Fiberglass cloth

[sryan]

I'm building a 26ft boat (Top Hat) and I'm preparing to fiberglass the hull soon. I would love to have a beautiful mirror finish using Awlgrip. I plan on using 8oz fiberglass cloth and I was wondering if I should add a second layer of maybe 1oz. Would that work? Is there a better way of preparing the hull for the Awlgrip to get the mirror finish? I do plan to paint the hull with a dark color.

Thanks,

Stu

[George Roberts]

"Would that work?"

It might make the paint look better, but I don't think that 8oz glass is sufficient for a boat that size.

[JimD]

Use the weight of cloth recommended by the designer. Fill the weave fully though successive thin coats of epoxy, applied in succession before the prior coat fully cures. Final smoothing is by sanding. If the hull needs fairing as well as smoothing, fair with epoxy/microballoons mix and sand after curing. Seal microballoon faired hull with a final thin coat of epoxy. Very fine sand. Paint.
At least that's what I do.

[Spokaloo]

On your last couple of filler coats, use some microballoons in your epoxy to reduce sanding effort.

You MUST longboard the hull to get that mirror finish. Its extremely difficult to accomplish with power tools even for veterans.

After getting her fair and smooth, 3-4 coats of a high build primer will give you that ultrasmooth finish you are looking for.

E

[rbgarr]

Are you sure you want a high gloss 'mirror' finish. Hylan recommends against it.

We'd love to see photos!

Thx

[James McMullen]

One layer of 8oz fiberglass cloth and dark colored high gloss paint will pretty much guarantee that your high gloss mirror finish will last forever---or until the sun shines on it, whichever comes first. Do you have a boathouse to keep her in? Or a velvet-lined bag? Do you just like making things difficult for yourself or what? :p

I can't think of an easier way to achieve print-through of the weave than a single light layer of cloth covered by glossy, dark paint.

[JimConlin]

One layer of 8oz fiberglass cloth and dark colored high gloss paint will pretty much guarantee that your high gloss mirror finish will last forever---or until the sun shines on it, whichever comes first. Do you have a boathouse to keep her in? Or a velvet-lined bag? Do you just like making things difficult for yourself or what? :p

I can't think of an easier way to achieve print-through of the weave than a single light layer of cloth covered by glossy, dark paint.

Epoxies shrink as they cure and they take a while to reach final cure, so if you fair epoxy that's not fully cured, the subsequent curing will reveal glass texture. So, before fairing and painting, it's a good idea to fully cure the epoxy either by waiting a couple of months or heating the part for a few hours. A day in the bright sun under a dark tarp will probably do it.

[Spokaloo]

Wet glass to complete fairing filler can be within 2 wks. Had exactly zero shrinkage issues with any of it, and this is over 24oz biax. Id have to say I reccomend the opposite, actually. Working wet on wet you can get an amazing molecular bond with epoxy from substrate to faired surface.

E

[paladin]

I cheated....I built my boat in Thailand....in a "barn" with not end or sides, sheet metal roof....did all epoxy work in the early morning or late evening hours. Top of metal was painted black and then we used 7 mil plastic roll down sides....after laying up the wood epoxy we just rolled down the sides and let natures autoclave take over...worked grrrrreat...

[JimD]

On your last couple of filler coats, use some microballoons in your epoxy to reduce sanding effort.
E

Agreed. It reduces sanding effort and also seems to help fill those strange and annoying little areas that just don't seem to want to fill.

[Bill Perkins]

Stu ; I went with Sterling ,another top notch brand of Linear Polyurethane . With my paint order they sent a WB article on Linear Polyurethanes over wood by Doug Templin ( 78:21), updated to include their new products . It covers the final prep for a gloss finish in detail . They might well send you a copy.

Sterling products are mentioned specifically ,but this is generally useful info . I chose Sterling because a couple of experienced formites recommended it ,especially for roll and tip application as opposed to spraying . I chose to use the flattening agent , as the super high gloss seemed inappropriate for the work boat derived design I was building . I've had to do some touch up because of wear from the fenders while at the float as well as some launching and docking indiscretions . This was easy to match in with the flattened paint .

[sryan]

Everyone's input is appreciated. It is really great to have feedback from so many experts...thanks!

The boat will be kept in a boathouse on a lift so I should be able to protect the finish. Wish me luck!

Thanks,

Stu

[eastern270]

I built my boat 3 diagonal layers of okuome ply. Longboarded and faired til my arms fells off. Rolled on a couple thin coats of epoxy. Washed and sanded again. I used one layer of 10 oz. cloth on the hull and 2 layers on the keel. Rolled on 3 more thin coats of epoxy. Primed 2 times with epifanes 2 part epoxy primer. Sanded and washed and sprayed 3 coats of epifanes 2 part polyurethane. Just like Jim Conlin mentioned above as it cured over time I could see the print through gradually very lightly of the fiberglass even after all the work I did. My personal opinion would be to use many coats of a high build primer. I am still very satisfied with my finish. I hope this helps with your decision. Try to post some pics. I like that design and almost bought a set of plans. Good Luck.http://i250.photobucket.com/albums/gg280/eastern270/my%20boat/P1010209.jpg

[pipefitter]

Careful of the liberal usage of high solvent, high build primers as they shrink for a much longer period than solid epoxy does. There is a guideline to optimal mil thicknesses described with most paint product schedules and many times, people tend to not carefully consider the thickness of the primer into the equation and it should be for the best overall results both short and long term. Seems that high build primers in modern times have replaced much of the fairing that should be done initially in the substrate itself.