Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: PAS on May 20, 2009, 11:13:30 pm

Title: G4
Post by: PAS on May 20, 2009, 11:13:30 pm

Hi
I hope you can help me.
In a recent article in a french magazine someone write that G4 was the best to hardened and impreabilize(?), (ok make it water proof paper), cardboard, etc.
I must believe this is true because I never tried it before.
Even more I don't know what is it.
Is, someone, out there,that could enlighten me about this G4? please.

Best regards from Portugal
Pedro Alves da Silva

Title: Re: G4
Post by: Stavros on May 20, 2009, 11:27:50 pm

Hi who makes G4 ?

I have allways used cellulose Dope or Sanding dope to stiffen and waterproof paper


Stav

Title: Re: G4
Post by: Colin Bishop on May 20, 2009, 11:55:26 pm

G4 is a one part polyurethane resin which cures by moisture. It is usually marketed as a pond or concrete sealant but is becoming increasingly used as arepair medium in the full size boating industry because, unlike polyester or epoxy resin, it can be used at temperatures down to freezing point and on damp surfaces - very useful given that most boat DiY repairs are carried out during the winter. I have used it on my full size boat and it does work very effectively.

You could certainly use it to seal paper or cardboard but it might be a rather expensive way to do so. As Stavros says, cellulose dope or sanding sealer would be just as effective  and probably cheaper.

http://www.marinemegastore.com/product-product-AQU_Q05170.htm

Colin

Title: Re: G4
Post by: Stavros on May 20, 2009, 11:59:10 pm

Thanks Colin just spent the last half hour trying to find G4 of course pond sealer DOH



Stav

Title: Re: G4
Post by: PAS on May 21, 2009, 12:27:10 am

Thank you guys.
I believe, now I have some hints to work with.

Hope to show, soon, my Phoenician birreme with some paper parts and no sawdust, (wife stuff <*<), just cutting and gluing.
Best regards
Pedro Alves da Silva

Title: Re: G4
Post by: dreadnought72 on May 21, 2009, 09:39:15 am

I've used G4 on my (paper) plates which cover the (wooden) hull of my HMS Dreadnought. I really can't praise it enough.

Andy

Title: Re: G4
Post by: Colin Bishop on May 21, 2009, 09:51:57 am

Yes, it's good stuff, you don't have to mix it but there are some potential drawbacks. As far as I know you can only get it in fairly big tins and being moisture curing, once you have opened the tin you have got a more limited shelf life than polyester or epoxy resins. One batch I bought had gone completely solid in the tin and had to be exchanged.

Colin

Title: Re: G4
Post by: madrob on May 21, 2009, 10:02:09 am

I take it this doesnt need a hardener then

Title: Re: G4
Post by: Colin Bishop on May 21, 2009, 10:06:59 am

No, just exposure to the atmosphere. Mist spraying with water can speed up the curing process.

Colin

Title: Re: G4
Post by: longshanks on May 21, 2009, 10:26:25 pm

Hi Folks,

Dont know if it helps but there is an article at CFS re using G4

http://www.cfsnet.co.uk/acatalog/ponds.html

They can of course supply

longshanks

Title: Re: G4
Post by: David T on December 12, 2018, 02:26:28 pm

HI GUY'SI have never used or taken part in a forum before and i am sure that i'll find the help i need using it.i am currently building the fairmount alpine and it is near time to seal the hull. now i am planning to use G4 but also graupner sk30 as a putty for the in-perfections. Any idea which one to use first as after doing some research i can't make my mind up.
PLEASE HELPThank in advance :-))