aaganz

I am restoring 2 old CL models built and flown years ago. The new Silkspan covering on the wings went on beautifully and smooth and tight in the first coat. I used an EzeDope:Water mix 30:70 %.

However, the second and third coats at a 40:60% ratio dried to a speckle pattern like running my hand over a sand/paint mix. Any idea why this is happening, and will the final 2 coats of Butyrate Dope (Brodak) smooth this all out??

Thanks for any info.
aaganz

JohnnyS

You will need to sand to get rid of the texture before finish coats. Wet sanding with 4000 grit may do the job.

Look up how to use "retarder" and see if you can figure out how to "retard" ezedope. Retarder with butyrate dope is the trick to get a smooth finish.

AJ Sun

Never hurd of the dope your using. I use Nitrate dope thinned with Retarder to pre dope the frame before cover. I use silk. Always have good results. Sounds like you may have thinned with Alcohol, or possibly you temp, was pretty cool best time to do silk is in the 70s you can mix a little MEK with your dope along with the retarder that usually slows drying. Try scotch brite, medium instead of 400 wet or dry. You finish with Butirate over the Nitrate. But never apply Nitrate over Butirate.

mgnostic

Did you by chance use a foam brush with the EZ Dope? I sometimes have the same problem with water base polyurethane. A foam brush will sometimes leave behind bubbles that show up as specks as described. I usually have better luck spraying or with a bristle brush. As already described a light sanding is your fix. One of the lessons of painting is that your top coat will never be any better than the layer underneath.

AJ Sun

Water base ? Dope? Is that ezedope? Thats new to me. If thats what it is. Again ive always used camel hair brushes when applying any dope old.school.101. Reds are also Maroon are tough colors to get applied and of course are my favorites. Usually. Spray with my top loader spray gun. Don't get me wrong. My paint jobs are not the best. I am going to.crash so why spend hours on a beautiful finish. Took me hours in the first place to build that gal. Not to offend just me
AJ.

aaganz

All,
Thanks for the good information. Yes, I am using EzeDope which is water based. I am using an "Artist Brushes" by Linzer, although the brush material is not given on the packaging. I have ordered 4000 grit sandpaper from Amazon, and it will arrive on Thursday. We'll see!!

The wrinkles previously noted have somewhat reduced with the added coats, and I hope will diminish further as the Butyrate Dope (Bradok) coats go on! See my next thread on "gloss"??
aaganz

mgnostic

With regard to gloss there are some YT videos by Windy Urtnowski (I think that is the correct spelling) on the subject of old school covering with dope, including how to achieve a high gloss finish. He is one of those old school control line guys who could create a perfect glossy finish. You will eventually use 4000 grit sandpaper after you go through 400,600,1000,2000 and 3000 grit papers. Followed by abrasive polishes . Most of these abrasives and polishes are available at your local automotive supply store such as NAPA or O'Rielly's. Speaking from experience, be careful sanding around the tops of ribs and other edges. It's easy to sand through the paint and into or even through the silkspan. Butyrate is interesting stuff. Applied in thinned coats it will lie pretty flat and can take on a nice gloss. It will sand best if you give it a couple of days to really cure. While it is mostly done in a day or two Butyrate will also continue to shrink essentially forever and may draw up the remaining wrinkles. You don't mention what color you are going for but it should also be noted that many colors of dope are rather translucent, especially yellows and reds. Unless you are going for the translucent look, which can be very attractive, you are better off using an opaque basecoat such as white or silver under your color, It's really easy to end up with a ton of dope on a model in the effort to get an opaque finish.

aaganz

Matt, Thanks for the insight. I need to be super careful with any 4000 grit sanding...I don't want to tear up the Silkspan! The butyrate dope is curing to a slightly glossier finish after 3 days, and maybe that will be ok. I had hoped for a more brilliant white, but the "Cessna White" seems the best I can do! I will add a final coat of clear dope in hopes of obtaining some gloss!
aaganz

aaganz

All,
The wrinkles on the Silkspan (with EzeDope) have smoothed out with additional layers of Butyrate Dope thinned (40:60).

However, there are wrinkle spots occurring on the leading and trailing edges where my Butyrate Dope is applied over the (old) tissue and dope (?), followed by recent UHU Glue Stick and White Glue + Water, plus EzeDope all used for "gluing" the Silkspan prior to shrinking.

On my next model, I may just use the EzeDope to "glue" to the frame (leading and trailing edges).

aaganz

mgnostic

It's always a bit of a crapshoot when you are working on top of old coatings.

AJ Sun

All the posts are pretty much the way it is. Going over old coverings is a crap shoot. Krylon and other spray coatings rustoleum. Never used them,but know other UC guys that have, with nice results. Using Non taughting Randolph silver Butirate Dope has always given me good results. I think Randolph Dope was the Dope SiG bottled. And possibly Brodak uses the same product, Tho they will not omit it. Use Retarder if you want a nice semi gloss. And top loader HVLP touchup spray units give real nice results.AJ

aaganz

AJ, et al,

I posted some pictures of my 2 Super Ringmasters in the "Super Ringmaster" thread just now. You can see how the covering is coming along on the 1953 model!

aaganz