4 DIY Port-A-Wraps

metaspencer

Active Member
Location
Urbana, IL
Hi all -- after reading on here in various places about DIY portawraps, I thought I'd try my hand at making a few: small, medium, a hitch-mounted version, and a take on a bollard. Some of the ones I mocked up are better than others and all are a little rough, but I'm posting in the event that others are making their own climbing, rigging, and roping equipment.

Some prefer store bought equipment of course, and that's fine. Maybe you see it as safer or better or not worth the trouble to make your own. But I've seen some pretty innovative and cool DIY tree gear out there.

So far, I've made: a bunch of slings, a few lanyards, a rope jack, a tree trolley, and these port-a-wraps.

A vid on making my 4 port-a-wraps is here:
 

Tom Dunlap

Here from the beginning
Administrator
Norm Hall and Scott Prophett were the originators of the Port-a-Wrap. The name is associated with one particular configuration of portable bollards. Even though the patent may have run out it seems respectful to not use their name for the tool.

@Dave Spencer came up with a version of a portable bollard he named Friction on Site or FOS. For some time ISC made them, I don't know if they still do.
 

metaspencer

Active Member
Location
Urbana, IL
Interesting history, thanks for that. I got the impression that "port-a-wrap" (and various spellings thereof) had become a generic term for related devices much like Kleenex, Taser, Xerox (for copy), or Google (for search). This is in part because Buckingham, Notch, Bartlettman, and several others are selling similar devices using that name.

I've heard of folks using tire rims ratchet strapped to the base of a tree as a base anchor, so wonder if related technologies preceded the "origination" you mention.
 

Cereal_Killer

Well-Known Member
Location
Ohio
Wow everyone's really jumping on the guy for trying to innovate and have fun? Not like he's trying to make a new product to sell, he's experimenting and learning and sharing.

Now if he were to be out to patent one of these to make money then yes I'd agree wholeheartedly that's wrong (and on that subject, I'm in the "what petzl did with the chicane is wrong" camp too) but he's just creating tools for him to use and showing his process and his testing.
If the goal is to kill innovation ya'll are on top of it! In no way did he claim he did anything original, just slight modifications to better suite his needs. Why start at the bottom when you can stand on the shoulders of giants.

The video isn't titled "I made a new device no one's ever seen before and the idea is all mine"...
 

Tom Dunlap

Here from the beginning
Administrator
Where is the wet blanket of smothering innovation?

THe use of language is totally separate.

Look at naming friction hitches. Jason Blake made an eponymous decision instead of using 'the hitch kinda like a tautline'. Now there are dozens of hitches with names to make them easy to understand.

Innovate away!
 

metaspencer

Active Member
Location
Urbana, IL
Wow everyone's really jumping on the guy for trying to innovate and have fun? Not like he's trying to make a new product to sell, he's experimenting and learning and sharing.

Now if he were to be out to patent one of these to make money then yes I'd agree wholeheartedly that's wrong (and on that subject, I'm in the "what petzl did with the chicane is wrong" camp too) but he's just creating tools for him to use and showing his process and his testing.
If the goal is to kill innovation ya'll are on top of it! In no way did he claim he did anything original, just slight modifications to better suite his needs. Why start at the bottom when you can stand on the shoulders of giants.

The video isn't titled "I made a new device no one's ever seen before and the idea is all mine"...
 

metaspencer

Active Member
Location
Urbana, IL
Interesting and rich resources. I've found, in my fiddling with different DIY friction devices (tied to a tree or the truck) that even the texture on the main pipe makes a difference. A bit of rust and patina has a nice slowing effect, though surely will show up on my ropes.
 

TheTreeSpyder

Well-Known Member
Location
Florida>>> USA
Correctamundo, water, oil, corrosion etc. change key CoF factor of mating surfaces coumpounding frictions calculated on.
Light corrosion will increase frictions until enough runs 'burns it off', then might need another turn to compensate..
.
i do tell grandson that is not age spot, that is patina' boy, whars yours? ;)


they're all portable bollards.

I've seen Viking age bollards and Phoenician too.
Yeah, that is right, just needed to carry around a ship as portable,
Instead of carry around tree as portable!



For capstan/bollard type frictions, my reference is:
Dr. Attwater's 1999 research paper "The Mechanics of Friction in Rope Rescue" (original link not available again, and this time MIA for quite some time, using Wayback Machine reference)
He calls these generically 'brake tube', we always said 'rope brake' also descriptively to function.
Right or wrong i never called it by by proper name of Porta-Wrap(had original version) unless to someone looking to buy etc. Dave Spencer ISA posts also helped theories too!
.
The research paper describes how pipe can be any diameter of same material mated to same rope and present the same amount of radial friction; for radial friction compounds by degrees not distance as flat friction does.
>>larger rope brake is softer arc on rope/retaining more efficiency
>>larger rope brake gives same brake force so more spread out frictions/heat
>>larger rope brake metal then is also bigger heatsink to the now less concentrated frictions also
BUT same frictions
.
As example it uses a CoF of nylon on steel .25 as base, this is a global standard/range shown in many guides(the EngineeringToolbox link)
Works also with amount of 180arcs as another multiplier
On page_6 shows 5x180arcs gives compounded friction value of 50, i read this as:
Control Leg/tailer man, has 50x the leverage over Load Leg>>2# Control Leg pull holds 100# Load (Leg)
>>like Control Leg in rigid lever of 50" with a rigid Load Leg of 1", 50:1 ratio
>>this and other numbers shown should ring bells and match experiences and link between experiences.
>>showing matching expectations in things not dealt with etc. as free confident expansion..
i have common flat/linear CoF's and also radial spreadcheat(link) made some time ago
>>the linear CoF's should match driving etc. experiences, and the radial arc CoFs should match rope brake experiences as well
.
i do call the turns a Friction Buffer, for if try to then pull load thru brake turns, they then work equally against you
>>a buffer region in either direction of pull
After rope brake/brake tube examples the paper seamlessly shows same math to rappel rack and fig.8
>>by virtue of collective arcs , even if sum is 1.74 180arcs
.
Verifed a lot of things for me at the time and also beckoned on with new light
>>also very key to my own sense of all this the 180arc
>>that also lends into my directional axis 'argument' of a retained directional affect from source focused linear force input forced into dispersed radial control
>>so force load is imposed on vertical or horizontal axis, and the 180s just change direction of force on that directional axis
This gives pulley effects, compounding/best nip etc. but all directionally
>>whereby i say all rope arcs have some of each reciprocal extreme effects of capstan vs pulley effects
>>compounding either dispersed radial frictions or directional axis force more
>>in reciprocal type trade off if one effect is shown more, the other recedes
Rope Brake study focuses on just one extreme end of arc power bandwidth
>>pulley the opposite at loss of (almost) all capstan effect
.
i call these out as all rope control mechanics are dispersed/radial controlled
>>Round Binding is nothing but, but then does not have the pulley and capstan effects(no linear input)
i define this as Round Binding against radial swell evenly, directionless, dispersed around
>>has no conversion to likewise dispersed radial control arcs, thus no conversion loss nor directionality from source input force
But ALL Hitches and Bends are focused, directional input of linear force thru Standing Part
>>converted to arc control, then see capstan friction loss
>>and pulley compounding directional as remaining directional influence from source input
Thus, a Constrictor or Bag Knot used to control radial input in Round Binding
>>loads rope evenly to nips w/o friction, as just a reflection force back w/o conversion, nor direction
Than if SAME Constrictor or Bag Knot used as hitch, now showing degrading frictions radially of capstan arc effects, and directional pull thru of pulley arc effects.

.
Blake's Hitch wikipedia quote: The first known presentation of this knot was made by Heinz Prohaska in an Austrian guides periodical in 1981; in 1990, he presented it in a caving journal, Nylon Highway. Separately, Jason Blake discovered the knot for himself and presented it to the arborist community in a letter to Arbor Age in 1994, after which it was enthusiastically adopted by arborists. It has since become well known under the name "Blake's hitch".
.
Thus called ProHaska by some IGKT etc., especially knot guru knudeNoggin; in respects, even tho he says that Heinz is not offended etc. by the Blake's name making the great hitch even more known, expanding usage quickly etc.
 
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flushcut

Well-Known Member
Location
Delavan, WI
I would be very cautious with your trailer hitch friction device. I have serious doubts that your MIG welder has the power to weld into that 1" plate. And clean off all of that rust before you use them, your ropes will thank you. Thank you for sharing.
 

metaspencer

Active Member
Location
Urbana, IL
I would be very cautious with your trailer hitch friction device. I have serious doubts that your MIG welder has the power to weld into that 1" plate. And clean off all of that rust before you use them, your ropes will thank you. Thank you for sharing.
Thanks for that. I think you're right about the rinky-dink MIG I've got
 

flushcut

Well-Known Member
Location
Delavan, WI
You're welcome.
Clean/grind/sand the metal down to shiny clean fresh metal before welding, any welding, and on thick sections some preheat would help greatly. With your machine 4-500*f of preheat of the hitch before welding would really help, as well as joint preparation V out your joints and make sure you are watching the puddle flow into the bottom of the joint.
Stay safe and keep on keeping on.
 

metaspencer

Active Member
Location
Urbana, IL
You're welcome.
Clean/grind/sand the metal down to shiny clean fresh metal before welding, any welding, and on thick sections some preheat would help greatly. With your machine 4-500*f of preheat of the hitch before welding would really help, as well as joint preparation V out your joints and make sure you are watching the puddle flow into the bottom of the joint.
Stay safe and keep on keeping on.
Dang preheating! I had intended to do that but it slipped my mind. I think I'll redo it ... big thanks
 

TheTreeSpyder

Well-Known Member
Location
Florida>>> USA
With nylon on steel standard FLAT/linear CoF .25 as in the att_frict research paper examples.
From spreadcheat guide made years ago:
cof.25-for-nylon-on-steel-turns-chart.png
180 arcs​
degrees contact​
friction leveraged​
names​
odd 90s comparisons​
.5​
090​
1.48​
x​
1.00​
180​
2.19​
Turn​
1.50​
270​
3.25​
x​
2.00​
360​
4.81​
Round**​
2.50​
450​
7.12​
x​
3.00​
540​
10.55​
Round Turn(RT*)​
4.00​
720​
23.14​
Dbl.Round**​
5.00​
900​
50.75​
Dbl.RT*​
6.00​
1080.​
111.32​
Triple Round**​
7.00​
1260.​
244.15​
Coil*​
8.00​
1440.​
535.49​
9.00​
1620.​
1174.48​

*knudeNoggin IGKT terms Dbl.RT and Coil (like for Prusic..)
** my personal terms, shoe horned in where none,
>>a Round is 360, Dbl.Round 720, Triple 1080
>> so that 360(Round)+ 180(Turn) = 540(Round Turn) logic etc.
'
These should HAUNTINGLY match experiences of such ropes on aluminum bollard/pipe/Porty as added and reduced turns/wraps;
so much so as to give a deeper feel to a now more tangible fabric of linked rather than separate points.
As to be so consistent, to confidently expand experiences with chart as also fills gaps.
>>IN THIS EXAMPLE: ~10xLeverage and 3x180 (Round Turn), then double that leverage for each successive 180 added!!!!
>>the higher CoF, the more this holds true plus some, like on wood.
>>higher CoF's go to tripling quading multipliers at some point for each added 180...
.
Perhaps light going on as can now more fully understand what happened before in some incident that is now just logical.
Also, shows perhaps should think of adding half circle 180 arc Turns, rather than full wrap 360 a Round increments. Over and again outside of this concept the 180 shows as key factor. From linear force as handled source input, 180s become simply the direction reverses on SAME LOADED AXIS of Equal and Opposite forces, lending right in/consistent with pulley effects of the opposite end of the arc power band/bandwidth range... Keeping the eye on the ball here, is not a 360, but rather 180 ball by that measure!
.
'Pasting' (my made up term) Turns tighter to 'rope brake' device, exaggerates the friction effects more;
just as a crossing/'frapping' turn does over another seated rope part in Clove etc.
.
Dyneema is closer to Teflon CoF literally, so these numbers ain't for that, but does explain why knots so tough to secure in the material !
.
In actual tree usage, a feel for the pattern on the fly, to command what happens, and read what happens as it is in progress, is more important than the school boy math that uncovers the pattern, and gives confidence in pattern as a logic. Also, how this can change with mated materials change, full spreadcheat can help fill in gaps, extending off real experiences with chart numbers science .
.
Turns on branch more base friction CoF, bigger branch is stronger, but an RT on smaller branch gives same brake force, but of more concentrated friction heat into smaller area, and less rope efficiency/usable tensile retained.
Rope itself does not get any weaker, just delivers less usable support
>>EXACTLY as a slanted(reduced math) vs. straight(full math) table leg would
>>for it's displacement against vertical space (height attained)
>>and it's displacement against vertical load (support attained)
 
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treesap

Well-Known Member
Location
east TN
im having my dad build me one today, just ordered 18ft of 5/8" tenex tec to make a dead eye sling, got 10ft of 5/8" bar for less than $10, and an old winch drum for free, gonna cut the flanges off the drum, and weld up the pins, and loop, going to be SUPER handy


also, Treestuff has code "FREESHIP" that negates ALL shipping cost, standard, 1 day, doesnt matter shipping is free
 

metaspencer

Active Member
Location
Urbana, IL
im having my dad build me one today, just ordered 18ft of 5/8" tenex tec to make a dead eye sling, got 10ft of 5/8" bar for less than $10, and an old winch drum for free, gonna cut the flanges off the drum, and weld up the pins, and loop, going to be SUPER handy


also, Treestuff has code "FREESHIP" that negates ALL shipping cost, standard, 1 day, doesnt matter shipping is free
Boom! Sounds like a DIY masterpiece!
 

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