Polyester Flowcoat Question

[Wotname]

What is the fundamental differences between poly flowcoat and a general purpose laminating waxed pigmented polyester resin?

Put another way, can I throw some pigment into waxed laminating general purpose poly resin and get a serviceable flowcoat?

Are there additives in flowcoat that make it thicker or more thixotropic or self levelling or some such?

[HankOnthewater]

polyester resin does not contain wax, flowcoat does.
flowcoat is like general resin with wax added
you can add wax to a general resin to make it a flowcoat.

Yes, you can add to any resin, colouring or 'stuff' to make the resin thicker.

It make it thicker: cheapest is talcum powder, but should not used below the waterline or for tanks. There are other additives like Qcells, to make a fairing compound, easier to sand. There are dozens of products, each for a slightly different purpose.

[Wotname]

Perhaps I wasn't accurate enough.

I have a 10 kg can of GP polyester resin that does contain wax (can A).
I have a 10 kg can of GP polyester resin that does not contain wax (can B). I guess the wax was put in can A by the shop selling the stuff.

So I can add pigment to the stuff in can A and use it lieu of buying a can of flowcoat - yes or am I going to create some unforeseen problem?

I'm a new chum when it comes to poly resin; epoxy is my bestie!

[coopec43]

Wotname

I'd hang on to your resin as it has a long shelf life if kept cool.

I've only used flowcoat once and I wouldn't bother with it again.

I've painted the entire (fiberglass) bilge with two coats of "Rust guard". The paint expert at Bunnings said I could get the same product in their Marine Section but I'd pay double the price

Killrust is a similar product but considerably cheaper.

Home Depot product is probably Rust-O-leum

[Rucksta]

Flow coat pigment also makes the surface harder and able take polishing.
Added Styrene seems to improve self leveling and mold conformity.
Wax migrates to the surface forming an air tight seal to allow curing.

[Wotname]

Originally Posted by Rucksta

Flow coat pigment also makes the surface harder and able take polishing.
Added Styrene seems to improve self leveling and mold conformity.
Wax migrates to the surface forming an air tight seal to allow curing.

Good to know. I might have to look up the recommended Styrene ratios.

[Wotname]

Originally Posted by coopec43

......
I've only used flowcoat once and I wouldn't bother with it again.......

What concerns did you have about using flowcoat?

[boatpoker]

"Waxed Polyester" -
Wax rises to the surface and seals the polyester from the air which allows it to dry and harden. The wax must be removed before applying any other resin (vinylester, gelocoat, polyester or epoxy, ).

"Unwaxed Polyester"
Will never properly cure as long as it is exposed to air. deep in the laminate it will cure somewhat but will always feel tacky on the surface.

Boatbuilders typically lay up the hull with unwaxed polyester and apply waxed polyester as the final coat.

[coopec43]

Originally Posted by Wotname

What concerns did you have about using flowcoat?

I would only use it where I was dressing up some fiber glassing for show - maybe in the cockpit. But I would quite happily use thickened, pigmented polyester instead.