Cap strips for Patrol

[SpruceForest]

So if I understand the options for Patrol aft spar caps (all options 2024T3/T4 that provide adequate 126" cap stock ... NO sub on material type allowed), here's the summary:


Option 1. Have a minimum of about a foot (1' x 11') sheared into 3/4" x 11' x 0.063" strips and shipped from Spruce West (IIRC, their 12' shear is CA-located) at what appears to be $400 or more freight, plus material cost and shearing charges (~$600 - $650)

Option 2. Buy a sheet of 0.063" when in stock at Spruce East (I am in MD) and pay material, crate, and shipping to rip it up with track saw or cabinet saw... mill up another couple sets of aft caps in hopes of receiving some of the material and shipping cost reimbursement from resale/cost sharings (yes...I will need 0.063 sheet for other stuff, but that is still close to $1K)

Option 3. Buy 4 x 1/16" x 1" x 1" angle stock from Spruce East and rip the caps from the angle flanges (~ $160 material plus $250 shipping...likely combined with main spar caps for just a bit more in shipping... $410 for just the angles)

Option 4. Rip 16 x .032" x 3/4" off the edge of a rolled 4' x 12' x 0.032" at $206 for the material and ~ $85 for UPS ship ( ~ $300)

Option 5: Buy cap material ready-made from BH... have not checked pricing, but would likely combine with main spar caps and whatever else made sense.


So few questions re: those options:


Question 1: For those that have gone the Bob-approved 0.032, doubled-up cap route, was the reduction in price worth the additional PITA factor?

Question 2: For sheared stock (versus ripped on track or cabinet saw... have experience there), how much wind/bow was there to deal with, and again, size of pain pill?

Question 3: For ripped angle stock caps, did you rip off the free-edge taper or use as is (my engineering spider sense says no stiffness reduction with that minor chamfer/radius, but I've been an avionics guy for last 30 years of professional life, so in Bruhn or Perry on a near-daily basis to knock the rust off)


Finally, I'm figuring out that - unlike composite materials - aluminum and steel prices seem to vary a lot. As in half/double...wow. Put in an order for main wing spar caps yesterday with Spruce East and got a prompt note back asking if $245 for shipping was OK (this was from GA to MD... 8 x 1/8" x 1" x 12' bar stock... about $215 for material plus ship = $460). Given that the other vendor with stock wanted $560 BEFORE truck shipping, I had no issue with that. And before it is mentioned, local vendors here are sky-high on 2024T3/T4... might make sense on stuff that has to be trucked from CA, but just barely.

Todd (aka SpruceForest/P471)

PS - Ended up going with Option 3 above and added angle stock to the main spar cap order from Spruce East to ship sometime in June, but still interested in the pros/cons on options so that future patrol builders can reference this thread in their decision making.

TMS

[geraldmorrissey]

Having been through this I can offer a little insite. I bought a sheet of matl from a local supplier and had it sheared, then sold off the remainder. Yes it will deform and curve along its length and yes it is challenging to keep it located and straight over the length of the spar. LOTS of clamps and patience. Trying to get 2 .032 curved capstrips located and clamped so you get a contact condition with the spacer bars would be like trying to stick a piece of cooked spaghetti up a wild dogs butt. On extrusions, I would cut the tapered edge off. Build per print. On sheet stock, try to find plastic coated material as the shear plus the handeling can scratch the material. I always check local suppliers but I live in a airplane town so suppliers are easier to find. Your research will indeed help new builders.
Gerry
Patrol No Title

[SpruceForest]

Milled out my aft spar caps from 1/16" x 1" x 1" this past weekend. Sequence requires both horizontal and vertical feather board with a 3/32" kerf aluminum blade on a decent table saw, a 6' out-feed board (mine was just a handy piece of 3/4" stock resting on the L-shaped rear fence rail and an adjustable height outfeed table), with the first cuts creating the separate cap blanks with minimal waste, then a pass through to remove the radiused edge.

The caps retain just a bit of the residual material from the radius at the join of the angle, which is quickly removed along with edge smoothing and scratch removal on the faces with the usual die grinder/roloc medium and fine non-woven disks. The distortion was minimal, with some edge set on a few of the strips that was easy to address. With a 12' length, the offcuts provide both the extra material for the aileron hinge doubles (1/16" x 3/4" x 5-3/4" x 8) and another 36" or so of angle stock that looks suitable for a number of uses.

A good bandsaw with a well set up fence and outfeed table would also work, although the cleanup might take a little longer due to the file work to bring the width down to 3/4".

If you are buying pre-milled 1/8" x 1" x 12' cap stock for the main spar, the added shipping is pretty minimal for the angles - my cost to ship was only a couple dollars more when adding the angle to the main spar cap order (Spruce).

[RNF]

I've been trying to get rid of spars, spar caps, and more for two years. They are now free if someone will take them. Includes rear spar caps. See CLASSIFIEDS posted by RNF

[SpruceForest]

Rear Spar Cap Strip Rip Sequence.jpg

Just because someone will want the details at some point on how to mill on tablesaw:

1. Rip as shown above... hold-downs are key to making this operation safe!!!
2. Remove the sharp edge left on the cap strip from the inner radius of angle with 2" medium ROLOC non-woven abrasive pad
3. Sand edges square with P220 on block (this should remove about 0.002"
4. Polish any scratches/remaining edge burrs with fine 2" ROLOC non-woven abrasive pad


IMG_3821.jpg

The mess that one pass makes... always stop and clean up after each pass, as those strips off the ATB blade kerf and the remainder of the angle join can be nasty if trapped in blade

IMG_3823.jpg

First pass removes one side of the angle...

IMG_3824.jpg
Second pass (no change in setup) mills off the remaining strip, leaving just the square piece of waste from the apex of the angle

Reset fence and hold-down for the 3rd and 4th passes which get rid of the radiused edge.

[sjt]

I remember getting a 4x12 sheet for $333, it is now $453.33. I picked up the sheet @ Wicks on the way home from Oshkosh carried in the back of a Suburban.

1/16 capstrips are required for rear spar. I used a lite portable saw to cut stips from a 12 foot sheet.
I also used the home made 12 foot straight edge.


s.jpg

Straight edge was made by using the actual side of the 4x12 sheet as a reference edge. Several lengths of aluminum straight edges sold at Big Box stores were set against the reference edge.

I then took a length of mdf and some gorilla glue to permanently hold the edges - creating a new longer reference edge.

What ever heavy thing I could find was used to hold mdf in place while glue was setting.


a.jpg



Weights holding mdf down until glue set.
b.jpg

I added tape to bottom of new reference edge so that it could slide around and not scratch sheets being cut.

One important feature is the mdf was longer then the glued up lengths of aluminum straight edges.

I wanted that extra length to be available for using a clamp when I wanted to run the saw.

c.jpg

Here is a picture of using my straight edge to cut material for flaps.

Not shown in picture is the clamps that hold the extra length of MDF to secure guide while in use.
I used styro foam sheet to hold aluminum off table during ripping.

The small battery powered circular saw with metal cutting blade make a lot of chips.
A fan or air compressor is need to blow chips away during the cutting process.


rip.jpg

I needed fans to blow chips away. This picture shows the C-clamps on the ends.

Also, the sacrificial styro foam can be seen under sheet.

I went to goodwill and got portable circular saw. The 12 volts ones are of no use to anyone. There are no more 12 volt cadmium batterys.
I add two wires that replaced battery; I used a 12 volt battery charger to power saw.

An extra person would be helpful to vacuum up chips while ripping strips.

ch.jpg


I found a 7 1/2 inch very thin kerf saw blade. I put that blade on my 10 inch table saw

I cut a thin kerf in a 12 foot 2x4 to help with cleaning up the edge after cutting.
kerf.jpg

[SpruceForest]

I've been trying to get rid of spars, spar caps, and more for two years. They are now free if someone will take them. Includes rear spar caps. See CLASSIFIEDS posted by RNF

I’d have taken you up on the offer if not near DC.