Dimpling the Fuselage - Flush vs. Dimpled

[mayo3808]

I used my hand squeezer to dimple the fuselage were I could and then used my "C" frame dimple die holder (rod) to dimple the other places that I was unable to get with the squeezer. Also used a large punch to clean up any dimple area. I had no problem with power coat cracking or damage to the fuselage frame. Another suggestion is to apply left over pro seal to the fuselage skins before final riveting. This can be done neatly by using masking tape to tape off places were pro seal will be applied. I too would dimple the fuselage sides again. I used protruding rivets on the bottom of fuselage.
Merry Christmas everyone.

[psalter]

I have dimpled one complete Panther, helped with a second, and if I was to do it again, I would still dimple it, fuselage and all. I like the flush rivets, especially with any type of vinyl graphics. But, it is to each person's individual choice, and how much work they want to put into it.

[PlaneDan]

I chose flush because at the time I thought that the only difference was time, and that the flush was stronger than protruded. However, if I had it to do over, I would never do that to the steel cage again. There are areas that a standard squeezer cannot reach and the solution I used to accomplish making the depressions, in more than one place, cracked the powder coat. The surface becomes wavy, and while I fear no serious lack in strength, I also see no reason to do it. Hind sight is so good, isn't it.

[psalter]

Rick,
Yes, it was the 100 degree male die with an 1/8" pilot and a #30 hole. The sharper angled 100 degree die did slightly better in the steel than the 120 degree die since there is no female die to squeeze against.

Dan and I did our fuselages long before we had ever heard of the dies from Cleveland that could use a #40 hole, so we never tested that configuration.

I would get some steel tubing to try a few holes to get an idea of how it does before you start the fuselage. Even if you have to get some from ACS, it is cheaper than a fuselage.

Just a reminder, don't be Hercules with this, start out lightly on the test pieces until you get a feel for what you need. I also used a scrap piece of aluminium with a dimpled hole in it to use to test the dimples in the fuselage.

[at7000ft]

The technique varies depending on the area of the fuselage. For the 5/8 tubes with no obstructions we use a standard rivet squeezer with a 100 degree male die. (In tests we found the 100 worked slightly better than 120 degree ones). Then set the depth based on a test sheet of .032 aluminim dimpled for the rivets.

For the 1.5 tube, if you had a large enough frame for the squeezer, you can use the same technique.

The problems come in where multiple tubes meet and you cant get a squeezer in. In those cases, i used a bucking bar (cylindrical steel about 2 in in diameter with a hole at the end for a dimple die) and again used a 100 degree dimple die and struck the bucking bar with a hamer against the frame to form a dimple. I tried to keep the blows light, and was conservative with the depth. We have also used a center punch and created the depression.

Paul

I am ready to squeeze my cage 'dimples', just to be clear you used a 100 degree male die with a 1/8" diameter end, and you started with #40 holes or #30 holes?

RIck H

[jsteere #39]

Thanks guys for your input on forming the dimple in the fuselage tubing. I have decided to take the flush rivet route. The first order of business is to order a piece of square tubing and hone the process.
John

[Lynn]

I've dimpled the entire fuselage cage with the exception of rivets that are hidden behind the wing roots. First I purchased one ft. of piece 5/8 x 5/8 x .035 tube to practice on. The method that worked best was to modify a little chrome plated Craftsman pin punch (3/32 punch). I shortened both ends, with the pin end being a chrome taper ending in a polished spherical shape. The square end happens to fit in a hollow on the swivel end of a Harbor Freight c-clamp, but any clamp screw could be drilled to work. The punch is grabbed by the clamp screw, so it spins with it. I drill just a 1/16" hole in the tubing, and the punch stretches the hole and pops through. With practice it's easy to determine the proper depth, and mark an indicator on the punch.
In those areas with structure behind the tube, this method won't work, but the frame is stiff enough there to just use the punch with a hammer. There is one hole on each side with too much weld proximate to the hole to allow a dimple. There I countersunk.
Use a dimpled piece of scrap aluminum to test dimple depth, and pad the back side oh the c-clamp. These dimples are still not perfectly formed, but work very well.

[av8shar]

I decided to go ahead and dimple after I saw Paul's at SNF, I was leaning against not doing it prior to SNF based on some earlier discussions but I wanted the appearance to be the same as the tail cone. Looking at Paul's fuselage I realized it was really just a depression vs. a real dimple. I tried one when I got home and it looked good so I pressed ahead; total time about 20 mins (bottom is not dimpled).

I used the male die and a flat die in a squeezer and just monitored the depression forming to gauge when to stop squeezing. There are a couple of places where the squeezer won't work so I just used a hammer on the die held in place (watch your fingers); again you are only making a depression. The recommendation was to use a 100deg die if you have one.

I am a first time builder and did not have any issues with this process. I have pics on my Picasa site that show what it ended up looking like.

Andy Shorter

[psalter]

The technique varies depending on the area of the fuselage. For the 5/8 tubes with no obstructions we use a standard rivet squeezer with a 100 degree male die. (In tests we found the 100 worked slightly better than 120 degree ones). Then set the depth based on a test sheet of .032 aluminim dimpled for the rivets.

For the 1.5 tube, if you had a large enough frame for the squeezer, you can use the same technique.

The problems come in where multiple tubes meet and you cant get a squeezer in. In those cases, i used a bucking bar (cylindrical steel about 2 in in diameter with a hole at the end for a dimple die) and again used a 100 degree dimple die and struck the bucking bar with a hamer against the frame to form a dimple. I tried to keep the blows light, and was conservative with the depth. We have also used a center punch and created the depression.

[rlweseman]

From Tony Spicer:

First, a question about your last sentence. What’s your definition of a “normal builder”? Didn’t know there was any such animal

Yep, the depressions bother some people.

I used a piece of .035 wall square tube and did some testing to see first-hand what a depression looked like.

https://picasaweb.google.com/tonyboytoo ... 1682927730
https://picasaweb.google.com/tonyboytoo ... 4545013122
https://picasaweb.google.com/tonyboytoo ... 3618957538

Based on that, I elected to go with protruding head rivets in the cage. The very last rivet was pulled about two hours ago.

Tony