What is the best epoxy surface-coat for the first layer of an epoxy and s-glass layup? (This will be the coat that goes directly onto the mold, to be followed by the s-glass and West 105/205 epoxy).
Freeman 705 has been recommended. Anyone used it?
Best epoxy surface coat ?
What is the best epoxy surface-coat for the first layer of an epoxy and s-glass layup? (This will be the coat that goes directly onto the mold, to be followed by the s-glass and West 105/205 epoxy).
Freeman 705 has been recommended. Anyone used it?
Epoxy
Take a look at PTM&W they may have something.
Ian
x2 on aeropoxy. Not as toxic to boot. It does take a loooooooog time to cure, but it really wets the material out well and quickly
I use Aeropoxy too. The mid-range temp stuff takes a while to cure, especially in the 55 degree shop in winter. My wife loves it when I put parts in the oven or else leave them next to the heater in the bathroom overnight.
Surface coats add a bunch of weight to the part. Freeman 705 is great for molds but is very thick and thus heavy and brittle.Originally Posted by Christopher Crowe
My best results with a wet lamination is to use a thin laminating resin and then add talc (even baby powder) to the resin and a little pigment so you can gauge the thickness of your coats. I actually heat my resin to reduce the application viscosity and make it gel sooner. I like to use a cotton roller (available at Walmart or home store for a few bucks) to apply the the resin the the surface. Then also use a chip brush (with bonded bristles) to fill in where the roller skips.
Wet out the pre cut fabric on a table top wetting board and then lay in the fabric once the surface layer has become rubbery and sticky to the touch. This is important to not start to soon or allow it tho harden. too soon and the surface coat will wick into the fabric and result in pinholes in the surface, too long and the fresh resin will not be able to sufficiently crosslink with the surface coat resin resulting in chipping and delamination.
What I mean by "bonded bristles" is this. When using low cost brushes, the bristles come out easy and make a pain out of your work. here is what i do. buy your chip brushes in qty. use one gallon icecream bucket to put about a half inch of baby powder in the bottom. use a second and put about a half inch of lacquer thinner or acetone in. next set up a piece of scrap wood to use as a rub block. Mix up some resin and thin it down with acetone to make it runny and very wick-able by the bristles. one by one stir the solution with each of the chip brushes making sure the thinned resin wicks up into the metal crimp holding the bristles. next dip the brush in the thinner swirl it around and clean the resin from the hairs from leaving a space of about a half inch from the metal crimp band. Next wipe it off and then swirl it around in the baby powder to dry up all the resin and thinner from the bristles. next, use the board to rub the brush on to knock off chunks of powder. place the brush in a storage container with baby powder in it to suck op any resin you may have missed. when the resin cures, the thinner in it makes it a bit pliable as well as bonds the fibers together up under the metal crimp band and the powder insures the bristles are free from resin leaving them soft and ready to work with and not have the fibers come out messing up your work, specially with surface coats.
Good Luck
Corey
SCT Sports Cars
OBTW - most baby powder these days is cornstarch, not talc, as some folks respond to talc like asbestos, etc.
We have several Talc mines around here. It's pretty strange stuff as it comes out of the ground.
Cornstarch powder is labeled as such. The cheep baby powder is talc and it works great for surface coat as well as filler. It is also sandable for ease of doing the body work and paint prep. You can also use calcium carbonate but it is hard to sand and is hard to blend the lumps out when stirring.
Almost every surfacer, body filler, feather-fill, primer out there contains talc because is works great.
Talc is safe and has been for use for years in a wide range of household products and so far even hypoallergenic. There are always rumors to ban every thing that exists on earth but to my knowledge, talc is very safe to use. you are using resins and solvents, and paints and you are worried about talc ??????
FYI Talc is one of the main thixotropic filler in Freeman 705 also as well as BONDO. It is also used in concrete surface coats to get the tough smooth surface on decorative facades.
No sweating the talc baby powder, sweat the guardrail.
Corey
SCT Sports Cars
I don't worry about talc, I was just stating why it's not used in cosmetics as much any more.
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