What is best treatment for a mast

cougarmeat

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I apologize for a non-boat question but I’m guessing the same supplies/materials apply. I need to make two masts to put a radio antenna up in the air - just a wire, not big hardware. I plan on using 2 x 3’s - maybe two parallel with a “spacer” - a 2x3 segment (maybe 2 ft long) sandwiched between the 8 foot lengths. I’m envisioning 8 ft 2x3’s running parallel (with a short 2x3 spacer between them) for three segment (24 ft) and the last 8ft 2x3 coming up from the middle of the last two parallel pieces - unless I keep two parallel all the way to the top (four 8ft segments = 32 ft high).

But I am lazy and without skills. What is the easiest way to treat the wood to extend its outdoor life? I’m pretty sure that somewhere along the process I’d paint them flat black to add a little stealth. And I’m guessing that whatever treatment I’d use, I should apply it to each piece before I put them together; rather than treat them after pieces are assembled.

This is one of those things that is so easy to think about and so difficult to actually DO. I justify my procrastination by our continuing below freezing temperatures at night and occasional snowflakes during the week.

This will probably be done outdoors on cheap, plastic saw horses with newspaper underneath to catch drips. I think I’d have to treat 10 pieces of 8 ft 2x3’s

To tie this back to kayaking, it will help me keep in contact with some boating nets (nets = a meeting place at a particular time/frequency. Not a fish catching device)
 

mick_allen

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I don't know the strenght needed, but would assume you'd have to account for fore and aft movement as well, so 2x3's on the front and back would also have to be added. So in plan there'd be 4 long pieces glued on the 4 faces of the short spacers.

In addition for continuity, you'd have to scarf each of the long pces together to make approx 4 pcs about 22' long w/ spacers betw. Scarf joints at 8:1 gives 12" overlap or loss per joint.

And then add the last 8' pce for an additional 7' ht [assuming 1' overlap]. Then get about a 29' mast or so.

-quick answer, don't really know it it'd work too well.

edited to add, maybe make the lower spacers wider, [rather than solid, just repeats of the main structure], so that the base is wider and narrow as it gets higher. That should be relatively easy to do, and if so, maybe the last lift could quite easily be 1x2 exteriors pcs supporten the last 2x2.
 

JohnAbercrombie

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Dec 7, 2011
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Victoria, BC
How heavy is the wire you are putting in the air? If it's a receiving-only antenna, or even low power TX, you might be able to get by with something very light. Think of typical POW setup or North Korea antenna!
When I had a ham setup, I had a 'Moxon' antenna about 24' up on the end of a couple of aluminum tubes that fitted together (ID=OD sorta thing), with a very sturdy 6' base structure- which also held the rotor..
Quite stealthy as I painted the tubes green/black and the antenna arms were very cheap 'crappie' fishing poles.
Something skinny with very light guys (Spectra?) might do the job for you.
Just make it strong enough to not break in 'normal' conditions. If it comes down in a storm and doesn't hit anything expensive, you can just fix it and put it up again.
I'm a wood construction enthusiast but sometimes other materials work better.
 

nootka

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Campbell River
Is this for an 80 meter dipole?
If so, you might need a center mast to support the feedline (and balun if you are going to use one).
Or you can use 14 gauge wire or bigger, but doesn't that assume strong masts with guy wires?
 

cougarmeat

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Sep 17, 2012
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Well … I was hesitant to go into detail in the Boat Building forum - except to discuss weather proofing the wood. This is for an HOA controlled neighborhood so any “beam” that rotates or something that needs three sided guying is out. I can abut the mast to fence corners and it will be pretty well hidden (i.e. non-objectionable). For a few years I have had a 30 Jackite telescoping fiberglass mast in one corner - it is hidden by a tree from the neighborhood side of the street. It's possible to spot from a main parallel commuter road on the other side of the house - but vehicles there are moving about 40 mph and occupants are focused on other things.

Our winds almost always come from the west or slightly south and the neighbor to my west has a big-ol-Ponderosa that blocks most of it.

My original Jackite telescoping fiberglass pole starts inside about a 10 ft PVC pipe and I’ve never had a problem with it. But it has suffered through many winters and just supports a long wire running up its length (folding back on itself for the last 3 ft when the top zip tie succumbed to UV rays).

My intension is to replace the fiberglass mast with two wooden structures, on each inside corner of the fence. Because of the property alignment, I have a pipeline to South America and hope to hang a 20M Half Square up about 25 feet. Then, about 5 ft above that, add a long wire horizontally across the top. Or make it an inverted L coming down one mast. Just playing in my mind here. Not sure about the interaction between the two antennas - maybe just one long wire. About anything would be better than what I have now.

I figured the 2x3’s with a 2x3 spacer between them would be ridged enough. Embarrassing note - I once tried to make a mast of PVC pipe; three 10 ft sections. When I tried to stand it up, it bent over like McDonald’s Arches - not a good afternoon.

One end of a 2x3 “pair” would be placed flush with the end of another 2x3 pair with a 2ft 2x3 between them - so that spacer would extend up about a foot for each pair - and held with four bolts (2 on each section) Maybe there’d be another 2x3 piece bolted in the middle of the 8ft pair.

Or I could stagger the two halves so they don’t meet flush at the same place on each side.

This isn’t something I’m good at. What did Harrison Ford say when the lady ask him to “fix the plane” in Six Days and Seven Nights (circa 1998) “…I’m not one of those guys …"

But I figured I had to treat the wood for weather proofing and so my posting here. Would flat black paint be good enough or do I need some kind of sealant and/or sanding. I figure if it lasts 3 - 5 years, that’s fine. I’m sure the bolts/hardware will cost more than the lumber. There is no way I can guy it from any direction the wind blows. So it has to be self supporting - as with the Jacket, I can start it inside a PVC pipe strapped to the fence corner. That would anchor the base.
 

cougarmeat

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Sep 17, 2012
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If I had the skills, I would certainly be building a sailboat in my back yard (I don’t think HOA can stop that), Of course, as all boat builders would do, I’d start with the mast first :)
 
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