Most substrates common to your application are best prepared by cleaning with a 50:50 mixture of isopropyl alcohol (IPA) and water.. Where heavy grease or oil is present there may be a need to first cut the oil or grease with a degreasing solvent, but this should always be followed by a IPA-water cleaning to ensure that any residue or film is cleaned up. Some plastics and paints may also have an additive which has a low surface energy and thus impede adhesion.

These may require removal by abrading, priming or using an adhesive or tape suitable for that surface.

One way to assess cleanliness is that a surface prepared for bonding should be as clean as one prepared for painting.

WHY ISOPROPYL ALCOHOL?

Isopropyl Alcohol is a good cleaner for many surface and adhesives. It is clean and does not have contaminants that leave behind a residue ;on the surface. The 50:50 IPA-water will clean many light oils an dirt from surfaces. The flammability is also considered lower that other petroleum based solvents. Note: when using any solvent, be sure to read the manufacturers directions and precautions for proper handling of such material.

PROCEDURE

Spray or wipe the solution onto the surface with a clean rag or paper towel until it is dry.
Sometimes it is better to use one rag for cleaning and one for drying. Cotton rags and heavy paper towels work best. Be sure to change rags and towels often to avoid smearing dirt and contaminating already clean surfaces. After cleaning, the tape or adhesive can be applied and the surfaces can be mated.

OILY SURFACES

On surfaces with an oily film, the 50:50 IPA-water solution is usually adequate, where heavy oils or grease is present, a degreasing solvent such as 3M Citrus based cleaner (tm), Heptane or mineral spirits are suggested to cut the film. The more oil present, the more important it is to change rags. These types of solvents usually leave a residue behind, and it is necessary to follow up by cleaning with the IPA-water solution.

HEAVY GRIME OR OXIDISED SURFACES

If there is a hard film of dirt, oxidised paint or oxidised metal, it will probably be necessary to abrade the surface. Scotch Brite(tm) pads (green or maroon) or abrasive paper 220 grit or finer can be used to cut the problem surface and expose a suitable layer on which to bond. Always clean the surface with the IPA-water solution as outline above after abrasion.

ABRASION - WHAT DOES IT DO?

Abrasion of a surface can serve several functions. It can be used to remove caked dirt or oxide as outlined above, it can be used to create additional surface area which may enhance adhesion, and it can be used to smooth the surface to obtain more flatness and therefore surface contact with the tape or adhesive. Very small scratches in the surface, generated with circular motion rather than a straight line motion are most desirable. A surface with lots of micro scratches in it can have 30-40% additional available surface area for the adhesive to make a bond.

PLASTICS & PAINTS

Some plastics and paints require special surface preparation because of additives which impede adhesion. 4952 VHB(tm) tape used on low energy materials will often have good adhesion to these substrates and should be considered for evaluation.

DO'S FOR SURFACE PREPARATION

1. Always clean with 50:50 IPA-water solution prior to bonding.
2. Clean heavily oiled of greasy surfaces with a degreaser solution prior to IPA-water cleaning.
3. Make sure surface is dry before applying tape or adhesive.
4. Change rags and towels regularily.
5. Abrade to remove heavy layers of dirt of oxidation.
6. Always assume surface to be bonded is contaminated in some way.