So was the workmanship as utilitarian back then, or "better"?

I purchased the 2X about 10 years ago. My son purchased his about 15 years ago. I did not notice much difference in construction quality of the 3 tents. All of the tents were hand made in the USA and looked like home made tents. I can not speak for todays quality.

Just going off the photos Roger posted as part of the mini-review... does the workmanship look significantly different?

I pulled my tents out and took a look at them today. In general, the workmanship is better with straighter stitching than the photo in the minis. However, mine don't look like works of art. Maybe, by experience, they are art that works.

Stephenson has a long writeup on his site about different types of stitching and their inherent strengths. I can say that Warmlite has been very helpful with any questions and they are supposedly good with guarantees. I think that good seam sealing also helps keep threads from coming loose or tearing the fabric.

I have poked holes in my fabric, damaged the end of a pole and worn through some of the fabric where the pole inserts into the sleeve. All of these things were repaired at home with hand tools, urethane or silicone, and stitching. It is good to carry some extra fabric, thread, silicone for sil-nylon, and a muti-tool. I have never had anything happen during a trip that prevented me from setting up the tent properly.

I hope you don't think I am sounding like a saleman for Stephenson, but they make a 3R model that has sitting room at both ends and more ventilation. It is massive inside with some additional weight. On many trips and sometimes sitting out long storms, we have never complained about sitting up in the 2X or 2R unless there was three of us.

Hi Roger,

Just how pressurised would it have to be? Seems to me an inflated bike tube would be sufficiently stiff and strong to lay carbon fiber around, and they aren't exactly made from exotic materials. But on second thought I think creating a custom-bladder out of rubber or whatever would be a bit complicated, but you could easily create a mould for CF out of this stuff:

http://www.plastimake.com

It melts at 60 degrees C and sets hard and strong, pretty sure CF can handle that sort of temperature.

Good question, but ...

You are trying to replace a steel mandrel which has CF cloth wound aroung it tightly and then it is wrapped very tightly with PE tape before thermal curing. I dare say a bike tube might withstand the compression if inflated hard, but what diameter would it be when inflated hard withough the constraint of a tyre? And how do you keep the exact curvature you want for the specs? Remembering all along that you are trying to make a tube about 8-9 mm OD.

I'll pass on the problem of finding such a curved tube to start with.

Cheers

Yeah, I am with Roger. I do not believe the the presurized rubber version would quite work. A lot of good thought, though.

As for the requirement that the poles be 8-9mm, I question that. Larger poles could easily be as effective, perhaps more so, in a prebent configuration. As light or lighter, too.

A simple lost wax process is by far much simpler. A split mandrel could work, too. But, you loose some strength over steel mandrels, again, not a big deal. I would guess some designed in curvature will be lost from internal or external forces on the tube. Process design would be different at any rate.

Anyway, carrying curved tubes is not as neat as straight tubes. I would again bring up the Dyads curved tubes which are a bit awkward to pack. Shorter sections of precurved poles also pose an interesting problem of assembly in the field. Like the Stephensons tents they could be placed in odd arrangemens, not at all conducive to sliping through the sleeves...

Well, as I said, on second thought I don't think a pressurised tube would be that effective, but you guys both seem to have missed the second part of my post about the Plastimake stuff, which has a glass transition temperature of 60 degrees C. It would be relatively easy to use this stuff to wrap and set carbon fiber around, and then it would melt out at less than 100 C - a lost wax process I guess but even more effective than using wax?

Hi Jeremy,
I don't think that 60C will have much of an effect. Actually, I don't think that 100C will have that much of an effect. Epoxy is quite rugged. Note that not all would be suitable, though. Nor would all survive steam heat. Anyway, a production problem easily sorted out. Some of the epoxy will stand up to 200C (~420F) easily. circuit boards for instance, used to be floated over liquid solder.

Generally the layers are taped together, along with thermoset epoxy. Then the whole thing is baked for a time. Untaped and de-cored for further processing. The tape usually shrinks a bit applying a tight compression, squeezing excess resin out. This is used for fishing rods where a taper is desired. Fairly easy as it sits. Short lengths are much easier than long lengths. A largish machine can make the whole thing go much faster...continuous. Used for arrow shafts and other mostly "extruded" type pieces. The fabric is usually wrapped, usually hi-linear layers and "square" type tapes and cloths. Varying the layers can achieve your desired result...lots more to this, but in general. High pressure is used to force the resin in and to force the fibers into close proximity to each other.

There is no real constraint to making individual curved pieces for poles. Indeed, one of the problems is getting them straight. I believe that with the low temp plastics (a lot of different types besides the one you mention) the problem would be lack of internal compression strength. The plastic would soften slighly and not be stong enough to support the internal fibers very well in the setting phase. So, you end up waiting...up to a week for many epoxies at room temp. (Though it seems hard after 4-6 hours, the chemical process will continue up to a week till maximum hardness and strength is reached.) The longish lead time will cause some problems in manufacture, supply, storage, etc. Really not conducive to mass manufacture, cheaply.
This is just one manufacture problem, not insurmountable...but costly.

Lost wax is a process using some material (it doesn't have to be wax) that when heated, runs out of the object. It actually started hundreds of years ago, for metal casting (bells?) hence the name.

Hi James

> This is used for fishing rods where a taper is desired.
Dunno about CF fishing rods, but I do know that many fibreglass rods start parallel and are ground down into a taper. Easy to do on a production basis.

Lost wax for curved CF poles? I suspect the wax, or Plastimake, will melt during the epoxy curing process. Um - well before the curing has got very far. Tricky.

Cheers

Edited by rcaffin on 05/07/2012 16:40:44 MDT.

Do you have to heat-cure carbon fiber poles? I was under the impression that some of the resins used could be air-cured.

Yeah, there are lots of epoxies out there. I was thinking of quick process stuff that requires *some* heat, though. WIthout heat you probably couldn't create a continuous process. Once it is fairly well set, you could cut it and increase the heat melting the mandrel out and finishing the cure. Anyway...just thinking out loud.
As roger says, tricky, but doable.

Roger,
No, Fishing poles are NOT made by grinding them. (Well maybe old ones were.) They use quite fine mandrels, wrapped.Tips are often solid, though.

I think the problem might be finding a pre-preg with the right epoxy to handle the temperatures. Not a big range available commercially.

> Fishing poles are NOT made by grinding them. (Well maybe old ones were.)
Yeah, well, I admit I was talking about Jarvis Walker rods from the 60s and 70s. That was then.

Cheers

It seems to me that making a thin hollow bent CF tube requires a flexible Stainless steel wire inserted into flexible plastic tubing. The tubing ideally needs to be slightly stretched (ie increased in diameter), by the wire. Once the CF is set, removing the wire will allow the tube to shrink to its original size. Further, pulling one end of the tube causes it to shrink still further allowing it to be removed.
A few points:-The tubing needs to be sprayed with a release compound, I am trying silicon lubricant.
The curve of the wire/tubing can be set by clamping each end the required distance apart and allowing it to hang free giving space to wrap the CF around it. Very tight bends not practical.
Strongest results would be to use two layers of tape wound diagonally in reverse directions.

I am trying this out and will (hopefully) advise results. :-

Roger, I finally got around to finishing this- thanks for writing it. I as many here wish I could get a hold of one of your tents.

----------
See new thread 'The CAFFIN tents come!'
Cheers
Roger

Edited by rcaffin on 06/08/2012 04:43:48 MDT.

Congratulations on finding a way to bring these to market !

Can't wait to see some at the 2015 GGG.