How to make durable, mold-resistant, glass bottle trail signs for the Ko'olau Summit Trail (KST).

In the previous post, I discussed ways in which to make a wooden trail sign that would be durable outside. In this one, I show you how to make an even more durable sign, for the KST, out of a glass bottle!

Surface mildew/mold will obscure even the most durable wooden trail signs eventually (on the KST as little as 3 years). In my search for a high gloss finish that would prevent sign-obscuring mildew/mold and algae growth, I realized that a high-polish glass might do the trick. Sometimes you find bottles on trails, and they have nothing growing on them. 

You'll need a bottle with a mouth that is wide enough to get your hand in somewhat. I found that a Laura Scudder's peanut butter jar, from Safeway stores, works well. There is a shorter bottle and a longer bottle (26 oz). The longer bottle will allow bigger text, but slightly heavier to carry in your backpack. Another good option is a salsa bottle. Most brands of salsa (like Tostitos) in the grocery stores come in bottles that have very wide mouths. At Foodland I've seen a brand called "Arriba!", in the ethnic food isle, that looks even a little wider!

It is very important to clean the jar properly inside with warm water and soap, and to rinse it well, so that no microscopic fatty film remains—the fat will keep the paint from sticking. It is just as important to make sure the label is peeled off on the outside and the glue is completely cleaned off; otherwise it'll be a perfect spot for mold to gain a foothold, and this is precisely what you are trying to prevent in the first place! I found that if you put it into the dishwasher, the remaining glue left over from peeling the label off by hand, will harden, and it'll be impossible to remove completely. The best way is: soak the bottle, peel of what you can, use a rag and "Goo Gone" ($3 at Lowes), and then wash the bottle by hand to avoid micropscopic dishwasher residue. 

All painting is done on the INSIDE of the bottle. I used a thin surgical-type nitrile glove to dip a finger in paint, and write the letters "KST" on the inside of the glass, with an arrow above and below. If your hands are too big for this, ask someone with smaller hands to help you. Or alternatively, a "hobby paint brush" like the kind you painted with as a kid, works well. Lowes has 'em for $3/set.

Unlike my sign in the photo, try fitting both the arrow and letters onto the flat face of the jar so that both are visible from the same angle at the same time.

Paint the background with a 1 inch synthetic paint spunge brush ($1; found at City Mill, Ace Hardware, or Walmart).

Buy a quart can of high quality exterior/outdoor semi-gloss 100% acrylic latex paint. It'll cost between $10-20. The second important point is that it should be a "paint+primer" combination, because the primer will make the paint stick to the glass. Glass is not an ideal substance for paint to stick to, so a high quality paint+primer is important. I used Valspar Duramax (from Lowes), in the photos below.

I used a dark green for the text and a bright yellow for the background. You need a background paint color too (added after/on top of, the lettering and arrows), for a couple of reasons: 1) block out sunlight that will enter and heat up the inside of the glass (like in your car!) and possibly cause the paint to peel and moisture to condense inside the bottle; 2) to make the sign highly visible.

The peanut butter jar lid is covered in an enamelized ink of some sort, and I'm crossing my fingers that it will protect the lid from rust. If you find at some point that your sign's lid has rusted in the mountains, paint your next sign's lid with a layer of "Rustloleum protective enamel".

Keep some water and paper towels ready for paint clean-up. The process of painting in the bottle is a bit of an art that requires a steady and delicate hand, so be warned.

Be sure to paint the text twice (let dry inbetween) and then the background twice (let dry inbetween), or until there is no more clear glass left. It helps to paint and dry the arrow and lettering separately, so that each can be rotated to the bottom of the bottle while drying...otherwise the paint of one of them will drip/run down the side of the bottle. The same goes for the background paint--paint it in sections and rotate to bottom to dry. Let the paint dry properly between each layer before doing the next the case of the background immediately behind the text, perhaps as many as 4 days, because I've found that the background layer tends to eat/bleed a little into the text if the text is only dried for 1 day.  The bleeding might happen anyway, but you aught to have plenty of text left. Also be sure not to get paint on the outside of the bottle, or at least clean it well immediately after spilling, so that mold can't find a home! After the final layer, leave the bottle open for a week to make sure that the paint achieves full cure before sealing it!
I did experiment with sanding the inside of the bottle with 120 grit paper in an attempt to get the paint to theoretically stick better. I pressed harder at some point because the sanding dust quickly prevented the paper from sanding effectively, and then the bottle broke in my hand. Miraculously I wasn't cut. I used the smooth and sanded sides of a big shard for the experiment, and it seems that the paint does NOT stick significantly better to the slightly roughed-up surface. So sanding brings no benefits apparently.

I initially sealed the lid with flexible water resistant "contact cement" in the top spiral (thread), but I think the fumes from curing may have liquidized the paint somewhat, so perhaps that's not recommended. Maybe it would work if one sealed the bottom-most spiral covered by the lid, in this way, with just a little cement? Seal the outside perimeter of the lid/glass snugly with waterproof and sunproof GE Silicone II caulk (Walmart has small tubes for $5). Elastomeric adhesive (Lexel; $8 at Lowes) will also work but might perhaps not last as long. These measures are to keep water out of the bottle and to stop the lid from rusting from the spirals inwards. It'll also keep ants out; the little buggers can find their way in along the spirals! It might also help to keep some curious person from unscrewing the lid. Just be sure to leave the last spiral in the glass that is not covered by the lid (the "neck"), free of adhesive/caulk, because it'll give the wire you'll use to attach the sign to something a snug groove to wrap around (see photo below).

There are many good areas along the KST to put up these signs, but they would be especially helpful along the section between Poamoho and Pupukea, where there are many places to get lost or disoriented.

Like I suggested for the wooden signs in an earlier post, buy a 10 ft PVC pipe at the hardware store for $3 (3/4 inch diamater might handle the weight of the bottle better in strong wind than 1/2"), and let them cut it into 2 or 2.5 ft sections. I like 2.5 ft. Then at home drill holes to attach two or three pole sections to each other with 1/4 inch stainless steel machine screws + nuts (other types will rust faster). This way, you can carry the pole in short and convenient sections in your backpack, and reconstruct it in the mountains to as high as you need it. Put in two bolts per overlapping section of pipe, to prevent the pipe from rotating around a single bolt.

Use a hacksaw to saw off one side near an end, into a sharp point. You can then easily hammer or push one 2.5ft segment into the ground/mud before attaching the others.

Drill two holes spaced an appropriate distance apart in one segment designated to be the top part of the pole, through which you can loop a piece of rust resistant wire (Hillman brand "Dand-O-Line" multipurpose green vinyl-covered galvanized wire; at Home Depot; $8) to fasten the bottle to the pole.

Paint the PVC pipe to adjust it's visibility (more/less; I'd go for more) and to give it UV protection. Wipe the pipe with a wet rag first to clean it. Let dry, and then paint.

Take UV resistant zip ties/cable ties in the event you need to tie it to a tree or a stake you hammered into the ground. I discuss some options in my post on wooden trail signs. You can buy a small rubber hammer and/or ground stakes for about $5-10. 

Once at the spot where you want to attach the sign on the trail, loop the Dand-O-Line wire tightly around the remaining glass spiral/groove not covered by the lid, twist it a few times maybe, and then feed it through the holes in the PVC pole and twist again to fasten. Remember to take a pair of pliers with wire cutters ($5) into the mountains with you to do this. 

I haven't had time to actually test a sign on the trail, but I have high hopes for it to last many years. It just depends if the heat causes the paint to peel inside the bottle at some point or not.  So far, the paint has survived a month in full sun in the garden.

The component with the shortest life might be the wire, but even so, it should last a long time, and is easily replaceable in the field.

While I might not get up on the KST soon, I hope that you and your signs do! Have fun making and putting up your signs. And Mahalo for contributing to the trails!!

[--July 2015--]

No comments:

Post a Comment