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Aluminum Former Press

FoamyDM

Building Fool-Flying Noob
#1
I had an idea. Mainly due to my flying Sub marine project (see Signature). And I'm wondering if anyone has every tried to make aluminum former from Aluminum cans?

In this day and age you could probably 3dPrint your own press. with a removable Die sets to shape it. kind of like a button maker. then it's a matter of making the rib shapes, printing and pressing... then you can skin with real aluminum and mini rivets :)
 

Hai-Lee

Old and Bold RC PILOT
#2
Without the expense of tooling up and making die there is a simple method of using Al skinning with rivets.

Cut the can sheeting to size and cut some overlap strips. Punch small holes from the outside of the panel through the joining strip and fit AL wire piece through hold. On a dome shaped hole fit the rivet into the dome and from the internal, joining strip side hammer the rivet for compressive distortion. Repeat for each rivet. Use as many joining strips as you require.

Normally the whole thing is glued first before riveting. When the sheet/panel is completed it is formed over the ribs and glued into place. If using Al ribs just have mounting tabs bent alternately for increased surface area to glue to. The glue I would recommend is multipurpose polyurethane adhesive.

Tube spars can be fitted through AL ribs by forcing a round metal bar through the rib over a slightly larger hole, cut the centre in a cross pattern first so that you end up with some tabs for the glue to adhere to.

If repair becomes necessary the dome rivet head can be sanded/filed off and high heat will destroy the glue bond.

With structures of greater dimension and a requirement to rivet the skin to the ribs the structure will need to be built from one end progressively as the Al rivets cannot be easily done within a closed space.

Have fun!
 

FoamyDM

Building Fool-Flying Noob
#3
Wow, Nice. A picture or two would add greatly to that detailed description of Al sheeting. The 3d printing was to remove the tool cost to form perfectly mirrored custom Al ribs. I'm thinking like meal gauge building studs.
 

Hai-Lee

Old and Bold RC PILOT
#5
Sadly after 3 wives and 7 children, (aged 38 to 10), I am lucky that I even have a computer.

I would love to provide lists of complicated equipment and procedures but I now rely upon the tooling on the ends of my arms:(.

For wing ribs you could use a profile cu out of card, balsa, or similar and place it upon the Al sheeting. Draw around it with a pencil.

Remove the profile and trim the sheet to around 1/4" from the pencil line. Then cut from the edge of the cut sheet up to the pencil line at distances from a quarter to half an inch all around the cut sheet. For a glued in rib bend each alternate tab in an opposite direction or in the case of a end riveted construction all the tabs are bent towards the working side. For riveting I would use a dremel to drill the rivet holes and a pair of pliers to do the rivet compression. Modify the jaw if you have the ability.

Any lightening holes in the rib should be punched or made before tracing out the profile. Additionally where drainage is required small nicks can be made in the bottom of the rib to allow the water to flow freely. Lightening holes can be easily and neatly cut using a leather hole punch set onto an aluminium bar rather than steel of timber.

Do not forget the glue!

have fun!
 

Hai-Lee

Old and Bold RC PILOT
#6
To get uniform ribs and construction you can use the leather punch set to punch holes for fitting of AL tubes as in a jig to be removed upon wing completion. The jig holes in the profile can ensure that each rib marked and cut out is almost perfectly identical.

have fun!
 

rockyboy

Skill Collector
Mentor
#8
I wonder if using ABS at a very high fill percentage (like 80% or more) would give enough strength to a 3d printed mold/die set to form aluminum can stock... perhaps if the mold side of the 3d print was embedded in something like a plaster cast to provide extra support - the 3d mold could then be pretty thin...
 

Hai-Lee

Old and Bold RC PILOT
#9
Strength and even larger pieces can be built in by using folded seems.

To join pieces or sheets just fold over one edge, (1/8"), almost 180 degrees on 2 sheets and then fit the 2 bends together so that they grip on each other and then flatten with some force. With a little glue in the join the strength of the seam is far higher as is the rigidity.

Appropriately placed folds and seems can increase the structural strength markedly for a minor weight increase.

As for 3D printed ribs used in conjunction with an AL skin the aforementioned glue would be excellent. You could still use the rivets BUT you would require some extra washer or similar to stop the rivet from pulling through the plastic over time.

Due to the nature of the printed plastic and the heatsinking properties of the AL I would suggest that you look at a printed version of the "Girder" type rib. A similar style or appearance as the original wing ribs but made so that each cross-brace is meaty and therefore strong. Do not waste material where it is not needed!

Similarly a printed spar or spars if an "I" beam type with provision made for CF or other strengthening element.

Have fun!