Application of Fillers

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Simon Burke
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1 Application of Fillers Interfill 830, Interfill 833 and Interfill 835 including fast cure versions The ability to profile large yachts is a key element in the paint processing. It is the most labour intensive feature and often the most difficult. Filling tends to be a wasteful process with as much as 50% of the material being sanded off, thus presenting a dust hazard both to the operator and to the final finish unless high standards of cleanliness are observed. Prior to Filler Application Standards and control of fillers is of paramount importance. Controlled storage is equally as important to paste like materials as it is to liquid paints. Cold fillers apply badly, are prone to pull on the fairing battens and are highly susceptible to microaeration, resulting in pinholes or worse, larger occlusions in the film. Fillers should ideally be stored between C (60-70 F) The texture of the filler at ambient temperatures has significance to the profile attained. If excess pressure is needed on the fairing battens then undulations in the profile will occur as the batten distorts. If the profile is to be accurate when the batten is drawn, the potential to maintain the batten to a given curve whilst drawing off excess filler is a pre-requisite. In cases of filling straight panels, the same level of accuracy is required especially where raised filler meets portholes or surrounding central depressions. Record the following in the coatings diary: Record batch numbers to be used Check actual weight of fillers to ensure it is within recommended limits Note conditions at time of application The mixing exercise, when using paste like fillers such as Interfill 830 (YAA867/YAA868) and Interfill 833 (YAA813/YAA814), is of paramount importance, so check both before and after application for evenness of colour. Ensure air is not incorporated during the mixing process. The entrapment of air in fillers, whilst not necessarily evident during the new building process, will ultimately become manifest as blisters or craters (depending on temperature) as air within the void expand and contracts. Since quality fillers are manufactured under vacuum, and therefore essentially devoid of air at the point of manufacture, the inclusion of aerated fillers within a paint scheme may well invalidate guarantees. Always check for air inclusion before application. All fairing battens and blades should be checked prior to commencing the filling process to ensure the edges of the blades are smooth and devoid of defect. are smooth. 1 of 5

2 Filler Application Interfill 830 Application techniques vary widely between fairing contractors and a full discussion of the various approaches would not be possible in the limited space here. Below are some basic pointers for those approaching this for the first time. For a more detailed discussion, contact your International Paint Technical Representative. Spread mix out on a board to avoid excess heat build-up, and to keep the working life as long as possible. Apply firmly in an even spreading action. When fairing a hull, two or three 'cross coats' of Interfill 830, applied before any extensive sanding work, will ensure the original shape in maintained. When hardened, sand to profile using abrasive paper. Where large areas have been faired, sand with a long-board (minimum length 1 metre) to achieve the curvature of the hull. Scratch marks in the surface of Interfill 830 should be filled with Interfill 833 or Interfill 835 for those persons preferring spray filler for the refining process. After Filler Application Note actual quantity used in the filling process. Pinholes and occlusions in filler greatly increase the labour content and are a key factor in many of the delays occurring on larger vessels. Outside of aspects relating to storage, air may be introduced into the combined components by over-zealous mixing. (see earlier paragraph) That apart, voids of this nature must be filled, as they will cause defects in the paint system. It is normal practice to rub down/sand the filled surface with coarse grades of paper e.g or grade wet or dry (depending on product type) - this will cause certain voids to become enlarged whilst other smaller holes may become filled with rubbing debris. You are advised to check the grades of paper to use for sanding various stages of the paint scheme as outlined in The Importance of Good Sanding Practise to ensure the correct grade is chosen for the product of your choice. Using the wrong grade, even at this early stage, may result in a substandard finish. It is essential that sanding debris be cleaned away before a decision is made regarding the forthcoming procedures to be adopted. If the profile is reached after rubbing down, the need for finishing filler (e.g. Interfill 833) becomes limited to filling small pinholes and scratches often evident after rubbing down. If minor irregularities still remain a thicker application of Interfill 833 or even further applications of Interfill 830 may be required. The degree of cure can be measured by using a Shore D hardness tester and the results recorded in a table or diagram to give a representation of the hardness of filler over the vessel surface. Sometimes omitted from the contractor s itinerary is the need to radius all angles. It is poor painting practice to allow angles to exist where dirt, seawater and possibly cleaning fluids can collect. All corners should possess a radius. The foregoing applies primarily to the application of Interfill 830 (YAA867/YAA868), heavy-duty yet lightweight filler with good anti-slump and sanding properties. It is envisaged, however, that some refining of the Interfill 830 will be required. 2 of 5

3 In practice some pinholes and occlusions will occur and the occasional depression or scratch will be present. Attending to pinholes and occlusions with Interfill 833 (YAA813/YAA814) will be ineffective unless good lighting is available. Even with this facility and with a distinctive green colour making it easy to see against the classic grey of the Interfill 830, it may prove necessary to repeat the process several times over. As a final check, it is a good idea to roll a thin coat of primer over the surface to highlight any remaining problems in the knowledge that this coat may be rubbed away. Interfill 830 Fast Cure (YAA867/YAA869) is particularly suitable for application over large areas at lower temperatures and also for filling smaller areas when rapid sanding or over-coating is required. It possesses all the other properties associated with standard Interfill 830. Be aware that by definition the nature of fast cure products is to have a pot life shorter than for standard products. Do not mix excessively large amounts as this generates heat (exotherm) that results in a rapidly solidifying product. Check the data sheets for pot life figures. Interfill 833 Easily Sandable Finishing Filler Interfill 833 (YAA813/YAA814) is smooth to apply, as it incorporates extra fine grade extenders, and cures to an easily sandable surface. Interfill 833 is ideal for the applicator that prefers using filler battens and blades during the finish filler process. The green colour of the filler allows for easy visual assessment of the rectification of fine defects. Interfill 833 Fast Cure (YAA813/YAA815) as the name suggests, cures very quickly. It can be sanded and over-coated much quicker than the standard product making it ideal in the M&R field or for larger areas where the temperature is relatively low. Note: Once the sandable time of fillers has been exceeded it should be sanded to promote good adhesion. Sanded filler may be left for a period up to 3 months before over-coating with further epoxy filler or with Interprime 8 series. In certain environments, particularly during large temperature and humidity changes the surface of the filler may be seen to possess a greenish hue or in the case of Interfill 833 the green colour looses it distinctiveness. Should this occur it is advisable to sand the filler surface to remove this discoloration even it the 3 months period has not been exceeded. Interfill 835 Sprayable Fairing Compound For the applicator preferring a sprayable fairing compound Interfill 835 (YAA855/YAA856) is also available. Red/brown in colour and easily sandable, again we see good colour differentiation between the sprayable fairing compound and heavy-duty filler to aid the applicator. Application should be by conventional spray (pressure pot). Typical gun settings would be a mm fluid nozzle with bar (15 25 psi) on the pressure pot with an output pressure of bar (40-45 psi). Recommended wet film thickness per application is 800 microns. 3 of 5

4 Note: excessive wet film thickness of Interfill 835 may lead to retarded drying and a risk of solvent absorption into sub-coats. Keep to recommended application thickness. Interfill 835 ultimately dries to a smooth finish suitable for sanding with medium grade wet or dry paper. Up to 5% of thinners YTA910 or YTA920 may be added but it is advised that you do not exceed this figure for this could increase over-spray. If any further adjustments to application characteristics are required it is advised that the output pressure be slightly reduced. This allows for the application of a wetter coating without the risks of increasing over-spray. Two coats may be applied in certain circumstances when surface irregularities have not been overcome. However it is stressed that the over-coating times are rigidly observed. Interfill 835 should not be used as spot and build filler. Such use will result in cracking. Additionally it should not be used over inadequately sanded and prepared Interfill 830 as this will inevitably lead to sanding marks showing in the subsequent finish coat particularly in dark colours. Alternative fillers to the Interfill range Introduced into the range are Epoxy LG Filler (IAA700/IAA701) and Epoxy Finishing Filler (IAA650/IAA651). They are classic two-component solvent free epoxy based fillers that are suitable alternatives to the Interfill range albeit that they are used slightly differently in practise. Both products have excellent application, sanding and profiling qualities as a the following will explain. As with all two-component fillers the components should be accurately mixed until a homogeneous mix of uniform colour is obtained. Note that if the components are cold the do not mix well, so it is advisable to have them at room temperature for few days prior to use. Do not thin the products with epoxy solvents, as this will cause unnecessary shrinkage and solvent retention. Epoxy LG Filler The layer thickness of Epoxy LG Filler (IAA700/IAA701 will vary depending upon the roughness of the substrate, method and conditions during application. It is advised that the pot-life figures are studied before use and that the quantities of filler mixed are such that pot-life in the ambient conditions is not exceeded. Do not use the material once pot life is exceeded since application properties will be compromised. Epoxy LG Filler is suitable for application conditions between 10 C - 40 C. At temperatures under 10 C the product will not cure. To achieved best results, as with all epoxy-based fillers the humidity should not exceed 80%. It is also advisable to ensure that the surface temperature is 3 C above the dew point to prevent condensation affecting the material. Once cured the product can be sanded and whilst it is common practise to sand with P40 P80 grade paper it is recommended that further reference should be made to The importance of good sanding practise. It may be necessary to apply more than one application of Epoxy LG Filler to achieve a suitable profile. 4 of 5

5 Epoxy Finishing Filler Once the Epoxy LG Filler is suitably sanded and the sanding debris removed, the surface can be refined with Epoxy Finishing Filler (IAA650/IAA651). Being a surfacing filler it has great ease of application, spreads easily, filling the minor defects existing in the surface of the heavy duty Epoxy LG Filler. The application conditions that apply to the heavy-duty filler apply equally to the finishing filler. Once cured, the finishing filler is normally sanded with P120 P180 grade paper but it is recommended that further reference should be made to The importance of good sanding practise, since grit size affects the final appearance of the paint scheme. It may be necessary to apply several coats of Epoxy Finishing Filler until an accurate profile is obtained. It is also recommended that the final layer is continuous over the entire surface filler surface thus providing a protective barrier for the underlying heavy-duty filler. Epoxy Finishing Filler is also suitable for inclusion in paint systems for underwater use. Important notes when using filler Epoxy LG Filler and Epoxy Finishing Filler Depending on the profile of the vessel s plate work large amounts of filler is not always required and often the heavy-duty filler (Epoxy LG Filler) is omitted and Epoxy Finishing Filler is the sole filler used. This practise is acceptable but the reverse is not, and when using Epoxy LG Filler it must be totally covered with a protective layer of 1,000 microns (minimum) of Epoxy Finishing Filler. In the event that no filling is required it is recommended that an additional layer of Epoxy GP Coating be applied after the holding primer and prior to the application of Midcoat Flat HS (see specifications for further details). The information given in this document is not intended to be exhaustive. Any person using the information without first making further written enquires as to the suitability of the information for the intended purpose does so at their own risk and we can accept no responsibility for the subsequent performance of products or for any loss or damage (other than death or personal injury resulting from negligence) arising out of use of such information. The information contained in this article is liable to modification from time to time in the light of experience and our policy of information development. 5 of 5

Two coats are normally recommended. Some service may require mils DFT

Two coats are normally recommended. Some service may require mils DFT SELECTION & SPECIFICATION DATA Generic Type Description Features Color Finish Primer Dry Film Thickness High solids phenolic-epoxy High performance, high solids, epoxy lining that is recommended for a