PolyFiber minimums

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KWK

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The PolyFiber book mentions 3 PolyTone colors can be used without PolySpray beneath, just a single layer of PolyBrush. All 3 are metallic, one blue and two silver. Are these difficult to spray evenly? I wrote to PolyFiber but they are mum.

I also wonder how it would end up with no PolySpray to sand smooth, but the book mentions PolyBrush can be smoothed with an iron.

One PolyBrush, smooth with iron, 3 PolyTone layers, done. Sounds like a savings in time, effort, money, and weight. There must be a catch (which is why I'm buying their Practice Kit).
 

Turd Ferguson

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I don't think you'll be happy putting paint, or polytone over brushed on polybrush.

You can reduce polybrush and spray it. It comes out smooth - no bumps to show through the finish.
 

TFF

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Normally it’s 3,3, and 3. First coat of poly brush by brush then two sprayed. Then others sprayed. If you try to brush the stuff with any below, it leaves brush marks. First coat brushed is to get the stuff to wrap around the threads to lock it on.
 

Dan Thomas

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Normally it’s 3,3, and 3. First coat of poly brush by brush then two sprayed. Then others sprayed. If you try to brush the stuff with any below, it leaves brush marks. First coat brushed is to get the stuff to wrap around the threads to lock it on.
Yup. One brushed coat isn't nearly enough buildup.
 

TFF

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Most of this paint is solvent. Not necessarily hard to paint but it is not modern car paint. It’s easier than dope, but more dope like which is a version of lacquer.
 

Jim Chuk

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I don't think you will have much success smoothing the polybrush with an iron. The polybrush will melt and stick to the iron. Then you will have a real mess. If you are trying to save weight and $, you can use less poly spray, especially on the underside of the wings and fuselage. Also, use polyspray for part of the final coat. I had a Kitfox 1 that was mostly gray color. That was poly spray and still looked ok at 30 years of age. I used the same thing on my latest Kitfox 4. All the gray color is poly spray. JImChuk
 

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Dan Thomas

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The brushed-on Poly Brush smooths out when the next coat is sprayed onto it. Each succeeding coat melts into and fuses with the one below it.
 

KWK

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I don't think you will have much success smoothing the polybrush with an iron. The polybrush will melt and stick to the iron.
It's a technique given in the PolyFiber manual, and they list the temperature range to use. I'll give it a try with the Practice Kit. If it sticks, it should come off with MEK, of course.
 

TFF

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Little corners of pinking can be melted down. An RC trim iron is perfect for the job. You cannot run an iron over the surface like one did shrinking. Spot only. More like point only.
 

KWK

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Thanks. The manual wasn't clear which to use. They did talk about ironing out runs and the like, so that would imply the small iron.

In addition to the Practice Kit I'm buying, a friend at my EAA chapter has loaned me an old Sonerai rudder to practice on.
 
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TFF

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I’m reposting this here. I had it in another thread. This is what a show plane builder uses to cover homebuilts.
Lifted from the biplane forum from smizo


“3M 30-NF Adhesive to glue fabric to airframe basically following stewarts system instructions with a few other little tricks.

Weave sealed with straight 30-NF rolled on open areas using a 6" foam paint roller. wipe off excess using blue shop towels.

PPG Delfleet Evolution Primer F3970 mixed 3:1 with F3971 Hardener and then 1/2 part F3331 Reducer and 1 part DX814 Flex Agent.

Top coat with Sherwin Williams Acryglo base clear system.”
 

Jim Chuk

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You can use an iron on the poly brush in certain ways, and I'll tell one that I use. I have some clear plastic, it's probably about 1/64" thick, maybe even thinner. I have about 6" wide strips of it about 24" long. I will lay it over the finish tape, that has been coated with plenty of polybrush, and iron down the pinked edges and melt them into the poly brush. While the poly brush is still hot, it will stick to the plastic and lift up and be a real mess if you try to pull it off. But I have 3 or 4 pieces of plastic handy, and by the time I iron down the last piece, the first one is cool and pops right off. At that point, you can see shinny areas where the poly brush melted, but when you spray on the next coats, that dissapears, and now the pinked edges of the finish tape stay in place. And getting poly brush off an iron is not an easy process. MEK or not. JImChuk
 

KWK

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Hmmm, I had the impression everything in the PolyFiber process dissolved in MEK. Good to learn it's not so, before getting in to trouble.
 

Jim Chuk

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The problem with the poly brush stuck to the iron is it gets burned on and then the MEK doesn't want to dissolve it. JImChuk
 

don january

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I'am right in the mix of covering a plane with the Poly fiber process and found quickly not to be to impressed with your first pass of P-brush just concentrate on soaking the fabric to the core. Sanding is a maybe if you let dry for a very long time. Once a few coats are added by spray or brush let next step Poly-spray be your sanding base and if your fabric is still there from sanding your a$$ off then toner or paint of choice is in the near future.:)
 

KWK

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... poly brush stuck to the iron... gets burned on...
At about what temperature should I worry about burning on? For the flattening process, they recommend 200 to 225 F.
 

Dan Thomas

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If you take a closer look at the roll of picked tape, you see that the pinks get bent outward toward the outside of the roll. That's from the tightness of the rolling, and setting the roll on its end also seems to bend them outward. Now, if you lay that tape down on the fabric the same way you would use a tape dispenser and packaging tape, the pinks are already wanting to stand up. Turn the roll over and lay the tape down that way, as if you were unrolling carpet on a floor. Pinks are bent down and will stay down.

The other secret is to do it exactly as the book tells you. Paint a strip of Poly Brush along the place the tape will lay and let it set. Then lay down the tape and brush Poly Brush through it. It will dissolve the previous layer and that alone will absorb much of the solvent and stiffen the Poly Brush immediately, making it less likely that pinks will stand up.

I never had to iron pinks down. Follow that manual.
 
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One method of dealing with PolyBrush sticking to the iron when blending the edges of pinked tape, is to use a layer of Teflon coated fiberglass cloth between the iron and the Polybrush. Iron the pinked tape down with the Teflon tape between it and the iron, wait for the polybrush to cool then lift the Teflon tape off. I find a model Airplane Monocoat iron best for this.
 

PTAirco

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Hmmm, I had the impression everything in the PolyFiber process dissolved in MEK. Good to learn it's not so, before getting in to trouble.
It does dissolve with MEK. Every Polyfiber product does. Right down to nothing. Read the manual. Six times.
 
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