I tried to insulate some lines by "painting" them with a couple of coats of water based Minwax Polycrylic varnish. This was a complete failure: the lines had shorts on the reel. So I need to either learn how to do this right, or how to buy properly insulated lines and perhaps suffer a drag penalty. I hope people can share their knowledge of insulated lines for this thread. In particular, perhaps John Vlna, who has been using lines insulated with water-based polyurethane, can detail the brands of products and the details of how he did it for those of us who need to learn. And Fred Cronenwett has a lot of knowledge on buying insulated lines that would be valuable if we could collect it here. And perhaps there are some others who can contribute what they learned about insulated lines.

Pete

Thanks, John. Maybe Clancy will join in.  But the questions I had in mind remain: What brand, type, color, gloss, etc.  of polyurethane did you use? Did you apply it with a foam brush? Did you just pinch a soaked foam brush around the line and run to the end or did you carefully paint each side of the line? The details of technique may be important, and these details could determine the uniformity with which the material is deposited. I tried a couple of techniques using foam brushes and ended up with excess material in places (droplets on the line) after the first coat. The second coat went on smoothly but maybe to thin.
Pete

Making insulated  Lines

Here is my procedure. After making the lines I string them up on miniature telephone poles. I use denatured alcohol to clean them. I use water based polyurethane, although I have used the regular ‘oil’ based stuff. The two brands I have used are McCloskey (water) and Minwax (oil), both are clear,  no special reason they are just what I had on the shelve.

 I then take a saturated cloth (wear rubber gloves here) and wipe the lines down. I use the cloth quite wet, and watch for droplets. The water based polyurethane dries fast so droplets aren't as much of a problem as with oil based polyurethane. I use two coats, appling the second after the first has thoroughly died. So far the lines seem to hold up well. The only problem set were ones that I neglected to clean

Pete,
I agree on the spraying , I just think it would be to hard to get enough paint on the lines.

Hope the info helps. I am planning some comparisons to the nylon coated and self made lines to see how high speed is effected, I don't think it matters much on slow speed. You saw how well my MO-1 flew slow speed at the NATS and that was with nylon coated lines. High speed was not good, but I only had a 4s battery, since then I have gone to 5s and hi has improved a lot.

john

On my scale models I only use one insulated line; the ground line is bare. Only half the drag penalty. Works for me, but apparently not for everybody. Difference is drag is easily observed, even at scale model speeds approximately half of what carrier planes achieve. I use the insulted line on the up elevator and rig my handle to give about 1/8" down elevator when held at neutral. I use the Surflon from Jans that Fred mentioned.
Chuck

I have used several weight lines depending upon the weight of type of model

Surflon has several weight lines available

Line Weight (Surflon)            wire diameter without nylon coating
20 lb                                                   ??
30 lb                                                 .013
45 lb                                                   ??
60 lb                                                 .019
90 lb                                                 .022
135 lb                                               .025

In general I use these weight lines for the following size of model

30 lb - for models in the 3-5 lbs range

60 lb - for models in the 5 - 12 lb range
          however for competition rules may require thicker lines for the heavier models, so read the rules so you know

90 lb - I only use this if the rules require that diameter of line

135 lb - I have only used this once for a 18 lb, 1/4 scale morrisey Bravo with a four stroke 90 for power

All of my models either fly with the 30 lb or 60 lb test line since all of them weight between 3.5 to 7 lbs each. The Camera plane (80" span) weighs in at 11.5 lbs and still flew it 60 lb test line. If that model was a CL scale model it probably would have flown with 90 lb test line to meet the minimum wire diameter requirements. If CL scale rules require a larger diamter I would pick the correct weight line to match the wire diameter. The rules regarding line length and diameter has changed in the last few years.

Fred C.

CL scale requires these wire diameters wire for competition

Model weight             line length             diameter (braided, 2 lines)        Surflon wire
0 - 1.5 lbs                 35 - 70 feet                .012                                 30 lb test
1.51 - 2.50 lbs           54.5 - 70 feet              .012                                 30 lb test
2.51 -4.00 lbs            54.5 - 70 feet              .012                                 30 lb test
4.01 - 8.00 lbs           54.5 - 70 feet              .018                                 60 lb test
8.01 -12.00 lbs           65 - 70 feet                .021                                 90 lb test
12.01 - 16.00 lbs        65 - 70 feet                .024                                 135 lb test
16.01 - 20.00 lbs        65 - 70 feet                .027                                     ??
 
The rules also specify that models shall fly less than 60 mph which is usually not a problem for CL scale models.

Fred Cronenwett

The list of wire AMA requirements and surflon lb test is for reference only....

We care about the actual wire diameter of the nylon coated line, so the million dollar question is what surflon line do I need to buy to meet the requirement for a .012 wire for a model that weighs less than 4 lbs. I not suggesting that we add the Surflon brand name and lb test to the official rules. After measuring the 30 lb test line, it measured at .013 which makes it legal for models less than 4 lbs and will meet all the rules.

This is just a way quickly figure out what lb test line to buy to meet the wire diameter requirement for competition.

I have an old roll of Surflon 140 lb test line and it's slightly different wire diameter than the current 135 lb line. I have no idea how they come up with the lb test rating, and we probably don't care or need to know. I think that each manufacturer will probably have a similar product and call it different names, and the wire diameter will vary.

All I really care is what is the wire diameter and this chart allows folks to quickly determine what surflon line to purchase to meet the requirement in the AMA rule book.

The reason for the face and question marks on the 16-20 lb model weight range is that Surflon currently does not have nylon coated line that will meet the AMA line requirements.

Fred

FWIW .. In addition to Mike Stott and myself, Bill Harney, Ralph Burnstine, Jeff Perez, Dale Campbell, Dick Byron, Australia Graves, Ed Rhoads, and just about everyone who used a digital system in the 70s and 80s bought their lines from Netcraft in Toledo.