Glen-L.com

Hi folks,

I will be fiberglassing my Malahini in a few short weeks and need to get some input as to the process for my particular build. I am using Meranti BS1088 plywood on the sides and bottom and want to leave the sides finished bright (clear) and I will only be painting the bottom hull and up the sides a little. I intend on using a spray rail over the chine on the sides as well.

I have the video and book.. got that part down.

Because I am mixing finishes... not 100% paint and not 100% bright, I am looking for advice as to how to do the process properly.

I am thinking of using a 6oz cloth on the bottom hull, wrapping over the sides and transom about 3" to match the paint-line. I was thinking of using a ligher 4oz cloth on the sides & transom to ensure more transparency and overlapping the bottom 3" to double-up.

I am still not 100% on the process of 'feathering' the lapping joints. I get that you apply 1 layer.. say at the bottom hull.. and then let it 'harden' before sanding. But how long.. we talking a few hours or next day? If its still 'tacky' then wont that make the epoxy gum-up the sanding material?

So is it...

Apply bottom layer 6oz... wait till it gets 'hardish'... feather sand the edge... dust it off.
Apply side layer 4oz... wait till it gets 'hardish'... feather sand its edge... dust it off.
Apply next layer of epoxy... wait till it gets 'hardish'... apply next layer.
Repeat till weave is filled.

My concerns are:

Best tool(s) for feathering the edges.. I don't want to damage the brightside finish.
Timing.. to avoid sanding between layers of epoxy.. how do I do this.. I can probably make it a 'long day' project and get it all done depending how long I have to wait.

_________________
Ian (aka Iggy)
My Malahini Build

Iggy,

I did just the process you describe. 6oz bottom 4 oz sides, overlapped the bottom 3" or so on the sides and transom. Came out great, glad I did 4oz on the sides.

Youll likely have to wait 12 hours or so to feather in summer temps. I found if I waited more than a day it was more difficult to sand. Either way it loads up sand paper fast. I used a detail random orbit sander and then a sanding block to feather. I started with 60 and finished with 220 grits.

I'd wait to apply the epoxy over the glass in the evenings as the temps cool. It will keep tiny out gassing bubbles from forming and of coarse more pot life in cooler temps.

_________________
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if you use a cabinet scraper you can feather the edge when it is green. it does a much better job + no dust
-Billy

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(insert witty phrase here)
Billy's Belle Isle website

Yep, Billy hit it right on the head!

_________________
Bill

I told my wife we needed a three-car garage for my projects...she told me to ask her for permission next time before I buy a house.
http://www.unitybuild.net

Cabinet Scraper, like this thing?

http://snaintonwoodworking.com/store/in ... 8dbf6fc5ba



How do you use that to make a feathered edge in green fiberglass/epoxy?

I thought that the 'sanding' process was to gradually thin the edge so that the next layer will not have a 'bump' underneath it at the leading edge.

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Ian (aka Iggy)
My Malahini Build

This is just one tool to get to the same end. When the epoxy is firm but not sandable yet you can use the scraper make the edge virtually invisible to the next layer. Sanding does the same thing but you have to wait longer for the epoxy to cure to a sandable state.

_________________
Bill

I told my wife we needed a three-car garage for my projects...she told me to ask her for permission next time before I buy a house.
http://www.unitybuild.net

I can't seem to picture how you use that scraper to taper the edge. Do you run the epoxy past the edge of the fiberglass mesh ahead of time and then feather the 'extra' instead of sanding down the cloth later?

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Ian (aka Iggy)
My Malahini Build

There is a little lip on the edge that you use to scrape with.

You hold the tool at an angle with the lip down and pull it.

I've never used one for fiberglass,but I have for removing varnish

I would assume for glass, you would pull it along the edge of the cloth or bridge the edge to taper it down?

_________________
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tragedies obscured by the occasional miracle, followed by a good bottle of beer.

Don't Dream Your Life, Live Your Dream

Warren is right-
the scraper will shear off the rough edge of the cloth/epoxy cleanly.
i add a step before scraping when i want a more precise edge to my cloth and that is run tape along the edge where i want to end my cloth and glass onto the tape surface. when the epoxy has hardened to the point where it is not tacky i take a knife and lightly score the cloth along the tape line and remove the cloth and tape. gives a perfect line to scrape and a clean edge for the blend. Ian... not totally needed in your case where the boot stripe will hide the overlapping cloth.
-Billy

_________________
(insert witty phrase here)
Billy's Belle Isle website