1/4 Scale Salto**

[Cliff Evans]

Peter thanks. sorry this is probably a very new member question. if i were to spray paint the fuselage can this be done directly over the white finish?

Yes, you can but you will need to flatten it down with 40 wet and dry "wet" to give the gel coat a key.

[geoff_crew]

Cliff,do you mean 400 wet and dry?
Geoff

[Cliff Evans]

Cliff,do you mean 400 wet and dry?
Geoff

Yes, damned fingers!!!

[andynrose315]

run into a little problem with the glass fibre over the wing. applied a light cloth and spread thin coat of epoxy resin careful with the proportions of resin hardener etc and not to apply too much or lift the cloth. in patches the resin remains tacky after best part of a week. i think it is a result of temperature being too low so moved the wing into a warmer area. looking for help on best way to proceed. i have read on rcgroups various threads to remove tacky areas by sanding. some appear to have applied another coat or use acetone. before making a mess thought i would ask and see recommendations of others.

[Cliff Evans]

You can try using Talcum powder! I had a similar problem with a paint that remained tacky. I searched the web and found that someone had recommended using talcum powder to help dry the paint off, and it worked. Not sure what it will be like on resin. I will ask John Hall, he is the expert on resins.

[fibreglassjohn]

Quite possibly a result of poor initial cure due to the low temperature....how low was it? If prolonged poor initial cure this can prevent ever getting a full cure. I would place the wing at 25°c for 24 hours and then reassess. If still tacky, I would recommend carefully wiping with acetone on a rag (not tissue) sanding will probably make a sticky mess and compromise the integrity of the glass fabric.
I believe this is glass/epoxy over thin ply? If so was the ply surface sanded to remove the release agent used during its manufacture? this could inhibit curing . What kind of epoxy was used? some do not work well in thin layers or as coatings.

[andynrose315]

so it is glass over ply and the ply was lightly sanded beforehand. i have been using easycomposits laminating resin. i’m guessing but the temperature likely to have been 15 degrees and this would have been for several days as i was away from home. i will keep in a warm place and see if it improves. the resin was a new purchase. the residual that was left in the pot has cured ok and not tacky in the surface.

[Peter Balcombe]

I have sometimes found that the EL2 resin cures with a tacky surface despite having been weighed out accurately &/wel mixed,then cured in temperatures above 18 C.

Leaving the item for a while in as warm room seems to improve the cure, but not necessarily make it go completely hard!
Peter

[andynrose315]

left in a warm room for several days and tackiness has reduced and gone in most places. a few small areas i used a little acetone and all seems ok.

Is there a resin that is recommended for this type of application as from Peters comments this may be EL related. Last thing i want to do is repeat for the other side and wing.


thanks for the responses above

[Cliff Evans]

I have always found that the West system is very reliable.
https://www.ebay.co.uk/sch/i.html?_nkw= ... xEQAvD_BwE