Can 1" tubing be made with an infusion process? I just watched a large flat part being made with infusion. The process looks much less messy than a wet layup.
Yes but I think it’s faster and cheaper to do it with a wet layup and a bladder.
O.k., thanks.
Small tubes are best made with bladders or mandrels and shrink tape. While it IS possible to make one with infusion it wont be as easy.
Bladders
http://www.piercanusa.com/composite.html
Shrink tape
http://www.shrinktape.com/products/index.aspx
http://www.acpsales.com/search.php?mode=search&page=1
If you go the route with a mandrel and shrink tape be sure to use Frekote or another semi permanent release because wax will just ball up and make it almost if not impossible to remove the tube.
Mcmaster.com carries stock material that can be used to make the tool.
Thanks for the links and info. Is making tube with a bladder mold different than making tube with a mandrel and vacuum bagging? My intuition (or memory from hearing about it somewhere) is telling me that making tube with a bladder mold is the process of using compressed air to inflate the bladder which pushes the composite into a two piece female mold. Is this right?
I am finally starting to tool up and work out my procedure, but not everything is settled. I did run a dry test with my new vacuum pump and vacuum bagged some econoweave 44 on a 1" aluminium mandrel using Airtech Sleeve bag KM1300. This is how I am leaning, but I am always interested in other ideas. The one thing I will not be able to do is use heat, at least not nicely controlled heat like an oven, although I do have a heat gun, so I think heat shrink tape might be out. I bought some Rexco Partall for use on the mandrel, and I am configuring an arbor press for removal.
Forget partall. It is PVA based and it will be a pig to release. Use a semi permanent release, and use the sealer of that system as well.
As for an oven: when doing a mandrel layup, it is critical to use heat. This will expand the mandrel, and after cure it shrinks back, being able to release it. You already have a heat gun, now source a cardboard box, and there is your oven.
It is Always handy to be able to clamp the mandrel in something that can be rolled. A lathe-like clamp.
Interesting observation. I hadn’t considered the benefit of curing with a hot mandrel, thus creating a greater margin of contraction when cooled. However, I have made small specialed ovens for projects unrelated to carbon fiber, and I can assure you, it is more difficult to get uniform temperatures within any enclosure than one might imagine. If one samples the temperature within an enclosure that was not properly designed, there are going to be hot and cold spots. Maybe the cure temp window of composites is more forgiving? I will give the idea of heat more thought.
Making tubes is how I got into working with composites and having tried every process under the sun I found the easiest, fastest and most economic way to make tubes was with latent curatives, mandrels, shrink tape and a diy convection oven. The oven cost a bit to make but paid for itself very quickly and enabled me to make very high quality parts that meet or exceed prepreg/autoclave fiber resin ratios.
I am still working out the best approach. The one problem with heat shrink tape as just told to me by a Dunstone rep is that it does not work well on square tube, as all the force is concentrated on the corners. To do square tube requires finicky corner tooling to direct and spread the force over the whole tube.