Ideal Canister Redux

[Paradox]

Having received several comments and suggestions on what should go into a superior holder for registers (canisters) on summits I have distilled them and (of course) given extra weight to my opinions.

Problems with current canisters.
1) Canisters get removed/stolen.
2) The registers get wet within three years.

No person or design can prevent anything from getting stolen. If a register is placed on private property and the property owner removes it, then shame on the person who placed the register without permission. However, If a register or anything else for that matter, looks like it belongs in its present place then it is less likely to be removed by an owner, guardian, crusader, or thief. IMHO, the current generation of canisters has a boorish appearance. Many look like they should be kept under a kitchen sink (PVC piping), and most should be kept in a landfill (pickle jars, etc.). Think about it. We are out there in the woods for the views, the flora, the fauna, the fresh air, yet our holy grail is a piece of plumbing pipe with stainless steel fittings?!?!

Allrighteethen, it seems to me that the thing that belongs in the woods is... WOOD. Trees are made of wood, signs that give us information are made of wood, boxes that hold the registers at trailheads are made of wood, bridges over streams are usually of wood. Wood belongs in the woods. Why not canisters? After all, most of the summits we place them on are in the woods.

I have designed and built a prototype wood canister and it appears below. If it looks out of place, it is because the background is not the woods, but rather a keyboard and computer screen.



Here are some additional pictures of the prototype.

Notable design features
1) Phylosophy:
A) WOOD is unobtrusive and what folks expect. (see above)

B) Cheap material cost. (see above)

C) Everything outdoors gets wet eventually, Hence make it to shed as much rainwater as possible, but allow it to dry as quickly as possible.

D) Condensation is the major source of water ingress, rain is secondary. How do I know this? Short answer: I don't. However, I have lots of firewood in my yard and if it hasn't rained in a few days the firewood is dry. Condensation can be addressed by consulting a few references. A Psychrometric Chart can be obtained frome the TRANE Company, a firm involved with HVAC equipment and applications. The chart and software can be downloaded for free. With this chart you can determine the amount of water that is available to turn a 3"X5" notebook register into saturated paper pulp on a daily basis if it is placed inside a container of non-hygroscopic material (PVC, polycarbonate, glass, etc.) Just a few numbers: typical daily diurnal temperature variation in the northeastern U.S. is about 20-25 degrees F depending on the season. Typical relative humidities are in the 55%-75% range during the daytime hours. Hence, between 1 -8 grams of water will condence on the walls of a 1 liter, glass/PVC container as the temperature drops during the evening hours. If the paper register is able to contact this water it will absorb it and gradually get wetter with time (days, weeks, months, years). Glass, PVC etc. absorbs essentially none of this water. BUT, my wood canister contains approximately 550 grams of wood and can absorbe approximately 60 grams of water. Yes... 60 grams of water under the same conditions!!! This was determined from Equilibrium Moisture Content vrs Relative humidity Graphs that can be obtained from many sources including Bruce Hoadley, Understanding Wood, Taunton Press 1980. The wood will keep the paper from getting soaked.

Practical Design Features
2) WOOD: pressure treated lumber (PTL), resawn to 3/8" thickness. The copper, arsenic, chromium of the treatment will render it relatively rodent resistant.
3) Designed and assembled such that all surfaces meet to an angle +/or joinery that will shed water.
4) Internal surfaces not painted or coated. Therefore, nighttime condensation will be adsorbed by the wood and then dry during the course of the day.
5) External surfaces likely to be exposed to water are coated with WAX. ie.: top, bottom, and endgrain. WAX is very cheap and excellent for preventing splitting of wood, and it is an excellent material for preventing moisture ingress. Dark colored external surfaces that will heat up in the sun and dry out the inside.
6) Internal register holder of metal mesh (hardware cloth) that will allow the notebook to stay away from the sides that will accumulate condensation.
7) No hinges to rust or freeze. Only moving parts are the door and the elastic cord to hold the door shut.
8) Two square socket drywall screws to hold it to the tree.
9) Weak link A) the elastic cord, without it the door falls off. B) Not bullet proof. C) Not Lawyer proof: while still widely available, PTL is under attack by trial lawyers.

 

[Tom Rankin]

Looks good to me, but in NY, canisters are edicted to be PVC.

 

[DougPaul]

Just a few comments:

5) External surfaces likely to be exposed to water are coated with WAX. ie.: top, bottom, and endgrain. WAX is very cheap and excellent for preventing splitting of wood, and it is an excellent material for preventing moisture ingress. Dark colored external surfaces that will heat up in the sun and dry out the inside.

The wax likely won't last very long. PTL for direct burial fence posts is supposed to last 20 years or so. I suggest straight PTL of a type suitable for direct burial. (I'm no expert on PTL--at least some forms are designed for direct burial.)

6) Internal register holder of metal mesh (hardware cloth) that will allow the notebook to stay away from the sides that will accumulate condensation.

Galvanized (or stainless steel) hardware cloth, I hope. An opening in the bottom will let moisture out. (But consider the effects of wind--the mesh floor should be high enough above the opening that liquid moisture will not blow up to the register.)

7) No hinges to rust or freeze. Only moving parts are the door and the elastic cord to hold the door shut.[/quote]
The elastic cord is a weak point. Sun will kill it fairly quickly. Consider galvanized or stainless steel (nautical) hardware. And a latch that will keep the cover from blowing up in the wind.

8) Two square socket drywall screws to hold it to the tree.

Even better if there is a space between the tree bark and the back of the register to allow the tree room to grow.


Re PVC canisters:
Many moons ago, I had a summer job in a plastic insulated cable research group at Bell Telephone Labs. (Back when BTL was the real thing...) One of the things that I learned was that the daily temperature cycling would (slowly) pump water into a sealed plastic container (or cable). Thus the contents of any sealed plastic container are likely to get wet after a while.

Reason (in case there are any physicists in the crowd ):
The temp of the inside lags the temp of the outside. Water is driven from warm to cold and the plastic is permeable which allows a slow flow of moisture from the warmer side to the colder side. Thus during part of the day water is driven in and during part of the day water is driven out with a net influx.

Doug

 

[Paradox]

Wax on cars and furniture doesn't last long because the layer is so thin. And both get rough use. I have actually dipped the important edges on this box in melted candlewax. The wax moves into the pores over 1/4". Wax has been used for centuries for this purpose when drying dimensioned lumber, because it prevents splitting. If the roof splits rain water will come in, game over.

Yes, galvanized hardware cloth, I've got lots of it.

Yes, the door and wind may be a problem. I'm going to put it on a tree at my home this weekend and see how it fairs over the winter.

The shock cord that holds the door shut will eventually fall apart. However, it is only exposed to the sun when the door is opened. I just replaced some shock cords on a tent that were over 30 years old. They were still usable its just that they were beginning to fall apart near the metal ties that were placed to form loops. I thought springs made of stainless were very poor at being springs due to the non-elastic nature of stainless.

 

[RoySwkr]

I'm going to put it on a tree at my home this weekend and see how it fairs over the winter.

Please post your coordinates so I can sign in and test it. It will also save me a visit to whatever peak it goes on.

 

[Kevin Rooney]

If you're really serious I'd suggest you remove the wire staples used in the box's assembly. Over time, they'll rust and likely cause gaps around them, allowing the opportunity for water to enter.

Might be better off starting with a box assembled with a waterproof, marine-grade wood glue.

 

[TCD]

I suggest Helmsman Spar Urethane (brushed, not sprayed), 2-3 coats on the wood. That will hold up for many years. Use 316 SST for the metal parts. A 316 SST spring (if you can get one) could substitute for the shock cord.

 

[Paradox]

Please post your coordinates so I can sign in and test it. It will also save me a visit to whatever peak it goes on.

Thank you Roy, the canister is now mounted near the summit of Mt. Paradox 780': NAD27 19T 0286173 4848381, be sure to visit our fabulous museum and gift shop!

... Even better if there is a space between the tree bark and the back of the register to allow the tree room to grow.

Just screwed it up good (literally) with about 1/2" of room.

If you're really serious I'd suggest you remove the wire staples used in the box's assembly. Over time, they'll rust and likely cause gaps around them, allowing the opportunity for water to enter.

Might be better off starting with a box assembled with a waterproof, marine-grade wood glue.

On the test box about half of the galvanized staples are coated with wax. I have used one of the polyurethane boatbuilding glues.

I suggest Helmsman Spar Urethane (brushed, not sprayed), 2-3 coats on the wood. That will hold up for many years. Use 316 SST for the metal parts. A 316 SST spring (if you can get one) could substitute for the shock cord.

I have used spar varnishes in my boat building/refinishing experiences and they are great in areas that get alot of use/abuse. However, I believe parafin wax is perfect for this application. It is essentially impervious to the oxidative/thermal effects of sun. Studies have shown it to be the best water vapor barrier (better than epoxy and oil based alkyd varnishes for a given thickness, the only materials better are glass and metal foil) Another benefit is that it is almost free, with no scrap value (I had initially considered copper foil as roofing material.) The downside is that it is soft and easily abraded. Please don't walk on the top of the box, use it as a handhold, or allow sails and lines to run over the wax coated surfaces.

Thank you for the spring suggestion I'm looking into it.

 

[Paradox]

I suggest Helmsman Spar Urethane (brushed, not sprayed), 2-3 coats on the wood. That will hold up for many years. Use 316 SST for the metal parts. A 316 SST spring (if you can get one) could substitute for the shock cord.

The staples are only necessary for assembly of the box to allow the glue to set with proper alignment of the parts. Do you happen to know of a supplier of monel or stainless staples for a narrow crown Bostich stapler?

 

[MichaelJ]

What holds the pencil or pen in place? Is there enough space for multiple notebooks and multiple writing implements?

 

[Muddy2Shoes]

If varments chew the life out of pvc, they will have a great time with wood--regardless of type or finish. Stay away from anything elastic as most elastic cord becomes useless in the cold. Personally, I like the visibility of the white PVC and it takes a beating when you have to hit it a few times in the winter to open it.

If maintenance is needed to existing canisters, we should post the needed fix so the next person up can add a pencil, new plastic bag, etc.

 

[RoySwkr]

After seeing the quintesssential PVC register, I made a trip to Mt Paradox to check out the one made of natural materials. It was a little hard to find as it was not on the highest tree in the area, which presumably will be corrected in future placements. Please let me know its new home so I can add that peak to my list as I have already signed the register

Like future users, I did not bring the diagram with me and it was a little hard to figure out how to open it. I thought about writing LIFT HERE in indelible marker, but in keeping with its construction philosophy it might be better to add a small block or knob to pull on the bottom of the panel. Adding the words PEAK REGISTER would keep people from thinking it was a birdhouse.

 

[Ed'n Lauky]

Personally, I like the visibility of the white PVC.

The advantage of the white PVC is that it is a bit easier to find. If you have ever wandered around the top of mountain looking for the canister you know how difficult it can be to find the thing. Making the canister blend into the trees could make it next to impossible to find in some situations.

 

[Jason Berard]

Paradox, are there any new observations to report on this?

We have problems with moisture in the log books at the CT. River campsites, and are thinking of a new design. Currently the logs are held in a ziploc baggie in a metal mailbox. I know condensation is a major culprit...

The sites also flood, but I think I can solve that by raising the box height.

I'd love to hear how this has fared over the last year plus!

 

[TCD]

You could probably minimize the moisture by using doubled heavy duty Ziplocks, and putting a silica moisture absorbing packet in both the inner and outer bag.

 

[DougPaul]

You could probably minimize the moisture by using doubled heavy duty Ziplocks, and putting a silica moisture absorbing packet in both the inner and outer bag.

A silica moisture absorbing packet has a limited capacity. In a long-term high-moisture application like this one, I expect that it would simply fill up and cease to be helpful.

Doug

 

[TCD]

Yes, I thought of that, too. But I am guessing that the actual amount of moisture migrating into a heavy duty (say 5 mil) bag will be pretty small. It might be enough to make a paper logbook damp and musty, but not more than a silica packet could handle. Also, with doubled bags, very little moisture would get into the inner bag, and the silica should be able to handle that for an extended period.

Actually, I think the larger risk is people simply not completely zipping the bags. A small unzipped opening is going to let a LOT more moisture in than would migrate through the plastic.

When you have a bunch of untrained folks opening and closing the containers repeatedly in an uncontrolled environment, it's hard to assure containment...

 

[Brambor]

bottom opening

Perhaps designing something with bottom opening instead of the top. Water will not get in. Some kind of PVC pipe attached to a metal (wooden) pole that will pull from the bottom

 

[DougPaul]

Yes, I thought of that, too. But I am guessing that the actual amount of moisture migrating into a heavy duty (say 5 mil) bag will be pretty small. It might be enough to make a paper logbook damp and musty, but not more than a silica packet could handle. Also, with doubled bags, very little moisture would get into the inner bag, and the silica should be able to handle that for an extended period.

Read my earlier comments about day-night temp cycling pumping water into plastic-jacketed cables. The lower part of a cable span between poles could literally be filled with water.

Actually, I think the larger risk is people simply not completely zipping the bags. A small unzipped opening is going to let a LOT more moisture in than would migrate through the plastic.

When you have a bunch of untrained folks opening and closing the containers repeatedly in an uncontrolled environment, it's hard to assure containment...

Always a hazard with random users...

The plastic bag could protect against short-term wetting, but as noted above, it may not be helpful in the long run.

IMO, a container that is open on the bottom (through a tube or housing extended below a floor) that is long enough that water will not blow upward) is likely to be best, but I haven't tested it.

Doug

 

[Brambor]

minor idea

PVC pipes are cheap.

1. Buy two pvc pipes. One larger. The smaller one should fit inside the larger one.

2. Buy caps for each of the pipes.

3. Buy 4 rubber plugs

4. Buy a durable lanyard or guy line

5. Take the large cap, drill minor hole to thread a lanyard.

6. Take small cap, drill minor hole to thread a lanyard

7. Cut lanyard 1.5 the length of the larger pvc pipe

8. Thread the lanyard though the inside of the cap and plug with rubber cap. Make a knot large enough to prevent the lanyard from escape.

9. Place large cap on the large pvc pipe with the lanyard inside of the pvc pipe so that the 1/3 of the lanyard sticks out

10. Attach the small cap to the lanyard with rugger plug

11. Attach (GLUE) the small pvc pipe to the small cap on lanyard and attach bottom pvc cap to the small pvc pipe.

12. Slide small pvc pipe into the large pvc pipe and attach bottom pvc cap.

13. Attach pvc pipe to a wooden stick with hose clamps.

14. Stick the Stick into the ground

15. open the bottom cap - the small pvc pipe slides out, open the small bottom cap and hide your journal. Replace caps.

16. done

P.S. Label external PVC pipe with notice about journal and instructions on how to open the canister.