Gargoyle

I am currently putting together a GP Spacewalker ARF. The instructions call for 30 min Epoxy to join the two wing halves.
A fellow I work with recomended 3 Hour Epoxy, sighting that you have a longer working time. I know that in the past I worked on a couple of projects that the wings were barely together & the Epoxy was already starting to kick. Besides the working time, is there any other advantage's or drawbacks to the 3 hour Epoxy

Cheers

George

saramos

Slower setting epoxies tend to be stronger once cured. For joining wing halves, the biggest benefit will be the extended working time. Both 30 minute and 3 hour epoxies will be strong enough for the job. You can also find 45 minute, 60 minute, 90 minute and two hour epoxies. My personal choice would be an epoxy that will give me enough working time without excess cure time, and still meet or exceed the instructions recommendations.

Scott

Lightfoot

My Feedback: (1)

I found a product that was labeled a 1 minute epoxy. I bought it just to see what it would do. The first attemt at mixing it was done in a small plastic container and it got so hot that it melted the container. The next attempt was in a small paper cup. It set so quickly that there was insufficient time to mix it thoroughly.

Normally, I use what is known as "2-ton" epoxy. It takes about a half hour before it even starts to set and takes about 24 hours to cure completely. I like the extra working time and the fact that it gets maximum penetration in the wood. It is probably far stronger than would ever be needing in a modeling application.

Fubar-One

My Feedback: (1)

Mix large amounts of epoxy in a paper plate or similar. This allows the heat to dissapate due to the large surface area. This will give you plenty of working time, more than you need. If you mix it in a cup, the heat builds up, the epoxy starts to set up, more heat, faster setup, etc.
I mixed up too much 5 minute epoxy in one of those little cups and had to throw it out the door into the yard because I thought it was about to burst into flame. Blistered my fingers in the process.
I still mix small amounts in those little cups but for large amounts of epoxy, 5,12, 30, whatever, I mix it on a plate or something. Never had it set up too soon since.

cwrr5

My Feedback: (32)

Neat trick: if you use the lid to a butter container(or similar) to mix epoxy, when you're done using it, and allow it to cure, you can flex the lid a few times to remove the old epoxy and re-use the lid. The epoxy doesn't like to stick to the smooth plastic as well as more porous surfaces.

cknaack

My Feedback: (1)

Depending on the viscosity of the epoxy, a longer working time can be a benefit as it allows the epoxy to penetrate the wood better. I like the Anchor Bond products, mainly due to the lower viscosity, wider choices of working times, and the bottles come with pumps. The other benefit is that Anchor Bond can be purchased without Mercaptan, which can affect your health.

Just my $.02

CafeenMan

Don't ever use anything faster than 30 minute epoxy, particularly 5-minute epoxy. I wouldn't bother with the 3 hour stuff. It probably takes over 24 hours to cure enough to handle the parts. If you need a lot of 30 minute epoxy it will heat up a cup like the faster epoxies, so the idea about mixing in a shallow container is a good idea.

However, for joining wings, you don't need much epoxy.

Deadeye

Epoxy is so messy! I'm building almost exclusivly with ProBond Polyurethane glue. Cheaper, stronger, lots of working time (3+ hours).

P-40LUVR

30 minute epoxy is PLENTY strong enough..thats all I use to fuse the wing halfs together and I have put some planes in at full speed and everthing turned to bits of balsa but the wing joint never budged and I do not use fiberglass to strengthen either.

Gargoyle

Is the ProBond Polyurethane glue fuel proof ?

George

Silvaire

My Feedback: (50)

Just some thoughts on the subject of epoxies...

For fast setting epoxies, I like to use the bottom of a full aluminum soda can right out of the 'frige. This keeps the epoxy cool and buys you some extra time before it sets up. The only concern is that if the humidity is high, you can get some condensation that puts water into the mix. A minor issue is that there is usually an ink stamp on the bottom of the can that will color the epoxy. It cleans easily with a wipe of MEK or lacquer thinner.

A product I have recently found and REALLY like is Devcon Plastic Welder. It is a little hard to spread nicely and dosen't flow smooth, but it sure dose stick! This stuff has incredible adhesion on most plastics (except polyethelene types) as well as probably anything that epoxy will bond to. Cheapest place to buy it is Walmart, at about $2.25 for a "twin syringe" type dispenser like with some epoxies. It really benefits from the "cold pop can" mixing method.

Arlen