Hey Jim,

  I have some Tyvek so tomorrow I will
do some experiments and  let you know
what works or doesn't.
I could always mail you a Tyvek "letter"
for you to play with.

   I have always wondered about this material.
It is low stretch and obviously fiber reinforced.
It is U/V resistant and doesn't fray.
    If it was laminated it might be a useful for
smaller racing sailboat sails.

Stand by - More to come.

- K

Porsche_Jim,

There's a blurb out there on bonding Tyvek. That might be helpful. Will see if I can find it again.

Tyvek is just another form of polyethylene. In this case, randomly oriented spun fibers. If you have used any UHMW plastic, it is pretty slimy but not nearly as soft as Teflon. Of course we're talking about Ultra High Molecular Weight polyethylene. So the stuff is slippery, and is used for applications that can  benefit. Some plastics need to have their surfaces etched and activated before being able to bond to them: ETFE is like that. But, the chemicals that can do this can be very, very nasty. Not Joe Bellcrank stuff.

I am currently running an experiment on a sport plane. It had a million hinges on it (a biplane with flaps) so I took the regular mylar strip hinges and dry fit them. The controls were too stiff. (We all know this.) Then I cut away a V on both sides, making the flex portion of the hinge piece about 1/4" wide. The flaps now drop of their own weight. I think a set of hinges with a large bond area and a 1/4" flex area are going to be plenty strong. Time will tell via testing.

For 1/2A's, years ago I used discarded mylar drawings. This was the cheaper, but more durable alternative to paper stock. Not the mylar that you draw on. An E-size drawing had enough material for several modeler's lifetimes....   The stuff worked fine. The drawback was slitting the typically thin 1/2A surfaces to install it. Instead, take two 1/16" strips and laminate them together with the hinges embedded. The sand the edge and butt glue to the surface. Lay flat on the bench and sand the face of each surface which gets rid of the bump from the embedded mylar. Done.

Divot McSlow

Keith,
I appreciate your efforts. If flies barely stick, I doubt dope will either.

 I've been tearing my garage apart trying to clean up a dropped ceiling while also looking for the one Tyvek mailing envelope ISTR keeping.
There was a place in the garage where I keep (kept) materials for testing, but it got relocated during the ensuing damage control.
Oh well. Back to sewn hinges on 1/2A.

Thanks again.

If you are using the Tyvek hinges like the Dubro or pinned hinges drill a hole through the tabs and use toothpicks or bamboo skewers to lock them in place.  Cut flush after a drop of CA.

Here's the blurb I read previously from a material supplier's website on their comments/recommendations for bonding Tyvek material.  Of course, our use is specialized, so tests like Goozy did are the real indication of what might work best--or if it will work at all.

"Gluing Tyvek--

A number of adhesives can be used to glue TYVEK, either to itself or to other substrates. In general, water-based adhesives that provide quick tack and fast drying are preferred. However, the first step in choosing an adhesive is to determine how it will react with TYVEK. Testing a small TYVEK sample is the best way to make this determination. Natural-product adhesives based on starch, dextrin, casein or animal byproducts are preferred to synthetic-based adhesives. Hot animal glue is an excellent adhesive for adhering TYVEK to paperboard. Water-based synthetic lattices also bond TYVEK to itself and a variety of substrates. Ethylene/vinyl acetate adhesives are especially useful, as are the acrylic pressure-sensitive adhesives. Synthetic adhesives often contain low-molecular-weight materials that can act as solvents at elevated temperatures, causing swelling and wrinkling. Solvent-based single-component polyurethane adhesives provide optimum adhesion (lap and shear), flexibility and water-resistance for adhering TYVEK to itself and a variety of substrates."


This info was once hosting on www.materialconcepts.com but now that information has been "lost to the web."

Acrylic pressure-sensitive adhesive referred to above is commonly known to the Home Depot crowd as double-sticky tape. That might work ok if you had a smooth doped finish to stick it to. But not to bare wood of any kind.

I would try the following (because they seem promising, and because I have most of them):

Shoe Goo
Pacer Formula 560 Canopy Glue
RC Z 56
Balsalock from FAI Model Supply

Remember that water will not go thru Tyvek (envelopes, house wrap, etc.) but water vapor will. So gluing an area (not just a narrow line) with a water-based glue means that it will have to exit via exposed wood, or else will take a very long time for the water content in something like white glue, TiteBond, etc. to drop to a point where the glue develops reasonable strength. So I would say that sealing the wood to moisture before you try gluing it is going to make the cure cycle much more problematic. Additionally, more glue (thick glue line) is not better. A thin film that is in full contact is likely best. The exception to this is when a rigid part is being bonded to a flexible part, or when the CTE of the two materials is very different and you know it is going to go thru large temperature cycles. In a balsa to Tyvek joint, neither would be considered rigid. I'm talking about metals here, with high modulus.

For this application, what you want is a glue that has decent shear strength--you don't care about tensile strength. So a more flexible adhesive is likely superior. If you wanted to try a chemically reacted bonding material, (and this was a paying job), I'd be sure to include EC 2216 modified epoxy. This is the only adhesive that I know of that the FAA/DOD has approved/accepted for bonding to some acetyl plastics, which is a tough job. But I don't think modelers are going to have this on hand, or want to go buy a minimum quantity, which is why it's not on my list above.

You might have good luck with over and under style hinges where you put a thin coat of, say, the Formula 560 on one side of the Tyvek and let it dry. Then iron it to the wood. The problem is going to be how you finish over that...

Another user reported that PL Premium Bulldog Grip by LePage was good. This is a polyurethane mastic as used in a home construction glue gun cartridge. I haven't used that before, so know nothing of it. Not interesting enough to buy a huge cartridge when I need 4 drops or smears per hinge....

There is no doubt in my mind that there is a suitable adhesive. Here's why:  Did you ever try to open a white and green Tyvek shipping envelop and almost sprain your fingers trying to pull and pry open the glued flap?


Divot