Doppin techniques w/vid

Thanks for the post minerken! I've been meaning to make a post about this but since Friday I've been buried in a fence building project that still has quite a ways to go.

All - I have recently become a recipient of one of Ken's dopping handles and heads and I can truly say that I was extremely impressed with the design and craftsmanship. I've been free-handing for a while but it's been leading to a loss of skin because my wheels are fairly tight together on my home brewed cabbing machine. Lately I've been playing with the idea of dopping again and Ken's device as rockjunquie has attested to is well-designed and it feels as good in the hand as anything I've ever tried. Personally I think he should be asking quite a bit more for them with the amount of time he spends on them but that's another subject. I especially like that he made mine of a certain shaft size and showed me how I could go down to my local hardware store and purchase materials for more heads if needed.



On the subject of releasing - whether it's Ken's heads, or nails, or aluminum rod, dowels, or ... I've always just had a hard time with it and don't feel like I've ever found the "perfect" combination. Sadly, to me, dopping equates with breaking stones trying to get them off and I just can't get past it. I've tried acetone several times in the past and it just doesn't get it done for me given the wide range of materials that I'm working with at any given time. In this example picture this is a medium hardness orbicular rhyolite I call "wildflowers" - I work with it a lot. I soaked it in acetone overnight and when putting some pressure on it the dop broke loose and took a deep divot of material with it. Ken's theory is probably correct that the glue soaked into the material.



The "best" combination I've found to date for not breaking stones was poplar wood dowel with a healthy dollop of JB Weld - with removal being done with a mini hacksaw blade held very close to the stone. In that method the glue is just such a pain to mix and apply and keep the sticks secure long enough for the glue to set. Based on the mild success I had with that system, I'm toying with the idea of continuing to use these metal heads but finding a soft plastic sacrificial layer to add between the metal and stone that allows me the option of the mini-hacksaw blade if they don't fall off from immersion in very hot tap water, or from being in the freezer overnight.

I read your post about it before and I've been trying a variation of it using *very* hot tap water and maybe one in four came off like that for me. Our water heater is set to much hotter than I would feel safe getting a stone on the wheels without burn marks. I also stuck the wildflowers stone in the freezer for two days but it didn't budge so into the acetone it went.

I haven't read this entire thread, but on the rare occasions I use a dop, I use Locktite gel. Never a problem. Fast and easy.
To remove the cab from the dop, I lay it on my soldering brick, heat the dop (a nail) with mini-butane torch, and in about a minute or two, the cab slides off the nail head.

That's really interesting information - I just now tested my hotest water and it's around 141 F at which point this says I'm still 100% bonded.

I'll try a test with boiling water and see what happens.

I'm only asking, as I don't know, but I find this stuff interesting.

I'm assuming that the cab itself will need to reach 212 F before the glue bond is weakened to 25% of initial strength.  Will the cabs survive that sort of heating in boiling water without fracturing?  Seems like kind of a risky venture, depending on any imperfections in the cab.  Then again, I really don't know, and that's why I asked.

When I use my Genie, I have spin on wheels for the 50 and 100k. I use those with diamond paste. I hold the dop close to the stone and touch it to gauge the heat. When it is almost too hot to touch, I pop off the stone. Our tap water is super hot. DH put it about 165, which I don't like, but that's pretty hot for tap water. I'm thinking that my stone gets a bit hotter than that. I haven't cracked any stones. I did a fluorite today and I did use the 50 and 100, but I didn't let it get hot. I popped it in acetone. I know all too well what happens when you over heat a fluorite. After I pop off the stone, the glue is usually still a little soft and easy to remove with my snap blade.

star bond CA glue. It's like super glue.

Boiling the stone and dop will work with CA.  Facetors use that technique a lot.  I would put the dop and stone in a pot on the stove and bring it to a boil -- let it boil for a few minutes or until the stone falls off.  Take the pot off the heat and let it cool down a bit before taking the dop and stone out.  If the stone is still on the dop, gently pry around the edge of the stone and it should come off.  Let the stone cool all the way down.

The biggest problem with heat sensitive stones is not getting them too hot or too cold, it's stress from extreme temperature change.  I dop with wax when I cut opal and I get those puppies pretty hot (too hot to touch).  I've never cracked one dopping.  Just let them cool down by themselves and all is well.

I usually use medium

eta the blue label