Laminating gelcoat is hard in 16 hrs??

[Mr Efficiency]

Adding filler must affect the permeability of the gelcoat ?

 

[ondarvr]

Adding filler must affect the permeability of the gelcoat ?

If you're referring to the Cabosil, it's a normal ingredient in gel coat and resin to adjust them into a usable viscosity, infusion resins would be about the only ones without this type of silica.

 

[Mr Efficiency]

OK, so extra thickener added to brushed gelcoat to get the requisite thickness in one go, does not create any problem of greater permeability ? You clearly know more than most about this subject.

 

[ondarvr]

It's not that it doesn't or can't have an effect, it's just that it's already in the mix. If the silica isn't wet out by the resin correctly it would be possible for it to wick water quicker, the amount added to thicken the gel coat wouldn't be a problem if it was mixed in well. If it was thickened with talc or other fillers it could create a problem. But most things added at low levels don't have a huge affect, although in lab testing it might be noticeable.

 

[Mr Efficiency]

Thanks for that, it seems that the effects of adding "solids" is not just dependent on the amount, but the type of solid. I've had little to do with gelcoat, preferring to paint after moulding.

 

[kapnD]

Fun Fact...My material supplier said most of their Cabosil sales were to McDonalds for thickening their shakes.

Damn, I gagged at that!
I knew there was a reason that I haven't eaten at McD's for over 20 years.
I won't even take the lid off my cabosil container without putting on a respirator, and I mix it in a closed container with a small hole for the agitator shaft.

 

[ondarvr]

Fumed silica (Cabosil, Aerosil) is a food grade product used in many things, ketchup, Mustard, BBQ sauce, or anything else that needs to be thickened with a non nutritional food additive, with no flavor.