FREQUENTLY ASKED QUESTIONS

 

1.  What are AUSPREG UV Curable pre-pregs?

 

Auspreg UV products are an exciting range of Vinylester or Polyester resin impregnated fibreglass pre-pregs of various re-enforcements that cure using light instead of heat. The technology was developed to enable rapid production of composite based products using a faster, cleaner, more cost effective mechanism than traditional hand lay up methods as well as being easy to store, ship, and apply. Auspreg UV pre-pregs can be used for small or large structures without the requirement for heavy molds, refrigeration or ovens. Auspreg UV comes in roll form with the adhesive resin already impregnated into the fibreglass.

 

2.  How are Auspreg products made?

 

AUSPREG UV products are made through a unique process of encapsulating UV reactive molecules in the polyester or vinylester resin system that causes the resins to cure under light rather than through heat or temperature. The machinery that manufactures the AUSPREG UV products was specifically built to administer an exact measurement of resin onto fibreglass so as to control exactly how much resin is used.

 

Therefore every metre and every kilo of impregnated fibre glass weighs exactly the same and has exactly the same thickness. Once impregnated with resin, the fibreglass pre-preg is sandwiched between two sheets of polythene that protect it from drying out and from curing. The rolled up pre-pregs are then placed in 6 layer foil bags and sealed to protect them from light or drying out.

 

3.  What are they made from?

 

There are two main options within the AUSPEG UV line of products

  • Polyester resin impregnated glass for standard uses, and;

  • Vinylester resin impregnated glass where protection from heat or corrosion is required

There are then three types of woven glass substrates used within the pre-preg. These are available in weights from 225 gsm right through to 2000 gsm in all types of constructions CSM (stitch) Uni, Biax, Double Bias, Triaxial, Quadraxial, and combinations of these:

  • E glass for standard uses

  • C Class for chemical resistant applications

  • S glass where higher strength applications are required

 

4.  How are they applied or used?

 

The process of using Auspreg UV pre-pregs is based on standard vacuum bagging techniques.

 

Step 1 Take the pre-preg roll out of its sealed foil bag

Step 2 Roll out pre-preg onto a clean flat surface

Step 3 Cut pre-preg to desire length or shape

Step 4 - Remove the black layers of polyethene

Step 5 Roll out pre-preg, wet side down directly into mold. Apply multiple layers where required.

Step 6 When the lay-up is complete, vacuum bag the structure

Step 7 The mold is then exposed to sunlight or artificial light for a suitable period during the vacuuming process. There's no risk in too much light. The product cannot be over cured.

Step 8 Once cured, remove from mold and begin process again.

 

5.  If the product cures with light, how much working time do we have?

 

As long as you can cut out 75% of natural light in the work area, you will have up to 8 hours to work with the product before it dries out. With low light levels, it won't cure but it will eventually dry out.

 

6.  What lighting should we use in our workshop to prevent the product curing?

 

The product cures in light spectra of 360-420 Nm. This is the neon range so if you use standard incandescent light bulbs or other wire element globes these will not affect the pre-preg.

 

7. Are there any special curing requirements such as post cure or ramp up?

 

There is no need for pre or post curing. All of the curing is done by exposure to UV. The only requirement is that light must be able to penetrate the entire surface area so that if you have curves or corners, particular attention must be paid to making sure the lights are set up in such a way as to satisfactory light all areas. There is no detriment in over exposing if you need to have lights on longer to reach and cure certain areas.

 

8. How do I know when the Auspreg UV is cured?

 

The product is cured when it is dry to touch and completely rigid. If in doubt, leave lights on longer or contact us for verification. Another method of determining complete cure is with a hardness test. Cured product should achieve a minimum barcole hardness test result greater than 50

 

9.  What equipment do I need to use Auspreg UV pre-pregs?

 

The mould you use must be suitable for vacuum bagging. You will need an appropriate suction pump within a minimum pressure of 0.75 atmospheres. For lighting, sunlight during Spring, Summer and Autumn is the best source of UV but if this is not reliable or weather does not permit or the part/s are too large to manoeuvre, then a bank of UV lights must be set up. You will need one mercury vapour or metal halide of at least 400W (commonly used in warehouses) per square foot (30cm2) of pre-preg. These lamps typically cost between US$60-80 and are available from most industrial electrical suppliers.

 

The pre-preg will need to remain under the lights for 3 minutes per layer to cure but may need longer if you are using multiple layers at the same time or a honeycomb core structure in between layers. Lights should mounted approximately 30cm from the pre-preg. For more specific information about lighting, please see our "Recommended Lighting" instructions page.

 

10. Can Auspreg UV be used for core sandwiches?

 

Certainly can. This involves a two step bagging process; Gel coat down (if required) then pre-preg laid into mold, bagged and exposed to light. Prime the core and lay into the cured pre-preg, put down the inner skin layers and bag this down and expose once again to the UV. Alternatively, you can use one of the new technology PP honeycomb cores that are translucent and cure through in one easy step without priming.

 

11. Where are Auspreg UV pre-pregs used?

 

Auspreg UV pre-pregs have been successfully used and continue to be used in the following market areas:

  • Defence & Law Enforcement Ballistics panelling on vehicles and Ballistic panel inserts in Bullet proof vests. On site Battle field repairs.

  • Aeronautical Repair kits, Cock pit shims

  • Building & Infrastructure reinforcement of concrete or metal structures

  • Petrochemical on site repairs to oil and gas pipes through patches or pipe wrapping.

  • Water & Sewage on site repairs to water and sewage pipes.

  • Renewable energy Mirror panels, photovoltaic (Solar) cell Panels and backings, Wind turbine blades and nacelles (Canopy housing & rotor hoods)

  • Transportation truck sides, fairings, guards, floor and wall panels. Marine Hulls, decks, bulkheads, tanks, canopies and cases.

12.  What exotherm levels are seen?

 

Typical exotherm temperatures are around 45 C. However the more layers used the higher this will be. The maximum level experienced was 100 C for 15 layers of product.

 

13. What are the benefits of using this technology?

 

The benefits of using UV curable pre-pregs include:

  • Fast & cost effective curing time Rapid curing using light for as low as 3 minutes per layer.

  • Ease of shipping Goods can be shipped anywhere in the world without the need for air conditioning

  • Ease of storing Goods can be stored in standard warehouses for up to 12 months without air-conditioning required Long shelf life Goods remain completely useable for up to 12 months

  • Reduced odour up to 60% less styrene than conventional hand lay up pre-pregs

  • Very low shrinkage les than 0.2%

  • No post curing required / No heating required

  • Minimal mess eliminates 95% of resin handling than conventional hand lay up pre-pregs

  • No need for expensive consumables or infusion systems

  • Multiple layers can be cured at once.

  • Reduces waste of both resins and glass compared with hand lay-up methodologies

14. How are AUSPREG UV pre-pregs shipped?

 

Small quantities of product or airfreight portions usually under 300 kilos are sent via FedEx dangerous goods shipping and can be delivered anywhere in the world within 3 days. A 10m / 26 kilo sample roll costs around US$700 to FedEx courier / airfreight door to door.

 

Production quantities of Auspreg UV are shipped via standard LCL or FCL sea freight. No refrigeration is required and the goods are unaffected by higher temperatures or humidity during shipping. Goods are supplied in 40-50 kilo rolls in a foiled bag, then boxed and palletised. The width of the product varies depending on requirements from 100-127cm

 

15. How are AUSPREG UV pre-pregs stored?

 

One of the best features of Auspreg UV pre-pregs is the ease of storage. Simply ensure they remain in their airtight sealed multi layer foil bags and kept on a horizontal level plane such as a shelf or palette. The pre-pregs are not affected by heat and can be in environments up to 80C without any affect to the pre-preg. There is no need to refrigerate them.

 

16. How quickly can we get product to test?

 

Small mini samples 20cm x 20cm are available to be sent to you by Fedex. These are sent at no charge providing you can supply your courier account number. These can be dispatched same day as requested and will arrive to you within 3 working days. Sampling quantities of up to 10m / 26 kilos can be dispatched once payment is received and again can be delivered within 3 working days via FedEx. Most of our items are made to order and we usually send out the very closest AUSPREG UV pre-preg we have to your requirements. Specific products are then made to order after successful initial testing

 

17. What are the minimums, lead times, and prices?

 

Minimum quantities are 300m / 450 kilos per item. These are produced at a surcharge. Standard production runs are 1000m per item / 1500 kilos. Lead times are generally 2-4 weeks Ex Melbourne, Australia depending on the type of glass or resin required. We endeavour to provide written quotations via email or fax within 24 hours of receipt of all enquiries. Prices are in the range of A$13.50-$20.00 a kilo depending on type of resin and glass used. For an exact quotation, please contact one of the Australian Composite offices.

 

18. How do I pay for my AUSPREG UV order?

 

We accept all major credit cards (VISA, AMEX, Bankcard). For orders over US$50,000 we require wire transfers and L/Cs are recommended for orders over US$100,000 Pre-payment in full is required at time of order as our standard payment policy. Special order goods are only produced once payment is received in full.

 

19. How much does the product cost?

 

Auspreg UV resin impregnated fibre glass is sold by the kilo for items 500 gsm and greater. For products under 500 gsm, they are sold by the metre. For a complete price list of the AusPreg UV range, please contact us so we can advise complete details.

 

20. Who is the company that manufactures AUSPREG?

 

Auspreg UV is manufactured exclusively by Australian Composites Pty Ltd. A Melbourne based manufacturer and division of The Specialty Group, one of Australia's largest technical textile mills and specialty composite pre-preg manufacturers who have been in business since 1978. The company is ISO9002 certified and accredited suppliers to the Australian and New Zealand Departments of Defence. The company occupies 4 factories across a 35,000 sq ft multi building facility. It has two complete test laboratories and a full R & D and technical team. More information about the company and images can be found at www.specialty.com.au and www.auscomposites.com.au.

 

 

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