Just wanted to see what people have been using successfully.
Currently I'm into the Superflite system, but their varnish seems a bit pricey, especially the reducer?
I wanted to ask a few questions:
The superflite manual seems to suggest that I have to re-varnish the whole structure when I redo my fabric. I can't just remove the old stuff, see that varnish still exists, and recover it. True, false?
What kinds of varnish does everyone use here? The cost of the 2 part + reducer from superflite is a little steep and I'm curious if there are any viable alternatives. I've already seen thinned epoxy suggested, but I think I'm leaning towards varnish because thats what the manual wants. At the end of the day, the price of 150 for a gal of reducer and a quart of each part of the varnish isn't the end of the world, but how much varnish does it take to cover an airplane??
Which leads me to my next question. How much varnish does it take to do a whole max?
What kinds of brands and models of 2 part varnish have people been using with success that don't break the bank? The superflite isn't that bad but I'm curious if I can get more for less that also works, so to speak. I'll just buy superflite if that's the ideal outcome, to be honest.
When I varnished my Max I used regular polyurethane varnish (Minwax as I recall) for two coats and a third coat of Polyfiber epoxy varnish in the areas that I thought needed protection from the Polyfiber glue. I did not apply any varnish to the leading edge (where the glue is applied) nor did I apply varnish to the rib cap because I wanted to have a direct bond to the wood. The glue from the Polyfiber system and further coatings will protect the wood from moisture and there have been no problems.
Interesting. So I'm not supposed to varnish where the fabric cement attaches? Or I guess I am? The manual seems to suggest that I should, but your idea of using cheaper varnish for non glue areas is very very clever! I may do that!
Interesting. So I'm not supposed to varnish where the fabric cement attaches? Or I guess I am? The manual seems to suggest that I should, but your idea of using cheaper varnish for non glue areas is very very clever! I may do that!
Use the expensive varnish, epoxy or whatever that will resist the solvents in the fabric glue, on areas where you glue the fabric down. Use hardware store varnish everywhere else like the interior of the cockpit, interior fuselage ply, etc.
Had you gone with Ekobond or 3M Fastbond for your fabric cement and latex paint you could have gone hardware store, waterbased even, varnish only. Since you're using a solvent based, expensive system, you're kind of stuck using expensive chemical resistant varnish, at least where you'll be putting more solvent over top of it. I like getting my thinner out of the kitchen tap for a penny a gallon.
Way back in yesteryear the original TEAM organization put out a series of tapes.One of them was on covering and it was helpful but the lack of protective gear used would be cause for pause.
Does anyone have a clear idea on if you need to put new varnish over the airplane when you remove the fabric that was previously on varnish? I'm assuming my plane already has varnish on it as it was done with the polyfiber system. When I remove my old fabric, can I just start working, or do I need to paint new 2 part varnish on first?
Good or bad, building my MiniMAX I used marine, exterior spar varnish. I did a thinned coat with the thought it would soak into the wood a little better than "full strength", and then a second coat straight out of the can. I was building very weight conscious so I really brushed it out rather than slathering it on. Since I didn't expect it would hold up to the MEK in PolyTac, I used Stewart System (3M Fastbond) water based (or is it water borne?) adhesive and followed with latex primer and paint.
The only reason I'd think you'd need to re-varnish after removing fabric to re-cover would be if you used a strong solvent (MEK?) to help loosen the fabric and compromised the varnish in the process.
Had you gone with Ekobond or 3M Fastbond for your fabric cement and latex paint you could have gone hardware store, waterbased even, varnish only. Since you're using a solvent based, expensive system, you're kind of stuck using expensive chemical resistant varnish, at least where you'll be putting more solvent over top of it. I like getting my thinner out of the kitchen tap for a penny a gallon.
Ekobond is $216.95/Gallon, 3M Fastbond is $129.00/Gallon, and one quart of SUPERFLITE U500 FABRIC ADHESIVE is $25.50 (yielding 3/4 of a gallon when cut 2:1 with acetone as directed). So Superflite System 7 is hardly the... "expensive system". Acetone and denatured alcohol are both about $10.00 a gallon in my neck of the woods. Hardly what anyone would consider expensive.
So Superflite System 7 is hardly the... "expensive system".
From the Superflight FAQ page: How much can I expect to spend on Superflite covering materials for my plane? Depending on the color of paint that you choose, for a Cub-sized airplane, you can expect to spend anywhere from $4000-$4500. That includes everything you need from fabric to finish.
When I covered my Airbike in 1997 I used the Superflight System. Only had to cover wings and tail. Total cost was about $1200 as I recall.
I covered the Eindecker in 2015 using Fastbond and latex paint. Total cost about $400. (I went back and checked my expense record. Total cost of covering was $300. The cost of the vinyl markings was $160, bringing the total cost up to about $460.)
Ekobond is $216.95/Gallon, 3M Fastbond is $129.00/Gallon, and one quart of SUPERFLITE U500 FABRIC ADHESIVE is $25.50 (yielding 3/4 of a gallon when cut 2:1 with acetone as directed). So Superflite System 7 is hardly the... "expensive system". Acetone and denatured alcohol are both about $10.00 a gallon in my neck of the woods. Hardly what anyone would consider expensive.
technically, if you didnt already have the supplies, youd want to add in the cost of proper PPE for using the superflite stuff. also, the extra cost of the solvent resistant varnish may also sway the cost. id be willing to bet that its about even, after you figure all that in.
i have not yet covered an airplane so take that with a grain of salt. i do, however, intend do use the fastbond glue on my projects. already bought a quart of it!
From the Superflight FAQ page: How much can I expect to spend on Superflite covering materials for my plane? Depending on the color of paint that you choose, for a Cub-sized airplane, you can expect to spend anywhere from $4000-$4500. That includes everything you need from fabric to finish.
When I covered my Airbike in 1997 I used the Superflight System. Only had to cover wings and tail. Total cost was about $1200 as I recall.
I covered the Eindecker in 2015 using Fastbond and latex paint. Total cost about $400. (I went back and checked my expense record. Total cost of covering was $300. The cost of the vinyl markings was $160, bringing the total cost up to about $460.)
Get your facts straight dude. First of all a minimax is not a "Cub-sized airplane". Second, 90% of that cost quote is for the UV and color coats. Again, 90% of that $1200 quote is for UV and color. The Eindecker is more accurate.
Actual fact, from covering my minimax, not an estimate or hearsay, but actual real world numbers; enough Fabric to cover the whole airplane /26 yards = $201.50 2 quarts of Superflite U500 fabric adhesive. = $51.00 2 gallons of latex @$32.98/gallon = $65.96 Grand total = $318.46 <-------Real world number based on actual fact, not a guestament or hearsay.
technically, if you didnt already have the supplies, youd want to add in the cost of proper PPE for using the superflite stuff. also, the extra cost of the solvent resistant varnish may also sway the cost. id be willing to bet that its about even, after you figure all that in.
i have not yet covered an airplane so take that with a grain of salt. i do, however, intend do use the fastbond glue on my projects. already bought a quart of it!
PPE = box of nitrile gloves from Harbor freight, about $8 bucks. Superflite is acetone base so its no worse than your wife doing her nails. Total Boat epoxy is about $50 bucks a quart vs $18 for polyurethane. I considered using Ekobond so I could use water based polyurethane, But savings on varnish did not come anywhere near offsetting the cost of Ekobond. Or Fastbond for that matter.
And if you have ever used polyurethane on your boat You wouldn't dare put it on your airplane. And if you did, then it would be in your best interest to keep it out of the sun. Polyurathean has 0 UV resistance. Just sayin.
A quart of Ekobond should do a Minimax, maybe 3 pints depending on how much taping one does. So say $100. Say $20 for polyurethane varnish. Then we have $50 for U500 plus acetone and $50 for Totalboat epoxy. Sun's gonna eat your epoxy same as poly, they're both organic compounds, so's Dacron. Paint protects 'em all, so does a hangar roof or enclosed trailer. I'll take the simpler, less toxic process for $20 more.
Oh boy, I didn't mean to start a fight here! I can gleam at least that it seems like I only need a quart or two of varnish at worst case though so.. that's cool.
Man, you are testy! Is that your nature, or have I done something to set you off?
Nope, Just comparing the cost of covering a Piper Cub to covering a MiniMax is just utterly ridiculous. No matter what covering system you use. And $1200 to cover an Airbike??? What, you use paint laced with gold? Cover it twice?
A quart of Ekobond should do a Minimax, maybe 3 pints depending on how much taping one does. So say $100. Say $20 for polyurethane varnish. Then we have $50 for U500 plus acetone and $50 for Totalboat epoxy. Sun's gonna eat your epoxy same as poly, they're both organic compounds, so's Dacron. Paint protects 'em all, so does a hangar roof or enclosed trailer. I'll take the simpler, less toxic process for $20 more.
You will need at least 2 quarts of Ekobond. I'm already on my second quart of U500 and still have one more wing to go. Its not going to take any less Ekobond to do the same job. You are dreaming if you think you are going to varnish an entire MiniMax with one quart of poly. Epoxy will far out last poly by a long shot. Yes, hanger it. Glad to see your following my advice.
Oh boy, I didn't mean to start a fight here! I can gleam at least that it seems like I only need a quart or two of varnish at worst case though so.. that's cool.
You didn't, I just can't stand to see someone dealing out miss information. If you are going to varnish the entire thing, you will need at least 3 quarts. But you probably won't have to do the whole thing. My guess is the reason the manual tells you to revarnish the whole thing is so you have a known coating before you apply the glue. Acetone will dissolve and soften polyurethane or any other one part varnish. If your varnish looks good when you remove the fabric, test a small area with the glue and see if it starts to krinkle and dissolve. If not, probably no need to revarnish. Use your own judgment.
Ah, that's a good point. If this plane was done with the polyfiber system, then the varnish is probably not going to be destroyed by the acetone. Polyfiber is a two part varnish, right?
Nice! I'll probably wait to buy varnish until I get the wings uncovered, then. If its only tiny little spots that need covering, I'll probably just use epoxy since I have a couple bottles of it. No use spending 150 dollars on supplies to patch what amounts to a few square inches of wood.
I had made a mistake while covering my wings with fabric. Before constructing the ribs, I had fine sanded the full length RS-1 spruce rib-stock, because a finely sanded rib absorbs much less varnish, and that is one way to keep weight down to make weight for Part 103.
After making the ribs and then the wings, I went ahead and applied regular polyurethane varnish to the entire wing ( 2 coats ) and then used Stewarts Ekobond to glue the fabric to the wing .
Later on I realized that the top and bottom of the ribs where the fabric attaches, should have been rough sanded with 220 grit sand paper ( and not fine-sanded as I had done ), for better bonding with fabric.
I also read somewhere that after rough sanding, one should use a shop-vac to suck off all wood dust from the top and bottom of rib. Or compressed air can also be used. Wiping the rib after sanding will have the effect of sealing the pores of the rib with fine wood dust, which will prevent the varnish from soaking/ penetrating into the ribs.
Experienced builders already know all these, but as a newbie, this is something that I lost sight off.
I wonder if it made a big difference, but may be I will keep this in mind for my next build.
You will need at least 2 quarts of Ekobond. I'm already on my second quart of U500 and still have one more wing to go. Its not going to take any less Ekobond to do the same job. You are dreaming if you think you are going to varnish an entire MiniMax with one quart of poly. Epoxy will far out last poly by a long shot. Yes, hanger it. Glad to see your following my advice.
I only used 3 pints in 1999. Maybe it doesn't go as far now? I did use maybe a gallon of varnish, then poly is a good deal less cost than an equal amount of epoxy. Epoxy and poly will both last equally long if protected from UV. My 20 year old test panel is still holding up outside 24/7/365.
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