Question for Builders of Resin Biplanes

[Amo Aero]

Have any of the struts on your finished models warped or sagged over time? I'm interested in hearing from anyone who has built 1/48 resin biplanes from Planet Models, Rest, Copper State, Silver Wings or Karaya.

 

I have some kits from each of these manufacturers. I'm wondering if it would be worth the effort to scratch build replacement struts to avoid any warping problems or if the struts are sturdy enough to stand the test of time.

[JackG]

I've only built a few 72nd models from Choroszy, but none of them are more than 5 years old.   That said, so far so good - struts still look to be standing straight.

 

Some sleuthing over the internet, it seems warping is something  more likely found during the casting process.   What can happen as the resin ages is that it may become even more brittle, but this seems to be the case only when left bare and not painted over?

 

regards,

Jack

[Amo Aero]

That's good to hear about your Choroszy models.

 

So far the only resin models I've built are 1/72 scale and not biplanes. I always reinforced the LG with brass rod or tubing so never had problems with the dreaded "gear sag". OTOH, scratching all the struts for a 1/48 biplane is something I would like to avoid if possible.

 

Yes, warping can happen during the casting process if the parts are pulled from the molds before they are fully cured. Resins typically don't develop their full strength until well after the advertised cure time. Some manufacturers "post cure" their castings by placing the filled molds in a low temperature oven (or better yet, a pressurized oven). Post cured castings are very resistant to warping. The problem is, I don't know which manufacturers do that and which ones don't. From what I've seen of various manufacturer's kits, it's surprising how many don't do it. Resin kits can also warp if left in a hot car or in direct sunlight.

[Paul Thompson]

I've never had a resin strut that wasn't warped, to be honest. That includes those reinforced with wire (wire reinforced wings too, on a pair of 1/48th Albatros kits from before the flood). I haven't lived anywhere particularly hot or left kits in warm storage. The worst offenders have been Choroszy, but these days I never use resin struts at all, except as patterns to make replacements. A real pain when there is delicate detail cast into the strut. In the past I've used some CMR struts which have survived okay, but they were really too thick for accuracy.

 

I would suggest that if your Choroszy struts arrive unwarped in the box then they may be okay so long as the wing isn't too heavy. If warped, I don't think there's any point in straightening them for use because they will go off again. Hard to say - it may well be a combination of temperature and humidity that governs it, assuming they left the manufacturer okay.

 

Paul.

[Amo Aero]

On 11/16/2018 at 2:18 AM, Paul Thompson said:

... these days I never use resin struts at all, except as patterns to make replacements. A real pain when there is delicate detail cast into the strut.

Yes, that is exactly what I hoped to avoid. Looks like there will be strut scratching in my future. Thanks Paul.