Masking the rim for sandblasting?

[scotties22]

So I am getting ready to sandblast what I hope is going to be my entry into the carving contest. My question is: How do I protect the rim while I blast the bowl of the pipe? I have tried, unsucessfully, to mask it. Do I leave it bare and just blast the top of the bowl at an upwards angle and hope for the best? I'm at a bit of a loss. Any advise would be great.

[LatakiaLover]

Scottie,

Don't let the sand hit where you don't want it to.

Hope this helps.

George

[scotties22]

Geeeee....Thanks, George..


You do know who you're talking to, right??? (see tag line )

[LatakiaLover]

Actually, I know exactly nothing about sandblasting.

I just noticed that Rad wasn't logged in when your question came up, so stood in for him.

Please don't shoot me.

[Sasquatch]

I agree with George. Hope this helps.


I've successfully taped off the top of a pipe or other areas with masking tape or electrical tape. Duct tape doesn't work too well. And yeah, just try not to lift the tape - angle the blaster so that the top of the pipe is "hidden" or, direct the blast head such that the tape is taking the sand almost straight on. It's easy!

[scotties22]

That's kinda what I thought. Taping the shank and stamp area isn't a big deal. The top of the bowl on this pipe I just can't get the tape to stick to without running it dowl the bowl.

[oklahoma red]

Perhaps you could turn a piece of wood to a diameter that matches the diameter of the top of the bowl. Then turn a smaller diameter that would be a snug fit into the chamber. Turn that smaller diameter a bit undersize then wrap it with some tape to make a snug fit. Basically a custom fit plug. To be safe, pinch the top of the plug and the bottom of the bowl with one hand while blasting with the other. Avoid blasting straight into the joint between the plug and the top of the bowl. If the bowl is not round the same method should work if you can carefully contour the plug to match the shape of the top of the bowl. Another thought to seal the joint would be to run a thin string of modeling clay on the top of the bowl close to the edge. Insert plug, squeeze the crap out of it, wipe off the squeeze-out and have at it. Again, avoid shooting straight at the joint. With this method you might not need to have a plug going into the chamber. It would be a custom fit "lid" sealed with clay.
Also in the spirit of Rad: "hope this helps".
Chas.

[Rodneywt1180b]

Is the rim flat or is it tapered, curved or otherwise irregularly shaped? How thin is the rim? If it's really thin it could be the tape doesn't have enough surface area for a good bond.

The wooden lid idea is a good one for flat rims, could be a bit tricky to do with anything else though.

It's been many years since I've played with the stuff so I might be wrong but IIRC rubber cement can be painted onto a surface and you can peel it off after you're done. You could essentially make your own tape with it. Experiment on some scrap first to make sure it'll hold up to blasting.

I don't think I'd try silicone because silicone is known to interfere with finishes if you don't get every last bit of it cleaned off a surface.

Just a few thoughts,
Rodney

[andrew]

I've never masked a rim. I've never needed to. I blast up and make sure I don't hit the rim. Even if you do hit it, its not the end of the world, unless you REALLY hit it and blast a chunk off your pipe... that would suck.

Just touch up the rim after you're done if you do nick it.

[e Markle]

I blast up and make sure I don't hit the rim.

What he said. I don't mask it off.

[caskwith]

I sand the rim to about 500 when on the lathe if I intend to leave it smooth. Before blasting I mask it off with electrical tape, trimming the edges with a sharp knife. When blasting try to not to aim for the edge of the tape and hold it down with your hand if necessary. After blasting go back to the 500grit or whatever your finishing grade is and give it a light going over the crisp the rim edge and take out any little bits where the bead catches it then buff and wax as normal.

[Charl]

I do it like Chris, masking tape all over the top, including over the chamber. You do get different thicknesses though, so use the thickest you can get. I also have found a vinyl off-cut piece (the ones they use when doing sandblast patterns on glass) that I use for the stamp area. It's really thick, sticks well and it can take full on blasting without any damage underneath.

[Charl]

Sorry, I meant electrical tape and not masking!

[scotties22]

Yeah, sorry. I should have mentioned the shape of the top of the bowl. It is not flat at all. And the front (or whatever you want to call it) is higher than the back and it has a pretty good arc to it. It is sanded to 400 and has a coat of stain on it already.

The vinyl they use for glass is a great idea, Charl. As it happens I have a stained glass store (that does classes and sells supplies) right around the corner from the house.....sometimes I really do like living in the city . I think I will stop in there today and see what they have that might stay on the top of the pipe.

I thought about holding my thumb at the edge of the bowl as I blast, but my gloves are pretty big for my delicate lady hands and there is a lot of extra rubber around my thumb.

Thanks boys. I'll let you know how it comes out.

[oklahoma red]

If your glass shop can't help you, find a place that makes grave markers. They use what is known as monument tape in their blasting process. They may also call it sandblast stencil. Very thick but cuts well with an Xacto knife. Those places normally cut their letters and patterns with a computerized vinyl sign cutter.
Chas.

[RadDavis]

I've tried masking rims, but it's a pretty worthless endeavor.

I just keep from blasting the rim as best I can (There will almost always be a little overspray), and then hand sand any blast marks afterwards.

Rad

[The Smoking Yeti]

there is a lot of extra rubber around my thumb.

That's just weird.

Cheers!

Yeti

[scotties22]

Get your mind out of the gutter Yeti There's only room for one and I was here first!!

[d.huber]

Just touch up the rim after you're done if you do nick it.

Ditto.

Sent from my SCH-I510 using Tapatalk 2

[scotties22]

It turned out okay. I had one little spot that I had to touch up, but the rest of the rim was fine. Thanks, boys.