Phil Kriley's Progress

[Kent Ashton]

I wet out the hardener cup, then balance the empty resin cup and the hardener cup. Then I pour in as much resin into the resin cup as I intend to make, and then pump slow hardener . . .

Jeez Phil, come on down to the 21st century. Do you ever want to fly that thing? I gunk in some resin, check my spreadsheet, add the hardener to come up to the total weight on the spreadsheet and mix. It's gotta take 1/5th the time. When you start wetting out spar caps, the balance routine is going to get old. Heck, send me your address and I'll send you a donation for the "Buy Poor Phil A Scale Fund". No one should have to endure what you're enduring.

Your friend,

[Jack Morrison]

Phil

One other thing you might do is run a fan on the parts you are working on directed at the exhaust fan, it will remove any fumes and sanding dust from reaching your face and also will help keep you cooler. This works great also when sanding under the strakes or bottom of the fuselage, blows all the dust away.

 

Jack

E Racer 113

[Phil Kriley]

Kent - I don't know where you got the idea that I was poor, and for your information I already own a postal scale. I used it in Chapter 3 when I was learning how to do layups.

 

Since I rarely do layups by myself, I've found that letting my son mix the epoxy while I work the layup keeps us from wating any time. Scale 5 times faster than my balance? I don't believe that for a minute. Will I ever get the plane done? I dunno, but it seems like I'm making good progress. I've been at it for 6 months and am in Chapter 7. I had a 4-week layoff because of the MGS epoxy shortage, so really I've only been working for 5 months.

 

Jack - thanks for the suggestion to run a fan - I will do that. When I was heavy into r/c planes, I developed a severe alergy to Super Glue - CyA (cyano-acrylate) and had to switch to more expensive "odorless" CyA glues AND use a fan on my workbench. Good idea to do the same on the plane.

 

I did a lot of sanding last night - working on shaping the rear - and used my belt sander with a vacuum hose attached to it - very little dust, so that's an improvement! Thanks for the input guys!

[Phil Kriley]

I shaped one side of the fuselage bottom Saturday, but I evidently cut too deeply with the jig saw. I thought that exposing 1/4 inch of the longeron meant 1/4" of the wood, but apparently the fiberglass layup counts as part of the longeron. After using my belt sander to get 1/4" of wood to show, I then rounded the corner - but I have at least a 1/8 inch gap between the corner and the template... So I guess I'll lay a bead of micro along the length and try to build it back up some. On the other side, I'm just cutting down to expose 1/4" of the longeron INCLUDING the fiberglass. Hopefully after rounding it will be closer to the template.

 

Man, that's a lot of sanding!

[Phil Kriley]

Did the 45 degree cut on the pax side, and it turned out a little better than the pilot side. I've started the sanding process, and I think it will be closer to the shape of the template than the other side. I'm still debating whether or not to try to bring up the first side some with micro...I'm afraid I might make it more of a mess...maybe better to just leave it alone...

[Phil Kriley]

I continued sanding the fuselage bottom last night, and then decided to make up some micro to fill in some low spots. The dry micro didn't want to stick, and wetter micro wanted to sag. What finally worked (I hope) was to tape plastic over the micro to hold it in place. Hopefully when this cures I'll be able to complete the sanding and move on to installing the antennae.

[Drew Swenson]

Paint on a coat of pure epoxy first (enough to wet---but don't get too thick). Then lay in the dry micro.

[Jack Morrison]

Peel ply also works good on wet micro to keep it from sagging.

 

Jack

E Racer 113

[Phil Kriley]

Jack and Drew - both excellent suggestions - thank you! We removed the plastic last night and it looks pretty good, but I think peel ply would have looked better. I've got some serious sanding ahead for tomorrow! Groan...

[TMann]

The boat guys use clear packing tape (the 2 inch wide stuff from Office Depot, Lowe’s and the like) to handle problems like this if the area is small enough to allow it's use.

Just lay in your micro (or in their case gel-coat) stick on the tape while conforming to shape.

This tip courtesy of my father-in-law (a boat guy.)

[Phil Kriley]

Thanks T - that tip will come in handy when I start filling in the holes caused by the 5-minute epoxy blobs!

[Jon Matcho]

Paint on a coat of pure epoxy first (enough to wet---but don't get too thick). Then lay in the dry micro.

Phil, don't forget to always do this when putting micro on bare foam -- it's documented in Chapter 3.

[Phil Kriley]

Phil, don't forget to always do this when putting micro on bare foam -- it's documented in Chapter 3.

I'll review Chapter 3, but I think you mean to put down pure epoxy before applying DRY micro - right? I don't think we want pure epoxy under the micro slurry when doing a layup such as the fuselage exterior - right?

[Jon Matcho]

Actually, it may not be documented in Chapter 3, but it's still a good practice:

 

1) Paint a very thin layer of epoxy when applying dry micro to... anything.

2) Squeegee a very thin layer of wet micro when bonding glass to foam.

 

Also...

 

3) Consider painting cured micro w/a think layer of epoxy when either:

a) further building up, or

b) laying up glass on top of it

 

Sound right? Hope that helps!

[Phil Kriley]

Sounds right Jon - and I'd add that micro that you are going to lay glass over should be sanded with course paper first. Then epoxy, then glass, then more epoxy and squeegee the excess. And peel-ply everything - if for no other reason than it looks better!

[Jon Matcho]

Sounds right Jon - and I'd add that micro that you are going to lay glass over should be sanded with course paper first.

Unless you're the glass up onto foam, then you do everything in one fell swoop. Curing the micro on the foam first -- forming a hard skin and then sanding BEFORE applying the glass -- is known as 'hard shelling', which there's been a fair amount of discussion here and on the other lists/forums.

 

Personally, I don't believe that 'hard shelling' is better than the plans instructions. I recall reading about concerns relating to delamination.

[Drew Swenson]

On applying the epoxy first to glass prior to putting on dry micro. Dry micro has a problem sticking to anything unless you wet the surface with epoxy. And yes---you do all at once. Paint on with a brush, then immediately lay down the dry micro.

 

On foam: You will never forget to put on slurry first (fairly wet micro). Just try it and see what happens.

 

Don't do hardshelling---big no-no.

[Marc Zeitlin]

Don't do hardshelling---big no-no.

Not true. Do you have test results showing there's a problem with hard-shelling?

[Drew Swenson]

<snip>Not true. Do you have test results showing there's a problem with hard-shelling?<snip>

 

ok, I'll bite---Please show me the evidence that hardshelling is good. I am pretty easy to convince.

[Marc Zeitlin]

<snip>Not true. Do you have test results showing there's a problem with hard-shelling?<snip>

 

ok, I'll bite---Please show me the evidence that hardshelling is good. I am pretty easy to convince.

I performed hardshelling on hotwired foam. I then laid up glass over it. I also laid up glass with wet micro on hotwired foam. I let them both cure. In both cases, when peeling the glass off of the foam, the micro/foam interface failed, NOT the glass/micro interface.

 

So, whether the glass/micro interface is as strong in a hard-shelled layup as in a wet layup or not wass immaterial for the epoxy I was using (Safety Poxy and/or equivalent) - the micro/foam joint fails first because it's the weak link in either case.

 

Also, even if the glass/micro interface did fail first in a hard-shelled layup in a peel test, I'd contend that it wouldn't be a big deal. In any layup where you've got micro under the glass, the surface area is relatively large and the layup is NEVER in peel - it will always be in shear.

 

How's that?

[Drew Swenson]

Perfect. Did you have to prep the hardshell (any kind of sanding)?

[Marc Zeitlin]

Perfect. Did you have to prep the hardshell (any kind of sanding)?

Yep. Gave it a good swipe with 100 grit or so to rough up the surface.

 

Hard shelling is good for breaking up large layups, like the wing skins, so that one person can do them solo without taking 12 hours. Micro one day, sanding and glassing the next. You can also do a lot of contouring before the glass goes on, so it can be a bit easier to get the fibers straight. Not a real big deal, though.

 

I know that many folks don't like it, and it's certainly not good for every situation nor a panacea, but there are times where it can be a useful technique.

[Phil Kriley]

In my case, I was not doing "hard shelling". I had some low spots along the longeron that needed to be built up, so I used micro covered with plastic to help it conform to the curved corner. I also use some micro to build up some low areas at the rear of the plane. Anything that looked shiny got sanded.

[Jon Matcho]

Hard shelling is good for breaking up large layups, like the wing skins, so that one person can do them solo without taking 12 hours. Micro one day, sanding and glassing the next.

That's really appealling actually. I tend to do better with many smaller tasks so far.

[Phil Kriley]

Moving forward again - we installed the marker beacon antenna last night.