Stitch & glue - glass seams

[Guest jeff t]

I'm thinking about building a nesting dingy this winter - but I've never seen a finished stitch & glue dingy. My concern is the look - do the glass tape seams stand out proud from the plywood pieces ? Even if filled and sanded, what stops it from looking lumpy with a high gloss finish coat.

none@none.com

[Guest Frank Hagan, Weekender, O]

Good question. I haven't built with glass taped seams on the outside of anything; the boat I did build used a layer of glass on the outside (the entire hull). The keel wasn't glassed, so there is a "seam" where the glass ends and the plain wood begins. Being ever practical, I figured the fish wouldn't mind the seam down there too much, and I suspended sanding and filling ... (I must be a designer's worst nightmare ...)

Anyway, most plans I've seen usually use a full layer of fiberglass cloth on the outside of the boat, and taped seams inside. Sometimes there are taped seams UNDER that full layer of cloth on the outside. Filled, then sanded until they are feathered in, you have to look really hard to see where the fiberglass tape is.

fshagan@ev1.net

[Guest Joe Nelson]

I like to use 1" wider tape than recommended so you have room to taper the fiberglass tape edges with a scraper and sander. Then you use a big drywall taping trowel (12") and just like drywall...transition the tape to the rest of the hull with a mixture of epoxy and microballoon mix or silica. Microballons sand much easier than silica but is soft (good for sanding) but can absorb water so you need to recoat the microballoons with another layer of un-thickened epoxy. The Microballoon mix from S3 has microballoons and silica mixed so its a little tougher than plain microballoons but still sands well.

But the process is trowell and sand, trowel and sand until the desired level of finish is acheived. If you get on the sanding when it is just dry enough to not gum up your sandpaper, it sands easier than if left for weeks prior to sanding. Then wash with a scotch bright pad and warm water...allow to dry and recoat with the mix....sand...sand...sand.

Sanding is the most dreaded chore we do. But its what makes the difference.

Avoid dark colors of paint...fiberglass print through is more common with dark paints than lighter paints.

joe_nelson22@hotmail.com

[Guest Joe Nelson]

Forgot to mension...the coating of microballoons with unthickened epoxy is only necessary after your last coat just prior to painting. I like to coat the whole boat with a couple coat.

Then there is the debate over drying time for epoxy prior to painting. Thats another thread.

I would recommend that anyone that is new or thinking about buiding...should download the S3 Epoxy Handbook and read Devlin's Boatbuilding book. With these two resourses behind you...you will be confident and ready.

joe_nelson22@hotmail.com