My favorite weapon for dimpling is the DRDT-2. First up are the holes for the stiffeners.

I draw some lines on the inside of the skin of all the places I should NOT dimple. Mainly because the rivets in these holes are not flush.

There are two hole sizes, so in the forward part, where the engine is mounted, we need a bigger dimple die set.

The places I can’t reach with the DRDT-2, I’ll use the squeezer.

With th soldering iron, I melt the blue vinyl and remove it where I need to rivet the skin. I leave the rest on there to prevent scratching the skin.

Clumsy, I forgot to prime four side panels of the inside of the baggage compartment. Extra work.

Dimpling the floor panels of the baggage compartment. Almost ready to build the fuselage up again.

Time: 5 Hours, Rivets: 0/0 (2019-12-08)

Time: 3 Hours, Rivets: 8/0 (2019-12-11)

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Bummer, now I need an additional prime session. Oh well, it turned out I missed some spots anyway.

Before riveting the side skin to the fuselage there are some specific parts you need to check. Mainly on the firewall, because the side skin is so close to the vertical stiffener, there is no way you can rivet anything to it once the side skin is attached. Also blind rivets (sometimes called pop rivets) are not strong enough here.

With a huge amount of parts primed, the amount of dimpling is equally extreme. Not only the skins, but also all the parts.

Besides dimpling, also attaching the nutplates needs to be done after priming.

After getting over the aggravation of the missed baggage side panels, I figured out they also need trimming (considerably I might add).

Those gussets side rivets will be completely unreachable after the skin is riveted, so now is the time to do it. Actually the manual holds a brief list of all the tasks that MUST be done before riveting the side skin.

The only task on that list I couldn’t figure out was riveting the longeron for the rudder pedals. It must be riveted on the firewall before the skin, but with what angle?
I’ll make a note NOT to forget it just before riveting the skin (what could possibly go wrong).

The plans don’t mention the brake pads, but I figure they can safely be riveted.

Time: 5 Hours, Rivets: 98/1

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After deburring I use the Scotch brite pads to scuff the Aluminum, before dimpling. I specifically use this order to minimize the damage on the pads. You can only use them for one such a session, but scuffing without deburring will rip the pads apart quickly. Also scuffing after dimpling has similar effects, because the dimple rips the pad.

To dimple the skins, I really like the DRDT-2. According to some fellow builders the C-Frame is “better” because of the impact, but I don’t think Aluminum is affected that way. The DRDT-2 provides consistent dimples and is fast. Also if you give me a hammer, I might hit other stuff then just the plunger of the C-Frame.

I always check the other side if I got all holes. Sometimes I skip one (mostly due to printing on the blueing).

The same dimple sets that are used in the DRDT-2 can be used in the squeezer, with the same result. Due to the limited reach through the length of the yoke, this method is not applicable for skins. But stiffeners and ribs are easy dimpled this way. Ribs are almost impossible to dimple with the DRDT-2 because of the flanges.
The pneumatic squeezer is very versatile, because you can dimple and rivet with it. You have to be careful though, if you misfire it will punch holes in Aluminum of this thickness.

The narrow parts of the ribs are even for the squeezer unreachable. Here I use the dimple set with ordinary pliers. It’s really slow and cumbersome, but it is only a few holes that need this treatment.

The Spars and the doubler plates are too thick to dimple. It would distort, deform and probably damage the parts. Fortunately because of its thickness you can use the countersink drill (called machine countersink in the manual). Setting the depth of the drill once and then drill away.

Time: 5 Hours, Rivets: 0/0 (2019-01-09)

Time: 5 Hours, Rivets: 0/0 (2019-01-12)

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Since the material is thick enough it is easy to countersink.
The ribs on the contrary can easily be dimpled. In this case with the every so beautiful squeezer. If you would try to countersink the ribs that would go horribly wrong because of the thin material.

The rear spar of the wing is a special case, the thickness of the Aluminum is somewhere between the ribs and the main spar. You can dimple it, but it will not be as “deep” as the rib dimple. So I do both dimple AND countersink the rear spar. Although the countersinking doesn’t take away that much material.

Afterwards I spot-primed all the countersunk holes. Again probably not necessary, but better save than sorry. Also on the Sunday I primed the leading edge skin and some trailing edge parts I forgot earlier.

Time: 5 Hours, Rivets: 0/0 (2018-10-03)

Time: 3 Hours, Rivets: 0/0 (2018-10-06)

Time: 3 Hours, Rivets: 47/0 (2018-10-07)

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After fitting the left skin it turned out the HS0005 and HS0006 were in the exact right spot. So (with some luck) it turned out to be no real problem.
Next up De-burring, the most tedious part of building a plane, however at least I can sit down for a while on my new stool.

The fact that I cut my finger to one of the spars, shows that I’m not de-burring in vain. Almost the last step before priming is dimpling. Although I tested with the RV Training Project to dimple after priming, I decided to dimple first and then prime.

The DRDT-2 is expensive and I only use it for dimpling (so far), but it makes dimpling really easy. I never tried using a C-frame, but whacking something with a hammer, will probably not work for me. Besides the loud bang and strain in your arm, changes are I either miss the plunger (and dent the skin) or hit it so hard it breaks.
With this device I can hardly screw up. The most important thing is to place the skin with the right side up.

My planning was to also prime today, but I underestimated the de-burring and dimpling.

I did remove the vinyl partly on the outside, where the rivets should go. I see many builders use this method, with a soldering iron, so I’ll try it too. However I don’t see the point of doing this very precise as it is only temporary.

Time: 8 Hours

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