MTI® Hose - Microporous Vacuum Line

MTI Hose from DD-Compound is the industry leading microporous vacuum line, it is used in resin infusion to maintain vacuum along its full length throughout the process, this greatly reduces the risk of dry areas in more complex infusions, typically the hose is used for perimeter vacuum on centre or conventionally fed infusions.

Its working principle is like that of breathable waterproof clothing, in that it will allow air to pass through the membrane but effectively seals off when it is reached by the resin front, the spiral that is in the core of the hose will maintain the vacuum to any uninfused areas that would normally have become isolated in a traditional infusion stack.

The MTI hose has an uncompressed outside diameter of ~13mm, the internal spiral hose has an O.D. of 10mm and an I.D. of 8mm.

How to Buy

The MTI Hose is available to purchase by the metre or in wholesale coils of 100m. Prices shown are per meter, volume discounts are automatically calculated.

Volume Pricing

We believe we offer unbeatable prices on vac bagging consumables. To make comparisons easy, select the different pack/roll sizes from the drop-down menu above:

Further Information

Increasing Reliability

MTI Hose will increase the reliability of infusions particularly of new and complex infusions where the precise flow path has not been established, this will reduce the likelihood of scrappage and defects which could offer huge cost savings in production.

Self-Regulating

As the resin flow is almost entirely halted by the MTI hose the timing for clamping the vacuum line is no longer a critical factor in the process meaning that is does not need to be continuously monitored, in fact it is perfectly possible to maintain the vacuum throughout the cure without drawing resin into the vacuum system. Although we would always recommend the use of a catch-pot as a precautionary measure, MTI Hose will generally render a catch-pot redundant so it would be possible to run a direct connection to the vacuum pump.

Since the MTI Hose will not draw off any resin a precise resin to fibre ratio can be achieved by simply measuring the quantity of resin entering the part, this allows for excellent consistency and repeatability between parts.

Typical Use

Typically, the MTI Hose is laid around the perimeter of the moulding wherever vacuum needs to be maintained. The ends of the MTI Hose seal easily and effectively using conventional vacuum bagging sealant tape the vacuum hose connection can be made by feeding the vacuum hose into the MTI Hose and sealing with sealant tape, this vacuum hose would typically breach the bag through the sealant tape on the flange. Note that unlike some of the other products in our microporous range the MTI cannot be easily heat-sealed, however conventional sealant tape can easily achieve a perfect seal unlike with the other materials. Although the hose will still allow for full vacuum to be achieved it will slow the initial pull down time so take care to ensure to bag generally conforms well to the mould before closing to reduce the pull-down time or pre-evacuate the component through the feed line..

Leak Fixing

It is a common misconception that MTI Hose and similar microporous products eliminate the need to ensure that the vacuum bag is perfectly sealed, the (incorrect) theory being that as the vacuum can be maintained through the cure that the bag can be held down even with a leak, although it is true that a microporous vacuum line might be able to help to hold a bag and material roughly in place in the event of a leak it will not do this effectively enough for the part not to be severely compromised. The reason for this is that once the membrane has become 'wetted' with resin it is no longer permeable to air and so you should consider it to be sealed, with this in mind once the part has infused fully the MTI hose will be fully covered in resin and sealed therefore no longer able to draw out the air caused by a leak.

Related Products

MTI Valve - Resin Inlet Regulator

The MTI Valve can be used in conjunction with microporous vacuum lines/strips, its purpose is to create a regulated back pressure on the resin inlet which ensures that the part does not become over-saturated with resin and in turn increases the consistency of infused parts.

After all the reinforcement has become saturated the MTI Hose will no longer be applying high vacuum to the component, this allows any microbubbles to shrink almost completely as opposed to expanding as would typically be seen in a traditional infusion with a resin-brake zone, this effect greatly reduces the potential for voids near the evacuation media.

MTI Hose - Microporous Vacuum Line

MVL is a low-cost alternative to the MTI Hose; MVL in the most part serves the same role as the MTI hose however the membrane used does not completely prevent resin ingress over prolonged periods and end-sealing is slightly more difficult and requires either heat-sealing or a combination of sealant tape and duct tape. As the MVL pores are not completely closed by the resin any air remaining in the part can still be evacuated even when MVL is wetted out by resin.

MVS Microporous Vacuum Strip

MVS is used where vacuum is needed in the centre of the part rather than the perimeter, being flat form it does not cause a 'print-through', this is available in 2 widths; 100 and 300mm.