Sig Kadet ARF restoration

[speedbirdted]

Fuselage covered. Now I just need to do the wing and tail pattern and the covering will be over with.

I ended up making the scallop pattern differently than I had planned out in the concept drawing above. I did a trial fit of them with the longer and thinner pattern and didn't like it as much as I thought I would, so I made them much shorter and blunter and also increased the thickness of the stripe quite a bit too.

I feared the covering would not stick to the firewall because I coated it in resin, but it does just fine. This is tempting me to try and cover the cowling with the left over covering which would eliminate the potential color matching problems. I can't do this with the gear though because it has metal components, and if I need to paint it I might as well also do it to the cowl...

Speaking of fiberglass stuff: the wheel pants, at least the current design, aren't gonna work. I'm not sure if I measured the width of my wheels wrong or underestimated the width of the glass cloth layup, but the end result is the same. They don't fit! looks like I need to design some new ones. Good thing I only made one of the current design...

 

[cyclone3350]

Thanks for sharing your glass mold for the cowling. I have used foam before to glass parts and then solvent the foam away. I was looking for ideas on making a mold from a plug. I think will give this one a try.

 

[TooJung2Die]

Fuselage covered. Now I just need to do the wing and tail pattern and the covering will be over with.

I like it! 😎👍

 

[speedbirdted]

Thanks for sharing your glass mold for the cowling. I have used foam before to glass parts and then solvent the foam away. I was looking for ideas on making a mold from a plug. I think will give this one a try.

I used to do it that way too but I now prefer the method I outlined. I thought it would be more work, but honestly I find it to be less because so much less surface prep on the finished part is required. Plus, the layup adhesion is leaps and bounds better, and you have the tooling to make a new part at hand if some destructive event happens to the one you already have made.

I'm honestly a little tempted at this point to try and make an entire aircraft out of fiberglass. Maybe to build some hypermodern pipedream design ideas I have occasionally that are totally incompatible with balsa...

Covering is done. It's my usual 10-foot covering job - that is, it looks great as long as you stand 10 feet away I actually used almost an entire 5 meter roll of each color; I guess buying two of each was good thinking.

And now I'm running into an expected problem, namely, how the hell do you spray latex???? Having never worked with it before this in any capacity, I didn't anticipate how thick it would be. I didn't even bother trying it in the spray gun, I knew it wouldn't work unthinned. The consensus online seems to be to use this stuff called Floetrol but it seems to be locally unobtainium so I'm searching for a substitute. I wonder if just water would work? Or if it would screw up the paint in some way...

I'm also thinking about how I fuel proof the parts. I'm not sure if Polycrilic can be sprayed, but it's worth a try I guess. Brushed on epoxy resin would look awful so I'm not even gonna bother with that. I was also thinking of using Rustoleum clear coat...

 

[TooJung2Die]

There are two thinners for water based paints I use from the grocery store; Windex because it dries fast, and Pledge gloss floor finish because it's acrylic and it dries glossy. And there's always water.

The thing I found about airbrushing any paint is when I think I have it thin enough it's still too thick. Too thick and it doesn't atomize well and sprays tiny globs. When I finally get the paint thin enough to spray smooth the pigment is very thin so it takes many coats to get an opaque finish.

If you want a clear gloss acrylic finish you can use the Pledge floor finish straight from the bottle.

 

[cyclone3350]

First off, I want to say, you did a fantastic job restoring one of my favorite Sig planes. What a great choice in colors. I totally agree with U on having to re do another external mold for a replacement part. Up until now, I have been vacuum forming my cowls and then fiber glassing the polystyrene plastic.( A Comet 54" Taylorcraft rehab photos) Great for reproducing, but too many steps to get the the finished product. Interesting that U mentioned doing an entire plane in fiberglass. That is my next idea for doing my latest project. https://forum.flitetest.com/index.p...hallenge-martin-xp6m-1-seamaster.67231/page-2. I am seriously considering doing the entire project from plug molds. I first got the idea from a video from Total Boat, but their mold making process seems to be very time consuming. Still sold on the idea, but I think your method looks to be much less in time. When I paint, I paint exclusively with latex. I will do a short reply on some of what I do to spray when I return.

 

[cyclone3350]

For latex, I have been using Behr Ultra Premium Enamel from Home Depot. This is an indoor/outdoor paint and so far, holds up very well to the elements for RC flying. Long sits in direct sunlight and an occasional surprise rain. As far as being chemical resistant, it is not. I do nothing but electric and this is not a problem for me. We do have a club member that is "MR, this should be an article in the Model Airplane News" type of builder. He uses gas and is strictly large scale. He is the one that steered me towards Behr. He finishes his models with a two part Auto clear coat. He then wet sands it down starting with 1200 grit and moving it up to a 2000 grit before finishing it with a three step down 3M rubbing compound. Not something I have the patience for. I will be experimenting with Klass Kote Epoxy clear over latex in the future. At least with Klass Kote, there isn't really a need to buff finish it. For spraying, I use an auto touch up sprayer and thin with a home made reducer. It is equal parts of distilled water, Armor All clear auto glass detailer/cleaner and denatured alcohol. I also add about ten drops of glycerin per quart to keep the paint flowing in the mid-west dry climate. Most latex sprayers I know, use blue windshield washer fluid and that seems to work for them as well. I sometimes spray Polycrilic over the latex for a gloss to semi gloss effect. Cassutt Racer is satin and the pattern plane is semi gloss. The Pup is Behr without a topcoat. BTW, I just by the three dollar sample size and they can color match just about any color one wants.

 

[speedbirdted]

What size needle and orifice do you use in the gun? I tried spraying some today and I needed to use tons of thinner to even get it to come out of the gun and at that point it was so watery that even really light coats were runny as all hell. I think the problem is down to me using a 1mm orifice. A lot of guys seem to say that's too small to do it with.

 

[cyclone3350]

What size needle and orifice do you use in the gun? I tried spraying some today and I needed to use tons of thinner to even get it to come out of the gun and at that point it was so watery that even really light coats were runny as all hell. I think the problem is down to me using a 1mm orifice. A lot of guys seem to say that's too small to do it with.

What R U using for thinner? Auto windshield washer seems to be the preferred choice. Yeah it is blue, but it doesn't affect the color of paint. I make my own thinner using equal parts of Denatured alcohol, distilled water, auto detailers glass cleaner ( Clear Armor All ) and 10 - 15 drops of glycerin per quart. The glycerin can found in CVS or Walgreens and this will help with the flow. I thin the paint down to a consistency of milk or coffee creamer and spray for large areas with a auto touch up gun. For my Paasche VL, I used the medium size needle and a little more thinner. There will be some clogging. I run some of that home made stuff through the gun every so often or @ the first hint of clogging.

 

[TooJung2Die]

What size needle and orifice do you use in the gun? I tried spraying some today and I needed to use tons of thinner to even get it to come out of the gun and at that point it was so watery that even really light coats were runny as all hell. I think the problem is down to me using a 1mm orifice. A lot of guys seem to say that's too small to do it with.

1mm is too small. Use at least a 1.4 and most people go even larger for thinned latex.

 

[kilroy07]

I've been chipping away at the glass bits, when I get time. Today I did major work on the cowl molds.
<Snip>

I really like this, well done!
Curious if this is a one off, or if the mold can be reused?
Wasn't sure if the demolding process destroys the Hydrocal (I've played with it myself and you're right, MUCH stronger than Plaster of Paris.)
I would think the plug might just pop right out, so maybe it is good to use again.

A quick thanks for taking the time to document, LOTs of great tricks/tips!

 

[cyclone3350]

I really like this, well done!
Curious if this is a one off, or if the mold can be reused?
Wasn't sure if the demolding process destroys the Hydrocal (I've played with it myself and you're right, MUCH stronger than Plaster of Paris.)
I would think the plug might just pop right out, so maybe it is good to use again.

A quick thanks for taking the time to document, LOTs of great tricks/tips!

I second that thought. Hope U can post some pics. Curios to see how U finished off and painted the cowl. Did U get to the wheel pants?

 

[Turbojoe]

I take it this is a Kadet Sr.? Can't really tell the size from the pix. If so you and Joker are making some awesome posts on this bird. I especially like the posts about 'glassing. I've made several plugs from kit cowls, windows etc using what we used to call "pour stone" I forget what it's called these days. I built a very nice vacuum former box but have had only about a 50% success rate. I never seem to get the temp and droop of the plastic quite right and it sometimes ends in failure. I don't even try any more as the plastic sheet isn't cheap enough to be wasting like that. I need to start learning to fiberglass parts as I'd like to make a cowl and wheel pants for my Sr. for when I get around to building it. I plan to use (steal ) every good idea that you and Joker post in your threads. Good stuff guys! Keep it up please.

I've been in this hobby for decades but I never fail to find new and useful info on a daily basis.

Joe

 

[cyclone3350]

I take it this is a Kadet Sr.? Can't really tell the size from the pix. If so you and Joker are making some awesome posts on this bird. I especially like the posts about 'glassing. I've made several plugs from kit cowls, windows etc using what we used to call "pour stone" I forget what it's called these days. I built a very nice vacuum former box but have had only about a 50% success rate. I never seem to get the temp and droop of the plastic quite right and it sometimes ends in failure. I don't even try any more as the plastic sheet isn't cheap enough to be wasting like that. I need to start learning to fiberglass parts as I'd like to make a cowl and wheel pants for my Sr. for when I get around to building it. I plan to use (steal ) every good idea that you and Joker post in your threads. Good stuff guys! Keep it up please.

I've been in this hobby for decades but I never fail to find new and useful info on a daily basis.

Joe

I am with U. I did the same with a vacuum former. I am up to about 70% success after starting out @ 40. I was buying the sheets in 8' X 4" size. Very cumbersome to cut to size.

 

[speedbirdted]

What R U using for thinner? Auto windshield washer seems to be the preferred choice. Yeah it is blue, but it doesn't affect the color of paint. I make my own thinner using equal parts of Denatured alcohol, distilled water, auto detailers glass cleaner ( Clear Armor All ) and 10 - 15 drops of glycerin per quart. The glycerin can found in CVS or Walgreens and this will help with the flow. I thin the paint down to a consistency of milk or coffee creamer and spray for large areas with a auto touch up gun. For my Paasche VL, I used the medium size needle and a little more thinner. There will be some clogging. I run some of that home made stuff through the gun every so often or @ the first hint of clogging.

I was in a pinch so I just used distilled water. I'm guessing that was part of the issue because the paint didn't want to seem to atomize very well, though I'm not sure if this is down more to the needle size I was using or the thinner. Either way I'll mix up some of the formula you use before I try again.

No paint is on the cowl yet. All it has at the moment is a coat of primer and that was to expose areas that needed a little more sanding work. For now I'm not going to bother with the wheel pants. I will at some point but apparently my measurements were in error when I made the plug as I made one pant and then found that it was too narrow and didn't fit.

I really like this, well done!
Curious if this is a one off, or if the mold can be reused?
Wasn't sure if the demolding process destroys the Hydrocal (I've played with it myself and you're right, MUCH stronger than Plaster of Paris.)
I would think the plug might just pop right out, so maybe it is good to use again.

A quick thanks for taking the time to document, LOTs of great tricks/tips!

With Ultracal the molds will survive many, many pulls before there's any risk of them breaking on you. With Plaster of Paris they would only last two or three. If you just brute force it and pull the part out, they probably won't survive very long, but I prefer to get them out by blowing 100psi air in between the part and mold, and it will almost instantly pop it out with minimal stresses to either part. All I needed to do to get the molds of this ready to form another part was just wash the wax off the inside of them, and chip off the little bits of overrun polyester that got on the sides.

The only thing I don't like about it is it's a little expensive. A 10 lb bag of it (which you go through fast, making the molds for this and the Cub used about 90% of it) is 30 bucks. I'm thinking what I might do next is cover whatever plug I make in vacuum bagged glass cloth on the outside and then use that as a mold to bag the inside, though it would need a very heavy coat of release wax to prevent the whole thing just becoming one useless chunk of glass cloth and resin.

I take it this is a Kadet Sr.? Can't really tell the size from the pix. If so you and Joker are making some awesome posts on this bird. I especially like the posts about 'glassing. I've made several plugs from kit cowls, windows etc using what we used to call "pour stone" I forget what it's called these days. I built a very nice vacuum former box but have had only about a 50% success rate. I never seem to get the temp and droop of the plastic quite right and it sometimes ends in failure. I don't even try any more as the plastic sheet isn't cheap enough to be wasting like that. I need to start learning to fiberglass parts as I'd like to make a cowl and wheel pants for my Sr. for when I get around to building it. I plan to use (steal ) every good idea that you and Joker post in your threads. Good stuff guys! Keep it up please.

I've been in this hobby for decades but I never fail to find new and useful info on a daily basis.

Joe

Yeah this is a Senior. The difference though is his is the kit version while mine is the ARF version. There are many differences between the two. I personally prefer the kit version, as it tends to come out lighter. The ARF has almost the entire forward fuselage built from ply which is really not necessary.

I built a vacuum forming table many moons ago. I used it up until it was broken by movers. My strategy for getting the droop right is I built a wooden rack that went in my oven, with a bar running across the frame below where the plastic was suspended. Once the plastic drooped enough to touch this bar I would remove the top portion of the rack from the bottom portion which had the bar on it, turn on the shop vac that supplied the vacuum and then put the top portion on the actual table itself. I used pegboard with automotive sealing tape and I never had any problems with excessive leakage.

I used to use it to make cowls out of ABS but upon realizing that fiberglass is far superior I seldom used it after that except for windshields. I might actually revisit using it to make female molds for vacuum bagging out of ABS but they'd need considerable reinforcement to survive in the vacuum bag and still produce a usable part.

 

[Flightspeed]

Some of y’all spend so much time working on airplanes🤣 I just like to fly them, y’all’s looks so good😂

 

[Turbojoe]

Yeah this is a Senior. The difference though is his is the kit version while mine is the ARF version. There are many differences between the two. I personally prefer the kit version, as it tends to come out lighter. The ARF has almost the entire forward fuselage built from ply which is really not necessary.

I built a vacuum forming table many moons ago. I used it up until it was broken by movers. My strategy for getting the droop right is I built a wooden rack that went in my oven, with a bar running across the frame below where the plastic was suspended. Once the plastic drooped enough to touch this bar I would remove the top portion of the rack from the bottom portion which had the bar on it, turn on the shop vac that supplied the vacuum and then put the top portion on the actual table itself. I used pegboard with automotive sealing tape and I never had any problems with excessive leakage.

I used to use it to make cowls out of ABS but upon realizing that fiberglass is far superior I seldom used it after that except for windshields. I might actually revisit using it to make female molds for vacuum bagging out of ABS but they'd need considerable reinforcement to survive in the vacuum bag and still produce a usable part.

I figured it was a Senior. Mine is a kit version. I do intend to add ailerons and bolt on wing. Might even entertain the thought of an opening door to facilitate battery changes. I have a ton of CF that I could use around the door area to maintain strength in that area. I've checked and FG cowls for the Senior run from $30-$45 PLUS shipping! I may take the time to make my own from FG. I have a bunch of it in various weights. I don't have any epoxy resin though. What is the most affordable resin out there?

Joe

 

[cyclone3350]

I was in a pinch so I just used distilled water. I'm guessing that was part of the issue because the paint didn't want to seem to atomize very well, though I'm not sure if this is down more to the needle size I was using or the thinner. Either way I'll mix up some of the formula you use before I try again.

No paint is on the cowl yet. All it has at the moment is a coat of primer and that was to expose areas that needed a little more sanding work. For now I'm not going to bother with the wheel pants. I will at some point but apparently my measurements were in error when I made the plug as I made one pant and then found that it was too narrow and didn't fit.



With Ultracal the molds will survive many, many pulls before there's any risk of them breaking on you. With Plaster of Paris they would only last two or three. If you just brute force it and pull the part out, they probably won't survive very long, but I prefer to get them out by blowing 100psi air in between the part and mold, and it will almost instantly pop it out with minimal stresses to either part. All I needed to do to get the molds of this ready to form another part was just wash the wax off the inside of them, and chip off the little bits of overrun polyester that got on the sides.

The only thing I don't like about it is it's a little expensive. A 10 lb bag of it (which you go through fast, making the molds for this and the Cub used about 90% of it) is 30 bucks. I'm thinking what I might do next is cover whatever plug I make in vacuum bagged glass cloth on the outside and then use that as a mold to bag the inside, though it would need a very heavy coat of release wax to prevent the whole thing just becoming one useless chunk of glass cloth and resin.



Yeah this is a Senior. The difference though is his is the kit version while mine is the ARF version. There are many differences between the two. I personally prefer the kit version, as it tends to come out lighter. The ARF has almost the entire forward fuselage built from ply which is really not necessary.

I built a vacuum forming table many moons ago. I used it up until it was broken by movers. My strategy for getting the droop right is I built a wooden rack that went in my oven, with a bar running across the frame below where the plastic was suspended. Once the plastic drooped enough to touch this bar I would remove the top portion of the rack from the bottom portion which had the bar on it, turn on the shop vac that supplied the vacuum and then put the top portion on the actual table itself. I used pegboard with automotive sealing tape and I never had any problems with excessive leakage.

I used to use it to make cowls out of ABS but upon realizing that fiberglass is far superior I seldom used it after that except for windshields. I might actually revisit using it to make female molds for vacuum bagging out of ABS but they'd need considerable reinforcement to survive in the vacuum bag and still produce a usable part.

That is exactly how I did my vacuum forming. Right down to the wooden rack. Yes droop is the secret to a good outcome. I would eyeball it. I like how U had a marker for the right droop. I never thought of that. much more consistent that way. I will do that next time.

 

[speedbirdted]

I figured it was a Senior. Mine is a kit version. I do intend to add ailerons and bolt on wing. Might even entertain the thought of an opening door to facilitate battery changes. I have a ton of CF that I could use around the door area to maintain strength in that area. I've checked and FG cowls for the Senior run from $30-$45 PLUS shipping! I may take the time to make my own from FG. I have a bunch of it in various weights. I don't have any epoxy resin though. What is the most affordable resin out there?

Joe

I have always used the Sig polyester resin. I bought a 32 oz container of it for about $30 and I've built 5 cowls with it to date and have barely used a quarter of it. It smells pretty rank when it's curing, so you have to use a well ventilated area or do it outside. Respiratory PPE is a must in either case. I dislike doing it outside however as it does not cure well if the temperature drops below about 60 degrees or if it's too humid.

 

[speedbirdted]

Today was the first day in a while that I had actual time to work on airplanes (!) I tried @cyclone3350's formula for thinner and it works very well! I think the glycerin and larger needle is what makes it really work, as I added some glycerin to just washer fluid and it worked almost as well. The coats still come out very light and many are required but they're much less splattery and don't just run off like water. Unfortunately now that I have the gun set up to spray the paint nicely I found that the color matching was done rather poorly. It's not close enough that I'd be happy with it. Oh well, time to run back to the store and see if I can get something that fits a bit better. I think the fact that the scraps of covering I brought them were shiny might have messed with the machine so perhaps I'll go over them with fine sandpaper to dull them down.

However... just because I could I also covered a bit of scrap fiberglass with the Chinakote I used on the airframe just to see if it would be a viable alternative to paint. Usually film type materials don't work well on fiberglass because air bubbles pop up like nobody's business but somehow this material is immune to them, just like how I was able to iron the material onto itself to do the patterns on the fuse and wing. The adhesive also works incredibly well on it - it pretty much welds itself to the surface. It's more difficult to peel off fiberglass than wood!

Naturally that's the route I ended up deciding to take. Not only would the color be a guaranteed match but it would also match the shine perfectly too. If only I knew this route was right under my nose for months maybe I'd have this done a lot quicker...

I wish I still had the Saito stickers that this engine came with. They'd look quite nice slapped onto the cowl.

Unfortunately the drawback of using a film covering on fiberglass is the seams are very difficult to hide away. I tried to put them more towards the bottom of the cowl, more shielded away from prying eyes. I actually did the entire base color on the cowl with two pieces. One which covers about 75% on the top and the other just on the bottom. The engine cutout helps immensely with this as you can cut the covering right there and shrink it up on the little bit at the front so it conforms nicely with minimal additional pulling or wrinkles. One day I'll figure out a way to do it with one piece...

Unfortunately I do not have enough yellow covering left to do the gear with and plus that has metal components anyway so it's better to just paint it instead. Same with the struts.

On another front I got all the CG fiddling out of the way today. It required 6 ounces of nose weight to balance, plus mounting the battery to the back of the firewall. I expected this airplane to need nose weight anyway as the engine is very lightweight for its displacement. Total weight I couldn't check because it was over the 8 pounds that my scale is capable of measuring.

Engine was also fired up today to check if the fuel system worked, which it does just fine. I thought maybe the relatively low position of the tank would cause issues but if anything it just prevents the engine from flooding out which is nice. I forgot how nicely this engine runs. It sounds like a sewing machine at idle, it's just so quiet. To get it started all you have to do is grab the spinner and flick it backwards to bounce it off compression and it fires up every time.

Initially however totally forgot to put a piece of fuel tube on the breather nipple which resulted in a nice river of oil on the bottom of the fuselage after a few minutes of running. I wonder if I put a seperate tank just for oil in the fuselage if I could reuse it?