Sikaflex Marine Handbook

Notes on Substrates (continued)contain paraffin waxes as anairdrying additive. If bondingneeds to take place to this side thepanel needs careful abrasion,cleaning with Sika ® Cleaner-205and priming with Sika ® Primer-206 G+P or Sika ® Primer-215.Thin, transparent or only lightlycoloured GRP parts are UVpermeable(see the section undertransparent substrates).PlasticsSome plastic materials can only bebonded with mechanical/chemicaltreatments (flaming, plasma,chemical oxidation), e.g.polyethylene and polypropylene.As it is not possible to supply clearrecommendations for bonding ofmany plastic compounds, becauseof the many different mixconstituents and internal andexternal release agents, it isrecommended to contact Sika.Checks can be made on thematerials to determine the properpreparation suitable for yourpurposes and we can thereforeadvise you accordingly.AluminiumAluminium and its alloys aresupplied in sections, sheets, panels,profiles, and castings. Thepreparation instructions depend onwhich Sikaflex ® product isinvolved. For surface-treatedaluminium (chrome-plated,anodised or coated) cleaning withSika ® Cleaner-205 is often the onlypreparation needed beforebonding.Galvanised SteelGalvanised steel is either:■ hot galvanised (strip galvanised),■ electrolytically galvanised,■ hot galvanised (hot dip).For the first two substrates thebase is clearly defined and thesurface composition is mostlyconstant, whereas the surface finishof the third is not constant and theadhesion properties need checkingperiodically. We stronglyrecommend pretesting.22