Alrighty campers, as you can see over in the build thread I'm getting close to having my boat foamed and Bondo'ed out. For those more experenced glass layers, a question. How smooth do I need to make the quasi-plug before laying down my first of likely three layers of mat. The first layer was intended to fill in the imperfections with the follow ups for looks. Open to reccomendations.
The smoother the better of course, since the fiberglass will not cover up any flaws. From the practical standpoint, as long as there are no holes for the resin to leak through and there are no abrupt changes in elevation, you should be fine. You want the fiberglass to touch the surface at all points so that there are no air pockets underneath that will cause a weakness. Looking at your 27 Oct pictures, those look a little too rough to get a layout. Are you really going to use fiberglass mat? Mat is pretty thick and will definitely add to the surface roughness, which you will have to sand out to get a smooth hull. Mat is also usually pretty stiff and may be hard to get to lay down One layer of 4 to 6 oz woven cloth is usually plenty.
It'll be woven, not the chopped mat. I'll upload more pictures prior to going at it but I've got a layer drying right now around the bulges fixing the divits.
if you want to assist in getting a better bond on rough surfaces and don't need as much strength (nothing in model boating accept maybe the dead center keel line doesn't fit this) make "slurry". add micro until it gets thick but not peanut buttery, kinda milky colored then lay it down. place the glass over that and stipple it down with raw epoxy. Stippling is taking a brush and stabbing at the areas till it wets out. use a squeegee to remove wrinkles and shape contours. cheap harbor freight 25 for $5 brushes are perfect for this. be careful not to overwork the area as you will squeeze out all of the slurry but you do want to squeeze some of it out to keep the weight down as well as to keep your hull shape.
