Pultruded CFRP tubes can be produced relatively cheaply, but still have high strength and good dimensional stability. The tolerances for the inner and outer diameter are small, usually between max. 0.1 mm and max. 0.2 mm, depending on the diameter. The tolerance for straightness is predominantly less than 1 mm over a length of 1 meter.
Please note: Internal release agents are used in the pultrusion process, which migrate to the part´s surface. A pre-treatment of the adherent due to this is nescessary. These have to be roughened (abrasive paper 220 grit) and cleaned very thoroughly. Epoxy resin or cyanacrylate (superglue) is used for the bonding itself.
The straightness of pultruded CFRP tubes is due to manufacturing reasons worse than the straightness of CFRP tubes which are manufactured with the "Pullwindig"- technology. Wound carbon tubes perform best, but are also much more expensive. Smaller diameters are straighter than large diameters. Pultruded CFRP tubes are the right choice when high strength should be achieved at a low price. The tolerances in the inner and outer diameters are low, but vary depending on the diameter typically between 0.1 mm and 0.2 mm. The straightness to 1 meter is in any case less than 1 mm.