Gordon Brown Posted March 15, 2015 Share Posted March 15, 2015 Dave, PU (polyurethane) resin is not the same as Polyester resin, PU is safe on foam and is water based, Polyester will dissolve polystyrene foams such as Depron instantly due to the styrene content. Quote Link to comment Share on other sites More sharing options...
Gordon Brown Posted March 15, 2015 Share Posted March 15, 2015 Iqon, it's many years since I used polyester resins (used to make my own windsurf boards) but you might have problems sanding it as it tends to remain tacky unless you use a wax additive. The wax rises to the top and excludes air, which allows the resin to set completely. Resins used for one coat applications are often sold as non-air inhibited which has the wax additive. You need to check! Quote Link to comment Share on other sites More sharing options...
iqon Posted March 15, 2015 Share Posted March 15, 2015 the wing that got done is drying so i have no reason to believe the other wont...I`ll know more in morning Inspiration to glass came from - Danny's "poor mans Spitty" page 47.have a look at his vids, very usefulso if it goes wrong i know who to blame..... Quote Link to comment Share on other sites More sharing options...
Gordon Brown Posted March 16, 2015 Share Posted March 16, 2015 Iqon, the resin will certainly set but if the surface is exposed to air it will remain tacky unless it has the wax additive. The tackiness makes sanding very difficult. As I recall,on my windsurf boards I would use three layers of glass cloth, these being applied with wax free resin, but they always remained tacky, and sanding out lumps and bumps was almost impossible as the abrasive paper clogged in seconds. A final coat of resin with wax allowed a full set and sanding to be done. For planes I have used PU and epoxy with glass cloth, the PU is much easier to use but I don't think it has the strength of polyester or epoxy. However, as the additional strength is probably not critical I'm happy with PU. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted March 16, 2015 Share Posted March 16, 2015 Don't look at me I used epoxy and peel ply What Gordon says is spot on, the wax is added to polyester resin to create what is sometimes known as finishing resin and is for a single layer or final layer. The resin with no wax does indeed leave a gummy surface this is what I would call a laminating resin, the stickiness helps the next layer of glass cloth to bond really well. Those of you that are members on RCSB should take a look at John Ransons Venom build, he has just done some comparisons between the various finishing materials, makes interesting reading. Lots of the large scale guys are using G4 pond lining resin to great effect. Cheers Danny Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 16, 2015 Share Posted March 16, 2015 Just a tip I picked up some years ago, to keep the glass cloth weave nice and straight and to stop the cloth from fraying while cutting , spray a coat of hairspray /laquer on it while its layed out flat . It holds the weave in place until you apply the resin. It works with polyester or epoxy resin but have not tried it with water based types. The resin dissolves the laquer quickly one applied. It is very useful when laying up carbon fibre cloth if you want to see the weave when set. Another tip is to remove any puddles or excess resin with kitchen towel. The paper towel soakes up the excess and leaves a perfect uniform coat saving un-necessary weight. If you have used the lay up resin that hardens and remains sticky , give it a wipe over with acetone . It removes the stickyness and allows for easiersanding but is very smelly and mightvupset SWMBO. Edited By Engine Doctor on 16/03/2015 10:22:03 Edited By Engine Doctor on 16/03/2015 10:26:02 Quote Link to comment Share on other sites More sharing options...
Former Member Posted March 16, 2015 Share Posted March 16, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
iqon Posted March 16, 2015 Share Posted March 16, 2015 either way - its dry , dont think its dry enough to sand but it is dry enough to re cloth, cloth not sticking to it so for me its good enough to recover.weighed wing before i started and has added no weight, we are only talking thin coat on 1/3 rd of wing..now it`s re covered ... Quote Link to comment Share on other sites More sharing options...
iqon Posted March 22, 2015 Share Posted March 22, 2015 All done and dry, ready to start painting, was easy to do when you get the hang of it, downsides, smell when its curing and having to have heating on as it needs to be at least 20c Quote Link to comment Share on other sites More sharing options...
onetenor Posted March 22, 2015 Share Posted March 22, 2015 Amytl acetate smells far nicer. Pear drops smell. and yes it is actually used to flavour pear drops. but it still needs care in use Very flammable and fumes as bed as thinners etc. Can be used in Cellulose / acetate paints. paints Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted March 22, 2015 Share Posted March 22, 2015 Some years ago a friend of mine started producing glassed glider fuselages (epoxy and polyester) as a sort of cottage industry business supplying some well known kit producers. Working in a small heated shed which was well insulated against variations in temperature, the ventilation turned out to be inadequate. Unfortunately, dally exposure to resin fumes over a period of only a few months destroyed the delicate lining of his upper nasal tract which resulted in a reduced sense of smell and taste, as well as being very painful for a long time afterwards. The damage was irreversible and sensitized him against working with those materials ever again. As they used to say in 'Hill street Blues' "Let's be careful out there"............................ Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.