UHMW

[w7lpn]

I was wearing out the nylon washers seperating the antenna base from the ground on my bug catcher. I got some remnants of Ultra-High-Mechanical-Wear plastic from a local plastics supply house. The workable size pieces were very cheap. Anyway, I knocked the steel washer out of my P/U towing stinger and hammered a 1"X3/4" circle cut out with a 1 1/4" OD hole saw drill blade, then placed a sguare remnant above and below, drilled 3/8" hole thru all 3 pieces, split & seperated a coax pig-tail. There was an immediate immprovement in SWR, ease of tuning, better power output on the meter, especially on the lower bands. Of corse the nylon washers wear, mash down flat or even get split or get cut, but 1/8" max seperation vs 5/8" minimal is what's helping me. Alan Applegate says use the natural color due to possible RF conductivity in the pigments of black or colored UHMW. I think that I will mount my mobiles like this from now on. I'm no guru, but hope this helps some tinkerer like me. Please add your hints & clues you've learned.

(WARNING! $mart-A$$ repellant added to this thread) http://www.qrz.com/iB_html/non-cgi/emoticons/tounge.gif

[w7lpn]

That repellant must be too strong. http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif

[WB2WIK]

UHMW = ultra high mechanical wear?

I never heard of that.

To me, UHMW always meant ultra high molecular weight, and that is a category of plastics.

Sounds like what you did works, so why change anything?

WB2WIK/6

[n4bfd]

On a bit of topic variation, what kind of bug catcher are you running? I picked up a 3.5 foot stainless steel stalk, 80 and 40 meter 4" coils and a few whips and such for 20 bucks at a hamfest awhile back, I have not had the chance to get them installed.

[w7lpn]

1. N4BFD- Hope you enjoy it. Cap hats are a vast improvement. I've got the Texas Bug Catcher 4" #480 coil, everything else is home built, scavanged etc. I use a 3' aluminum mast to a 36" loop type cap hat. The coil is mounted on a 4' X 3/4" stainless mast.
2. UHMW.. "molecular weight" is right. I was quoting my brother who was unsure of the right name & the supplier never corrected me. Thanks. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

[VE1IDX]

I have used the UHMW plastic for a few years now and never had a problem even with the black stuff. I did the microwave test first however. When I started a new job a couple years ago I was amazed to see UHMW everywhere on the machines. It provides a low friction high wear surface.It must be tough as we bolt 3/4 inch thick sheets of it to rotating reproducer machines in order to blank off a die and we use air impact drivers to do it.

[K8ERV]

Sounds interesting. Anyone know of a mail-order source? No plastics supply house around here.

TOM K8ERV Montrose Colo

[WB2WIK]

Quote[/b] (w7lpn @ Dec. 31 2007,17:23)]2. UHMW.. "molecular weight" is right. I was quoting my brother who was unsure of the right name & the supplier never corrected me. Thanks. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif
UHMW plastics have their primary application in vibraton dampening, not RF insulation.

Trust me, been doing this a long time...

[VE1IDX]

Quote[/b] (K8ERV @ Jan. 01 2008,15:49)]Sounds interesting. Anyone know of a mail-order source? No plastics supply house around here.

TOM K8ERV #Montrose Colo
One of many. Just Google for "UHMW".

http://www.sdplastics.com/uhmw.html

Or if you don't mind a little cross border shopping

http://www.leevalley.com/hardwar....6,43581 (http://www.leevalley.com/hardware/page.aspx?c=1&p=43210&cat=3,43576,43581)

This is what I typically buy. It is a 3 pound selection of odds and ends and very reasonably priced.

[w7lpn]

Quote[/b] (WB2WIK @ Jan. 01 2008,19:03)]Quote[/b] (w7lpn @ Dec. 31 2007,17:23)]2. UHMW.. "molecular weight" is right. I was quoting my brother who was unsure of the right name & the supplier never corrected me. Thanks. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif
UHMW plastics have their primary application in vibraton dampening, not RF insulation.

Trust me, been doing this a long time...
I'm sure you're right, but if it's durable, easy to work with, remnants are cheap, is there some other reason we shouldn't use it? Usually if something is specifically made for your purpose, the price goes up. Using scrap for another purpose other than intended is usually cheaper, until the demand for scraps goes up. http://www.qrz.com/iB_html/non-cgi/emoticons/rock.gif

[VE1IDX]

I wouldn't say the primary use is vibration dampening but rather providing a wear resistant contact surface. UHMW is described as self lubricating and having a were resistance of up to 10 times that of carbon steel. In the plant I work it is used everywhere to moving surfaces come into contact and since it is chemically inert it is safe for use in the food industry. (We make molded products for the food industry).

http://redwoodplastics.com/index.php?content=products_UHMW

[K8ERV]

Thanks for the link. As in many cases the hi ship cost kills the deal.

TOM K8ERV Montrose Colo

[w7lpn]

Quote[/b] (K8ERV @ Jan. 02 2008,09:26)]Thanks for the link. As in many cases the hi ship cost kills the deal.

TOM K8ERV #Montrose Colo
I would not be opposed to picking up some peices for you & shipping them. The plastics place with the scraps is right around the corner. No idea of shipping cost? It's kinda heavy for plastic.

[K8ERV]

That is very kind. Mostly interested in thin stuff for washers etc. Pls get an asst and let me know ship cheapest way, no hurry. Tom

tlamb@mesa.net

TOM K8ERV Montrose Colo

[wa8rti]

UHMW is common in woodworking catalogs. Comes in many lengths, widths, etc. Used for facing saw fences to make them more slippery, making guides to fit miter gauge slots, etc.

[kf4vgx]

I was wearing out the nylon washers seperating the antenna base from the ground on my bug catcher..



What do da "Bugs' think about it http://www.qrz.com/iB_html/non-cgi/Skin/Default/PostIcons/icon11.gif