Mould in XPS

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Mould in XPS

Author	Message
Massimiliano	M Massimiliano posted 4 Years Ago HOT Topic Details
M Group: Forum Members Posts: 167, Visits: 1.1K	Hi, I know polyurethane foam is better but is not easy to find and costs a lot for large molds, so I would like to use polystyrene foam or XPS. When I am done with shaping the plug, what could I use to cover it to sand flat and smooth until a polished state?
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Duratec Styroshield is made specifically for this purpose. Otherwise you can use any epoxy, though epoxies are generally not so easy to work with. If you can build up a reasonable thickness, it is probably easiest to use epoxy to seal the foam, and then switch to using regular 2k primers and paints to get the surface finish you are after.
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Massimiliano	M Massimiliano posted 4 Years Ago HOT Post Details
M Group: Forum Members Posts: 167, Visits: 1.1K	+x Hanaldo - 3/13/2020 1:01:11 PM Duratec Styroshield is made specifically for this purpose. Otherwise you can use any epoxy, though epoxies are generally not so easy to work with. If you can build up a reasonable thickness, it is probably easiest to use epoxy to seal the foam, and then switch to using regular 2k primers and paints to get the surface finish you are after. Thank you Hanaldo. Where one could buy Duratec products in Europe?
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Warren (Staff)	Warren (Staff) posted 4 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 7.9K	If its a plug for a mould, you only need the epoxy to stop other (easier to sand) products eating into the foam. Basically anything with styrene in will likely harm the XPS unless you coat it and seal it first with epoxy. Typically what we would recommend for a pattern surface is our Pattern-Coat Primer which is high build, very easy to sand and easily polishable to a reasonable gloss. If you need a very high gloss you can also use the Pattern Coat Hi-Gloss as an ultimate high shine pattern. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Massimiliano	M Massimiliano posted 4 Years Ago HOT Post Details
M Group: Forum Members Posts: 167, Visits: 1.1K	+x Warren (Staff) - 3/13/2020 1:31:46 PM If its a plug for a mould, you only need the epoxy to stop other (easier to sand) products eating into the foam. Basically anything with styrene in will likely harm the XPS unless you coat it and seal it first with epoxy. Typically what we would recommend for a pattern surface is our Pattern-Coat Primer which is high build, very easy to sand and easily polishable to a reasonable gloss. If you need a very high gloss you can also use the Pattern Coat Hi-Gloss as an ultimate high shine pattern. Thank you Warren, I bought both the products. I still would like to know where to buy the Duratec products in Europe, would really like to give them a try! Anyone knows?
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Check the Hawkeye Industries distributor map here: http://www.duratec1.com/hawkeye/?page_id=1373
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Massimiliano	M Massimiliano posted 4 Years Ago HOT Post Details
M Group: Forum Members Posts: 167, Visits: 1.1K	+x Hanaldo - 3/15/2020 10:14:01 AM Check the Hawkeye Industries distributor map here: http://www.duratec1.com/hawkeye/?page_id=1373 Thank you very much!
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Chris Rogers	C Chris Rogers posted 4 Years Ago HOT Post Details
C Group: Forum Members Posts: 120, Visits: 933	The Styroshield is great compared to nothing - it actually lets you use polyester resin on EPS - but it isn't perfect. You have to be careful to get complete coverage and it sometimes still leaves holes where there were small bubbles or gaps. I have used it mostly so EPS can be covered in a few plies of chopped strand mat and then a polyester tooling paste that is machined to the final shape. For preserving the initial shape with a reasonably consistent offset, I agree with Hanaldo that a layer or two (or more) of 200g e-glass in epoxy is probably a decent substrate - but it will be like fairing a surfboard - very easy to burn through, dent or crush. You may find it's easiest to smear the foam with thickened (with Q-cell or phenolic balloons) epoxy and then place dry fabric over and wet through using a brush (or paint roller) and wetout roller to smooth out. Be careful to fully cure the epoxy (maybe with some heat) and remove blush and sand (or better yet use peel ply on the glass layer). If the epoxy is not completely cured the polyester primer (Pattern Coat Primer) will not fully cure - it'll stay gummy and you'll have to acetone it off. Same goes with Duratec primers which are similar.
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Massimiliano	M Massimiliano posted 4 Years Ago HOT Post Details
M Group: Forum Members Posts: 167, Visits: 1.1K	+x Chris Rogers - 3/15/2020 9:25:11 PM The Styroshield is great compared to nothing - it actually lets you use polyester resin on EPS - but it isn't perfect. You have to be careful to get complete coverage and it sometimes still leaves holes where there were small bubbles or gaps. I have used it mostly so EPS can be covered in a few plies of chopped strand mat and then a polyester tooling paste that is machined to the final shape. For preserving the initial shape with a reasonably consistent offset, I agree with Hanaldo that a layer or two (or more) of 200g e-glass in epoxy is probably a decent substrate - but it will be like fairing a surfboard - very easy to burn through, dent or crush. You may find it's easiest to smear the foam with thickened (with Q-cell or phenolic balloons) epoxy and then place dry fabric over and wet through using a brush (or paint roller) and wetout roller to smooth out. Be careful to fully cure the epoxy (maybe with some heat) and remove blush and sand (or better yet use peel ply on the glass layer). If the epoxy is not completely cured the polyester primer (Pattern Coat Primer) will not fully cure - it'll stay gummy and you'll have to acetone it off. Same goes with Duratec primers which are similar. Thanks a lot for the good suggestions!
	Reply Like 2