Constructing a Nearly Indestructible Salad Bowl

[Adam]

In our Composite Materials class we created these cool bowls using carbon fiber prepreg pieces, shaped into a metal bowl-shaped mold. There are seven layers. We did a vacuum bag debulk after layer 4. The most difficult part was ensuring that there was no "bridging" of the material and minimizing wrinkles. 

 

 

 

[lo_0l]

On 2/13/2023 at 4:06 PM, Adam said:

In our Composite Materials class we created these cool bowls using carbon fiber prepreg pieces, shaped into a metal bowl-shaped mold. There are seven layers. We did a vacuum bag debulk after layer 4. The most difficult part was ensuring that there was no "bridging" of the material and minimizing wrinkles. 

 

 

 

This looks awesome @Adam! What are you making next? 🙂

[Mongo]

How is a vacuum bag debulk procedure different to the procedure that creates the final part... (different other than simply not introducing the heat to melt the resin)?  Can I reuse the bag for several debulks?  Can I reuse the bag for the final part?

[John Kimball]

On 2/28/2023 at 4:21 PM, Mongo said:

How is a vacuum bag debulk procedure different to the procedure that creates the final part... (different other than simply not introducing the heat to melt the resin)?  Can I reuse the bag for several debulks?  Can I reuse the bag for the final part?

The debulk process is just vacuum bagging the part for a few minutes to consolidate the plies before moving on. the more plies you have, the more loft the part will have. Debulking decreases the loft. On contoured parts it's very a very important step. 

The only difference in debulking and curing is the heat. Debulking can be as short as 15 minutes under vacuum or overnight. Sometimes a pressure debulk is needed in the autoclave, and sometimes a heated debulk is needed to help the resin flow a little bit.

Typically, debulks are used every 4 plies, but depends on the thickness of the part. The bag can be reused for the debulks, but aren't usually used again for the cure.