Post-mortum on Ambroid Cement: the verdict is in!

Rusty:

When this hydro was built things like exopy, CA and finishing resin did't exist. In a re-make I plan to use all of these in it's construction especially in protecting the balsa surfaces in or near the engine bay.

Also considering the use of an exhaust collector next time. Have you any experience with or knowledge of the refurbished ones offered by Matt at EX Model Engines?


Cox .049 Exhaust Collecter (Refurbished)

SD

You can try alcohol and cornstarch and see if you can revive the balsa.

Yea, the surface of the wood looses integrity, but when dried out from the oil it is back to about normal. I think a little saturation is why my Super Ringmaster nose came apart easily. It didn't seem saturated other than at the seam though. The block is solid and I didn't remove much from the joint, but I did lather on a couple layers of Testors cement (a Celluloid like Ambroid) prior to assembly so it won't get oil damaged.

Phil

SuperDave wrote:...Also considering the use of an exhaust collector next time. Have you any experience with or knowledge of the refurbished ones offered by Matt at EX Model Engines?...

No Dave, never tried one. It seems like it should work pretty well, but no first hand experience.

The main problem with Ambroid is that like many solvent based adhesives or paints, it's constantly shrinking. It will totally pull away from a two sided joint as much as 3/32". Ambroid from years back in my opinion was a far superior product. I still use it nowadays but it's as thin as water and just runs all over while 20+ years ago it would really be quite thick and you could build it up. As far as oil soaking is concerned, I've used K2R http://www.amazon.com/K2R-SPOT-LIFTER-6-PACK/dp/B0014E9FNO . As you can see it's expensive. It does work and it takes repetitive coats for the problematic areas like tank and engine compartments. Used in conjunction with a Monokote iron and a paper towel after application can really remove the oil to the point paint and glue will once work again. Ken

Dave,

There are no moving parts in the exhaust collector. It is a solid cast piece and assuming it's all in one piece it should work as advertized.

They do not make an air tight fit and some oil will flow out around the collector. I would still fuel proof.

Ron

Ron:

Thanks as always for your input.

I have the Cox exhaust DEFLECTORS from Bernie but not the exhaust COLLECTORS from Matt. I'm looking for something for a hydroplane in circular water course about 25 yards in diameter.

The COLLECTORS look like they'd pitch the exhaust overboard better than the DEFLECTORS. Just looking for someone with experience on a boat rather than an aircraft.

SD