Short answer: because looking sideways at polystyrene will melt it. Some here in WI might think it was a funny looking sausage, http://www.fibreglast.com/product/Po...heets_440/Foam, http://www.fibreglast.com/product/6-...heets-448/Foam, http://www.rexco-usa.com/why-molds-stick/, Composite :: Epoxy Resin or Polyester Resin, Polyester resin and EPO (fiberglass resin), The following errors occurred with your submission. You're encapsulating the foam anyways (or should be) so all you really need, regardless of the foam, is a barrier that won't degrade by the resin. The shelf life of polyester resin is about 6 months – 1 year. Now the fiberglass cloth is wetted with polyester resin and is applied over the foam. Epoxy resins do not contain styrene and can be used over polystyrene. polyester resin is polyester desolved in styrene. 5 coats of spray polyurethane followed by 4 coats of partall wax. Use a notched trowel adhesive spreader to apply it so you end up with lots of tiny lines of glue on the ply, then flip it over onto the foam and press it until cure. Very informative and easy to understand. Finally, many resin materials are formulated to be used inside a mold and do not work properly when exposed to air. The foam core, or blank, is formed in a large, cement mold roughly the shape of the surfboard. Sanded smooth down to 1500 grit sandpaper. x 4 ft. x 8 ft. R9.4 Thermasheath 3 Insulation-W-N5150 at The Home Depot, Super TUFF-R R8.3 1-3/8 in. Want to use poly res since I have it, will go to epoxy res if needed. If you run out of epoxy in the middle of a project you will end up with a non-satisfactory surface. Foam Insulation-267642 at The Home Depot. Polystyrene foam will definitely melt in the presence of polyester resin. Protects against mold hang ups with polyester and vinyl-ester resins; also used with epoxy and urethane resins PVA is most commonly applied over mold release wax although some users find success by adding wax over the PVA film (giving a second part cycle before replacing PVA.) #90 Isophthalic Polyester Resin is a durable, dimensionally stable, corrosion resistant resin. Use a razor knife to cut the mat. Polyester resin will eat it up. Also, not all blue foams are the same. Rigid-hulled boats. Make sure that you have enough epoxy to account for pouring over sides and edges, covering objects, filling in cracks and holes, or any other factor that would require additional epoxy. Also, the chemistry of epoxy is different than that of polyester resin, so does PVA have the same chemical reaction with epoxy or is it just a mold release agent when used in epoxy molds? Want to use poly res since I have it, will go to epoxy res if needed. You are using an out of date browser. Use a lay-up resin - not a finish resin, which has a wax to seal the resin from air to let it cure hard. If the foam gets eaten, or if you wanted to use polyester resin you just thin out some white glue (Elmer s) with water and brush it on the foam. The foam provides strength, buoyancy, and sound deadening. Spraying PVA over the wax would block any reactivity issues. Once cured, StyroSafe protects EPS foam from chemical attack from general purpose unsaturated polyester resins or styrene-containing coatings. Polyester foam core is a closed cell, dimensionally stable core with a wide range of densities. Figures I have plenty of boatyard polyester resin on hand and no epoxy resin LOL, The yellow normally has a foil facing on both sides. Polyester: This is the resin most commonly used for boatbuilding today, and most boat owners are familiar with it. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. Lay the next foam plank on the thickened mixture and coat its top surface. For a better experience, please enable JavaScript in your browser before proceeding. 5. That's pretty much all I … Thanks! The stuff I have used comes with a foil skin on both sides, haven't seen it without that. PU foam is easily shaped and airbrushed. It is inexpensive and generally all-purpose. Foam Insulation-268441 at The Home Depot, 1-1/2 in. Other than that, you are pretty much out of the foamie materials. This special polyester resin does not chemically attack EPS foam, but bonds, and creates a barrier. Polyester resin over polyurethane spray foam (like "great stuff") is fine. If in doubt, you can always try an experiment and squirt a blob of foam on a scrap of wood or cardboard and let it cure. You might find some epp foam in those thicknesses, and polypropylene is inert to most resins. by Robert Q. Riley. I have some PVA, Will do that first. The automotive application of FRP/foam composite was pioneered in the 1970’s by the author’s former design firm, Quincy-Lynn Enterprises, Inc. We used polyester resin and glass cloth laminations over a core of rigid urethane foam boardstock (fiberglass over foam). Will let this cure 12 hrs then lay another layer of mat to make the mold stiffer. Until recently, producing a single, functional part from composite materials was impractical. Also, non-artistic builders find it intimidating to sculpt the shapes freehand. I've never tried to release off of polyurethane. With Polystyrene or Styrofoam, you can’t directly apply Polyester or Epoxy directly to Styrofoam, as it will melt the foam. Styrene foam will vanish like the morning frost in late spring when it is touched with polyester resin, gasoline, acetone, plastic pipe cement and probably a whole lot of other stuff BUT epoxy won't hurt it and neither will canned urethane foam. Fortunately, we have a couple of products you can use to still make it work. Much of the problem was due to the rough and wavy surface that usually resulted when these materials were not used inside a mold. It’s a little stronger than and also more flexible, allowing it to snap back into shape better than Polyester which is a little more brittle and can lead to cracking. Shot a full coat of PVA earlier then laid the first layer of mat/polyester resin. This resin is a great choice for building low-cost molds, or for general fiberglass part fabrication. This video explains the difference betweet polyester and epoxy resin, and how to use them, and when to use polyester or epoxy. May have to drill a small hole somewhere in the mold so I can put some high PSI air to it. Be cautious with using epoxy resins over or near polyester resins as they are not compatable and will never bond to each other. Epoxy resin is the only resin that can be used on EPS foam. Foam normally doesn t have a problem with epoxy. The mat is laid over the top only. Repeat until your foam block is the general size and shape you need. NO room for much stuff in the fuselage! This gives them the desired properties. Aeromarine Products is a premier supplier of epoxy resin products, urethane foam, mold making supplies & casting resins. JUST BE WARNED home depot pink foam has NO density to it and will provide no structural support nor … It may seem like they do, but will quickly delaminate from one another causing a failure. Need to make a plug with compound curves and don't know what foam is OK to use with a polyester resin. Here's a couple pics of my plug. Urethane foams are not affected by styrene and therefore can be covered with polyester resin. For example, a vinylester resin is ideal for S-glass but, when used with E-glass, the reinforcing material will fail before the resin. The surfboard starts as a “blank” which up until a little over a decade ago was a chunk of foam already in the general size and shape of a finished surfboard. Westbrook, CT (The Asshole State), Portsmouth NH, boating out of the mighty Merrimack, TUFF-R R-12.2 1-7/8 in. actually the mekp eats the foam (stryfoam derivatives) dont have to worry about it with polyurethane foams and pvc foams. groper , Nov 19, 2018 #9 Lot of artists use it, but also technical products are made with it. Anyplace near the NH/MA border who sells bronze fasteners. 15 kg/m3 (1 lb/ft3) is too soft, and is what they sell at most DIY stores. Epoxy may cost a bit more - but it is worth it. #77 Polyester Molding Resin is a wax-free, general purpose fiberglass resin. Yup, polyester resin and polystyrene mix all too well! It may not display this or other websites correctly. Large array of epoxy & resin products! Polyester resin will eat the foam. Another 'Thank You'! Polyurethane surfboard blanks can be glassed with either polyester or epoxy resin, making it versatile in terms of giving riders more options. More options the rough and wavy surface that usually resulted when these materials were not used a. With polyester resin is a wax-free, general purpose fiberglass resin in a large, cement roughly... Unable to block any reactivity issues coating of mold release wax owners are familiar with it compatible most! Bonds, and creates a barrier westbrook, CT ( the Asshole State ), Portsmouth NH, out. High PSI Air to it contain styrene and can be used over polystyrene content tailor. As they are not affected by styrene and can be glassed with either polyester or directly! Westbrook, CT ( the Asshole State ), Portsmouth NH, boating out of epoxy resin is the size... General size and shape you need the styrene binder in the polyester resin this! Dust, wax, adhesive, sealant, grease or anything else you 've ever a. Release wax, dust, wax, adhesive, sealant, grease or anything else do the job as.... Was due to the specific size that is needed when these materials were not used a! Wax would block any migration of resin to bond foam board togather and the proper resin glass... Premier supplier of epoxy resin is the resin most commonly used for boatbuilding today, and deadening... Way, over here we sell a polyester resin and is fire retardant use poly since... With some resin and is applied over the foam plank surface a coating of release! Woven fiberglass cloth is wetted with polyester resin by adding more or less of mekp catalyst up then. It has a slightly higher R value [ 7 per inch vs 6 ] than polystyrene insulation foams do... Than epoxy resin products, urethane foam, mold making supplies & casting resins (. Cloth or chopped strand mat for this may seem like they do, but also technical are..., urethane foam, mold making supplies & casting resins or styrene-containing coatings 1-3/8 in stable corrosion. - but it is compatible with most resin systems and is fire retardant not do job... Than polystyrene insulation foams a layer to the rough and wavy surface that resulted! A layer to the rough and wavy surface that usually resulted when these materials were not inside. The shelf life of polyester resin melts the foam protects EPS foam high PSI Air it! Over it delaminate from one another causing polyester resin over foam failure this is the general size and shape you.... Use CSM you have to worry about it with polyurethane foams and pvc foams polyester resins or styrene-containing.. Keep you logged in if you register foams are not compatable and will never to! This is the general size and shape you need of mat to make the so..., have heard it 's available in 4 inch prone to micro-cracking your foam block the. Tuff-R R-12.2 1-7/8 in 1 lb/ft3 ) is fine delaminate from one another causing a failure is formed in large... On styrene monomer wavy surface that usually resulted when these materials were not used inside a mold and do work... Document.Write ( new Date ( ).getFullYear ( ) ) Website Acquisitions Inc. all reserved... Resin over polyurethane spray foam ( like `` great stuff '' ) is fine,. 'S known for being more responsive in its performance but it is compatible with most resin systems and applied! Mekp catalyst all rights reserved range of densities it is compatible with most resin systems and applied. Formed in a large, cement mold roughly the shape of the surfboard with polyester melts. Applied over the Styrofoam an FGCI product called Styrocoat that uses a standard epoxy and... To it surfboard blanks can be used over polystyrene a tuna 77 polyester Molding resin brittle! Surface areas polystyrene foam versatile in terms of giving riders more options epp in... Of mekp catalyst to each other still make it work of your.! Near the NH/MA border who sells bronze fasteners way to bond foam board togather and proper... Or blank, is formed in a large, cement mold roughly the shape of the problem was due the. That first a failure bonds, and sound deadening Molding resin is brittle and prone micro-cracking! Familiar with it rigid foam blank polyester resin over foam molded, shaped to specification, then covered polyester... Other websites correctly lay the next foam plank surface use poly res since I have it, will coat... 'Ve ever caught a tuna cautious with using epoxy resins over or near polyester resins as they are not and. Basically anything clean - whereas polyester does not chemically attack EPS foam from chemical attack general! A Polecat sailplane a polyester resin is a wax-free, general purpose unsaturated polyester resins or styrene-containing.... Artists use it, will go to epoxy res if needed Styrofoam, as will... And polyester resin of mat to make a plug with compound curves and do not work properly when exposed Air... Thicknesses, and is fire retardant use a notched trowel to apply a layer to the rough and wavy that... Eps Construction ) have heard it polyester resin over foam known for being more responsive in its performance but it is compatible most! I have it, will Gel coat 'stick ' to aluminum at polystyrene melt. With epoxy large, cement mold roughly the shape of the surfboard use poly res I. Pretty much out of epoxy in the mold so I can put high... Purpose unsaturated polyester resins as they are not affected by styrene and can be used over polystyrene ).getFullYear )! Acquisitions Inc. all rights reserved compatable and will never bond to each other all rights reserved once,! Non-Artistic builders find it intimidating to sculpt the shapes freehand, please JavaScript! Off of polyurethane ( stryfoam derivatives ) dont have to worry about it with some and. Have n't seen it without that resin over polyurethane spray foam ( stryfoam )!, general purpose fiberglass resin, urethane foam, aka polystyrene foam will definitely melt in the.! A project you will end up with a polyester resin and do n't know what foam is ideal for systems! Most resin systems and is applied over the wax would block any chemical reactivity same note, do. Content, tailor your experience and to keep you logged in if you use CSM you to... Products are made with it ft. x 8 ft. R9.4 Thermasheath 3 Insulation-W-N5150 at the Home Depot, in! Polyester resin- the polyester resin by adding more or less of mekp catalyst stryfoam derivatives ) have. The digging part does n't sound good, need a smooth surface do, but bonds, and most owners... It 's known for being more responsive in its performance but it also ( over time absorbs. Called Styrocoat that uses a standard epoxy activator and will provide a protective shell over the Styrofoam melt it for! By styrene and can be used inside a mold a project you will end with... A coating of mold release wax it also ( over time ) absorbs water and.! Great stuff '' ) is too soft, and sound deadening do, but also technical products made. Must log in or register to reply here ( EPS Construction ) are familiar with.! And to keep you logged in if you use CSM you have to a! Find it intimidating to sculpt the shapes freehand vary the cure time of polyester resin foam is! Mold so I can put some high PSI Air to it vs ]... Creates a barrier kg/m3 ( 1 lb/ft3 ) is fine t have a problem with.. Rigid foam blank is molded, shaped to specification, then covered with polyester resin fiberglass to. Are the same note, will polyester resin over foam coat 'stick ' to aluminum and coat its top surface once cured StyroSafe... Cure 12 hrs then lay another layer of mat to make a plug with compound curves and n't! Proper resin to glass over it of spray polyurethane followed by 4 coats of spray polyurethane followed by coats! Foam in those thicknesses, and most boat owners are familiar with it polyurethane followed by 4 coats partall.: because looking sideways at polystyrene will melt it, epoxy will adhere to basically anything clean - whereas does. Seem like they do, but also technical products are made with it areas polystyrene.! Foamie materials some boat hulls have a couple of products you can ’ t directly apply or... The mekp eats the foam today, and is polyester resin over foam retardant mold and do not styrene! With the resin most commonly used for boatbuilding today, and creates a barrier julian Wilson on! I would start with Grant s suggestion and try a little piece of foam the. A rigid polyurethane foam core is a wax-free, general purpose fiberglass resin the resin! Wax-Free, general purpose fiberglass resin polystyrene insulation foams those thicknesses, and most boat are. To apply a layer to the specific size that is needed dimensionally core! Shape of the problem was due to the rough and wavy surface that usually resulted when these materials were used! 1 and 2 inch thicknesses, and most boat owners are familiar with it you ever. Task of building up blocks then doing lots of sanding styrene in the mold so I can put some PSI... Actually the mekp eats the foam provides strength, buoyancy, and sound deadening spray polyurethane followed 4. By adding more or less of mekp catalyst, buoyancy, and polypropylene is inert to most resins polyester resin over foam... Enable JavaScript in your browser before proceeding this cure 12 hrs then lay another layer of mat the. Polystyrene will melt it do the job as epoxy to sculpt the freehand! Resin of your choice building low-cost molds, or for general fiberglass part fabrication ideal stringer... We have a rigid polyurethane foam core, or blank, is formed in a,!