?? 1st Attempt, Making Grip Abrasive from Bottle Glass ??

[boarderboy]

Am trying to use crushed brown and green wine bottle glasses to make an "intertwining snakes" graphic on a longboard deck.

Plan to abrade the pulverized glass in a tumbler to round off potentially skin-cutting edges. Have found conflicting on-line info re glass tumbling. Most seem to advise using no abrasive grit when polishing glass. (Not sure how I'd separate the glass from the abrasive medium anyway?)

I am debating now between using a "roller" gem tumbler or a vibrating one that's meant for heavier loads (cleaning rust off small metal objects or prepping shell casings for re-loads.)

Any thoughts on this?

Current plan is to use Wave Chaser's "salting" method, laying down a top-coat of urethane and then sprinkling the "glass sand" into the desired pattern.

Board has been fine-finished in several coats of quality polyurethane cut 50/50 with mineral spirits. Any advantage to using polyester or epoxy resin for the adhesive grip coat?

Any ideas appreciated, including the possibility that I don't need to polish the glass since it'll mostly be covered in resin, at least initially. I have a buyer for this board, though, and am worried about possibility of larger glass bits breaking off during long-term riding, creating a hazardous cutting surface for barefoot riding.

Many thanks!

BB

[Alaskan Rover]

I used to tumble rocks when I was a kid. Haven't thought of that in ages!!! I don't even remember what the heck got me into rock-tumbling in the first place...probably saw an ad in the back of Boy's Life magazine or something, because I think my project before that was raising Sea-Monkeys!

Anyway, from my rock-tumbling experience I've garnered a few pointers you may find helpful:

The tumbler I used was a horizontal rubber-barrel roller tumbler. If I remember correctly, the abrading grit was some sort of black silica. Starting off with coarse and ending with ultra-fine and then polishing powder.

Your situation, however, leads to a conundrum: I am not sure what size glass bits you're talking about, but I presume fairly fine. Rock tumbling, as the name implies, basically works via gravity, and is thus dependant upon the weight and mass of the objects to be polished.

I may be wrong, but I think in cases of minutia, the closer the size of the grit is to the size of the object, the less successful this abrading action is, unless over great time, (like for the making of ocean sand). Now, you can try to override that grit size/glass size ratio by going to a finer grit, but then its coarse-abrading characteristics are reduced...resulting in the conundrum I was alluding to, for to get rid of the sharp edges on the glass bits you need coarse grit. And round and round the conundrum goes...so to speak.

I don't know. Most rock kits come with at least 4 different coarseness' of grit plus polishing powder, so give her a whirl. I have no experience with vibrating polishers, so I am not sure, but something tells me that a tumbler would be a better bet for the glass bits I presume you'd be dealing with (0.5 mm or so??).

What size glass bits are we talkin' about, anyway?

The intertwining snakes sounds interesting. That's the 'Staff of Asclepius'. Is the guy an apothecary or a doctor??

I would definitely abrade the glass, as any resin, even epoxy resin, will wear-off over time, and you don't want sharp shards exposed, even if they're minute.

[boarderboy]

I was beginning to wonder if it was my breath. (More likely strident, sanctimonious environmentalism, but whatever...)

QUOTE=Alaskan Rover;307117] something tells me that a tumbler would be a better bet for the glass bits I presume you'd be dealing with (0.5 mm or so??).

What size glass bits are we talkin' about, anyway?

Not sure about size. "Winging" this one. Likely a mixture of dimensions, some a bit larger than the stuff normally found on grip tape.

Since I'm in a bit of a time crunch here, I'm "tumbling" both ways. Have a mixture of water, brown wine and beer bottle crushings, some coarse tumbling grit, and a half-lode of semi-precious tumbling stones rocking and rolling in a rubber cup tumbler right now.

Since the glass is Mohs' hardness 5 and the stones are hardness 7, there should be lots of abrading going on.

First thing tomorrow AM, I'm gonna use my landscape tamper cum garbage pale "pulverizer" to prep a batch of green glass. Gonna put that in a "vibratory" tumbler (I swear that's what they call it) in a dry brew of coarse leveling sand and pea gravel. Just polished off a Yuengling that will end up in that load...

(Ran into a Seagrove potter @ the state fair last year who uses crushed Yuengling bottles as the basis of a glaze mix for an entire line of his hand-thrown crocks...)

"The intertwining snakes sounds interesting. That's the 'Staff of Asclepius'. Is the guy an apothecary or a doctor??"

Neither. He's an NCSU undergrad, though a lot of our over-achieving plowboys do end up just down the road in UNC's med and pharmacy schools!

After I dry the glass, I'm going to filter it for size, dry it, and then lay down a thick coat of polyurethane as I X-acto off painter's-taped elements on the board. I'm then going to "salt" the glass onto the poly, and before it all dries, seal it up with a coat of similar spray polyurethane.

Finished varnishing the rest of the board today after I'd incised the guys name into the tail and "stained" the characters with an ultra-fine Sharpie. Last poly coat really made the lettering pop out.

Will post pics when done.

Cheers and thanks again!

BB

[boarderboy]

Since I'm in a bit of a time crunch here, I'm "tumbling" both ways. Have a mixture of water, brown wine and beer bottle crushings, some coarse tumbling grit, and a half-lode of semi-precious tumbling stones rocking and rolling in a rubber cup tumbler right now.

Since the glass is Mohs' hardness 5 and the stones are hardness 7, there should be lots of abrading going on.

First thing tomorrow AM, I'm gonna use my landscape tamper cum garbage pale "pulverizer" to prep a batch of green glass. Gonna put that in a "vibratory" tumbler (I swear that's what they call it) in a dry brew of coarse leveling sand and pea gravel. Just polished off a Yuengling that will end up in that load...

** but there is, of course, a learning curve ...

results soon

BB