Fiberglass Vacuum Bagging Technique...Resin Infusion

[Steve]

Is anyone using the new fiberglass process called Resin Infusion?

This is the process where you lay all of your fiber reinforcements down dry
(along with core material if required), then seal inside a vacuum bag (which
you can take all the time you want, no need to hurry as in normal vacuum
bagging proceedures), and then inject the resin which wets out the
reinforcements.

I have been using this process on my homebuilt sailboat (Core Cell foam
core, epoxy resin) and I am having terrific results. Resin ratios of 30 to
35% by weight. And best of all, no mess or fumes, sticky rollers, paint
brushes, etc. Check out my web site at
http://home.houston.rr.com/pieceofwork/ . I learned much of my fiberglass
techniques from the aircraft homebuilders web sites, so maybe I can return
the favor.

If you are ever in Houston, stop by.

Steve G
Houston, Texas

Remove the 'NS' from my email address to reply.

[Larry Smith]

"Steve" > wrote in message
...
> Is anyone using the new fiberglass process called Resin Infusion?
>
> This is the process where you lay all of your fiber reinforcements down
dry
> (along with core material if required), then seal inside a vacuum bag
(which
> you can take all the time you want, no need to hurry as in normal vacuum
> bagging proceedures), and then inject the resin which wets out the
> reinforcements.
>
> I have been using this process on my homebuilt sailboat (Core Cell foam
> core, epoxy resin) and I am having terrific results. Resin ratios of 30
to
> 35% by weight. And best of all, no mess or fumes, sticky rollers, paint
> brushes, etc. Check out my web site at
> http://home.houston.rr.com/pieceofwork/ . I learned much of my fiberglass
> techniques from the aircraft homebuilders web sites, so maybe I can return
> the favor.
>
> If you are ever in Houston, stop by.
>
> Steve G
> Houston, Texas
>
> Remove the 'NS' from my email address to reply.


Fascinating. Thanks for the link and report.

[Steve]

>
> I would think there would be a limit as to how many layers could be
> done at one time before the resin wouldn't penetrate all the way.
> I've been using Vinyl Ester Resin which has a lower viscosity than
> epoxy allowing better penetration so you can use a heavier, or more
> dense weave in the cloth.

No problems with this, but as you say, it is viscosity dependent. You have
to use low viscosity resins (both epoxy and VE commonly available) suited
for the process. You cant use your standard hand layup stuff. I mostly
layup 2 layers of 34oz triaxial stiched. But alot of my stuff is 4 layers
34oz and some is 4 layers 34oz with 2 or 3 layers 18oz biax. It wets it out
OK, but the thicker the layup the longer it takes. So you have to plan
properly, because the injection must be complete before the resin starts to
gel. With the resins I use, usually around 2 hours.


>
> It looks like an impressive way to do the resin work and without the
> hurry. Plus you don't have to work out the air bubbles, or chase them
> around as we often do.
Resin infusion yields some of the best void free composite work available
today. Air bubbles are a thing of the past, but dry spots are possible (no
resin). This is just something you learn to look out for and avoid the
situations that cause them. If you miss one of these during injection and
notice it, it is easily fixed during the injection.

>
> I'd think this could also work for small "patch work" if the bag could
> be sealed to the work surface with something like duct tape.

You can seal using packing tape, but I have found that RI is not worth the
trouble for small jobs, but a huge time and trouble saver on large jobs.
>
> It'd be interesting to get this to work on awkward shaped parts such
> as the engine mount reinforcements.

Without having seen them, I don't know if this would be a good application
or not. I would think you would set the reinforcements along with the
'normal' layup dry, and vacuum bag and RI the whole lot.
>
> Roger Halstead (K8RI EN73 & ARRL Life Member)
> www.rogerhalstead.com
> N833R World's oldest Debonair? (S# CD-2)
> >
> >If you are ever in Houston, stop by.
> >
> >Steve G
> >Houston, Texas
> >
> >Remove the 'NS' from my email address to reply.
> >
>

[Steve]

> The link to VIP off of your report goes on for a little bit about
> 'prints' and imperfections caused by the process. Have you had much of
> a problem with this? The biggest hurdle with composites is getting that
> perfectly smooth finish, and there is precious little room for
> imperfections. I like the idea of having the time to make sure
> everything is laid out perfect before adding resin, but having to get
> rid of a big lump where the feeder line ran would seem to make it a
> pay-me-now or pay-me-later prospect.

This can be a problem, but is easily avoided. My web site shows an
injection technique that I used when I started. Since I have changed my
infusion strategies. However, the feeder line as you see it could leave a
lump or impression in the surface. The way I do it now, there is no
problems. Check my web site again in a week or so, as I plan on updating it
soon with some new pictures.

My bulkheads turn out *very* smooth, textured from the peel ply. They are
as perfect as the foam was.

However, I think the other web sites are refering more to print through than
impressions. I believe this is a factor with low resin content layups.
However, I think that is something that can be taken care of when filling
and sanding. I am not really worried about print through.

>
> --
> ----Because I can----
> http://www.ernest.isa-geek.org/
> ------------------------
>

[Ernest Christley]

Steve wrote:

> This can be a problem, but is easily avoided. My web site shows an
> injection technique that I used when I started. Since I have changed my
> infusion strategies. However, the feeder line as you see it could leave a
> lump or impression in the surface. The way I do it now, there is no
> problems. Check my web site again in a week or so, as I plan on updating it
> soon with some new pictures.
>

I've got it bookmarked and will keep checking back. The wings of the
Delta are fiberglass, and are laid up on a flat surface and then mated
to the ribs. You basically have an 8'x8' triangle that has to be wetted
out at once. A technique that could eliminate the hurry and provide
better results would be a godsend.

Do you have any problems with pinholes?
--
----Because I can----
http://www.ernest.isa-geek.org/
------------------------

[Steve]

Pinholes are not a problem. Infusing the resing fills all voids, even under
high vacuum. Unlike hand layup vacuum bag, high vacuums can pull resin into
the bleeder, and result in pinholes. You may not completely fill the weave
on the surface, depending on vacuum level. You can always reduce vacuum
near the end of infuson to get a higher resin ratio.

--


Steve G
281-376-2682
Houston, Texas

Remove the 'NS' from my email address to reply.
"Ernest Christley" > wrote in message
...
> Steve wrote:
>
> > This can be a problem, but is easily avoided. My web site shows an
> > injection technique that I used when I started. Since I have changed my
> > infusion strategies. However, the feeder line as you see it could leave
a
> > lump or impression in the surface. The way I do it now, there is no
> > problems. Check my web site again in a week or so, as I plan on
updating it
> > soon with some new pictures.
> >
>
> I've got it bookmarked and will keep checking back. The wings of the
> Delta are fiberglass, and are laid up on a flat surface and then mated
> to the ribs. You basically have an 8'x8' triangle that has to be wetted
> out at once. A technique that could eliminate the hurry and provide
> better results would be a godsend.
>
> Do you have any problems with pinholes?
> --
> ----Because I can----
> http://www.ernest.isa-geek.org/
> ------------------------
>