Talk Composites - The Forum for Advanced Composites

How much heavier is a product made with resin infusion compared to prepreg?

http://www.talkcomposites.com/Topic32414.aspx

By HansenJC - 3/25/2019 4:04:48 PM

In another thread I asked about resin uptake of Balsa when used as a core. I have received various answer that are not answering the question, so let me go at it a different way.

If identical composite parts are made using any available method such as - but not limited to - hand layup, resin infusion, or prepreg, with a core of unsealed balsa and sealed balsa, Which would be the lightest and by how much would the weight difference be?

On another forum, I have received replies that seem to presume that it is common knowledge that resin infusion will weight a LOT MORE than if the parts are made with prepreg. Maybe all the old timers know this to be true and never use resin infusion to make light balsa core products.

But really now.... How much more is a LOT MORE?

Is there any data that will tell me how much heavier one is compared to the other?

For this discussion, please do not confuse the question by bringing up other core materials that you might think are better, lighter, stronger. That discussion will be a separate topic. First I want to know about balsa core.
By HansenJC - 3/26/2019 11:18:10 PM

 
Fasta - 3/26/2019 7:50:39 AM
When talking about infusing only a solid laminate it is likely you can get an equal resin content to pre pregs.

As mentioned above though when you add in any cores, with their edges, open surface cells of foams, bridging from a vac bag then all these gaps will fill with resin too and can make for heavier parts.

I have built the same small boat design in both pre pregs and infusion. The infused hull was exactly 10% heavier. Pre preg = 10kg , Infused = 11kg. The laminates will still have a great resin/fibre ratio but all the gaps will be full of resin. With balsa there maybe a chance that you infuse the wood too. Super strong but heavy.

Balsa is cheap, that's why they use it !



Thank you Fasta. This is very valuable information. If 10% is an attainable figure for my project which is a UAV frame/hull, it will round out to about 100 to 150 gram difference. So, all things being equal, the powerplant and battery system will need to lift that extra weight 100% of the time. It does not seem to be enough of a difference to not consider using infusion. This encourages me to move forward.