" OD Square Tube Coupler/connector/corner for cold frame

Hi, I've picked up a fair amount of 1/2" square tube that's used in closet systems - supporting the wire shelves.  http://c.shld.net/rpx/i/s/pi/mp/1363/prod_3099862803?src=http%3A%2F%2Fsite.unbeatablesale.com%2F%2FEB162%2Forgl1522.gif&d;=d94ddeca8805b06f5f7339b629c7270df34a2b26&hei;=245&wid;=245&op;_sharpen=1&qlt;=85 I'm looking for some connectors so i can make some frames. the link below is a coupler for round tube, but i've got square tube pictured in the link above. https://media2.masters.com.au/media/MASTERS/Product/1000x1000/900036043_0_9999_v1_m56577569830513162.jpg I' making some cold frames and will attach single pane glass panels, or some opaque corrugated plastic (just like cardboard,  but its semi-transparent plastic). I don't have a welder so i can't weld the frames together. I'd like to get some 3-way connectors so i can connect a vertical piece and two lateral pieces to make something like this: http://ecx.images-amazon.com/images/I/61w7DLvf8PL._SL1000_.jpg or even something like this: http://www.garden-products.co.uk/resources/images/23569_huge.jpg i also would like to have something like this swivel connector to use for the opening top window portion: http://cdn3.volusion.com/6vf93.6qdpf/v/vspfiles/photos/8940171567-2.jpg I can't seem to find any square tube couplers/connectors anywhere on the web (except for some that are in the UK) that are less than $5-$10 each. Has anyone else had a similar need, or know of a solution? if i made the drawings in ketchup, could someone reading this post 3-D print them for me to test/prototype??? thanks, Mac

Topic by MCrollman    |  last reply


Big Band Music Stands

I am the leader of a 17 Piece Big Band. Just like Glenn Miller or Harry James, I need to find a way to make some inexpensive but deco looking music stands. In the old days, they used to make them in all types, sizes and styles. Today, they have one kind. I would like to find a way to make some myself that can fold up and be transported fairly easily. If you have an idea of how to do this, I would love to hear from you. Please feel free to email me if you have questions. The stand should be in two parts, the base and the shelf. The shelf should sit on the base. The shelf should also have a lip for the music to sit on without sliding off. The total height of the back of the stand should be 36". The height of the front of the stand, where the music sits, should be approx 29". The width of the top portion, the part that holds the music, should be 22". The lip should be 3 to 31/2 inches. The base will vary depending on style and shape. I look forward to anyone who thinks they have a way to make these. They need to be strong enough not to blow away in wind, yet easy to fold and carry. After all, I will be moving 17 of them each time I perform. As far as the style, well, the more art deco looking the better. If I could have anything I wanted without the worry of cost, I would choose stands that looked like the front of a car from the 1930's and 40's. It would look as though it had a grill in front along with the large round lights, perhaps a cap on the radiator, large wide fenders and whitewall looking tires on the side. Now, that is just my if I could have anything idea. reality says a simple square or perhaps v shaped stand. Solid colored, perhaps made from corrugated plastic. Thanks for looking and giving this some thought. Blessings! Ashley ideas@mrlivemusic.com

Topic by MrMusic    |  last reply


Can combined troughs replace parabolic dishes for amateur solar cooking?

I have being doing limited testing of the combined trough shown below and it seems to work as expected. I used a 4ft by 8 ft piece of corrugated plastic for the big trough (too wide but I was reluctant to cut it). Compared to dishes, this was incredibly easy to make and actually gives more reliable concentration over a longer time period. Would anyone like to try it on tiny demo scale? (I mean something tiny made with 1ft by 2 ft paper perhaps) see if you can make a panel cooker with the design as a template? I think it will work with hemisphere curve, or parabolic curve, any curve or panel cooker shape that shines the light on a cooking vessel. Key points. 1 The troughs must be curved in directions that are at right angles to each other. 2 the long primary collector trough must be in line with the path of the sun.And thats basically it! The primary trough concentrates light in one plane and the secondary trough (the little wings round the red pot) concentrate it in the other plane. I then tried to get software to show if it was any good and It seems to show that it would cook for significantly longer than a parabolic dish. But the software showed that it was not as good as I had hoped. From running the software (art of illusion) I came up with the kyoto trough as a possible solution.The kyoto trough is a trough made by taking 2 halves of a parabolic trough and twisting them a little inwards roung the focus. This can focus all the light between the focal line and the bottom of the trough for a time period coresponding to the angle of twist. 15 degrees of twist coresponds to one hour. http://www.youtube.com/watch?v=uX9Z-nsUHiA. That is a really useful property because it confers reliability. The next part of the kyoto trough can just be an ordinary parabolic trough to do a final concentrationof the light onto the cooking pot. Well 2 small troughs to deal with 2 streams of light going towards the cooking pot from either side of the trough. Are any mathematicians interested in resolving the troughs into a Kyoto Dish? which would give much longer cook times than a parabolic dish.Brian

Topic by gaiatechnician    |  last reply


Knex Gun Force Standard

The problem is that almost no one has enough room inside to shoot a knex gun unless it's a total peice of ....you get the point. But, by going outside there are many other vaiables that effect how far a gun can shoot (eg. Wind direction/ speed, trees and other obstruction, etc.) Also power as in "can shoot through can" or "through 3 sheets of hard cardboard" can also be misconstrude in the way that range from the can is a main factor, point blank range is not always the most powerful range, often 1-3 inches away has exponentially higher power. What needs to happen is a tool be built (out of K'nex, what else?) that is not only easy to use but impossible to mess up, it should be able to give 100% accurate reading for all types of guns from the weakest to the most powerful. Also in terms of different types of ammo, rod size shouldn't matter( thats what she said) the only thing that should matter in terms of ammo is whether it is deer slug, rod, sligshot/ catapult rod(a rod with something the can grab the elastic), or other and specify what that is.Range is all to often streched beyond reality by saying it can shoot 200 yards, when really it might be able to shoot 50 yards tops when pointed strait but 200 yards if it is pointed strait at the sky. We need to bulid a target that you shoot from maybe 5 feet away and something mesures force, be it cardboard, or cans, or plywood, maybe even something that leaves a dent in it and you can mesure the depth of the dent to tell you how much force (eg. 1/2"=1, 1"=2, 1 1/2"=3, etc.)Also one last idea if you would prefer to stick to range outside, is that you divide the range in feet, by the number of cardboard sheets(or other medium)the gun can shoot trough at point blank range (say it shoots 63 feet, and through 4 sheets of thick, corrugated cardboard the equation would be F= 63/4= 15.75, so your force rating would be 15.75)These are only some ideas to get all of you thinking about a standard in K'nex gun power.-TheXenk

Topic by TheXenk    |  last reply


Collaboration: Underbody and wheel Fairings WITH Boat Tail for a MkIV Volkswagen Jetta (and possibly Golf)

The underside of your typical car will not have any skin/covering -- the outer skin of your car is known as a fairing and that is how I'll refer to it from this point forward ;) These open crevasses etc. create a great deal of drag force and turbulence to high speed air. This added drag is significant enough to warrant some manufacturers to install aluminum plates covering the entire undercarriage (which add weight).My big project over the next few months will be prototyping a partial fairing for the underside of my car. Additionally, I will be constructing wheel fairings for all four wheels an begin construction of a boat tail (likely in a Kammback Style. I am open to feedback, suggestions and comments of any type - that is why I'm posting here and will be updating my progress.This is a tentative list of things that need to be done - feel free to add.1. Acquire and install material for rear wheel fairing (Prototype has been Completed)2. Front Wheel Fairing3. Start Patchwork Under Tray (This is a huge project)4. Relocate External Mirrors5. Cover Front Grille as much as possible6. Buy ScanGaugeII (I promised myself for my birthday)Constraints1. No Permanent "Stock" body changes (no visible holes etc.)2. Must Be Removable Within 30 Minutes or so without special tools or lifting vehicle3. Must Collapse and Fit in Trunk4. Would like the deadline to be BEFORE a cross country trip (South Florida to San Francisco)MaterialsHere's what's on the table:1. Corrugated Plastic2. Possibly Fiberglass3. Flashing (as suggested)4. Clear Plastic Sheeting (similar to what is use for convertible rear windshields)FastenersI'm current exploring non permanent adhesives and methods of application/removal. This adhesive would be used in tandem with two part snaps. I have also decided on using fold over nuts where applicable.Why a Partial FairingI discovered that some of my exhaust components are the lowest points of my car. Considering the temperatures of these components, extra cost of materials AND the necessary curves to fit these components - I have decided to make this first prototype simple (hopefully all 2-d shapes).CostHonestly, I'm in college - a lot of my money goes to tuition and books (and engineering books typically come with a killer price tag). My goal is to make this cost effective so that someone else can mimic my efforts on their car/truck/etc. OR apply this to their MkIV directly. I will supply dimensions of the vehicle AND dimensions of my overall product as completed.CollaborationOne day, this will become an instructable. If a particular step warrants its own instructable -- I will post it ;) If someone has a MkIV Jetta and wishes to collaborate, please contact me. Having more brain power to come up with robust and unique solutions is a great asset.InspirationThe Probe V - Cd= .13770+mpg Civic Hatch Modifications (Cd estimated around .16)This photo below is a skid plate available for Mark IV Jettas and Golfs -- cost: $300+. It is made from 3/16" plate aluminum and notice that there are no undercarriage vents. This is good news for me as heat management is a major concern. This plate is available hereAs always, I'm open to suggestions etc. It's somewhat of a big project, so I'm taking it slow and steady so I don't burn out with everything else going on :POther Updates as of 3/30/07-Scratched previous task list - replaced with modification task list-Added boat tail and wheel fairing to overall project-Added Inspiration Links-added constraints category-updated fastener category-updated materials category

Topic by trebuchet03    |  last reply


Funny Labels

These are hilarious!!! There all REAL funny product lables that people have found. Here's the link to where I got them: http://www.rinkworks.com/said/warnings.shtml Product Warnings: • "Do not use if you cannot see clearly to read the information in the information booklet." -- In the information booklet. • "Caution: The contents of this bottle should not be fed to fish." -- On a bottle of shampoo for dogs. • "For external use only!" -- On a curling iron. • "Warning: This product can burn eyes." -- On a curling iron. • "Do not use in shower." -- On a hair dryer. • "Do not use while sleeping." -- On a hair dryer. • "Do not use while sleeping or unconscious." -- On a hand-held massaging device. • "Do not place this product into any electronic equipment." -- On the case of a chocolate CD in a gift basket. • "Recycled flush water unsafe for drinking." -- On a toilet at a public sports facility in Ann Arbor, Michigan. • "Shin pads cannot protect any part of the body they do not cover." -- On a pair of shin guards made for bicyclists. • "This product not intended for use as a dental drill." -- On an electric rotary tool. • "Caution: Do not spray in eyes." -- On a container of underarm deodorant. • "Do not drive with sunshield in place." -- On a cardboard sunshield that keeps the sun off the dashboard. • "Caution: This is not a safety protective device." -- On a plastic toy helmet used as a container for popcorn. • "Do not use near fire, flame, or sparks." -- On an "Aim-n-Flame" fireplace lighter. • "Battery may explore or leak." -- On a battery. See a scanned image. • "Do not eat toner." -- On a toner cartridge for a laser printer. • "Not intended for highway use." -- On a 13-inch wheel on a wheelbarrow. • "This product is not to be used in bathrooms." -- On a Holmes bathroom heater. • "May irritate eyes." -- On a can of self-defense pepper spray. • "Eating rocks may lead to broken teeth." -- On a novelty rock garden set called "Popcorn Rock." • "Caution! Contents hot!" -- On a Domino's Pizza box. • "Caution: Hot beverages are hot!" -- On a coffee cup. • "Caution: Shoots rubber bands." -- On a product called "Rubber Band Shooter." • "Warning: May contain small parts." -- On a frisbee. • "Do not use orally." -- On a toilet bowl cleaning brush. • "Please keep out of children." -- On a butcher knife. • "Not suitable for children aged 36 months or less." -- On a birthday card for a 1 year old. • "Do not recharge, put in backwards, or use." -- On a battery. • "Warning: Do not use on eyes." -- In the manual for a heated seat cushion. • "Do not look into laser with remaining eye." -- On a laser pointer. • "Do not use for drying pets." -- In the manual for a microwave oven. • "For use on animals only." -- On an electric cattle prod. • "For use by trained personnel only." -- On a can of air freshener. • "Keep out of reach of children and teenagers." -- On a can of air freshener. • "Remember, objects in the mirror are actually behind you." -- On a motorcycle helmet-mounted rear-view mirror. • "Warning: Riders of personal watercraft may suffer injury due to the forceful injection of water into body cavities either by falling into the water or while mounting the craft." -- In the manual for a jetski. • "Warning: Do not climb inside this bag and zip it up. Doing so will cause injury and death." -- A label inside a protective bag (for fragile objects), which measures 15cm by 15cm by 12cm. • "Do not use as ear plugs." -- On a package of silly putty. • "Please store in the cold section of the refrigerator." -- On a bag of fresh grapes in Australia. • "Warning: knives are sharp!" -- On the packaging of a sharpening stone. • "Not for weight control." -- On a pack of Breath Savers. • "Twist top off with hands. Throw top away. Do not put top in mouth." -- On the label of a bottled drink. • "Theft of this container is a crime." -- On a milk crate. • "Do not use intimately." -- On a tube of deodorant. • "Warning: has been found to cause cancer in laboratory mice." -- On a box of rat poison. • "Fragile. Do not drop." -- Posted on a Boeing 757. • "Cannot be made non-poisonous." -- On the back of a can of de-icing windshield fluid. • "Caution: Remove infant before folding for storage." -- On a portable stroller. • "Excessive dust may be irritating to shin and eyes." -- On a tube of agarose powder, used to make gels. • "Look before driving." -- On the dash board of a mail truck. • "Do not iron clothes on body." -- On packaging for a Rowenta iron. • "Do not drive car or operate machinery." -- On Boot's children's cough medicine. • "For indoor or outdoor use only." -- On a string of Christmas lights. • "Wearing of this garment does not enable you to fly." -- On a child sized Superman costume. • "This door is alarmed from 7:00pm - 7:00am." -- On a hospital's outside access door. • "Beware! To touch these wires is instant death. Anyone found doing so will be prosecuted." -- On a sign at a railroad station. • "Warning: do not use if you have prostate problems." -- On a box of Midol PMS relief tablets. • "Product will be hot after heating." -- On a supermarket dessert box. • "Do not turn upside down." -- On the bottom of a supermarket dessert box. • "Do not light in face. Do not expose to flame." -- On a lighter. • "Choking hazard: This toy is a small ball." -- On the label for a cheap rubber ball toy. • "Not for human consumption." -- On a package of dice. • "May be harmful if swallowed." -- On a shipment of hammers. • "Using Ingenio cookware to destroy your old pots may void your warranty." -- A printed message that appears in a television advertisement when the presenter demonstrates how strong the cookware is by using it to beat up and destroy a regular frying pan. • "Do not attempt to stop the blade with your hand." -- In the manual for a Swedish chainsaw. • "Do not dangle the mouse by its cable or throw the mouse at co-workers." -- From a manual for an SGI computer. • "Warning: May contain nuts." -- On a package of peanuts. • "Do not eat." -- On a slip of paper in a stereo box, referring to the styrofoam packing. • "Do not eat if seal is missing." -- On said seal. • "Remove occupants from the stroller before folding it." • "Access hole only -- not intended for use in lifting box." -- On the sides of a shipping carton, just above cut-out openings which one would assume were handholds. • "Warning: May cause drowsiness." -- On a bottle of Nytol, a brand of sleeping pills. • "Warning: Misuse may cause injury or death." -- Stamped on the metal barrel of a .22 calibre rifle. • "Do not use orally after using rectally." -- In the instructions for an electric thermometer. • "Turn off motor before using this product." -- On the packaging for a chain saw file, used to sharpen the cutting teeth on the chain. • "Not to be used as a personal flotation device." -- On a 6x10 inch inflatable picture frame. • "Do not put in mouth." -- On a box of bottle rockets. • "Remove plastic before eating." -- On the wrapper of a Fruit Roll-Up snack. • "Not dishwasher safe." -- On a remote control for a TV. • "For lifting purposes only." -- On the box for a car jack. • "Do not put lit candles on phone." -- On the instructions for a cordless phone. • "Warning! This is not underwear! Do not attempt to put in pants." -- On the packaging for a wristwatch. • "Do not wear for sumo wrestling." -- From a set of washing instructions. See a scanned image. ________________________________________ Assurances: • "Safe for use around pets." -- On a box of Arm & Hammer Cat Litter. ________________________________________ Small Print From Commercials: • "Do not use house paint on face." -- In a Visa commercial that depicts an expecting couple looking for paint at a hardware store. • "Do not drive cars in ocean." -- In a car commercial which shows a car in the ocean. • "Always drive on roads. Not on people." -- From a car commercial which shows a vehicle "body-surfing" at a concert. • "For a limited time only." -- From a Rally's commercial that described how their burgers were fresh. ________________________________________ Signs and Notices: • "No stopping or standing." -- A sign at bus stops everywhere. • "Do not sit under coconut trees." -- A sign on a coconut palm in a West Palm Beach park circa 1950. • "These rows reserved for parents with children." -- A sign in a church. • "All cups leaving this store, rather full or empty, must be paid for." -- A sign in a Cumberland Farms in Hillsboro, New Hampshire. • "Malfunction: Too less water." -- A notice left on a coffee machine. • "Prescriptions cannot be filled by phone." -- On a form in a clinic. • "You could be a winner! No purchase necessary. Details inside." -- On a bag of Fritos. • "Fits one head." -- On a hotel-provided shower cap box. • "Payment is due by the due date." -- On a credit card statement. • "No small children." -- On a laundromat triple washer. • "Warning: Ramp Ends In Stairs." -- A sign, correctly describing the end of a concrete ramp intended for handicap access to a bridge. ________________________________________ Safety Procedures: • "Take care: new non-slip surface." -- On a sign in front of a newly renovated ramp that led to the entrance of a building. • "In case of flood, proceed uphill. In case of flash flood, proceed uphill quickly." -- One of the emergency safety procedures at a summer camp. ________________________________________ Ingredients: • "Ingredients: Artificially bleached flour, sugar, vegetable fat, yeast, salt, gluten, soya flour, emulsifier 472 (E) & 481, flour treatment agents, enzymes, water. May contain: fruit." -- The ingredients list on a package of fruit buns. • "100% pure yarn." -- On a sweater. • "Some materials may irritate sensitive skin. Please look at the materials if you believe this may be the case. Materials: Covering: 100% Unknown. Stuffing: 100% Unknown." -- On a pillow. • "Cleans and refreshes without soap or water. Contains: Water, fragrance & soap." -- On the packet for a moist towelette. See a scanned image. ________________________________________ Instructions: • "Remove the plastic wrapper." -- The first instruction on a bag of microwave popcorn; to see the instructions, one first has to remove the plastic wrapper and unfold the pouch. • "Take one capsule by mouth three times daily until gone." -- On a box of pills. • "Open packet. Eat contents." -- Instructions on a packet of airline peanuts. • "Remove wrapper, open mouth, insert muffin, eat." -- Instructions on the packaging for a muffin at a 7-11. • "Use like regular soap." -- On a bar of Dial soap. • "Instructions: usage known." -- Instructions on a can of black pepper. • "Serving suggestion: Defrost." -- On a Swann frozen dinner. • "Simply pour the biscuits into a bowl and allow the cat to eat when it wants." -- On a bag of cat biscuits. • "In order to get out of car, open door, get out, lock doors, and then close doors." -- In a car manual. • "Please include the proper portion of your bill." -- On the envelope for an auto insurance bill. • "The appliance is switched on by setting the on/off switch to the 'on' position." -- Instructions for an espresso kettle. • "For heat-retaining corrugated cardboard technology to function properly, close lid." -- On a Domino's sandwich box. ________________________________________ Requirements: • "Optional modem required." -- On a computer software package.

Topic by LoneWolf    |  last reply


Heavy duty UHF CB radio antennas and why cheap can be much better....

If you not a fan of normal road cars then you might get some 4WD and go off road every now and then.There are even those doing trips to remote locations that take a few weeks.An essential piece of equippment these days is a UHF radio.In a convoy you might get away with a handheld one if the cars are not too far apart and the terrain suitable.Most peole however opt for a permanent installation in the dash or roof console.After that decision comes the hardest and often costly part: What antenna to use....If you trust certain online reviews and manufacturer claims then one thing becomes quickly obvious.If you need a sturdy and powerful antenna then you have to pay top dollar.Some come with heavy spring bases claiming to protect the heavy fibreglass rod if you hit a bush or trees branch.There is always a compromise between weight and stability.And trust me, on the right corrugations you prefer not to look at your antenna....So how are these expensive antennas made?As I don't have any own pictures and don't want to steal them from the net: Please search for the terms used if you don't know them already.To answer this let me go to the other types of antennas you can get for your UHF radio.There is the famous rubber ducky - a stubby antenna best suited for short range on difficult terrian.Then we have the fibreglass whip antennas that have more or less coils integrated or even consist of one single coil with different spacings in sections.Good for normal road use, not so much off road as they won't tolerate too much vibration, they often snap off the base screw.Most people now just ignore the short whip antennas of 15 to 30cm length as they usually only come with a gain of around 4.5-6db.I will explain later why that might be a misconception.The last ones are those steel whips with one or two "loading" coils.These coils electrically shorten the antenna.They also provide a matching to the 50 Ohm required for most transmitters and antenna cables.Usually they are designed to be 5/8 Lambda antennas.A good antenna for just receiving, like when using a scanner is not critical in length.Transmitting however means you need a proper Standing Wave Reflection or SWR ratio.For this the antenna needs to be tuned.To be of any good use your antenna needs to match the transmitting frequency.This works best if the antenna length is at 1/2, 1/4 or 5/8 of the corresponging frequencies wavelength.Also called Lambda if you look for antennas.In the good old 27-MHz days we were used to quite long antennas in our backyard, for the car we then opted for 1/4 of this - usually around 2m in length.For UHF however 1/4 wavelength already means you are down to about 16cm...Going for 1/2 is a good thing here as it is still quite short at about 34cm.Real difference when it comes to these Lambda factors is the radion angle produced.You can imagine a 1/4 to look like a huge donut with no hole, about 25° for the radiation angle.At 1/2 this will be flattened out to around 20°.A 5/8 Lambda ntenna can get as low as 16°.Imagine it like a flashligh that has adjustable focus.The light source is of fixed output as your transmitter.The lens does the job of the antenna.If you make the beam more narrow then the light intensity of a certain areas at a certain distance will increase.Means for the radio you get a longer distance your signal can travel with enough energy.This however comes at a price!Imagine you are at the bottom of quite stepp mountain and your mate is up on the top about 2km above you.A high gain antenna with a narrow radion pattern might not even reach up there, while a short stubbie with just 3db still has a chance due to the more spherical radiation.Also explain why low gain and with that short antennas work best in hilly terrain...Back to the thick ones...As you can see you can basically hide any type of whip antenna into a fibreglass rod.But most of the are as said "ground independent", means unlike your normal whip they don't need the spring or foot to be of low resistance to your car's body.How does that work?Well, exactly like these ground independent whip antennas with a spring base or metal pole base work.You know the earliest antenna was a dipol - look it up on Wiki ;)For our CB radios that means you have a metal rod or spring that is about 1/4 or in some cases 1/4 of the wavelenght long.This is connected to the shielding of the coax cable and provides the required ground for the mounted antenna.The big difference is that only too often a dirt cheap dipol is hiding in your expensive fibreglass rod ;)The complete antenna might bring over 2kg on a scale, but the actual thing allowing you to receive and transmit is a few grams of coax cable...HOLD ON A MINUTE!! Some will say now...My whip is 70cm long and my expensive heavy duty one with 9db is 2m long - how does that work with your wavelength theory??Well, it is not my theory, just a fact ;)Imagine a 1/4 Lambda dipol, then it would be all up around 35cm long.And funny enough, that is about the length of a $180 heavy duty stubby if you just tak the rod itself.Go 1/2 of Lambda and you get an overall length of the dipol of around 65cm - add the metal rod making the crew that holds the fibreglass rod and you have the common 70-75cm heavy duty antenna...Anything above this length usually is either just a long rod with noting above the 75cm mark or simple has the 75cm long dipol made from the coax cable at the top with the antenna cable going down the otherwise empty rod.Ok, I got it, either 1/2 of the wavelength or 1/4, so about 35 or 16cm long.Ground independent we add either 1/4 for the spring base and rod or 1/2 for the longer ones.And how again does it work with the gain of an antenna?If you trust Wiki then it comes down to the radiation pattern.These heavy duty antennas usually come with around 6 or 9db, the short ones with 3-4.5db.These values might give you an indication about the theoretically possible distance you can transmit but nothing about the terrain it is suited for.Common rules of thumb created by those selling antennas and radios is that you a high gain antenna on flat terrain and a low gain antenna in a hilly area.Around 4.5-6db seems to be the golden ratio here as these anteannas are equally bad for both extremes in terms of terrain options.What you really would need to know is the actual radiation patterns in a three dimensional plane.A straight whip or dipol as a more or less donut shapead radiation pattern.However, location affects this!Mounted in the middle of the roof it is closest to perfect, while at the corner of your bumper bar you will distord the donut and also block parts out with the body of your car.This is why for this type of mounting elevated antennas are prefered.Makes no sense to have a 16cm long stubbie mounted so the top is still lower than your bonnet...Any antenna with a loading coil (or several) or top load will have a distinctively different pattern.We speak of so called "lobes".If you see it in 2D then for example a 1/2 lambda straight whip will look a bit like the infinity symbol.A 1/4 Lambda of the same style looks more like two ping pong bats joined without the handles.Those with loading coils or linear arrays made from coax cable however can produce multiple, prefered lobes.Usually they are in the 4-6db range and claim to be "universal" or as "allrounder".Here you get a quite narrow main lobe of 12-16° with one or more but much shorter lobes going upwards at about 10-30° depending on the configuration.At short range, like in hilly terrain both lobes overlap while you get a dead area at greater distances.You can sometimes notice that when you are on a low level talking to someone up high.There are cases when with a bit more difference in angle to each other (in terms of height and distance) the signal jumps up a few numbers.You just went from the dead zone into the lobe ;)With just a db value for the anteanna but no details about the actual design, heavy duty antennas can fool you badly.In mayn cases a 1/2 Lambda straight whip on the roof will outperform a costly, heavy duty antenna mounted to your bullbar.This is the reason why the expensive ones are the biggest cheat - they just elevate a quite small antenna above your roof line.And since it is heavy it needs a big spring and you hope it will not break if you hit something on a narrow track.All while the thin stainless stell whip with the cheap magnetic base just flexes under all obstacles with no damage at all.Plus, if you really get into the thick jungle you can just take the magnet off until you are through LOLWhy is a SWR and power meter still an important tool to invest into?Those remembering or still using 27-MHz radios only know too well why you need a proper SWR and power meter.With the lenght of the antenna at these low frequencies and affecting factors new the antenna proper tuning is a must.The bandwidth of the channels also means you have to tune the lowest and highest channel so the are basically even, anything else and the old guys would scream "UNACCEPTABLE!" ;)Especially it you want to get the last out of your system without going illegal.For some reason we accepted the claims that an SWR reading of around 1:2 is fine and acceptable.Most of the radios lower the power output to protect the transmitter if the SWR goes to far out.Allows for simple mass production of antennas with fixed cable lengths that are usually well overpriced.The most expensive bit is the cable itself here...I had no time to build an analog SWR and pwoer meter that works properly on 27 and 470MHz, so I ordered cheap SW30 from China.With that I first checked my little collection of antennas then those of some of my friends.This includes everything from short rubber duckies over loaded and straight whips to heavy duty models.One thing that was obvious right away: most are far away from an SWR readin anyone with a 27MHz groundplane antenna on a long mast would accept.And only one heavy duty antenna had a SWR readin of below 1:1.6 for channel 1 AND channel 40!That one was relatively cheap noname brand.With that sorted I decided to tune at least my steel whip antennas.To my utter disappointment they were all just a tiny bit too short - a thing that would have caused a proper 27MHz antenna manufacturer to to keep a large stockpile of his antennas...I had one though that was longer than needed.And before you ask: Yes, I tested them on both my elevated bullbar mount AND a direct mount on the roof rack.Did not change much for the bad ones so I ignored the mounting position for the tuning.I checked the power once for both channels on my prefered antenna and got 4.4W.Mind you that one has a SWR reading of 1:2.2 and will no longer be used as I can't be bothered to make it longer.For some reason I thought I check the SWR and power everytime I cut a bit off the antenna instead of just watching the SWR reading.At original length I had a SWR of 1:1.9 on ch40 and 1:1.75 on ch1 with 4.6W.I kept trimming down by about 2mm increments until I got an even readin of 1:1.07 on both channels.And with every trim the power went up a little bit.I have a friend that is or better, was just at the brink of being unable to reach from my driveway when he is parked in front of his house.A radio check after the tuning revealed that instead of coming with a lot of static noise and sometimes cut out I got a solid reading of 2 on his end with a much more acceptable level of noise.However, I still struggles as badly to hear him...Funny thing is that test was with just a plain and straight whip of 1/2 Lambda, in my case the tuning resulted in a length of 38cm from the base of antenna screw to the tip.My fancy 9db high gain antenna that is just over 70cm long did not even reach him while I could hear him slightly better than on my tuned one.Changing the mounting to the roof rack gave me a clear reception and a signal strength of 4 at my friends end with no noise.Elevation and nothing around the antenna does matter...After all this, would I still bother to buy a ready to go antenna for 470MHz?Only if I had to.Getting some RG58 cable or re-using it from on old antenna is cheap enough.A standard screw mount with a grub screw to hold a steel whip sets you back less than 10 bucks, from China even cheaper.And most will find a soldered on connector on the other end of an old antenna to be salvaged if required.If you don't have any sring steel wire of about 40cm length then think out of the box ;)The packing of pillows and such often come with a sring steel wire to make the plasitc floil keep its shape, some old suitaces have thicker wire doing the same.And if you ask nicely you might get a bristle or two for free from a street sweeping machine at your councils depot ;)After all we only need a maximum of 40cm to have enough left to trim and tune down.What is left to do?Of course some distance tests to check how well such a simple antenna really really works in comparison to commercial models.I only have one 9db antenna and will check it first to see if on flat terrain there is much difference in distance for transmitting.Unless this difference is well above one kilometer I will not bother with a high gain antenna like this anymore and instead opt for a longer mast and 1/2 Lambda.Another thing on the to do list to try a ground plane antenna with topload to squeeze the radion lobe down to under 15°.The resulting antenna would be quite short here and using an elevated mast is a must have to get over roof level with at leat a few wavelengths of distance to the roof.I guesstimate that an optimised antenna of this style should result in a distance increase of about 10-15km of flat terrain while being utterly useless in a hilly areas.Plus, such a design is not really suited for a vehicle going fast on a freeway, so it will go on my house instead.

Topic by Downunder35m