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Best Plastics, Composites, Rubber for structural antenna parts

90157 Views 212 Replies 43 Participants Last post by  300ohm
Just a warning note about using ABS for structural parts that I've mentioned many times before - hopefully what you're planning to use is the thick walled stuff that has little or no flex. If you go to Rona or Lowe's or Home Depot and shake a 10 foot ABS pipe like a sword it flexes a lot. ;) It seems to be rigid, but its not. If you shake a length of PVC like that it will seem like a wet noodle, so avoid using PVC for structural use either, except when recommended in build plans.

From experience I'm clarifying that ABS should never be used as a pole or mast, and it should be carefully considered if you're thinking of using it as a horizontal boom of any length more than a meter or a few feet.
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drive to Home Depot or Lowes
No, no, no. They are about the most expensive places to buy solid copper wire. The electrical supply houses are much cheaper. (almost a third of the price)
You should open up your own storefront!
Well, DdDave could. And then make the big bucks selling 15 cent ferrules. :p

Hmm, I think the next time I put up some guttering, I will use the plastic ferrules. The aluminum ferrules, if you drive the gutter nail in too far, will bend and cant be easily unbent, even if you pull the nail out. No such problem with the plastic ferrules.
Thats enough for 4 or 5 houses ! :eek:
Dont know. I would drill two small holes and put a black UV resistant wire tie in there for extra insurance.
Nope, white nylon is not UV resistant. Marine Derlin screws and bolts/nuts are though.
Is CPVC and PVC the same thing? Thanks
Nope. In plumbing CPVC pipe is used for hot water and PVC fro cold water.

have sashed together the 2 straps using 3 tie-wraps, I think with a little glue this will be very sturdy for a stand-off...
Good job, but like mentioned before, white nylon isnt UV resistant and can deterioate pretty quickly in sunlight. The black nylon sold at Walmart in the auto dept, $2.84/100 pieces, is UV resistant.
Interesting. They also carry 3 way, 4 way and 5 way fittings. Pricey though.
Spray paint is easy but it takes more than one coat and you'll probably use the whole can.
I find one thin coat with the cheap 96 cents a can Walmart stuff works well. Ive painted other garden pvc pieces Forest Green with it and theyve lasted well for over 5 years, with some fading. More, heavy coats tend to peal off in time. One thin covering coat is the key. I painted my DBGHs Flat/Satin Black with it and they are in great shape after 1 year. Figure using 2 cans per DBGH.
Yeah, that is a nice simple sturdy build. What is holding the outer part of the reflectors, wire ties ?

I found some unknown plastic (the salesperson said it was one of a couple possibilities, but I forget what she said now)
Did she say if it was UV resistant or not ? If not, I would spray paint it with a thin covering coat for outdoor use. I personally wouldnt spray paint the driven element though.
300ohm dry fastens with a bolt when finished
Nope, just a single #4 X 3/8" or 1/2" wood screw. It holds it well enough. A pop-rivet is another possibility.
I have no idea if they're UV-resistant though.
Nope, not UV resistant. They would have to be painted or protected from the sun in some way.
whereas license plate fasteners ARE UV..
Yeah, forgot about those. So are marine nylon (Derlin ?) nuts and bolts, but pricey.
Yeah, depending on the rubber, it can deteriorate in a couple of years in the sun. But its not something you should run up the tower and change now. Wait till warmer weather, heh.

The performance of this GH is very good . Slightly weaker than my XG but its now abit closer to the target stations in Erie.
For channels below 30, it should be a bit better than the XG91. :p
I used 3/4" but next time i`d go with the 1" pvc. I`m skeptical on how this option will hold up outdoors but i`ll add it to the test mast.
Use the gray electrical pvc pipe, same OD size, and its UV resistant, and about 40% cheaper.:)
I was planning my next build based on a wooden pin (stud) that fits perfectly inside an 1" grey electrical PVC conduit, but I have some questions now that I read this:
You mean your mast is 1" grey PVC and the wood goes inside to stiffen it ? Thats fine. I did the same and used generous amounts of polyurethane construction glue around old broomsticks and pushed them in. So the broomsticks are pretty well sealed. Then I capped the top, but left the bottom open for any water to drain out.

PVC pipe is not an electrical conductor.
but filling the pole with construction glue bring it about the same price as the perfect fitted wooden dowel.
I didnt fill the tube, just liberally smeared the boomstick. Yeah, polyurethane construction glue (which expands a bit when curing) is about $4 a 10 oz tube vs $2 for Liquid Nails constuction glue. And once you open the tube, the shelf life is only a couple weeks. But compared to Liquid Nails, I think its worth it.
Just a tip to try to save some of the polyurethane glue.
Thats for the polyurethane glue. Polyurethane construction adhesive is different, looking more like Liquid Nails in color and consistancy and comes in caulking type tubes. :)
I wonder how acrylic plastic stands up to U.V. / sunlight ?
It doesnt last as long outside as LEXAN (polycarbonite) does, hence the price difference.

When I first built my greenhouse, I used Tuftex UltraVinyl sheets from Lowes on the roof. (Vinyl Grow Clear)
They said it would last 7 years, and darn it, thats all it did last until it got yellowed and brittle, heh.

I replaced them with the Tuftex PolyCarb sheets, which have a lifetime limited warranty. :confused:

When new, the blueish tint of the Vinyl Grow Clear sheets was better for the plants than the pure clear color of the PolyCarb sheets.
Anyone have any idea what this stuff is ?
Yeah, landscaping stuff. Around here, road crews use it (backed with finer plastic mesh cloth) to hold back dirt, so the dirt doesnt go into a ditch or whatever. Definately lasts longer than 10 years, but the wooden 2 X 2 white oak stakes its usually attached to dont. But its long enough for the dirt to settle/compact naturally.
Now if you get my idea ... if you strech a plastic mesh like that across a frame, you have plenty of possibilites to secure GH antenna elements - practically, easily and however / wherever you like.
Not sure I catch your drift. Wind load is a big concern.
Wondering if anyone can suggest a preferred wood type to find for the 1" dowel, maybe a harder wood variety or one otherwise less likely to warp with moisture.
I used broom handles. Theyre generally made from a wood less likely to warp, like straight grained fir. And since for some reason I always keep the handle when the broom wears out, I had a lot on hand, heh.

Wondering what is the wall thickness of the aluminum tubing used by antenna manufacturers (would help me determine whether 0.0625" wall thickness would be okay).
Actually, that varies a bit. The gauge used by AntennaCraft is a hair thinner than used by the old Channel Master products. 0.0625" wall thickness would be more than OK, and you could even go thinner, as you dont need the stiffness that long (54" free standing ends) vhf low elements required.

and found some 1/4" OD ABS plastic, acrylic and fiberglass rods, some used as tent poles or kite poles, but I don't know how much they would bend, or whether they would snap in cold weather.
If theyre fiberglass with real fibers in resin, theyll hold up very well. Other 1/4" OD fiberglass to look for are hunting arrows and driveway markers. Like tent poles, they are very strong and light.
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