Introduction
Applying the resist to the substrate is the most important step in the whole Sandblasting process. Not following these steps will cause damage to the item in the form of: frosting due to lack of taping up exposed areas, blow out of centers of letters due to lack of cleaning the surface or releasing air bubbles with the wire wheel.
It is important to follow the steps to ensure consistent and efficient production.
APPLYING RESIST IN COLD TEMPERATURES
- Heat up the substrate to take the chill off.
- Warming the resist prior to application will assist in better adhesion.
RE-ACTIVATING THE RESIST STICK SURFACE
The resist is normally tacky when it is ready to use. If the resist does not feel tacky because it has been over washed and dried for too long:
- The resist tackiness can be restored by applying the emulsion side to a cloth that been lightly coated with water, then applied directly to the substrate.
APPLYING TO LAQUERED SURFACES
On occasions you may need to apply resist directly onto lacquered timber, pewter tankards etc.. Remember the quality of the lacquer is an important factor. You may not notice any difference when applying/blasting/removing the resist to well cured lacquers.
As a guide treat all lacquered surfaces the same, the following need to be done quickly to avoid damage to the lacquer.
- Apply resist
- Blast at low pressure
- Remove resist as quickly as possible.
APPLYING RESIST TO ROUNDED SURFACES
Example of a round surface is a whisky glass or wine glass.
A whisky glass has one curve (but basically flat) and is not very difficult to apply the resist to.
A wine glass has a vertical and horizontal curve. Presuming it is a logo and text underneath, simply cut the resist at 10mm in, at an angel on either side of the resist -- they then become two independent parts. Apply the bottom half to the glass, release the carrier sheet on the bottom half, now apply the top half overlapping the two 10mm cuts you have made.
APPLYING RESIST TO ROUGH SURFACES
When working with rough surfaces such as brick or Powder coated substrates we need to make sure the resist will adhere to the substrate during sand blasting. This can be achieved by:
- Lightly heating up the substrate, this will help the resist to adhere better.
- Applying RZ-2 Adhesive to the resist for extra adhesion.
- It might also help for a very coarse surface to apply RZ-2 adhesive to the substrate.
In Summary
- Heat substrate to take the chill off it.
- Re-activate resist with slightly moistened cloth.
- FAST is key when working with lacquered surfaces.
- Round surfaces NOT a problem, just cut in 10mm.
- Heat and RZ-2 adhesive may need to be applied for resist to stick better.