Dave,
A few ideas from my experience.
1. Check that the yellow resin is free of small lumps from crystallisation. If
lumps are present, warm tin in a pan of warm water and let it soak at a modest
temp. Don't try to rush it and the crystals will go away with no trouble.
2. I could not find a lowest recommended temp for curing on the 420 data sheet,
but the lowest temp. I could find referred to on a lap strength chart was 22
degC (72 degF). I think that if you try and cure it at less than that the resin
will not cure very well and may even retain a slightly sticky surface.
Data sheet pot life is 50 gm/25 degC = 2 hours & 100 gm/25 degC = 1 hour. It is
pretty exothermic so if you do larger quantities, they will cook off quite
quickly.
3. I found that a good technique was to lightly butter both sides of the joint
plus to dispense a bead on each surface. I used inexpensive plastic sandwich
bags with the corner cut off - works fine, just like a cake icer.
4. I found that the wings panels moved slightly after I placed them and then
placed long rectangular steel tubing and weights to keep everything flat. No big
problem but next time I would use clecos at key locations to make sure
everything stays put.
Have fun!
Cheers, John
A099, XS 912S mono, N262WF
Mooresville NC
DvdPar@aol.com wrote:
> Just about to Araldite top wing skin on. Can some one reassure me in use of
> Araldite 420.
> 1. Do you need to warm it up before mixing to get it more fluid?
> 2. How long is the working time?
> 3. Any other tips?
>
> Thanks, Dave Park
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