Hello,
How are these manifolds are vacuum bagged, knowing they’re one piece ? Or do the guys use a bladder ?
Thanks
One big envelope bag with 6 through bags
It doesn’t look like it was made as one piece to me. You can see prominent parting lines with what looks like some filler. It’s what I would expect to see if two (or more) halves (or thirds) were joined together after they were cured.
I.e., they might have made each half separately using vacuum bags and them joined them in a closed mold afterwards using more cf layers or even epoxy putty.
If it was to be made as one piece and in one stage, inflatable bladder molding would be one possible option certainly. There are other types of bladder than inflatable. Anything capable of apply pressure to the laminate that can be removed later can be used.
I have used bags of sand. I know someone who used zip-lock bags of warm water. I have also used an non-removable foam core which was cast in the mold (using sheet lining wax) ahead of time.
I once tried using wax with the intention of melting it out afterwards. It didn’t work at all well. Don’t try that one!
Looks like it was cured as one piece to me. Cure those pieces separate and then bond them together afterward would be possible but, would also be much more difficult than just doing it in one piece.
Bicycles are made in the same fashion, using an air bladder usually. My coworker is making carbon bike parts and he uses vacuum. either could be used for compaction. The parts he’s made are quite nice, made in one piece from a mold as shown in the pictures above.
The bikes are interesting because they are laid up in what seems like a pretty hap hazard manner to me… especially using unidirectional. Seems like they just throw it in there and then put the bladder in. Though having made some parts using a silicone intensifier, having over 100PSI in pressure on a part will push every fiber down into the proper shape. Bladders and silicone are one of the best methods of compaction in my opinion… not the easiest but, highly effective.
https://youtu.be/tT4yS5wTkY0?t=4m11s
you can check out the fine work done over at Koenigsegg. Their intake parts are gorgeous and thy are made in one piece using multiple piece molds with vacuum bag. They probably autoclave parts as well but, vacuum is perfectly acceptable. With the highly polished aluminum molds, the parts come out with an amazing surface quality.
Yeah Koenigsegg are the carbon fiber masters. Their parts look awesome. I wouldn’t mind owning one of their cars myself!
Can you explain how a through bag works? Is it also hooked up to the vacuum through the larger envelope bag?
Also if this was done in halves and bonded together secondary bonding style with no overlapping joints built into the mold how do you strengthen the seam? It seems as if butt joining would never hold and getting your hands inside the pipes are near impossible to get good adhesion with overlapping fabric.
Through bags play with peoples heads as they cant imagine a vacumed bag can expand as well as inflate lol
Imagine you have a mould for a simple straight 6" tube 1ft long
You need a 8" bag for your internal bag or at the very least one that’s bigger than your internal bore.
Outside bag has to allow for the external dimensions of the mould so lets say 12"
Run your sealant tape along either end of your 12" bag,don’t seal the bag thou keep the backing tape on.
Now thread your 8" bag through your 12" bag.
In the centre of your tape run pull the backing off the sealant and stick one side of your 8" bag.
So now you should have 2 " of sealant tape,8"" of the top of your internal bag bag and another 2" of sealant tape.
Run another bit of tape over the top of your internal bag so it connects with the 2" sections either end.
You can now seal the this end of the bag up.
Put you pipe mould in the bag from the other end,threading the 8"bag up the centre as you go.
Seal up the end of the bag using the same system as used on the first end
Now when you vac you job down the centre of your tube isn’t “sealed” in the bag its to atmosphere.
Your internal bag will pull down onto the job,the internal bag will expand an pull down on the internal surface
I got lost a little. I think I need to see a picture or video or a drawing, haha.
Did this write up a few years back on a simple part. The manifold is a bit more complex but same principle
http://www.belfastmetcomposites.com/how-to-internally-vacuum-bag/
it’s harder to explain than to do it 
we make car spoiler, seats and other in this way.