I am looking to create a 4x1.5m (6m total length approx) CF boom around 52mm OD.

We don't stock a tube in the size you mention but do have a couple either side of it.

When making long tubes in carbon you generally do not "screw" them together or try to make any thread in carbon as threads in carbon are either very weak or just turn to dust.

To make such a tube, you would use a slightly smaller diameter tube as a joining piece that slides inside the larger tube such that the stress and strain in the join area can be spread over a wider area thus meaning the join doesnt need to be such a vulnerable weak point.

The inner tube is often bonded in for such applications although you must rough the bonding surfaces, both to create a better mechanical bond as well as to remove any remaining release agents or contaminants from the original roll wrapping process used to make the tubes.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Would it be better to use a cut length of 47.5 mm ID or 46mm ID to slide into a length of 50.8 mm ID 

47.5mm ID tube has a rough OD of 50.3mm so half a mm difference should be ok. If youre ordering from us, when you place the order we can check they slide smoothly into each other for you incase there is any batch variation.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Hi, I am looking at an application that requires a similar length of pole ,but has to be able to be trans ported and assembled in  differing lengths. I have some more questions.

The overlap size depends on overall length, load, expected directions of stress etc.

When bonded together in one long tube you can get away with overlaps as lttle as twice the diameter of the tube either side of the join and it being strong.

However when using other fixings, the stength is massively weakened so you need a much bigger overlap due to the shear strains acting through your joining mechanism.

As a rough guess i would be looking at 6 inches either side of the join as a rough starting point for a good strong join especially if its not bonded on both sides.

I would look at either our PT326 or ET515 adhesive depending on the application of the tube.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

The total length needs to 6mtr. It must be able to be broken down to allow for transportation , max 1.5mtr sections. Be able to support up to 6kg at one end whist fixed to two points 1 meter apart.

Id suggest a 6 inch overlap would be fine to start with but ultimately you would need to experiment and see how it feels.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Hi,

I'm looking to construct a camera pole using 3 x 2.5m tubes to give me about 6m reach after allowing for 1.5m of handling length. I'm looking for guidance on the size of tube needed to support between 3-5kg in the highest-stress configuration of horizontal with all weight at the end of the pole. I'm also wondering if it might make some sense to fit a 2.5m rod inside the first tube as it would strengthen the pivot point and could also act as a jointing method for the attaching the first of the remaining two tubes? Any jointing solution needs to allow for the three tubes to be separated for transport.

Guidance on tube specification to support the expected load would be most appreciated.

Thanks,

Roy 

Hi, khalid, you may take a look at our team, www.singcomposiate.sg. We have extensive experience in non standard sized tube and should be able to help you on our project.