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Coating Polystyrene Letters to make them durable
Having recently acquired an old Hot wire cutter and carving tools I’ve been having fun and earning a few pounds by making letters for show stands etc. Up ’til now I’ve used self adhesive photo paper, cut on our graphtec to produce templates which seems to work OK. I saw an interesting article in a magazine which implies that it is possible to harden the surface of the foam sufficiently to allow outdoor use. Can anyone give me a clue as to materials and methods to achieve this as I would like to try out the techniques on a new sign for our workshop entrance.
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4 Replies
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I remember reading somewhere that if you undercoat the material. you can use a 1 shot enamel, 2 coats, which will give it a better shell.
I may be wrong. Jill or one of the traditional guys/girls may correct me on that tho.
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you can coat with a epoxy resin then spray colour must be epoxy thou .
chris
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Mark,
Assuming that you are talking about expanded polystyrene and not polyurethene foam. You can create a fairly good shell and a good surface using PVA, Unibond or similar. Once dry it is resistant to attack from most solvents, I’ve used expanded poly to make fibre glass mouldings. Main problem is the time it takes to dry.
One point to note is that a lot of places require that the material has a fire rating, you’ll get that with FRA poly, on its own, but as soon as you coat it with emulsion or similar it will burn, so most Fire Officers do not like the stuff at all.
Steve -
Hi Mark,
A good quality car Laquer might do the trick. I do not have the name at hand but I used this type of laquer which is made up of two tins Hardener and the laquer. It is flexible and lasts. It is important to have a flexible type when it dries otherwise it cracks by time. I use it to spray water transfers material after I overprint with a laser printer. A couple of passes should do leaving about 30 minute between sprays.cheers mate.
Joseph.
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