In this Instructable, I will show you how to mask off a particular area prior to sandblasting to protect it, in this case I will be masking off the emblem on a bike frame. This type of masking is ideal for aggressive sandblasting at a close range for long periods of time.
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Signing UpStep 1: Cover Area with Vinyl
Cover the area you would like to protect from sandblasting with vinyl (with adhesive on one side). Use enough vinyl that it covers more than the area you wish to mask.
Step 2: Shape Mask
Using a sharp blade, cut away the excess vinyl around the shape you are masking off.
Step 3: Cover Area with Electrical Tape
Mask the area again over the vinyl with electrical tape. Electrical tape will absorb a lot of energy which will prevent the tape itself from being sandblasted away. Without the vinyl underlayer, the adhesive on the electrical tape will embed itself into your metal which can be removed by hand sanding. I use the vinyl underneath because the adhesive on the vinyl does not get embedded as easily.
Step 5: Sandblast Area
With these two layers of masking material, your project is ready to be sandblasted. Remove both layers after you are finished completely with your sandblasting.
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It's a small internet! I work in blow molding. However, we just use duct tape to mask the molds and use a razor blade to trim to the pinch offs.
What masking material would that be? and were can I find it? Please.
The Instructable is indeed helpful to those of us who sandblast. I didn't know that vinyl/electrical tape was capable of absorbing/deflecting the blast media. I'll definitely be using that combo in the future.
Question: Would a couple layers of electrical tape work (without the vinyl layer)? Likewise, would a few layers of vinyl work?
1. Up to a point "rubber" types of media absorbs and deflects most of the abrasives energy - it flexes rather than cuts - but it will wear through eventually.
2. The direction of the gun has to be aiming the spray in a way that is either near parrallel to the edge of the masking media or from the center of the masking media, to the metal around it.
- The maskign lifting is much like laying a sheet of paper on a flat surface and blowing at it - the paper will lift.
But if you blow at the paper, from the center to the edge, it stays stuck to the surface.
As much as the tapes have adhesive, and the bond may be quite good, with enough air pressure and hits by the abrasive, done close enough, for long enough, the abrasive blasting can lift the masking.
The same masking process is used in the sand blasting of windows - and if you do enough of the same pieces, you could make up a "permanent mask" out of silicon adhesive or rubber sheet - with it laid, clipped, / clamped / temporarily bonded into position.
The other thing is that you can paint on masking, using either latex rubber or slightly thinned neutral cure silicon - with turpentine, or even the contact adhesive.
As long as it's sticky and rubbery and is easy enough to get off either before or after painting without the rubber dissolving into the solvent.
Though that tends to be more of a time and paint depth issue.
Though with powder coating - it might just come away after baking.
Worth experimenting with I think.
You can tap out the head badge rivet and buy new hollow pop rivets (3/32" stainless) at a few places on the internet.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120986658043
This Raleigh Sports has a 1977 or later head badge (as evidenced by the solid rivet, and I don't know a source for these), the 1976 and earler bikes had hollow rivets (like 3/32 above) that allow you to see into the head tube of the bike.
This badge has already lost all its paint. A good friend of mine who restores Cinellis recommends that you cut down a fine paint brush until there are just a few hairs available, and then repaint the badge under a microscope to get it looking like new again.
Good luck !!
NOTE: It is used for precision masks in stainglass, & glue chip, & gold leaf, glass works...etc.
I did a quick digital snap shot and emailed it to the sign shop and they sent back a very good rubber mask. (we both fugged the images a bit to MAKE-IT-FIT.)
The imaged mask was to be wrapped around a tube much like this bike example.
Saved a lot of screwing around looking for the sandblast mat materials.
Your instructable was well done and informative.
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