TECHNICAL BULLETIN #200

bare fiberglass bottom paint guide

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CONTENTSNew Fiberglass No Sand Primer 1

Systems to Paint Bare FiberglassBottoms 1

Boat Hull Preparation 2

No Sand Primer System 2

Interprotect System 3

Sanding System 4

Painting Tips 4

Associated Products 4

How Much Paint do I need? 4

SYSTEM 3: SANDING METHODPainting bare fiberglass, Polyester, Vinylestergelcoats or epoxy resin.

Use this system when painting new boats or where old antifoulingpaint has been removed.

1. Now that the hull has been properly prepared as per the Boat HullPreparation instructions on page 2 proceed to step 2.

2. Sand the hull thoroughly using 80-grit sandpaper. Rememberto change sand paper frequently.3. Repair all scratches, nicks and dings by sanding those area with80-grit sand paper then remove the sanding residue usingFiberglass Solvent Wash 202. Fill the repair areas with InterluxWatertite Epoxy Filler. After Watertite is cured sand repaired areawith 80-grit sandpaper until areas are smooth. Remove sandingresidue using Fiberglass Solvent Wash 202.4. Apply two coats minimum of Interlux antifouling paint.

International Paint, Inc.2270 Morris AvenueUnion, NJ 07083® and ® are registered trademarks of Akzo Nobel.

Products marked ® are registered products of International Coatings Ltd.

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Remember prior to sanding the hull,hull cleaning is very important.Sanding heats any remaining wax onthe surface, and then pushes it intothe open pores in the gelcoat. Thiswill keep any antifouling paint or primer you apply from adhearing.

An important consideration tohelp protect against osmoticblistering of the gelcoat is theapplication of the InterprotectSystem.

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HOW MUCH PAINT DO I NEED?Determining how much paint you will need is fairly simple.The estimated surface area in the chart below is based on theaverage boat size and type so actual square feet can vary. It is best to actually measure the wetted surface area of thehull. If it is difficult to do, a close approximation can be madeby multiplying the length overall, times the beam, times 85%

(LOA X Beam X .85 = wetted surface area). Then divide thewetted surface area by the square foot coverage per gallon, ofthe product you are using. The result is the number ofgallons needed for 1 coat. See product cans for per squarefoot coverage per gallon.

BOAT SIZE& TYPE

BOAT ESTIMATEDSURFACE AREA

FIBERGLASS NO SAND PRIMER

1 COAT

18' Power & Sail 120 Sq. Feet 1 Quart 2 gallons .5 gallons

21' Power & Sail 150 Sq. Feet 1.15 Quarts 2.5 gallons .75 gallons

28' Power & Sail 240 Sq. Feet 1.8 Quarts 4 gallons 1.25 gallons

31' Sailboat 270 Sq. Feet 2 Quarts 4.5 gallons 1.3 gallons

32' Sportfish 300 Sq. Feet 2.25 Quarts 5 gallons 1.5 gallons

36' Cruising Sailboat 330 Sq. Feet 2.5 Quarts 5.5 gallons 1.65 gallons

36' Powerboat 350 Sq. Feet 2.60 Quarts 5.75 gallons 1.75 gallons

41' Cruising 435 Sq. Feet 3.25 Quarts 7.25 gallons 2.2 gallons

42' Powerboat 500 Sq. Feet 3.75 Quarts 8.5 gallons 2.5 gallons

53' Cruising Sailboat 590 Sq. Feet 4.5 Quarts 10 gallons 3 gallons

53' Powerboat 650 Sq. Feet 4.85 Quarts 10.75 gallons 3.25 gallons

INTERPROTECT2000E/2001E4-5 COATS

ANTIFOULING PAINT

2 COATS

ASSOCIATED PRODUCTS2000E/2001E Blister prevention systemYPA200 No Sand Primer202 Fiberglass Solvent Wash – To clean bare

fiberglass prior to application.216 Special Thinner - To clean previous painted

areas.

YMA601 Fiberglass Surface Prep – Water based abrasive cleaner for bare Fiberglass.

2316N Reducing solvent – For clean up.2333N Brushing Reducer – For thinning and clean up.YAV135KIT Watertite Epoxy filler.INTERLUXANTIFOULING Check compatibility.

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FIBERGLASS NO SAND PRIMERNEW!NEW!• Fiberglass No Sand Primer eliminates the need to sand

prior to applying antifouling paint to new or unpainted boats.

• Recommended for new boat hulls, where sanding of the gelcoat may void manufacturer hull warranties.

• When properly overcoated with Interlux antifouling paint, the primer and antifouling paint will chemically bond together, ensuring excellent adhesion.

• It may be used on bare gelcoat (polyester or vinylester) and epoxy primed surfaces, and is compatible with most Interlux antifouling paints.

Use this guide if you have a barefiberglass, gelcoat or epoxy resin hull.The first thing you will need to do ischoose a system to paint below thewaterline with Interlux antifouling paint.Interlux has three systems to choosefrom No Sand Method, InterprotectBlister Prevention Method and a SandingMethod.

Review the feature and benefits of eachsystem and choose the best system foryou. All three systems are easy for “Do ItYourselfers” to complete. But if you arenot sure of your own capabilities or justnot comfortable doing this type of workjust consult your local Interlux Boatyardor Dealer. For a location near you visitwww.yachtpaint.com

SYSTEM 1NO SAND METHOD• Sanding is eliminated, before

applying antifouling paint.

• Perfect over gelcoats, where sanding of the gelcoat may void hull warranties.

• Only one coat of primer is required.

• Strong chemical bond between primer and antifouling paint, when overcoat window is met.

• Easy to apply

SYSTEM 2INTERPROTECT BLISTERPREVENTION• Easy application by "Do-It

Yourselfers" or professionals.

• Fast drying enabling a complete application in just days.

• Interprotect® is the only Blister Protection and Prevention coating that uses Microplates®. Microplates®

are a water barrier system similar to shingles on a roof, eliminating water intrusion.

• Interprotect® is a seal of approval fora future owner that the boat has beenprotected from future blister repair costs. This means added value and confidence to the buyer.

SYSTEM 3SANDING METHOD• Provides a mechanical bond

between boat hull and paint.• Cost effective.• Simple system clean, sand, clean and

apply antifouling paint.

Technical Assistance1-800-468-7589

Published: April 2003 SKU: BFG03

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BOAT HULL PREPARATIONSince the boat has never been painted, take extra care and timein preparing the bottom before proceeding to the system ofchoice.

Remove all contaminants and “Mold Release Wax” on thesurface as follows.

1. Scrub the surface thoroughly using soap and water and astiff brush. Flush with fresh water to remove soap residue andallow surface to dry.

2. Next scrub the surface thoroughly using Interlux FiberglassSurface Prep YMA601 and a Scotch-Brite® pad. If InterluxFiberglass Surface Prep YMA601 is not available use anabrasive powder cleaner. Scrub the surface thoroughly and

scrub only a few square feet at a time. Rinse well with plentyof fresh water.

3. Using the two rag method dampen one cheesecloth with 202Solvent Wash. Wipe surface thoroughly to soften and dissolvethe "Mold Release Wax". Use a second clean dry cheeseclothrag to remove the wax before the liquid dries. Be sure to changerags frequently.

4. Lightly spray the surface with water to insure allcontamination has been removed. If water beads up orseparates, wax is still present. Repeat steps 2 and 3.

At this point all mold release agents, wax and othercontaminants should have been removed. Proceed to one of thefollowing No Sand Method, Interprotect Method or SandingMethod.

SYSTEM 1: NO SAND METHOD

Bottom painting bare fiberglass, Polyester orVinylester gelcoats or epoxy resin

1. Follow the Boat Hull Preparation instructions on this page.

2. Using a 1/8 inch foam or 1/4 inch mohair solvent resistant roller,apply one thin continuous coat of Fiberglass No Sand Primer, applyin one direction only without recoating.

3. Only one coat of Fiberglass No Sand Primer is required.Antifouling overcoat times will vary due to wide variations intemperature and humidity. The only safe method to determinewhen the Fiberglass No Sand Primer is "Ready-to-Overcoat" is tocheck the paint film using the “Thumb Print” test. If the primerfeels tacky and you can leave a thumbprint in the paint film without getting any paint on your thumb, the Fiberglass No SandPrimer is "Ready-to-Overcoat". Test the paint film in the area youstarted applying the primer no later than 30 minutes after startingthe application. Continue testing every 15 minutes using the

"Thumb Print” Test until reaching the "Ready-to-Overcoat" stage.Immediately, begin to apply the Interlux antifouling paint once theprimer has reached the "Ready-to-Overcoat" stage.

Whether the boat is new or a fewyears old “Mold Release Wax”and other contaminants like dirt,grime, dust, oils and even roadsalt and dirt can be present onthe bottom of the boat. It is important to properly preparethe bottom of the boat before proceeding to the BottomPaint Systems.

"Thumb Print" test

Waterline

No Sand Primer

Antifouling Paint

Antifouling Paint

No Sand System Reference

Start cleaning the hard to reachareas first and pay extra attentionto those tough areas becausethose often are the areas mostneglected when cleaning.

Try dividing the hull into sections with tape or a grease maker.Then clean one section at a time. This method assures you donot overlook areas on the hull.

• When applying No Sand Primer to larger boats or surface areas where overcoat times cannot be met, please call Interlux for Technical Assistance 1-800-468-7589.

• Apply one thin coat, recommended WFT 3.0 mils wet; Fiberglass No Sand Primer may not hide the gelcoat completely when applied properly.

• Fiberglass No Sand Primer cannot be used with the following Interlux antifouling paints: VC17m Extra, VC17m, VC Offshore, Baltoplate, Micron 66, Micron Optima or Fiberglass Bottomkote Aqua. Do not use with any water based or vinyl based antifouling paints.

• Fiberglass No Sand Primer is moisture sensitive. Do not leave containers open during application. Once project is complete discard all remaining Fiberglass No Sand Primer.

• Do not apply Fiberglass No Sand Primer if the relative humidity exceeds 85% or if temperature exceeds 95o F (35o C).

SYSTEM 2: INTERPROTECT BLISTERPREVENTION METHOD

For new or non-blistered hulls.Use this system on new boats or used boats where allantifouling paint has been removed.

1. Follow boat hull preparation procedures as per instructionson page 2.

2. Sand the gelcoat thoroughly using 80-grit sandpaper.Remember to change sandpaper frequently.

3. Remove the sanding residue using Fiberglass Solvent Wash202.

4. Repair all scratches, nicks and dings by sanding those areaswith 80-grit sandpaper than remove the sanding residue usingFiberglass Solvent Wash 202. Fill the repair areas with InterluxWatertite Epoxy Filler. After Watertite is cured sand with 80-gritsandpaper until smooth. Remove sanding residue withFiberglass Solvent Wash 202.

5. Mix thoroughly both 2000E base and 2001E reactor prior tomixing together.

6. Mix three parts 2000E base to one part 2001E reactor, byvolume and allow to induct for twenty minutes prior to use. Mixonly what can be used in five hours.

7. Apply Interprotect® 2000E/2001E and continue on withcorresponding coats following overcoat windows listed on thecan of Interprotect® 2000E/2001E. Apply enough Interprotect®

2000E/2001E to build a 10 mil (.010 inch) dry film thickness.This usually takes 4–5 coats but the final dry film thickness ismore important than the number of coats.

8. Apply Interlux antifouling paint following the overcoatwindows listed on Interprotect® 2000E/2001E can.

Interprotect® is the only Blister Protectionand Prevention coating that uses Microplates. Microplates use a waterbarrier system similar to shingles on a roof, eliminating water intrusion.

The Interprotect® Microplates Formula provides:• Fast drying, easy application• A barrier in the epoxy coating to reduce water

damage to your hull• Sag resistance to insure the

elimination of sags and runs during application

Interprotect® has been the product of choicefor Boat Builders and Repair Yards since 1985.

Waterline

Interprotect®

Interprotect®

Interprotect®

Antifouling Paint

Antifouling Paint

Interprotect®

Interprotect® Application Reference

If maximum dry times areexceeded between thelast coat of Interprotect®

2000E/2001E and the firstcoat of antifouling, applyanother coat of Interprotect® 2000E/2001E and then besure to hit the proper over coating interval before theapplication of the antifouling paint.

These overcoat times do not apply to performance orvinyl antifouling such as VC17m Extra, VC17m, VCOffshore, Baltoplate and VC Performance Epoxy. Toapply performance or vinyl antifoulings apply at leastone extra coat of Interprotect® 2000E/2001E and allow todry 24 to 36 hours. Then sand with 80-grit sandpaper. Becareful to leave at least 10 mils dry film thickness ofepoxy after sanding. Apply the performance or vinylpaint of choice.

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FOR DETAILED TECHNICAL INFORMATION ON INTERPROTECT

Please call Interlux Technical Assistance Help Line at

1-800-468-7589 or send an email to

interprotect@yachtpaint.com for an auto responded reply that contains TechnicalBulletin #900E