REFLECTOR: sanding the cores

Jim Sower canarder at frontiernet.net
Sun Oct 2 23:05:37 CDT 2005


I saw that coming and got out my router and set the depth at about 1mm 
and routed a 1/4" wide groove in the core down the micro line. If I 
sanded it down to where the micro would interfere, I just routed that 
area out again. In the end, I had no problem with sandpaper bouncing off 
of micro, and I had few grooves something under 1mm deep to fill with 
micro before the layup. No problem!
Worked great for me ... Jim S.

Alex Balic wrote:

> Speaking of the sanding- as everyone knows it is difficult to sand the 
> cores, because the micro is about 50 times harder to sand than the 
> foam, so you end up with foam ridges surrounded by low areas of foam 
> no matter how careful (and I was really careful too, because I was 
> expecting this problem )- you can try to not run the micro all of the 
> way out to the surface of the foam while bonding, or as I did on my 
> canard cores (I learned my lesson from the wings) I used some of the 
> “Great stuff” canned polyurethane foam as adhesive to put the cores 
> together- you need to rub them together a bit to de-aerate the foam - 
> the stuff sticks great, and when it was done, it all sanded like a 
> monolithic slab- worked great, and no micro to mix either. I have a 
> very fine glue line, about a 16^th or so. Also did a test piece just 
> to make sure, and the bond line is stronger than the blue foam.
>
> -----Original Message-----
> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] 
> *On Behalf Of *Andy Millin
> *Sent:* Sunday, October 02, 2005 10:31 AM
> *To:* Velocity Aircraft Owners and Builders list
> *Subject:* RE: REFLECTOR: Triax which side is up?
>
> Andy,
>
> You're probably already glassing... I had wish I could get just 20 
> minutes with my cores before I glassed them. They are so easy to sand 
> when it is just the foam. I could have save considerable time in the 
> filling and sanding if I had done a little bit with a long (4' or 
> longer) sanding block. I would recommend it if you haven't glassed 
> yet. Just a 1/16" her and there can save a great deal of time and weight.
>
> FWIW,
>
> Andy
>
>     -----Original Message-----
>     *From:* reflector-bounces at tvbf.org
>     [mailto:reflector-bounces at tvbf.org]*On Behalf Of *Andrew Ellzey
>     *Sent:* Sunday, October 02, 2005 10:25 AM
>     *To:* Velocity Aircraft Owners and Builders list
>     *Subject:* Re: REFLECTOR: Triax which side is up?
>
>     That's my plans for today. I have my left wing core ready to glass
>     all shimmed and true on a true and level 4' X16' table that I
>     built. My plans are to lay plastic on top of my dry wing, lay out
>     my triax and get it as perfect as I can before anything has been
>     wet out. I am also am thinking I will pre cut it somewhat close to
>     size when I am finished and carefully fold the triax length wise
>     no more than maybe twice and then lay it on the edge of my table
>     in front of my wing. When this is complete and I know that I have
>     a full day to start the final glassing, I then know that I won't
>     be rushed to straighten the squiggles when my wing is wet. See
>     attached photo.
>
>     Andy
>
>         ----- Original Message -----
>
>         *From:* Alex Balic <mailto:alex157 at pwhome.com>
>
>         *To:* 'Velocity Aircraft Owners and Builders list'
>         <mailto:reflector at tvbf.org>
>
>         *Sent:* Sunday, October 02, 2005 2:31 AM
>
>         *Subject:* RE: REFLECTOR: Triax which side is up?
>
>         I’m thinking Alan didn’t wan to spend the time to pull them
>         all out- it is very, very tedious, I did mine all dry- laid
>         the glass on the cores and pulled with rubber gloves and a set
>         of pliers- you can put a lot of tension on them, and I had
>         little trouble pulling the slack out- just took a few hours to
>         do it- I was told that my triax was in “usual” condition as
>         far as the squiggles are concerned. As far as if they matter-
>         yes they do- the triax is designed to be laid so the roving
>         takes the tension loads of the structure. If the roving is not
>         straight, then the resin, and the smaller biax fibers end up
>         doing this job- as you can tell, the biax layer is much less
>         substantial then the roving- in filament winding structures
>         like pressure vessels, the roving is applied under quite a bit
>         of tension to obtain the proper strength of the bottle, and
>         the same would apply to our wings- even though the thickness
>         of the glass on there is quite substantial (can’t comment on
>         the hollow wings since I am unfamiliar with their specific
>         construction)-
>
>         -----Original Message-----
>         *From:* reflector-bounces at tvbf.org
>         [mailto:reflector-bounces at tvbf.org] *On Behalf Of *Andrew Ellzey
>         *Sent:* Saturday, October 01, 2005 11:44 PM
>         *To:* Velocity Aircraft Owners and Builders list
>         *Subject:* Re: REFLECTOR: Triax which side is up?
>
>         Thanks, to everyone for all the help.
>
>         Andy
>
>             ----- Original Message -----
>
>             *From:* Al Gietzen <mailto:ALVentures at cox.net>
>
>             *To:* 'Velocity Aircraft Owners and Builders list'
>             <mailto:reflector at tvbf.org>
>
>             *Sent:* Saturday, October 01, 2005 6:27 PM
>
>             *Subject:* RE: REFLECTOR: Triax which side is up?
>
>                     gently pull each strand of the triax to take out
>                     any slack and, just like Alex said below, it adds
>                     to the tension and taughtness and forgive me if
>                     I'm wrong he gents, but the strength of the entire
>                     wing as well
>
>                     It does seem that it make for a more rigid wing. I
>                     have to hope it doesn’t matter too much because
>                     anywhere I sanded through the primary and filler
>                     on my ‘Wingco’ wings I saw nothing but squiggles.
>                     Alan apparently didn’t think it was an issue.
>
>                     Al
>
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