Tack weld - epoxy v. CA glue?

Any thoughts on using epoxy v. cyanoacrylate glue for tack welding the panels before filleting?  Nick Schade seems to suggest using CA glue, but all the CLC instructions seem to favor epoxy with a syringe.

One advantage - it looks really easy to snip and pull out the copper wires after using the CA glue.

Thanks!

Alec


6 replies:

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RE: Tack weld - epoxy v. CA glue?

It probably has more to do with working time and reversibility.

Epoxy can take hours to cure while CA with accelerator is very fast. Also if too much CA accelerator is used or it is used improperly the glue migh fail under stress or with age. But since only a small portion of the joint is tacked with the CA it should not be a problem. While epoxy is still curing or "green" a heat gun can soften the expoxy and allow more working time.

 

RE: Tack weld - epoxy v. CA glue?

I would think it also depends on how tight the joints are. I haven't used accelerator, but I have had to wait almost as long for regular CA to dry on RC airplanes. JRC

RE: Tack weld - epoxy v. CA glue?

I used CA with accelerator to tack my WD12.  I found it very helpful in getting the seams perfect.  I was able to hold the seams in exactly their best orientation with one hand outside the seam while applying the CA and accelerator with the other.  If a seam goes wrong, there is a de-bonder fluid available from several different CA manufacturers which will loosen up the bonds within a minute or so, allowing for easy fixes.  It also is indespensable for getting the dried CA off your fingertips.  That having been said, a luthier friend of mine, who has actually put entire guitars together with CA, uses rubber finger-tip protectors from a stationary store to avoid having the CA bonded to his skin.

RE: Tack weld - epoxy v. CA glue?

Nail polish remover is good for unsticking CA bonds. It's a long story involving stuck fingers.

RE: Tack weld - epoxy v. CA glue?

Since the CLC and  Nick Schade  differ on the approach it is a matter of personal choice and the skill level of the builder.

There are many brands of disposable gloves that many manufactures of adhesives encourage users to use. The can be made from latex rubber or Nitrite and the choice of material could depend on one's allergies. The gloves protect the hands and fingers from being glued together, protect the skin from long exposure to the chemicals, and provide a wear area to prevent blisters.

The choice of the use of adhesive for tacking and protection of the builder, is the builder;s choice.

 

 

RE: Tack weld - epoxy v. CA glue?

It must be a morning for light bulbs.  Again, this is for S&G only.

We have to tack weld the deck and hull together through the cockpit and hatch holes.  Why not tack weld the hull panels and the deck panels themselves the same way, with the boat fully stitched together and holding the shape that I want in the end?  Of course it requires cutting the hatches before tacking, but that seems like it would be OK.

Couple of advantages, maybe: 

I don't have to keep un-stitching the deck and hull and re-stitching during tacking (this is especially attractive since I will probably be tacking in stages rather than doing it all at once).

I can use the CA glue to tack.  Since it dries immediately, I cannot use it to tack with the deck and hull separate.

 

I could use the CA just to weld the hard spots - i.e. panels that don't meet perfectly, putting on the glue then holding them in place by hand while spraying the accelerator.  I couldn't do this with epoxy.  I would be confident that the way I glued the panels would hold the difficult points in the exact shape that I want in the end.  Could even reduce planing or sanding later on.

After CA gluing the hard spots, I could epoxy-tack the rest.  The places I can't reach through the hatches could be tacked after separating the hull and deck, but that may not even be necessary and I could go directly to filleting and glassing.

Any down sides?

 

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