Sandblasting - candidates?

[Sasquatch]

I am just getting set up to blast, and was playing around with a couple of loser stummels the other day. One had a little fissure that I thought I might dissappear, and the other had some streaky/pitty areas, but both seemed reasonably solid.

My results were I think acceptable, on the bulk of the stummel, not a real deep blast, but nicely detailed etc, but it did nothing for the fissure but make it worse, and all the black spots turned into runs and opened up stuff that I thought was basially all right.

So the net result was I had blasted stummels that were still rejects.

Perhaps if I took off more material I'd be happy, but I'm wondering if I'm not just expecting too much from the process... what makes a stummel a candidate for blasting vs a smooth finish? Does blasting accentuate flaws rather than hide them or am I just needing to practice more?

[KurtHuhn]

It takes a lot of practice. And you need to experiment with media to find out what works better for you and your setup. It took me a while before I could read the wood and understand what was happening under the blaster, and even now I'm surprised from time to time. It also took me a lot of experimentation before I found the combination of nozzle size, pressure, media, flow rate, etc that works well for me.

For flaws - yes, some will open up further, and that's the gamble you take when you decide to sandblast. Small pinpricks shouldn't normally open up to become large flaws, but they might. Fissures will definitely get bigger and deeper.

And on top of that, different wood will blast completely differently. The Algerian stuff I have blasts nothing like the Spanish stuff, the Corsican stuff is different from both, and the Grecian stuff is different still.

[Sasquatch]

Thanks Kurt. I'll play some more and maybe post some pics.

FWIW I figured (correctly) that the weakest part of my setup was going to be airflow, so I went with an aggressive media to sort of make up for it. I grabbed 80 grit aluminum oxide (highest grit they had!), and expected absolutely brutal results, but found that I got a very controlleable blast, reasonably deep and reasonably detailed first try, = hey this is EASY!!! But then I noticed that every flaw in the briar was scooped out as though a tiny guy with a dental pick had been in there - just completely clean! I was better off before!

I'll spend more time and do a nicer piece once I have a moisture trap, and see what comes of it.

[Sasquatch]

Well, here she is: Not bad, not great. Smokes good, cuz it's pretty on the inside, just like me.

[ErichPryde]

Whoa dude. I think with some practice, you'll be throwing out some nice ones!

[TRS]

That's a really nice looking pipe, I'm verey fond of the basic shape. Are you wearing longjohns?

[Sasquatch]

You're lucky I wear anything. Making pipes "au naturel" stirs the creative juices, dontcha know.

[Philthy]

You're lucky I wear anything. Making pipes "au naturel" stirs the creative juices, dontcha know.

That is just sick! I wouldn't think of going nekkid in my shop - I always wear my crocs.

(Slight intermission now while everyone tries to scrub that mental image out of your brains)

Oh and by the way Sas, although I think you can get a little deeper on the blast (I am still trying myself) I find that pipe to be beautiful. Let me know if you want to make another practice/shop pipe with crappy briar (large).

Images of your knife in progress sometime this weekend.

[Sasquatch]

I'm glad y'all like the pipe. It was definitely on the "going for sale" stream before I found some pretty dodgy areas, particularly one fissure that I just couldn't live with - I'm surprised smoke doesn't come out the side of the shank. But it's my good luck I guess, I get a pipe out of it.

I'm not sure if I can get a deeper blast with the media I'm using. This one I kind of stopped just so my compressor wouldn't melt, but I'll be playing some more soon.

[TRS]

This one I kind of stopped just so my compressor wouldn't melt, but I'll be playing some more soon.

What size of compressor are you using, by the way?

[Sasquatch]

It's just a little twin tank thing I run a nail gun off of. I will be upgrading to 10cfm @ 100 pretty soon. This takes a LOT of air to do.

[Leus]

That's a mighty nice pipe. The stem needs more work, but the stummel is just great.

[Sasquatch]

Thank you! I really like it, and am enjoying it thoroughly. The stem was rammed home once I decided that the pipe was no longer for sale because of the adjustments required (not shown) by the fissure in the shank. I might refine the stem some and polish it up, but.... also I might not!

I needed a new pipe anyhow!!

[ToddJohnson]

Hey Sasquatch,

Unfortunately, I think you're not likely to get much better results until you upgrade your compressor. A decent blast can be had with a smaller compressor, but by "smaller," I mean a 5 hp. 60 gallon single stage. I suppose it could be done over a long period of time with a very small compressor, but it's not very practical.

Once you get a larger compressor, try blasting with high grit glass bead at 100+ psi using a 1/4"-5/16" aperture ceramic nozzle. If you go down in aperture, go down in pressure and move the gun closer to the pipe. Also, keep the gun moving so as not to end up with a poorly blasted and lumpy pipe.

I've found that aluminum oxide is pretty worthless for general blasting unless you just want the pipe to drop from a group 4 to a group 3. You need something that is "sharp" enough to cut, but not so aggressive that it cuts indiscriminately. Otherwise you can blast all day but you'll never create any contrast. A really good blast is about the contrast between highs and lows, and for me, the sharper the better.

TJ

[Sasquatch]

Thanks Todd. I went with a sharp media because I knew my air supply wasn't great. No air and no cutting action = no good, I figured. I will be picking up a "competent" compressor this weekend, and changing/mixing the media as soon as I can find something smaller. The place I picked all this stuff up at just had nothing at all higher than 80 grit.

I did a real gentle, even blast on the next pipe, and it's a sandblast, but not what a guy would call a detailed, great blast (unless you worked at Peterson).



More air, smaller particles, a few more half-dead pipes, and then the world is my oyster.

[Sasquatch]

PS Look how clean sandblasting got my hands!!!

[mathias65]

I like the pipe though.