Good evening,
Are you confused? ... I was :o).
Sandman!? ... I guess I took too much of my own medicine.
I overlooked the 'NOT' from Roger's initial email. So I was trying to answer
the wrong half of Roger's question. I was trying to explain how to get those
initial diagonal scratches out with sandpaper.
Greg and Mark are right. There are no problems with cedar. It'll soak up the
epoxy to create a perfect mechanical bond between the wood/epoxy/glass
lay-up. I think Bram mentioned it earlier. You either need a good chemical
bond or a good mechanical bond. While the epoxy is already hard but not
fully cured you can add another layer of epoxy without sanding and you will
get a great chemical bond (which is superior). Once it's fully cured and you
need to add another layer, you need to hit the surface with sandpaper to
create those keys Roger mentioned. 80 grit sounds like a good paper to use.
Fast but not too coarse.
I know long-boards are old school. I actually went back further and used a
smoothing plane (bigger hand plane) first. Something I wouldn't recommend to
everyone. The blade doesn't like glue at all and there are some other issues
(depth, chip breaker, round blade corners ...)
Because the shape of the hull is very well controlled by the amounts of
moulds and the even thickness of the narrow cedar strips, you start with a
fairly accurate shape and there is no need for fairing battens, power
planers or hand planes.
Orbital sanders are nice but I think there are a bit more difficult to use
if you are a beginner. I also recommend using them in a diagonal fashion. If
you are thinking about using an orbital sander, think about moving your feet
a lot. Don't stop in one spot. Keep moving your arms and walk along the
length of your boat.
These are my two cents worth. Put 'em in a cup and we might have enough for
a cup of coffee or some harsh chemicals by the end of next year ;o).
Cheers,
Felix :o)
P.S.: Some additional information (not so swift related):
I guess what West System is referring to is cold moulding. Multiple layers
of wood or veneer. Like Greg mentioned it's mostly oak that you might run
into problems. Stems or frames that are glued up from oak strips tend to
fail, when you don't hit them with some coarse sandpaper after they come out
of the planer. Especially the stuff below the waterline. Some say that with
oak you should only use 5200 or resorcinol (spelling?) glue below the
waterline. I'd much rather have my epoxy glue up fail after twenty years,
then poisoning myself with resorcinol glue and messing up the very
complicated glue up. That stuff is not so forgiving (Temperature, Pressure,
Mixture).
-----Ursprüngliche Nachricht-----
Von: Mark White [mailto:Mark@xxxxxxxxxxxxxxxxxxxxxx]
Gesendet: Dienstag, 20. Dezember 2005 16:42
An: rowr@xxxxxxxxx; swiftsolo@xxxxxxxxxxxx
Betreff: Re: AW: Aussie Swift taking shape
I believe that only applies to sanding epoxy, not wood, if that is the
concern, because the epoxy will soak into the surface of the wood no matter
what grit sandpaper you use, I used 120 before wetting out the wood
surfaces.
Mark
----- Original Message -----
From: <rowr@xxxxxxxxx>
To: <swiftsolo@xxxxxxxxxxxx>
Sent: Tuesday, December 20, 2005 7:44 AM
Subject: Re: AW: Aussie Swift taking shape
> If I remember correctly, I think that I read somewhere in the West System
> product info that you should not go with a smaller grain than 80 grit
paper
> for your final sand before epoxy, so that you get a good epoxy key into
the
> wood. Anything smaller than that makes it harder for the epoxy to bond to
the
> wood. This is however tough to do to get the minor scratches out after
major
> sanding.
>
> Any thoughts?
>
> Roger
>
>
>
> Quoting BDally6107@xxxxxxx:
>
> > Really good advice Felix. Especially about vacuuming the dust
frequently
> > (no point in sanding fine dust into really fine dust). Your input is
always
> >
> > appreciated. On the other hand, we need to get you back to work on a
Swift.
> >
> > Get with it man! We want to see you on the race course.
> >
> > With the epoxy/graphite powder on the bottom, I think wet sanding is the
> > real deal (no mask needed). Start with 200 grit and a 2 1/2 x1/4"
Mahogany
> >
> > long board that is the slightly long than your wet/dry paper (14").
Wrap the
> >
> > paper around the board and use plenty of water. You really don't want
to
> > breath
> > this dust so vac it up when it dries on your floor. Keep going up in
grade
> >
> > of paper and finish with 1000 or 1200 grit. It will look like a mirror
and
> >
> > will show where you need to do more work.
> >
> > A little reminder. PURCHASE AND WEAR A GOOD DUST MASK for dry sanding.
The
> >
> > full face type that covers your eyes works best (Fisheries Supply)
because
> > it appears that some problems come through the tear ducts.
> >
>
>
>
>
>
> This is the Swift Solo mailing list. For unsubscribe instructions,
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>
>
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