Stiff Collar Testing

First take a look at Construction to see how the stiff collar tips are constructed.

Here are the specs on the bolts that I built for testing. All were made with yellow siloflex at 48" long, and included a wrap of strapping tape over the tip end of the pipe to prevent water infiltration into the tip.

These are made in the traditional manner to provide comparisons to the new tips:
T1
 Standard Pool noodle construction following JP's instructions with the addition of friction tape and tight collar wrapping.
Weight: 14.40 oz.
T2
 This made with a pool noodle collar, with a 2 1/2" leather disk, with a 4" long pool noodle tip.
Weight: 14.90 oz

These are all made with the new stiff collars:
P1
 This was my first tip for proof of concept. It was built with all features including both leather disks.
Weight: 15.25 oz.
P2
 This was built with all features including both leather disks.
Weight: 15.30 oz.
P3
 This one has no large leather disk, only the small one.
Weight: 14.90 oz
P4
 This one had no leather at all in the tip. The only cover over the end of the tube was strapping tape.
Weight: 14.75 oz
P5
 For this one, after the testing of P2, I replaced the pool noodle with a new noodle. This one is intended for 45 degree angle testing to see if there is any wobbliness after hitting targets at an angle.
Weight: 15.40 oz
P6
 For this one, I reused the collar from P1, but built it with no small leather disk and no friction tape.
Weight: 15.20 oz

Note: For P3 and P4, I had a little trouble getting the collar to align correctly. This showed up with early problems with P4.

All of the materials used in the tips were from the same manufacturers. The pool noodle material was acquired from JP in september 2006 and is the same material used in all my bolts since then.

The testing consisted of a sequence of shots at an ISWC target at approximately 10 yards away. The target was consistently hit in the bottom half to minimize the rocking/tilting of the target. There was some rock when hit, but this was minimal. This should be a decent simulation of hitting a solidly held grounded shield at 10 yards.

I collected data after every 5 shots. This included the overall length of the bolt and the force resistance at 1", 1 1/2" and 2" of compression. I also noted stiffness and compression as I went along. I stopped the test when there was an anomally, or when the tip was clearly at or close to the failure point, or after 30 shots.

Weather:
P1 was tested with temperatures in the 40s
T1 and P2-P4 were tested together with shots 1-15 at temperatures in the mid 40s. I then had to stop for a while and resumed later when the temperatures were in the mid 30s.
T2, P5 and P6 were tested together in the mid 30s.

All bolts started at room temperature and obviously would cool down during testing outside.

Photo note: Click on an image to see the photo at full size.

T1
shots 1"
 1 1/2"
 2"
 length
0
 60
 80
 110
 51 1/2"
5
 50
 65
 90
 51 1/4"
10
 40
 60
 80
 51"
15
 40
 50
 --
 50 3/4"

After 5 shots, I noticed clear degradation by simply squeezing the outside. After 10 shots, it was almost at a failure level. After 15 shots there was no point in continuing testing this tip. The failure point was somewhere just after 10 shots. The friction tape did a good job of holding onto the tip, showing only a slight creasing at the base of the tip.

When measuring compression, I was not able to measure 2" of compression after 15 shots due to shortening of the length. It was clear that it was significantly degraded.

After cutting open, the interior showed significant destruction throughout the tip. The results are consistent with other testing I've done of these tips.
T2
shots
 1"
 1 1/2"
 2"
 length
0
 60
 85
 120
 52
5
 40
 60
 90
 51 3/4
10
 35
 50
 75
 51 5/8
15
 30
 40
 60
 51 5/8
20
 25
 30
 60
 51 5/8

This one held up about twice as long as T1. After 10 shots I could clearly tell that it was degrading faster than the stiff collar tips. There was some notable wobble of the tip on the pipe, but this wasn't alarming. After 20 shots, side compression was getting mushy, and lengthwise compression was getting mushy. I decided to stop after 20 shots since I figured it would be beyond failure in another 5 shots. T2 lasted roughly twice as long as T1.

After cutting open, the interior showed some notable destruction in the lower half of the tip, but not overwhelming. The upper half is still in pretty decent shape, although some cracks in the foam extend into the upper half.

The large leather disk had clearly rounded over a bit, due to the lack of support from the pool noodle collar underneath. This explains the degradation of the pool noodle at the base.


P1
This one was my proof of concept and didn't make any measurements. I simply shot it 10 times and then took it apart to see what happened.

The result was beyond my expectation. The pool noodle was solid. The tip was very stable on the end of the pipe, with virtually no wobble.

no photo
P2
shots
 1"
 1 1/2"
 2"
 length
0
 75
 90
 120
 52 1/4"
5
 50
 75
 105
 52"
10
 50
 75
 105
 51 7/8"
15
 50
 70
 100
 51 3/4"
20
 50
 75
 110
 51 3/4"
25
 40
 70
 110
 51 5/8"
30
 45
 70
 110
 51 5/8"

This test was astounding to put it mildly. About half way through I noticed a little softness at the base of the pool noodle near the leather. Even after 30 shots the tip seemed raring to go for more abuse.

There seemed to be some break-in degradation, followed by a very slow, almost unmeasurable degradation.

Throughout the test, The tip was very stable on the end of the pipe.

When cut open it was clear why the compression numbers were what they were. There is only a small amount of breakage at the periphery of the base of the foam which explains the little softness I noticed there when squeezing from the outside. The pool noodle is firm throughout and virtually completely intact.
P3
shots
 1"
 1 1/2"
 2"
 length
0
 70
 90
 120
 52 1/4"
5
 45
 70
 100
 52"
10
 40
 65
 95
 51 7/8"
15
 40
 60
 85
 51 7/8"
20
 35
 60
 90
 51 5/8"
25
 35
 60
 90
 51 1/2"
30
 35
 60
 85
 51 1/2"
This one performed similarly to P2. It showed some apparent break-in degradation followed by stability. After 30 shots, it did show a little more softness than P2, mostly at the base of the pool noodle. But there was still plenty of life left in the tip.

A circular crack appeared in the base about the size of the pipe. it was only about 1" - 1 1/2" deep, but the foam was still quite firm. It indicates that the pipe projected a little ways into the foam, but not far since there was no real degradation of firmness of the foam.
P4
shots
 1"
 1 1/2"
 2"
 length
0
 70
 95
 130
 51 3/4"
5
 50
 75
 100
 51 3/4"
10
 40
 70
 90
 51 1/2"
15
 40
 60
 80
 51 1/2"
20
 35
 50
 80
 51 3/8"
25
 30
 50
 80
 51 3/8"
This one performed similarly to P3. After about 15 shots it became clear that the collar was not aligned correctly and the tip was tilting a little. After 25 shots, there was a little greater softness than P4, especially near the bottom of the foam. It still showed a similar levelling off of the degradation, and if it hadn't tilted, the tip probably would have been as durable as P3. I stopped it after 25 shots because it was clear what was going to happen and so I could take a look at the collar.




This showed a circle of breakage similar to P3, except a bit off center and the breakage extended a little farther into noodle. Again, most of the noodle is firm.

The collar was a bit angled, resulting in the tip tilting a little. It was still solidly in place, therefore I conclude it was a failure in construction, not the foam. See my comments in the conclusions.
P5
shots
 1"
 1 1/2"
 2"
 length
0
 55
 80
 115
 52"
10
 55
 80
 120
 51 3/4"
20
 45
 70
 110
 51 3/4"
This test was my 45 degree target test to see if the tip got wobbly when hitting at an angle. The tip was solid throughout the test, and indeed there was virtually no noticeable degradation of the tip. Because of the lack of any degradation and no wobble at all, I didn't bother shooting any more than the 20 shots.

no photo.
P6
shots
 1"
 1 1/2"
 2"
 length
0
 60
 80
 120
 51 7/8"
5
 40
 70
 110
 51 5/8"
10
 40
 70
 100
 51 1/2"
15
 40
 65
 100
 51 1/2"
20
 40
 65
 95
 51 1/2"
25
 40
 60
 90
 51 1/2"
30
 35
 60
 85
 51 1/2"
This one performed similarly to P3. It was still going strong after 30 shots. The tip is still solidly in place on the pipe with virtually no wobble.



There are small cracks in the foam near the base indicating that the foam is stressed unevenly by a little, but clearly not severely. The foam is generally firm.

Go back to the Construction page.

See Conclusions for a summary of my thoughts.