p.v.a. or c.a.
 

Hi guys, I have built a few planes from scratch and have always used p.v.a. glues. I know this can be a bit heavy , but I have been told that c.a. glues form a brittle joint, and that cant be good, can it?. If the use of c.a. is best , would it be a very thin type or a thick one. I intend to build a 50 ins span volks plane. I think the full scale job is a home build. Thanks in advance Bill.

RE: p.v.a. or c.a.
 

For most wood kits, I find one of the aliphatic glues to be great, try TitebondII or titebondIII or Elmers Carpenter glue, all work great. CA is okay but IMHO far to expensive and possibly will become a health problem for the user. The aliphatics also give you a bit of working time for assembly.

RE: p.v.a. or c.a.
 

Hi Rodney Thanks for your reply. Bill.

RE: p.v.a. or c.a.
 

Stick with the PVA type glues that you have used. Use CA for tacking problem bends. If used in a confined area ie:workshop, you will end up with health problems with the use of CA's.

Cheers

RE: p.v.a. or c.a.
 

It seems like the e-flight folk often consider CA to potentially be heavier than pva. PVA losses weight as the solvent evaporates. With CA, you kind of have to watch how much you apply as the wood can soak up quite a bit of it. PVA might not be the liability it would first appear.

RE: p.v.a. or c.a.
 

You need both, plus epoxy for high strength joints such as firewalls. However at a push Titebond will do it all. Also Titebond is less damaging to your health.

However I will use CA and epoxy with a good extraction system. Just get a bathroom ventilation fan with ducting and set it up to sit on your bench at the point of fume production.

RE: p.v.a. or c.a.
 

Once I developed the CA sensitivity problem I found that breathing the fumes wasn't all I had to worry about. Touching some wood that hasn't cured for several hours can also trigger a reaction. My case is probably more severe than most because I can be affected even by sanding an area that was glued within the last few days.

I still use thin CA on occasion however never in an enclosed area, regardless of ventilation.

Regards

RE: p.v.a. or c.a.
 

In the above statement, the following is not FACT: "If used in a confined area ie:workshop, you will end up with health problems with the use of CA's".

I've used CAs of all sorts and manufacture, since the mid 1970s without problems and I occasionally can have asthma symptoms due to allergies to dust or some types of smoke. However, I have never had a reaction to CA fumes!

It's also a known fact that using CA correctly is the lightest method of construction there is. How can it not be; one tiny drop of CA, in comparison to a glop of other types of adhesives.

Having said the above, I think a person should use the adhesive they feel the most comfortable using. I have no problem with using and do use: CA, Epoxy, alphatic or poly types, Gorilla Glue, Ambroids, Duco, plastic glues, etc.

RE: p.v.a. or c.a.
 

A big thank you to all that replied to my question. Happy flying. Bill

RE: p.v.a. or c.a.
 

I have been using PU glue (such as Gorilla Glue or Elmers Polyurethane Glue) for the last several kits that I have built (from a .40 sized P51 thru 1/4 scale warbirds). I really like the PU glue as it expands (foams) as it cures and fills any gaps in the joint, grips like iron, and remains slightly flexible after curing (which I believe makes joints less likely to fail over time from vibration or minor impacts). It is also GREAT for skinning foam cores, laminating, and for mounting hinges (search these forums for specific articles). I still use some CA (mostly for stregthening balsa wood around a mounting bolt) and some epoxy (mostly for fuel proofing or fiberglass) and some PVA (it's tack time is less than the PU glue). It does take a bit of "learning" to use PU glue as it only takes a very small amount. It can be "kicked" by slightly moistening the wood (use an old CA "kicker" spray bottle with water and apply a light mist to the part before glueing).

PU does have a "down side". It will begin to set up in the bottle because of air (humidity) exposure. Best to transfer a small amount into a different, small squeeze bottle or syringe for use and keep the bigger container tightly sealed.

RE: p.v.a. or c.a.
 

OK first off, you should use CA in a well ventalated area. That said, you can build a lighter, STRONGER airplane with CA. With CA, your fits MUST be tight. if you fit a wing rib to a spar, and their is a .010" gap, thin ca WON'T bridge the gap, resulting in a weak joint. that same .010" is no problem for wood glue.

So when I lay out my plans, to cut templates to "kit" an airplane, I intentionally trace my inside fits (ex: the notch in a wing rib that saddles the spar) to the INSIDE, resulting in a part wit a very tight fit, that often requires sanding to "open up" to achive the desired fit. Then during assembly, I "tack glue" a structure together with thin CA (just a drop to hold it in place) and follow up with medium CA to finish the job.

CA will result in a lighter airplane for the following reasons. 1: it takes a smaller volume of glue to do the same job. 2: 1oz of CA is lighter than 1oz of wood glue. 3: because your joints fit tighter, you will need less structure.

CA will result in a stronger plane because you have got to FIT the plane together tighter from the start.

RE: p.v.a. or c.a.
 

Wow! Is that like"what weighs more, a pound of feathers or a pound of lead?". [sm=confused.gif]

RE: p.v.a. or c.a.
 

So sorry, fluid ounce to fluid ounce, CA is lighter.

RE: p.v.a. or c.a.
 

OK. That makes sense;)

RE: p.v.a. or c.a.
 

It does?
Properly used pva and ca are both stronger than the substate (balsa). PVA has a substantial solvent component that evaporates. CA does not lose as much mass on cure.