Rob Allen | How To Series | Bands

[@samosdolphins123]

very interesting lecture. It is the only one i found explaining the difference between extruded and dipped bands. I just did not understand one part of it. where you said that you cannot get a coloured band with an opaque middle and a colour on the outside if it has been extruded. because you used the word colour twice, once the colour on the outside which is the uv protection i assume but what is the other colour and what is an opaque middle? thank you.

[@RobAllenSpearfishing]

Sorry, this is an old video but the manufacturing processes is still the same. What I tried to explain is a way to tell if the rubber is extruded or, dipped. The cheaper way is extruding the rubber . When extruded, the colour is the same all the way through and, we feel not as good in performance. It can be opaque or, any colour they mix but no change in colour all through the cross section. The opaque type is pure latex with no colour additive. If they extrude it pure, with no colour, it will deteriorate in the sun. So, the dipped rubber is made pure, opaque in colour normally, then the last dipping is with a coloured rubber with UV inhibitors for sun protection. This is one way to show it is the better quality. But.... they can also dip all in one colour. I hope that is not too confusing 😁

[@mathewdavis-adventuresandd6643]

Thank you very much. I was ready to punch the monitor watching others with their hands in the way or those that were going too fast and not using the zoom function on their camera. I just tied my first band and I've got a couple more to do. Shouldn't be any problem now.

[@garystutzman2060]

Hi Rob can you do a KZbin video on the difference between small hole rubber bands and bands with 1/8" hole. Like power difference, and maybe stretch percent numbers. thank you Gary

[@RobAllenSpearfishing]

Hi Gary, no problem, keep a look out and we will schedule that rubber video in soon 👍

[@johnniekazija]

Hi Rob, when you calculate the length of the rubber I mean when you cut it to your desired strength, do you add 5 cm additional before you cut the rubber due to the bridals and the area of the constrictor knot?? for example I have 2 different brand rubbers I have bought for my 85cm gun and they have the declared length of 54 cm betwen the contrictor knots, thats kind of 3,4 coef. for my 92x2/3,4 ? right?, but the real length from the end of the rubber after the constrictor knot to the end of the rubber is actually 59cm doest that mean they are actually 3.1 coef stretch? I see some people advise adding 5cm before you cut the rubber? thank you in advance for your response and regards from Croatia

[@roballen1578]

Hi Johnnie, There are so many variables due to rubber type, diameter and or the users ability. We use 1/2 barrel length + 5cm as a start for rollers only. This can vary to other other guns. The suggested max strain on latex rubber is 400%. We feel at that max though, the rubber deteriorates quicker. We normally suggest around 370% if possible. Cut lengths are normally to the full size pre tied. When tying the wishbone in, the rubber does get stretched. If I measure a tied rubber to match a cut rubber I add 10mm per knot.

[@johnniekazija]

@@roballen1578 sorry for my bad english understanding (its not my native lang) if I understand and read correctly, if I need my rubber to be 54cm for example by chart, I should cut it at 56 ? this way I added 10mm/1cm to each knot to be used?

[@roballen1578]

@@johnniekazija no need to apologize. No, cut the rubber to the recommended length. Once you tie the rubber, it will stretch out a little if you re measure.

[@johnniekazija]

@@roballen1578 Got it now, thx a lot!

[@islandlife4141]

How do I tell band needs replacement?? Also can you tell me the length for the Tuna 900 in inches, not centimeters please..

[@chrisbonato728]

Hey Rob, do you have a size table for rubbers and twin rubbers for Rob Allen guns?

[@RobAllenSpearfishing]

Hi Chris. You can find all rubber lengths on our Rob Allen site under guns. www.roballen.co.za

[@chrisbonato728]

@@RobAllenSpearfishing found it, thanks Rob

[@walidabbas-tw1fx]

thx 👍

[@chrissfak]

Hi Rob, is there any +- tolerance in band diameters? If it is a 20mm band, is the actual diameter 20mm, or could be a bit less? I found mine to be 18.5-19mm (external) rather than 20. It looks a tiny bit thinner (almost 1 mm) than another 20mm band I used to use. So it seems there are some differences, even for the same nominal size. Or perhaps a new size not mentioned in this video?

[@RobAllenSpearfishing]

Hi Christos, There are slight variables but unlikely to be as much as 1,5mm? 0,5mm maybe. Saying that though, the rubber can shrink a little with age, how old is the under sized one?

[@chrissfak]

@@RobAllenSpearfishing No idea on actual age. So,in theory, RA bands come only in 14/16/18/20mm (no 19mm)?

[@RobAllenSpearfishing]

@@chrissfak Correct. Is it branded with the RA branding?

[@chrissfak]

@@RobAllenSpearfishing Yes, it is

[@RobAllenSpearfishing]

@@chrissfak very strange.

[@catyoutuberfunny8648]

I Need Rob Allen Brand Big Rubber 25mm I Think It's The Most Right For My Speargun Because It Uses 7mm Arrowheads

[@danielbergehed6223]

What rubber size chart do you use?

[@whynottalklikeapirat]

Probably this - I just used it with my riffe, works fine: www.google.com/search?q=rob+allen+rubber+size+chart&client=firefox-b-ab&tbm=isch&source=iu&ictx=1&fir=BeVmeYRrbjyIyM%253A%252C9eTcOvcun95ALM%252C_&usg=AFrqEzetORnjP4fvzDl323Y8RoFp11gmhg&sa=X&ved=2ahUKEwi1gIuq3ZbdAhUDLlAKHcElDGsQ9QEwAHoECAYQBA#imgrc=BeVmeYRrbjyIyM:

[@sa3h3d]

what is the max stretch of your rubber sir ?

[@RobAllenSpearfishing]

400% most set at around 350%

[@lmnop20sharks]

Hi, I want to try to make a 120 cm wooden spear gun. I am in the process of buying a 160cm spear. Can you tell me which band diameter I should use? How do I calculate the length of the bands?

[@RobAllenSpearfishing]

Band diameter is normally associated with the spear diameter. We use 2 x 16mm with a 7,5mm spear and 2 x 14mm with a 7mm spear. The length of the band is relative to how it is connected to the barrel, not the barrel length. On our guns the 1200 is the barrel length. Both the muzzle and handle are attached on either end. Most wooden guns have the handle and muzzle built into the stock. Make sure you have the same spacing between the mechanism and the muzzle to simulate the 1200 barrel to take a 1600 spear.

[@lmnop20sharks]

@@RobAllenSpearfishing thanks, why 14 mm bands with 7.5 shaft and not 16mm with a 7.5 shaft? The shaft I order is a 7mm to go with 14mm bands.

[@RobAllenSpearfishing]

@@lmnop20sharks Sorry, just edited. 2 x 16mm is for the heavier 7,5mm spear and the 2 x 14mm for the 7mm lighter spear.

[@lmnop20sharks]

@@RobAllenSpearfishing do you have a video on making speargun?

[@lmnop20sharks]

@@RobAllenSpearfishing the spacing you referred to is the overhang of the spear and the mechanism?

[@Mlj247]

Nice 👍🏿