Ever seen this happen???

bvartist · Post by **bvartist** » Fri May 18, 2007 3:46 pm

Today I was heating the stem on my latest pipe. As I was heating, the stem got what appeared to be droplets of oil or resin on it. I know I wasn't getting the stem too hot because it wasn't even hot enough to bend yet. I thought WTF, wiped off the oil, and continued to heat the stem. Managed to get the stem bent but I had to wipe off more of the oil(or whatever it was!!) However, when I sanded on the stem I noticed thousands of tiny pinholes in it! And I can't sand out the pinholes without totally changing the shape. Needless to say, I decided not to use that particular stem. Anybody seen this before???

Yes, it was a pre-made stem! Feel free to flame away, I have my reasons for using them, and I'm sticking to 'em!

David

Leus · Post by **Leus** » Fri May 18, 2007 3:47 pm

David,

You just melted it.

bvartist · Post by **bvartist** » Fri May 18, 2007 3:54 pm

I don't think I melted it. The stem wasn't hot enough to bend when I saw the oil appear. I could still touch the stem with my hands. I've melted a couple, and this didn't react the same way. It also wasn't in a small spot, but the full length of the stem.

RadDavis · Post by **RadDavis** » Fri May 18, 2007 5:31 pm

I've had that happen, even with rod stock. I haven't had the oil appear though.

It seems like little clusters of tiny bubbles in the vulcanite, and there's nothing you can do but start over.

When it's happened to me, they appear suddenly while sanding.

Rad

Post by **KurtHuhn** » Fri May 18, 2007 11:39 pm

I've had this happen before as well. And ike Rad, even with rod stock. There's nothing left to do but start over at that point....

bvartist · Post by **bvartist** » Sat May 19, 2007 10:31 am

I've seen pinholes in premades and rod stock. But this is the first time I'd seen a stem weep some liquid. My guess is when the stem was poured the batch of rubber wasn't blended well or there was something left in the mould. Strange stuff! I'm just hoping the rest of the dozen of those stems I bought don't do the same thing!

JSPipes · Post by **JSPipes** » Sat May 19, 2007 6:05 pm

Incidentally, you can melt the outside of the stem and have the inside be too cool for bending. Don't ask me how I know

bscofield · Post by **bscofield** » Sat May 19, 2007 7:34 pm

whenever I saw the little pin holes it was heat related, like Leus said.

Tano · Post by **Tano** » Mon May 21, 2007 12:25 am

Hi Guys,

Would this have anything to do with the kind of heat you used. Flame or hot air?

hazmat · Post by **hazmat** » Mon May 21, 2007 7:53 am

Are you using a flame to heat it? I think Tano may be on the right track, but I'm no scientist.

bvartist · Post by **bvartist** » Mon May 21, 2007 8:29 am

I use an electric hot plate. I've melted every stem I've tried to bend using a flame source. And my heat gun just gets too darned hot!

hazmat · Post by **hazmat** » Mon May 21, 2007 8:41 am

There goes that theory down the window.

Have you experimented with any of the other stems in that batch?

bvartist · Post by **bvartist** » Mon May 21, 2007 8:50 am

Not yet! I hope the whole batch doesn't react like this one did.

hazmat · Post by **hazmat** » Mon May 21, 2007 10:03 am

May want to check a couple just to be sure. Maybe heating the stem a couple different ways to see what the results are. I've never seen this, but I've never used direct heat to bend a stem that I can remember. First few I used the PIMO-suggested method of burrying the stem in salt and putting the whole mess in the oven. A friend saw me doing this one day and suggested a hot sand box, so I got a small, deep cast-iron pot, filled it with sand and just heat it up on the stove. I just stick the stem I want to bend in, leave it sit for a bit and it's ready to go. Nice thing is, if you don't get the bend you want right out of the sand, let it cool and put it back in. No problems and never had any holes appear to date. Of course, that will probably happen now.

Tano · Post by **Tano** » Mon May 21, 2007 7:39 pm

I beleive the sand method is used by eye glass stores to bend the plastic frames. I have had good results with a heat gun. I place it in a vice, put on leather gloves and hold the stem far enough away while constantly mooving it. I also make sure that I test frequently how soft its getting. Too close you will burn it too far just means that it will take longer.
Just my experience.

hazmat · Post by **hazmat** » Wed May 23, 2007 8:24 am

Tano.. yeah, it is something eyeglass makers use. The friend who suggested I use a hot sandbox used to hang around in a local pipemaker's shop who used the same idea. I believe it was Dick Johnson, but can't remember exactly.

bvartist · Post by **bvartist** » Wed May 23, 2007 11:50 am

A hot sand box would definitely be a good way to go. I'd think it would be more even heating. Biggest problem would be regulating the temperature, plus it takes some time to heat up. I've thought several times about finding a small cast iron pot to use on my hot plate. Wouldn't help with the problem I had on this stem though, or I don't think it would. You guys would have to see the problem to see what I did. I still don't think the stem melted, well it did melt, but not by too much heat applied. I still draw the conclusion that something was wrong with the stem blank. (thats my opinion and I'm sticking to it!

)

hazmat · Post by **hazmat** » Wed May 23, 2007 1:12 pm

I use mine on a gas burner set somewhat low. I've never had the temperature get higher than I wanted it to be to this point. Heating up time is only a few minutes, surprisingly and it holds heat for a good bit. If I turn the burner off when the temp gets to, say, 230 or so I can still bend stems in it up to 15 minutes later. I'm looking to get a small propane burner for use in my shop so I don't have to haul my stuff into the kitchen. Being a bachelor saves me from the wife or significant other being put off by the practice, but when I go to make a couple over easy and there's sand on the stove top, I get a bit wrankled at myself.

Frank · Post by **Frank** » Wed May 23, 2007 4:26 pm

Before I got a heat gun, I tried the open flame method. It never worked well for me.

The heated sandbox sounds like a good idea, but I've always had perfect success with a heat gun and a simple bending jig I whipped up from scrap wood.