Have a look at David Carter's R elevator construction notes.
Skin and stiffeners are exactly the same as for the rudder.
Jeff Orear <jorear@mari.net> wrote to the RV-list: Oil-canning is a term
used for a condition where if you press on an area of aluminium skin, for
example on a control surface, and an area next to where you are pressing pops
up. It is the result of having the skin in compression, where it is not tight.
On the control surfaces, the main way to prevent it is to ensure that your fixtures on which you build them are aligned properly so as to not build in a twist to the surface. I am still pondering why I have gotten some in one elevator, but that is another story. It has been suggested that due to the empennage control surfaces using .016 skins, one must be very careful how you handle them, such as removing the protective vinyl. Since the skins are so thin, one can easily distort them.
Mark Fredericks <Mlfred@aol.com> wrote to the RV-list: There's oil-canning, and then there's OIL-CANNING!!! The latter would allow some dimensional change in the structure, with possible bad results.
Why does a panel oilcan? Because (this can come from a variety of causes) it has a bit of diagonal tension. It really doesn't take much to do this, especially with the thin skins of the elevators, rudders, and ails.
So: can you figure out exactly where the tensions comes from? Can you alleviate this? I have seen squeezing the TE change a slight oil-canning to zero. If the surface is built, you might try this...a slight squeeze on either side of the loose area would probably give the best results. Of course, if your TE radius is already too tight, THIS could be causing the problem. I don't have a fix for that problem...
SCOTT R MCDANIELS <smcdaniels@juno.com> wrote to the RV-list: Some other things can cause the oil canning on control surfaces.
If the rib flanges are not adjusted to the correct angle to mate flush with the skin it will attempt to pull the skin to match the rib (the rib material is heavier than the skin, particularly the .016 that is on RV-3,4,and 6's). Since the tail surfaces do taper (particularly the rudder) the rib flanges have to be adjusted to something other than 90 deg.
Another thing that can cause a problem is after finishing the metal work you install the fibreglass tips. they sometimes don't lay flush on the skins or flanges that have been riveted on so that when you install the blind rivets it pulls the flanges out of line which then tweaks the skin. And we all know that tweaked skins can cause oil cans.
Jim Ayers <LeastDrag@aol.com> wrote to the RV-list: If you have an assembly that wants to oil can, you use a technique that will reduce, or even eliminate, the problem.
By riveting the ends of the elevator skin to the spar, you have contained any oil canning between the rivets. By adding a "centre" rivet, you have created twice as many areas which have half as much oil canning. And you just continue to add "centre" rivets, doubling the number of areas with half the oil canning, each time.
A modification of this technique would be used if there was an obvious high spot between a skin and the frame (such as the edge of the bottom or top fuselage skin along the longeron). You just install the third rivet at the high point, instead of the "centre" point. Then you use "centre" rivets in each of the unequal length areas remaining.
Again, be careful with getting a right angle off the spar for the stiffeners, NOT from the edge of the skin.
I cogitated for some time over which was the left and which was the right elevator horn. In the end, I chose the wrong one!!! Arrrgggghhh!!! By the time I'd realised that, I'd riveted it to the skeleton, and riveted the skin to the skeleton. I drilled some of the skin rivets out, and drilled the horn off, but there's really no way to accurately drill the right horn to the existing holes. Due to this and a couple of other screw-ups, the right elevator is now a write-off. But some of these notes were added during the second elevator build, so something's gained from it.
Check out Frank Justice's notes... the Vans manual is very thin & lacking in this area. E.g. it says "Don't rivet the horn on yet"... nowhere does it say later "Now rivet the horn on". Remember, you need to rivet the horn on before you put the skin on! Don't worry too much about FJ's "Alignment Checks"; given that the skin's predrilled, you can't adjust the elevator width anyway.
The manual has a typo; it says to rivet the E-604 to the E-605 tip rib. That
should be the E-603 tip rib. It's a little tricky to rivet the tip ribs to the
spar; the clecos always seem to interfere with where you want to put the
bucking bar. Just choose the right ones to use; I generally had 2 in place
whilst riveting. FJ says to drill the counterweight bolt holes 7/32"
-- this doesn't make sense since the bolts are AN3-14 (which incidentally
weren't supplied with my kit) which require 3/16" or #12
size holes.
Aligning and riveting the E-609 root rib to the spar is a bit difficult. Best way would be to rivet it on with the 3/32" rivets, then bend it to the correct angle. Except you can't tell the right place to drill the holes until it's been fitted to the skin. Oh, well, you can't win. Just do the best you can. Console yourself with the thought that these little rivets aren't structurally important: the steel elevator horn gets riveted to both the spar and the rib. I'm sure there's a better way, but here's how I did it: Cleco the spar to one side of the skin. Mark centrelines on the rib flange. Clamp the rib to the skin and spar so that you can see the flange centrelines through the holes in the skin. Use a setsquare to ensure that the rib is square to the skin and mark the edge of the rib flange on the spar. Remove spar and rib from the skin, clamp rib to spar aligned with the line, and drill through the rib into the spar with a 12" #40 aircraft drill. After I'd driven the rivets with some difficulty, it occurred to me that it might have been possible to do these rivets with the hand-squeezer. Damn!
Be very careful about getting the tip rib assembly square to the spar. The counterbalance arm needs to line up alongside the HS skin once the elevator has been hung. A slight angle too the arm and you'll either (a) have an unsightly diverging gap, or (b) need to file down the skin to give a uniform gap, or (c) file down the counterbalance arm. I ended up doing (b) and (c) to the tune of ⅛". Check also that the tip skin edges line up vertically above each other.
Build in the order that FJ suggests rather than the manual: rivet the E-604 to the spar after you've riveted the control horn on. Otherwise, when you move the spar, you'll knock something off your workbench with the tip rib. Murphy's law will apply, and it will be something glass and expensive.
Aligning the horn with the spar centre-line turned out to be quite easy; I pushed my file (without the handle) into the hole of the horn. This left the point of the file (which the handle jams onto) sticking out about 6 inches. I then lined up this 'pointer' with the centreline of the spar. With the root rib in the right position, I had to file 1/16" or so off the root end of the spar to make the horn fit snugly.
Jeff Orear <jorear@mari.net> wrote to the RV-list: I made an insert out of some 1/16" model airplane plywood that I had (I'm an RC pilot also) and marked the centreline on that. Then insert it into the tube of the control horn. Make sure that you have a nice snug fit with the insert and it will work great. Mark a centreline on the spar and line the two up.
Another method is to stick your thin metal rule in the tube and get it flush to one side of it, mark a line and then move the rule over to the other side of the tube and mark another line. Split the difference between the two and you have the centreline. This was a bit too difficult for me, so I used the plywood insert method.
Choosing where to drill the holes in the horn was difficult for me; in the end, I have 4 down each side of the horn attaching it to the spar, and 3 down each side attaching it to the rib, all ¼" in from the edge. I drilled the holes in the horn first, then used these as pilots to drill into the skeleton. Once these holes are drilled & deburred, go ahead and rivet the horn on. This makes the root end of the skeleton nice and rigid.
Chris Browne <cebrowne@duke-energy.com> wrote to the RV-list: If you want to use the holes in the tab to place a rivet all the way through the spar and elevator, it's OK as long the rivet location is OK on the elevator flange (3/16" from the edge, etc.) This was not clear to me, either.
After calling Van and looking at it, here is the answer. The two 426AD3-3.5 flush head rivets in the root rib are *not* structural since their only function is to hold it in place on the spar while you fit the skins and the horn. The spar and rib are held together by the 6 rivets in the elevator horn. The bottom line is that no additional rivets are required in the root rib tab. If you want, you can locate the elevator horn rivets in the spar so that they do go through the tab, but it is not required. It is just a little more difficult to rivet. The final strength of the assembly is the same either way. As noted in the drawings, the location of the ⅛ rivets in the elevator horn are nominal.
Before you add the RTV to the TE, put in a short piece of thin plastic drinking straw. This will allow a path for water to trickle through out of the elevator. This isn't needed on the rudder because it'll be mounted vertically so water won't collect. The elevators are a different matter.
Make sure that the counterbalance skin edge lines up neatly with the elevator
skin edge and with the tip rib edges. Any discrepancy will need to be filed
down to allow a neat fit of the tips (outside edge) and a neat gap between
counterbalance and HS (inside edge). Frank Justice's idea of riveting the tip
skin to the E-601 with AN426AD3-3 solid rivets worked OK for me; this gets rid
of a couple of pop rivets. 
Before rolling the LE, I folded the last ¼" or so of the edge down with my hand-seamers; that worked OK. Rolling the LE was again difficult, especially the outer layer of the skin since the inner layer gets in the way when you try to roll it down. I don't think the broomstick technique is very useful; I started my elevator LE with a broomstick taped to it as per the manual and video, but finished it off more or less just by hand.
Note that the lead counterweights supplied by Vans are NOT symmetrical lengthwise; one hole is nearer the end than the other. The hole nearest the end goes to the front of the elevator; otherwise the hole through the tip ribs will be too close to the tooling hole that's already there.
I mounted both elevators at the same time: see the end of the Left Elevator section for details.
I was a bit apprehensive about this, but it's not particularly difficult.
I did things in a slightly different order from the manual; particularly, I delayed squeezing down the TE until after I'd riveted the spar to the bottom skin. I think that was a good decision. I back-riveted the spar to the skin, mainly because I didn't think to use my hand-squeezer.
By back-riveting, it's possible to use solid rivets instead of pops to attach the horn to the trim tab. Place your back-riveting block on the edge of your workbench to allow the horn to go down beside it.
I folded the flaps at the ends of the trim tab by putting the skin in the jig,
with the edge of one of the V-blocks lined up with where the skin needs to
bend. 
Then I jammed the V cutout in, inside the skin, so that it holds the skin
tight. I used a hammer to tap the V cutout down really tight. Then I used my
fingers, and a small block of wood and a hammer, to fold the lower flap upward.
Drill the skin to the top of the spar, keeping the trim tab nice and straight and flat. Dimple the skin, and countersink the spar (you'll need to peel the skin back a bit to get in there).
I delayed riveting on the hinge until the left elevator was also about ready; that wasn't necessary. Just separate the hinge halves, and draw a line down the middle of the hinge... there's no room to spare if you're going to maintain the proper edge distance. Align this line with the holes in the spar and top half of the trim tab skin, clamp well, and drill. The hinge was a bit long for me, and I cut the root end to line up with the edge of the trim tab skin and spar. Then rivet on with the hand-squeezer.
Alex Peterson <alexpeterson@MCI2000.com> replied to the RV-list: Problem: On the HINGED sections of both the E607 and E607 spars, I cannot get any bucking bar or squeezer head I have to fit in the small space without hitting the hinge.
Use your squeezer and a small bar of steel to set the AN rivets. The bar goes between the shop heads and the squeezer set. The bar is anything thick enough, yet narrow enough, to keep the set out of the way of the hinge eyes. This set "extender" concept works in many places.
Finally, I drilled and pop-riveted the end flaps closed.
Have a look at David Carter's L elevator construction notes.
As for the right elevator, plus the added complication of the trim tab stuff...
Put masking tape on the root corners of the skin; otherwise each time you shift it, they'll scratch against the inside of the skin.
There's 7 stiffeners that are identical; mark them carefully so they go back to the right place. I used my chainsaw file to put little round notches on the top of the web of each one, and a little diagram on the back of an envelope so I could re-locate them all correctly.
RV-List message posted by: Charlie Kuss<chaskuss@miami.gdi.net>: How to attach the nut plates on the left elevator for the trim motor cover. The nutplates get riveted to the E-615PP reinforcing ring. It can be done one of 4 ways.
Personally, I think option #2 is the best.
I did option #3.
Drill the E615 trim cover plate to the skin (#41), and drill the nut-plate holes
to #41. Dimple all the #41 holes in the E615, prime, and rivet the 7 nutplates
on. Dimple the skin, and rivet on the stiffeners and E615. Perhaps first check
that the E615 doesn't interfere with the E602 spar; mine didn't. 
The #6 nutplates are very tight... I broke one screw trying to screw it in. And then worried for several years (no, really!) what to do about it. After that time had gone by, it was no big deal. By then, I had plenty of practice at drilling out rivets. So I drilled out the rivets holding the platenut with the broken screw, and replaced the platenut.
Rick Fogerson <rfogerson@baf.com> suggested to the RV-list: Rather than ream them out, take some of the oval-ness out. Before I installed nutplates, I put them in a vice and tried a screw in them. If they were so tight I couldn't get the screw in without slipping, I took a vice grip and carefully made the hole slightly more round by squeezing it until the screw was manageable but still tight. If you can still get to the end of the installed nutplate, you can try it but take it easy.
Rivet the skeleton together as for the right elevator. Having the horn riveted
on holds the root rib firmly, and stops the rear (trim tab) spar from flapping
round too much. 
It was hard to tell from the plans how many rivets hold the trim tab spar to the root rib; in the end I guessed at 2 * AN470AD4-4 and placed them about ¼" either side of the centreline of the spar. The end flange of the root rib needs to be bent a little so that it is parallel to the main spar.
There are a couple of flaps on the TE which need to be folded up and down to cover the hole next to the trim tab. I recommend you do things in the following order (I folded the flaps before dimpling, and had to use a pop-rivet dimpling tool to do the last 4 spar attachment holes):
Be careful lining up the rear spar with the skin holes; it's easy to get
off-centre on the flanges. Note that the 4 holes (top and bottom) nearest the
tip need to be drilled to ⅛" for pop-rivets.
I folded the flaps the same way I did my trim tab flaps using the V-blocks in the jig. I found that both flaps were a bit (⅛" or so) too big, and had to trim them back with snips. I was a little tight on the bend of the top flap, and had a little tear in the corner that I had to file out. :-(
In the RV-6 manual, regarding building the left elevator, Vans say something like "It is easier to route the trim-tab cable if skins are open for access" or something similar (I don't have the manual here with me). Ignore this: according to Chet Razer (crazer@egyptian.net), close up the skins and, when the time comes, "Grab the trim tab cable and pull it through, that works fine." That worked fine for me too.
When closing up the skins, don't rivet the rear spar to the skin, except for the pop-rivets at the outboard end.
However, I left a little too much room between the outboard end of the trim tab
and the elevator (maybe ¼" or so), because I hadn't riveted the flaps down
before fitting the trim tab. This in turn meant that the trim-tab was a little
further back than it ought to be, and that the holes drilled through the
elevator spar had minimal edge distance on the hinge. Again, the hinge needed
to be trimmed a little (¼" or less), and I cut it to line up with the elevator
skin and rear spar. 
Someone flying an RV-6 said to me "Don't worry about it. The trim tab hinge pin doesn't move." His wasn't secured at all. However, I don't feel comfortable with that... I have awful vision of what would happen if it did slide out an inch or two and jammed the elevator.
RV-List message posted by: "Are Barstad"<abarstad@bconnex.net>: I simply
used a part of the hinge that I cut and riveted it on the left elevator. Note
that you have to pay attention in order to get the required edge distances on
the 'mini-hinge'. 
I used the same technique, and I'm very pleased with how it cam out... here's the details:
Denis Walsh <dwalsh@ecentral.com> wrote to the RV-list: I used a pin about one quarter inch longer than the hinge and put a 90° bend in it. I then used a Dremel wheel and small file to put an ell shaped slot in the inboard most hinge loop. The slot is such that it is only exposed when the tab is at 90° or so (disconnected), so the pin is retained during all normal operation angles. to remove it you must disconnect the pushrod from the horn, and rotate the tab to 90°.
John Devlin <jdevlin@americus.net> wrote to the RV-list: An electrical ring connector can be used by crimping it to the hinge pin after removing the blue insulator. I used a 16-14 connector. Bend the ring back toward the trim tab. Drill a very small hole in the trim tab flange. Run a lock wire through the connector ring and hole. If the crimp loosens the connector will capture the pin and the lock wire will hold it in place.
Steve Johnson wrote to the RV-List:
>How to make everything fit flush: nutplates on the E615PP electric elevator
trim doubler: I mounted the nutplates and countersunk all the way down to the
steel using a deburring tool and lots of pressure. I then dimpled the cover
with dies for AN426-4 rivets. This gives dimples that fit snug into the
countersink, but the screws still don't sit flush. Countersink into the cover
dimple just enough to have the screw fit flush.
The gap between the HS and the elevator counterbalance arm is also affected by any angle between the HS and elevator. I snipped about ⅛" off the rear of the HS skin that the HS tips attach to to allow room for the elevator counterbalance skins. That was almost too much, by the time I'd fiddled about and got the HS-elevator gap right.
If the leading edge of your elevator rubs on the HS spar stiffeners, you could
radius the stiffeners a bit (according to the plans) or drill out the pop
rivets on the LE and tighten up the roll (according to the RV-list archives) --
I didn't have this problem. 
In mounting the lead weights, it's hard to know how much to allow for paint. From the RV-list, it seems that adding 1.5 oz at the elevator TE is about the right amount. I guess it all depends on how much paint you put onto the elevator, but from this it seems that an elevator gets about 3oz of paint.
RV-List message posted by: Mark Fredericks (Mlfred@aol.com): When installing the right elevator, the plans say to put the elevator "in trail" before drilling the hole in the horn for the centre bearing. Here's why...
You should install the elevator to the two outer hinges, and then mark the horn thru the centre hinge point (with the elevator in trail). Rotate the elevator thru its travel, and watch your mark- it should not move (except for the rotation). Adjust the rod ends until the mark simply rotates, and then drill the mark. Be ready to reposition your mark. I suggest masking tape, which can be removed easily. The slightest pressure from a drill bit or some other appropriately sized tool (inserted thru the centre bearing) will leave a visible mark for you to watch.
Thanks to Scott Brown of Florida RVation...
Although it's actually listed under the fuselage section, now is a good time to drill the control rod hole at the bottom front of the horn. It needs to be done while the elevators are mounted on the HS, and you would otherwise need to specially mount and un-mount them (yet again!) later. See the section on 'Mounting the Horizontal Stabiliser' about ⅔ of the way through Frank Justice's fuselage page for information on how to do this.
I found it easiest to put the HS with mounted elevators on a table (with the
elevator counterbalance arms hanging over the ends). Put pieces of wood on the
top of the HS, covering the counterbalance arms. Put some heavy objects on top
of the wood, and some lighter objects on the elevators themselves, so that the
elevators are held in line with the HS. Now you're ready to drill the holes in
the horns as explained by FJ.
The elevators will be removed when mounting the HS to the fuselage... don't permanently mount them to the HS yet.
The HS and elevator tips were both a bit too long... I fitted them in place, marked the edge of the aluminium, used a square to extend the line, then ground them down on my bench grinder. That worked well, but I don't know how to tidy up the hairy edges yet.
Ensure that the edge of your aluminium skins is perfectly straight... my elevator and counterbalance skins were at a slight angle, so I needed to file them back somewhat to match up with the elevator tips. A lot of fiddly work.
According to plans 4PP, the tips are attached with CS4-4 pop-rivets at 2"
spacing. According to the manual, the tips should be reinforced with .025
aluminium strips -- this is not shown on the plans. Don't start the rivet lines
too close to the TE, or there won't be room for the pop-rivet tails. I cut
several 2½"x½" strips of .025 aluminium... each strip is the backing for 2 or 3
holes. 
Probably a better scheme would be to use a single long strip, and to glue it to
the fibreglass before drilling, countersinking, etc. Or perhaps to use a bunch
of ¼" OD, ⅛" ID washers, one per hole.
When drilling the holes in the rudder, VS, HS, and elevators, drill them
exactly ¼" from the edge of the skin -- any more and you will run out of edge
distance on the fibreglass.
Various people have used various glues (Proseal, RTV, Shoe Goo) to attach the strips to the fibreglass. Long-term, it really doesn't matter too much, since the pop-rivets will be sandwiching the fibreglass between the outer skin and the strip. Short-term (i.e. until you've got all the pop-rivets attaching the fairing to whatever in place) it is important. I can disclose that balsa cement, despite its aviation origins, is not suitable. Similarly hot glue. I've re-glued them all with 5-minute epoxy, but that tends to let go if the tip flexes -- more of a problem with wingtips than empennage tips. Be sure to roughen the aluminium to give the glue something to stick to. Be sure to CRC your clecos so that they don't become permanent fixtures! Some people use flush rivets to attach the aluminium strips to the fairing, but I think that's overkill (at least for the empennage).
Machine countersinking the fibreglass can be done using your deburring tool.
Fig 6-12 of the plans says to close the front of the elevator tips with balsa, foam, or aluminium. You could even use a piece of steel, since this would help counterbalance the elevator.
Regarding mounting a beacon or strobe on the top of the VS, someone wrote: The strobe needs to be at the back of the VS, then the front part being higher blocks the light from hitting the canopy directly. The VS tip needn't be removable. The strobe is held up in place by an L shaped bracket of .040 attached to the VS rear spar (just the lamp and socket, the glass lens is permanently bonded in place). If it ever needs service, the rudder would have to be removed, not a particularly big deal. I have never had one go bad and it runs all the time.