covering/silkspan

friends,
I am building a new ship, and I have always used the Urtnowski/Whitely and others, method of using 00 silkspan on all surfaces. However, as you all know this can be difficult because of the easy ripping/puncturing of the 00 material..I am considering using GM on the wing/open bay and tail surfaces and using 00 type on the fuse..What is the general consensus here? The main purpose of using 00 on all surfaces is to save weight, but how much weight are we saving?
My question is this: Is it worth the grief trying not to puncture/rip 00 silkspan and then having to constantly be repairing it, while prep/sand & fill 00 on a wing to save weight????

What are your thoughts?

Thanks David

David,

I'm sure some will argue, but I don't think there's much difference in weight in the end. I suppose when you're concerned about micrograms, it's a consideration, but my buddy Pat Johnston used SGM silkspan on his Bearcat. 750 square inches and it came in at 61oz, so it can't be that heavy (although he is a pretty good builder).

I regretted using "00" on my classic, I-Beam ship, But it was as you say. It's puctures and sands through too easily and that plane has a lot of open area. It was a pain to finish because of the thin-ness of the material. Next time I will either use 2 layers of "00" or GM or SGM on such a plane.

My new ship has no open bays so I will probably use "00".

Thanks Randy
It has been sometime since I last built a ship..I just want to be rational and thoughtful about the process..I have built a few ships using the 00 method and it was always painful and time consuming because you are always fixing stuff...I would look at it and all these band-aid silkspan pathches everywhere...Of course I want to save weight, but at what cost???I would be curious to know how much weight is saved by using 00 as opposed to SGM/GM? Then I could make a thoughtful decision??? Thanks DAvid

Hi David,
There are many who believe that the extra substrate necessary to fill the OO makes it an actually heavier finish compared to GM or SGM.
I guess it depends on the level of finish that is desired. OO that is just sealed well (fuel proofed) would probably be lighter. Getting a glass finish tends to take more dope to fill it.
I wish I weighted mine and did a comparision, but I believe myself, that the patching negates any weight difference.
Bill <><

Bill,
Thanks for your reply--I did make a decision to use SGM on flying surfaces and 00 on fuse--I have learned so much from Windy over the years..He and Bob W. are the main reasons I have used 00 on previous wings/tail assy--My own experience in using the method was difficult, and time consuming..I have compassion for R.Powell who finished his USA 1 in 00 silkspan, wow, an I-Beamer must have been a nightmare.Not only that, have you ever watched the flexing characteristic's of I-Beamers? Will that be "amplified" due to using 00 silkspan?????
We use to make side bets at the field, (especially, during windy conditions) when the next corner of a fellow flyer's "Ares" would cause the wings to fold!!!It never did happen-(R. Campbell are you there?)..I think he used 00 too...

Just some thoughts David....

LAST EDITED ON Nov-17-04 AT 04:39 PM (CST)
 
David,

It was a pain. But I haven't seen any problems with flexing. Of course, some judicious use of CF in the spar, LE and TE probably helped that a bit.

But you can be sure, I'll never use a single layer of "00" silkspan on an I-Beam again.

edit: stupid spelling errors

I use GM silkspan for covering and finishing open bays. I cannot see much difference in weight, but noticed a significant increase in strength. I had to make some repairs to my Jamison last month and was amazed at the strength and resistance to tearing the GM covering displayed after it was filled and finished.

Some people say GM can actually be less work (and maybe less weight) than OO tissue, because the OO tissue takes more surface work prior to covering.

My problem is I am allergic to sandpaper, so it takes just as much work for me either way. LOL.

Hope your new ship works great,

Ron King

Life is what happens while we are busy making other plans.