Epoxy resin/hardener spray gun for hand lay-up

[canada911]

Hello guys,

I am actually doing hand lay-up with epoxy and FG/CF and like probably most of you guys I am loosing all the time on wetting the cloth with the resin (with a brush, squeege and roll)...

I know that with polyester we can use a special spray gun that mixes the resin and hardener (and also can chops the FG directly) and quickly wet the plies.

But Is there a similar technic for Epoxy? If not, is it du to the high viscosity of the epoxy?
Wouldnt it be possible to heat each part of the mixture (resin and hardener) and then automatically add/dose some solvent (I.E: acetone) to decrease the viscosity until it is sprayable? After this the spray gun could mix the 2 part and spray it (and during the spray the acetone would partially evaporate and the heat would lower down)...

This would save me alot of time... So just wanted to know you opinion on this?

Thanks!!

 

[berkshire]

The most common method of utilising epoxy resin with cloth for wet layups is a pre pregger.
A set of rolls through which cloth is drawn through a bath of resin, then the excess resin is squeegeed back into the tank for reuse. leaving the cloth with the correct ratio of resin. The cloth is drawn through as needed for the layup.
Here is a link to spray gun manufacturers.

http://www.fiberglass.com/equip/equip_2050.html

B.E.

 

[Compositepro]

Epoxy mixing ratios have to be far more precise and consistent than catalyst level for polyester. Changing the catalyst percentage in polyester will simply affect the gel time. A change in ratio with epoxy will severely degrade the properties of the resin. Low resin viscosity is also required for the catalyst to mix with the resin.

Speed of wet-out, however, is mainly related to viscosity, which a spray gun will not help. You can warm your tool to speed wet-out, but you will also reduce working time and gel time.

A VARTM process requires additional labor for bagging but less labor for wet-out.

 

[PanelGuy]

There are epoxies and spray equipment available these days. It is different from your PE equipment. I do not know if anyone is spraying by hand like you would in a mold but there is not realy reason why you could not.

Endurance Adhesive in St Paul is doing sprayable epoxies the are curing in under a minute or as long as you want.

AST may know more about dispense equipment.

AS well, if you lengthen the gel time on your epoxy (see your supplier for mix or a new formulation)you will see a longer cure time. But it is pretty easy to build a hot box or use a heat blannker to get your temp up to 120 and kick over a lay-up. Prepregs can get plenty expensive. I have scrimmed films down around $.60/sf, but the liquid bondlines are closer to $.09. It depends on technique and control.

I highly recommend looking at the Epoxy and see what better options there are. Let me know if you need more help.

Good Luck!