What is the best technique to apply silkspan?

[Juan Valentin]

     What is the best technique to apply silkspan? Dry rubbing the dope with your finger or damp brushing the dope only.
                                                                                                         Juan

[Balsa Butcher]

I use a brush but fingers work also. Like all finishes, surface preparation is the key to good results. In this case it is smooth wood with three or four coats of clear dope applied before the covering.  For a more detailed explanation go to Heman Lee's "Aeromaniacs" site (aeromanics(dot)com). Click on "Tips" and look for the article "Covering with Silkspan by Jim Ryan". There are some variations on his technique but it is a good primer on how it's done and will work well if followed. 

[Bill Little]

Hi Juan,

Damp using a brush and fingers where necessary.

BIG Bear
RNMM/AMM

[Tim Wescott]

I only tried putting silkspan on dry once, and it was an absolute disaster.

If you want it to shrink, you need to put it on damp.  Start with your airframe well-doped (the three or four coats that Pete mentioned), and brush dope through the silkspan to wood underneath.  The dope will blush like crazy, but that'll go away when you start sealing the silkspan.

[FLOYD CARTER]

Silkspan EXPANDS when wet.  Therefore, when applied dry, and then wet afterwards, it will only expand more.  And when dry, it returns to its dry size.  The only method is to thoroughly wet the paper before applying.

I usually pull it as wrinkle-free as possible across the structure.  Run a couple coats of clear around the edges (not in the center).  I always get wrinkle-free results using this method.

Floyd

[Juan Valentin]

Thanks guys,I`m getting ready to cover my Jetco Dolphin and I have already given the fuselage,rudder and elevators the 3 coats of dope. I`m planning on silkspan for those parts and covering the wing with SLC. I will be painting the plane.
                                                       Juan

[Jim Thomerson]

I put silkspan on dry on fuselages.  I dope it down around the edges, and make joints perfect.  After the dope dries, I wet it. then when dry, stick it down with thinner.  This will give you a smoother coat of silkspan than the other methods. 

[Mike Griffin]

Juan, I hope this not more information than what you asked for but here is the method I use.  To cover an open bay wing.

I lay a large terry cloth towel out flat.  Then I lay the panel,of silk span on the towel, smooth it out as much as I can and then mist it with a spray bottle of water.  I soak the tissue well.  Take the back half of the towel and fold it over the silk span and press down to absorb most of the water.  Lay the tissue over the half o the wing you are covering and work as many wrinkles out as you can.  Before I do any of this, I have 3-4 coats of dope thinned 50/50 on the air frame and saned smooth.

OK back to covering.  Once I get all the wrinkles I can out of the damp tissue, I brush around the edges of the silk span with thinner only.  You can used thinned dope to do this but I usually just use thinner.  If I have a spot that is not sticking down, I stick my finger in dope and rub it in through the silk span.  When the tissue drys and shrinks, I start brushing thinned dope until I fill the tissue and it becomes drum tight.  The last couple of coats has Zinc Sterate in it to fill better .

If you are using the new silk span from Brodak, check each side of the sheet for a rough and smooth side .  Make sure the smooth side is up.

Hope this helps.

Mike

[James C. Johnson]

I have no idea how I came to do silkspan like I do... but it works for me... I put on 3 coats of unthinned clear nitrate... then switch to low shrink Butyrate thinned 50/50... I pre-cut all the wing panels, if the tips are built up I do them first instead of one piece for the whole panel... bottom then top.. small pieces just get sprayed lightly... on the main wing panels I soak the whole piece in water and then wad it up and squeeze all the water out of it with my hands, gently unfold the piece and lay it on... I tack in down with a brush and use my fingers to make sure it adheres.. and smooth it out.. keep some thinner handy.. I apply to the surface near the fuse first... then stretch length ways to the tip gently and adhere it there ... then start pulling and painting the TE and LE gently... there is a learning curve to silkspan.. use the thinner to help lift the silkspan up if you get a little wrinkle... you don't have to pull this stuff "tight" when it dries it smooths right out... wrinkle on the wood don't worry about... you can make silkspan "band-aids" to fix things.. I don't clear dope my panels until they are all covered... I use sandpaper and an Xacto to trim ... be patient.. treat the bottom and top as 2 separate projects... I usually do the bottom and let it dry.. then the top.. have a place to lay the plane down... BTW, you aren't doing it right unless you poke a couple of whole in your nicely finished bottom.. don't be afraid to use your fingers... I have even dipped them into the jar/can to "paint" small spots..

What is your projected weight for the dolphin... I weigh my planes and components as I go along... this lets me know if I have to scrimp on the paint.. it is better to have a good flying airplane that is ugly than a pretty plane that is a pig.... My Dolphin came out at 43 oz with an OS 35S and it flies great... this little plane has a tendency to build heavy... I have seen one that was 48oz...

I have switched to polyspan on bigger planes .. it too has a learning curve...

JJ

[Juan Valentin]

Hello James
                    The weight of the plane before paint is 33oz that is with everything on.My buddy Alex bet me I couldn`t finish it below 45 ounces but I feel I can.My target weight is 40 ounces I will be painting it with dupli color and coating it with clear poly urethane. I checked the CG and is nose heavy at this time which makes me think is going to be all right. I`m using DUBRO 2.5 inch lightweight wheels and I could go for smaller wheels to shift weight. At time the plane is in the garage waiting for the solvent on the last coat to gas off.I have been waiting 24 hours between coats giving a light sanding with 800 grit sand paper. Wing covering will be SLC and the fuse,flaps and tail silkspan. Power is by ENYA SS30S. I have used polyspan to cover a whole ARF Nobler before,It came out very nice.Here are pics.
                                                                                        Juan

[James C. Johnson]

Juan... I use silkspan on my wing tips and poly span on the panels.. I find it easier to do..

2" wheels are usually big enough and look right.. back when the Dubro Slicks came out we put 2.5" ones on Ringmasters so we could do touch and gos...

I was just looking at the Dolphin plans.. I went with a 1/4" elevator vs the 3/16ths one with brace shown on the plans... if you get it to come in at 40oz you will really be happy with the way this plane flies... I like it as much as my Oriental.. I have plans to build a Dolphin in the 600 sq/in range possibly using The Allen Brickhaus Privateer as a foundation to steal ideas... it's a constant chord design.. the 30ss should be great.. and at 40 oz a Fox 35 would do well... IMO the Fox really likes 35-38 oz planes... I have read about stunters in the 48-50 oz range back in the day flying with a Fox 35 and I still wonder how they did it..

Jim

[MarcusCordeiro]

Juan

NICE!!!

Marcus

[Avaiojet]

Really nice!