Best Plastics, Composites, Rubber for structural antenna parts

90165 Views 212 Replies 43 Participants Last post by 300ohm, Oct 10, 2013

stampeder

Discussion Starter · Nov 26, 2008 (Edited)

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.

41 - 60 of 213 Posts

DigiDad

· #41 · Jun 3, 2009 (Edited by Moderator)

Clic Pvc Straps

I stumbled across an item at my local electrical supply store which might be useful to anyone building with PVC40 pipe and struggling to fabricate plastic stand-offs similar to those used by commercial antennas.

I am referring to the following item:
Arlington Industries, Inc. NM2005 Clic PVC Strap (Quicklatch)
http://www.foxelectricsupply.com/co...etail.asp?qsCatID=26189&qsProductNo=ARLNM2005

I believe this PVC strap could be used to easily attach reflector rods and zig-zag elements on the outside of the PVC pipe for quick prototyping and quick changes before contemplating any final drilling and gluing. It even accepts a square nut behind the front opening for ease of use. I’m sure it would also work fine for the final build, but you might need to glue the plastic strap in-place and further reinforce the latch with screws to withstand outside weather conditions.

It is marketed as a pipe hanger, but by turning it around, it could become a versatile stand-off suitable for a variety of uses. Normally it is sold in paks of 100, but my local store sold me the ½” version singly for $0.36/each (just slightly more than a PVC tee or elbow). It also comes in ¾” and larger sizes.

Here is some additional info:
http://www.av-outlet.com/images/arlington/quicklatch.pdf
http://www.arlcatalog.com/Rigid/Langford_I.pdf

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300ohm

· #42 · Jun 3, 2009

Very good find, and its UV resistant.

Browsing around electrical supply stores is a harder than browsing home centers or hardware stores. But I know the electrical supply houses must have a lot of useful antenna building stuff.

genx

· #43 · Jun 3, 2009

DdDave said:
For some reason these are EXTREMELY hard to find in Canada (impossible for me north of Toronto, anyway). I looked in 5 stores and the only kind anyone had were the aluminum folded sheetmetal ones. I don't know if it's because they don't stand up to the cold winters, or maybe it's just not a common practice in this area, but they don't seem to exist around here.

I do agree they are a great construction material if available locally. I spent a lot of time going through every isle of Home Depot and Lowes trying to find some other similar plastic tubing and could not come up with any good alternatives.

Just wondering, was anyone able to get these in Canada? I am getting ready to build and may have to order online if I have too.

DigiDad

· #44 · Jun 3, 2009 (Edited by Moderator)

RE: Post #41

My local Lowes and Home Depot both have a pretty good PVC selection, but I couldn’t find this particular PVC strap there (unless it was hiding in plain sight, as sometimes happens to me). Don’t know if this item can be a hard-to-find item elsewhere.

If anyone has difficulty locating, you might contact Arlington at: www.aifittings.com

300ohm

· #45 · Jun 3, 2009

was anyone able to get these in Canada

I found them at Ace Hardware here, but their website says:

Principal Subsidiaries: Ace Hardware Canada Limited; National Hardlines Supply.

I also found them at my Home Depot, but you have to buy the nails with them, so that ups the cost a lot. At Ace Hardware, you just buy the ferrules for 15 cents each.

DdDave

· #46 · Jun 3, 2009

Just wondering, was anyone able to get these in Canada?

My new solution for hard to find items in Canada:

Drive to USA, drop wife off at the mall, drive to Home Depot or Lowes, buy parts, drive back to mall, pick wife up, drive home.

This solution works especially well now that our dollar is on the rise! I used this technique last weekend to pick up some #8 solid copper ground wire.

300ohm

· #47 · Jun 4, 2009

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)

DdDave

· #48 · Jun 4, 2009

The electrical supply houses are much cheaper

I know, but I was there on the weekend and didn't have the time to go searching for stores that would probably be closed anyway. I did a search using the GPS I had with me and couldn't find any electrical supply places close to where I was anyway. At least I got the wire, which was my #1 mission.

genx

· #49 · Jun 4, 2009

300ohm said:
I found them at Ace Hardware here, but their website says:

Principal Subsidiaries: Ace Hardware Canada Limited; National Hardlines Supply.

I also found them at my Home Depot, but you have to buy the nails with them, so that ups the cost a lot. At Ace Hardware, you just buy the ferrules for 15 cents each.

no luck in canada it looks like we dont have them here. You should open up your own storefront!

300ohm

· #50 · Jun 4, 2009

You should open up your own storefront!

Well, DdDave could. And then make the big bucks selling 15 cent ferrules.

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.

genx

· #51 · Jun 4, 2009

300ohm said:
Well, DdDave could. And then make the big bucks selling 15 cent ferrules.

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.

Well I paid just that 16 cents a ferrule. The only thing is that now I have 250 of them

. This was the last missing part for my build.

300ohm

· #52 · Jun 4, 2009

Thats enough for 4 or 5 houses !

genx

· #53 · Jun 4, 2009

300ohm said:
Thats enough for 4 or 5 houses !

or 10-25 antennas

mlord

· #54 · Jun 5, 2009

Mail order source for "unobtainium" G-H rod spacers

It seems worthwhile to repeat this information here.

There is a USA mail-order source for unobtainium spacer material, similar to what I use in my own antenna builds. They can ship by post, worldwide.

See the original thread for details.

This material is rigid fibreglass tubing, 1/4" inside diameter and 1/2" outside diameter. Perfect for spacing solid aluminium reflector rods in a G-H antenna build. Other diameters are also available.

Cheers

balm

· #55 · Jul 16, 2009

Anyone,

I bought these electrical conduit straps (in the sched. 40 - electrical dept at HD) and glued them together using ABS cement - yellow quality.

http://s638.photobucket.com/albums/uu110/stanicet/?action=view&current=IMG_0285.jpg

Will this hold up outside, and is it UV resistant?

300ohm

· #56 · Jul 16, 2009

Dont know. I would drill two small holes and put a black UV resistant wire tie in there for extra insurance.

balm

· #57 · Jul 16, 2009

Hmmm, yes, good idea...

I was thinking of using a small metal screw with nut, but from what I read it's preferable to not have ANY metal near and in between the phase lines...

Then I was thinking about nylon screw/bolts, but I couldn't find any, plus I dont rhink this would be UV resistant either!

300ohm

· #58 · Jul 16, 2009

Nope, white nylon is not UV resistant. Marine Derlin screws and bolts/nuts are though.

balm

· #59 · Jul 16, 2009

Alright thanks, I'll check out a marine shop, I hope that's quite common, thanks

johnpost

· #60 · Jul 16, 2009

balm said:
Anyone,

I bought these electrical conduit straps (in the sched. 40 - electrical dept at HD) and glued them together using ABS cement - yellow quality.

Will this hold up outside, and is it UV resistant?

those straps are electrical PVC. The electrical PVC conduit is marked UV resistant. I would think the straps, boxes and fittings are also even if not marked. Mine have lasted a decade and a half OK.

PVC gluing with PVC primer and PVC glue is solvent welding. The glue has solvent and PVC resins which dissolves some PVC and then it reforms new polymer chains fusing the pieces together. ABS glues might include ABS resins and solvents, may not give a long lasting piece for PVC.

Having close bonding surfaces is important to a good joint, that is why with pipe/conduit and fittings you sometimes have to muscle them in with dry fitting, they are made for lots of contact. I would file down some of each strap at the mating point to give maximum surface contact. where the parts touch apply primer, glue and put in contact without movement for a minute. you might use a spring clamp to hold together for that minute, less movement likely than with your hands.

With a good quality PVC joint it will fail somewhere other than the joint when it breaks.

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