Problem Solver

Question Answer
My clear coating has turned cloudy Moisture from condensation or very humid conditions reacts with components in uncured hardener
Apply moderate heat to partially cured coating to remove moisture and complete cure. Caution – avoid out-gassing. See Safety.
Use 207 Hardener for clear coating applications and for bonding thin veneers where Epoxy may bleed through to the surface.
Apply coating at warmer temperature – epoxy is thinner at warmer temperatures.
Apply epoxy in thin even coats.
Apply moderate heat to release trapped air and complete cure.
Caution – avoid out-gassing. See Safety.
Bubbles have formed in the coating over a porous material (bare wood or foam) Air trapped in the material escapes through coating (out-gassing) as the temperature of the material rises
Coat the wood as its temperature is dropping – after warming the wood with heaters or during the latter part of the day.
Apply a thinner coat, allowing air to escape more easily.
Tip off the coating with a roller cover brush to break bubbles.
Avoid out-gassing. See Safety.
A waxy film has appeared on the surface of my cured epoxy Amine blush forms as a result of the curing process
Blush formation is typical. Remove with water.
See surface preparation.
Pinholes have appeared in epoxy coating over abraded fibreglass or epoxy Surface tension causes epoxy film to pull away from pinhole before it gels
After applying epoxy with 800 Roller Cover, force epoxy into pinholes with a stiff plastic or metal spreader held at a low or nearly flat angle. Re-coat and tip off coating after all pinholes are filled.
My coating is running or sagging Epoxy applied is too thick
Use 790 or 800 Roller Covers and roll the coating into a thinner film. A thin film will flow out much more smoothly than a thicker film after it is tipped off with the foam roller brush.
Warm the epoxy to reduce viscosity or apply the coating at a warmer temperature.
See Cold temperature bonding.
Coating curing too slowly
Apply the coating at a warmer temperature.
Warm the resin and hardener before mixing to speed the cure in cool weather.
Switch to a faster hardener if possible.
See Controlling cure time.
My hardener has turned red after several years of storage Moisture in contact with hardener and metal container
Red colour is a normal condition. It will not affect epoxy handling or cured strength. Avoid using hardener for clear coating or exposed areas where colour is not desired.
My fairing compound (using filler/407 or 410 mixture) is sagging and is difficult to sand Fairing material not thick enough
Add more filler to the mix until it reaches a “peanut butter” consistency – the more filler added, the stiffer it becomes and the easier it will be to sand.
Allow the wet-out coat to gel before applying the fairing material to vertical surfaces.
See Fairing.
I’m seeing fish-eyeing in my coating Contamination of the coating caused by dirty application tools and/or inadequate preparation of the surface
Ensure mixing equipment is clean. Avoid waxed mixing containers.
Ensure surface is properly prepared. Use correct grit paper for the coating, e.g. 80-grit for epoxy. See paint or varnish manufacturer’s instructions for precise surface preparation. After surface is prepared, avoid contamination – fingerprints, exhaust fumes, rags with fabric softener (silicone). Coat within hours of preparation. After wet sanding, rinse water should sheet without beading (beading indicates contamination). If rinse water forms droplets/beads, clean and dry and repeat operation – see Final surface preparation.
My paint, varnish or gelcoat will not cure over epoxy Epoxy not completely cured
Allow the final epoxy coat to cure thoroughly. Allow several days if necessary for slow hardeners at cooler temperatures. Apply moderate heat to complete the cure if necessary.
See Controlling cure time.
Paint incompatible with epoxy
Use a different type of paint. Some paints and varnishes may be incompatible with some hardeners. If unsure, test for compatibility on a coated piece of scrap material.
Use 207 Hardener, which is compatible with most paints and varnishes.
Epoxy surface not thoroughly prepared
Remove the amine blush and sand the surface thoroughly before applying paints and varnishes.
See Final surface preparation.
My epoxy mixture has not cured after the recommended cure time has passed Off ratio – too much or too little hardener will affect the cure time and thoroughness of the cure
Remove epoxy. Do not apply additional material over non-curing epoxy. See Safe removal.
Check correct number of pump strokes used – equal stroke of resin and hardener. Do not add extra hardener for a faster cure!
Check for correct pump (5:1 or 3:1 ratio) and pump group size e.g. Group A
Check pump ratio (see pump instructions). See Dispensing.
Low temperature epoxy mixtures cure slower at low temperatures
Allow extra curing time in cool weather.
Apply heat to maintain the chemical reaction and speed the cure. Unvented kerosene or propane heaters can inhibit the cure of epoxy and contaminate epoxy surfaces.
Use a faster hardener, designed to cure at lower temperatures. See Understanding cure time and Cold temperature bonding.
Insufficient mixing
Remove epoxy. Do not apply additional material over non-curing epoxy. See safe removal.
Mix resin and hardener together thoroughly to avoid resin rich and hardener rich areas.
Add fillers or additives after resin and hardener have been thoroughly mixed. See Mixing.
Incorrect products
Remove epoxy. Do not apply additional material over non-curing epoxy. See Safe removal.
Check for correct resin and hardener. Resin will not cure properly with other brands of hardeners or with polyester catalysts.
The epoxy I’m using became very hot and cured too quickly Batch too large, or left in mixing pot too long
Mix smaller batches.
Transfer the mix to a container with more surface area, immediately after mixing.
See Understanding cure time. See Dispensing and mixing.
Temperature too warm for the hardener
Use 206 Slow or 209 Extra Slow Hardener in very warm weather.
Application too thick
When filling large, deep areas, apply mix in several thin layers.
My joint has failed to bond Insufficient cure
See above.
Resin starved joint-epoxy has wicked into porous surfaces leaving a void at the joint
Wet-out bonding surfaces before applying thickened epoxy. Re-wet very porous surfaces and end grain. See Two-step bonding.
Contaminated bonding surface
Clean and sand the surface following the preparation procedure. See Surface preparation.
Sand wood surfaces after planing or joining.
Bonding area too small for the load on the joint
Increase bonding area by adding fillets, bonded fasteners or scarf joints.
Too much clamping pressure squeezed epoxy out of the joint
Use just enough clamping pressure to squeeze a small amount of epoxy from the joint.
See Clamping.