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Minwax and Paint on DTFB for Waterproofing

Daniel Kezar

Ultimate Cheap Skate
#1
i was wondering about people's experiences with minwax on dtfb for waterproofing. i have a couple varieties in the basement (one can of wood stain and one spray can kind) and a few projects that i want to waterproof so i can fly in winter. i want to see what works best and good ways to use it. how long to let it seep in to the paper, how to paint over it, does tape stick over it, ect...

i would appreciate the help and im sure it will help other people with it as well.
 
#2
I've done two builds using a small can of brush-on oil-based polyurethane Minwax, both using DTFB: an FT Flyer and, just a couple days ago, a Versa Wing. For each build, I first built the plane. Then I brushed Minwax onto about 1/4 of the plane at a time. As I finished brushing each zone, I wiped the remaining Minwax off that zone with paper towels.

For the FT Flyer, I let it sit for a day before I used a few light coats of Rustoleum spray paint. For the Versa Wing, I only let it sit for an hour or so before I gave it paint. In both cases the paint held up nicely. The Versa Wing has one chipped spot on the leading edge where the paint adhered better to the blue painter's masking tape I used in my two-tone paint job than it did to the packing tape used in the build, but it's small. I think the Minwax coat probably helped give the packing tape enough tooth to let it accept paint more readily (though Minwax wants to slide right off packing tape as well).

I haven't put the Versa Wing into the air yet, but the Flyer has been through multiple crashes across a couple flying sessions in deep snow (and, in one case, a beautiful landing with its tail sitting square in a drainage ditch full of snowmelt). There were zero water issues. Worked exactly as advertised. It also lent an extra iota of strength to the plane, it seemed. The paint held fast; the foam gave up before the paint did.

Biggest lesson: buy a cheap pack of foam brushes at a craft store or Walmart. Bristled brushes never quite recover from Minwax, no matter how you clean them, and not only are foam brushes cheaper, they also can be washed out enough to go for multiple uses.

Second biggest lesson: wear gloves. Minwax sticks to your hands for a couple days and makes them unpleasantly tacky, even if you're using decent soap to wash your hands.

And definitely make sure to follow the ventilation recommendations on both Minwax and paint. Minwax in particular will continue off-gassing for a day or two after it's been applied, so if you can shelter it safely somewhere with good exterior airflow, by all means do so.
 

Daniel Kezar

Ultimate Cheap Skate
#3
I've done two builds using a small can of brush-on oil-based polyurethane Minwax, both using DTFB: an FT Flyer and, just a couple days ago, a Versa Wing. For each build, I first built the plane. Then I brushed Minwax onto about 1/4 of the plane at a time. As I finished brushing each zone, I wiped the remaining Minwax off that zone with paper towels.

For the FT Flyer, I let it sit for a day before I used a few light coats of Rustoleum spray paint. For the Versa Wing, I only let it sit for an hour or so before I gave it paint. In both cases the paint held up nicely. The Versa Wing has one chipped spot on the leading edge where the paint adhered better to the blue painter's masking tape I used in my two-tone paint job than it did to the packing tape used in the build, but it's small. I think the Minwax coat probably helped give the packing tape enough tooth to let it accept paint more readily (though Minwax wants to slide right off packing tape as well).

I haven't put the Versa Wing into the air yet, but the Flyer has been through multiple crashes across a couple flying sessions in deep snow (and, in one case, a beautiful landing with its tail sitting square in a drainage ditch full of snowmelt). There were zero water issues. Worked exactly as advertised. It also lent an extra iota of strength to the plane, it seemed. The paint held fast; the foam gave up before the paint did.

Biggest lesson: buy a cheap pack of foam brushes at a craft store or Walmart. Bristled brushes never quite recover from Minwax, no matter how you clean them, and not only are foam brushes cheaper, they also can be washed out enough to go for multiple uses.

Second biggest lesson: wear gloves. Minwax sticks to your hands for a couple days and makes them unpleasantly tacky, even if you're using decent soap to wash your hands.

And definitely make sure to follow the ventilation recommendations on both Minwax and paint. Minwax in particular will continue off-gassing for a day or two after it's been applied, so if you can shelter it safely somewhere with good exterior airflow, by all means do so.
thank you! that is an amazing help! have you done anything with aerosol minwax? also, on a different topic, did you do anything to waterproof electronics before flying or just left it to fate?
 

SlingShot

Maneuvering With Purpose
#4
A lot of people say to use rags and forgo the brushes. Either way, "Wax on! Wax off!" Do not let it soak in. The foam can soften and get floppy soft if you get too much on. It only takes a light coat to get the effect that you want.
 

kdobson83

Well-known member
#6
Well, don't go too light. I went super light on my blunt nose versa, then painted. The areas with the paint worked well and resists the water. The spots that didn't have paint soaked the water right up the first dewy grass landing causing me to fix leading edges with tape. I now wipe it on thick with a rag, by the time I'm done, I go over it with another clean rag to wipe up the excess. Works good enough to fly off water.
 

Daniel Kezar

Ultimate Cheap Skate
#7
alright. so it seems like it's going to be the normal can kind, not aerosol. wiped on with a foam brush or rag. wipe off after. make sure to get the edges.
 
#8
thank you! that is an amazing help! have you done anything with aerosol minwax? also, on a different topic, did you do anything to waterproof electronics before flying or just left it to fate?
I haven't used spray Minwax. It seems like everyone on the forum is interested in it, but we're all waiting for someone else to try it first. :p I didn't waterproof any of the electronics, and I've expected every crash to destroy my batteries and fry my ESC, but so far I've had no trouble whatsoever, even when the power pod has gotten a fair amount of snow inside.
 

SlingShot

Maneuvering With Purpose
#9
Today I found a better pasture to fly in, as well as little farm pond that I can fly off of. Point being, I'm going to finish my Cub with floats. Regular Minwax for the plane proper, and the water based, baby powder and kraft paper method for the floats.

I will also be treating my electronics with the CorrosionX. Full report coming. Also, I can fly a jet again without freaking out :)
 
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Daniel Kezar

Ultimate Cheap Skate
#10
I haven't used spray Minwax. It seems like everyone on the forum is interested in it, but we're all waiting for someone else to try it first. :p I didn't waterproof any of the electronics, and I've expected every crash to destroy my batteries and fry my ESC, but so far I've had no trouble whatsoever, even when the power pod has gotten a fair amount of snow inside.
hmm. well i guess i will be the first to try it then!! mysterious can on the shelf in the basement, here i come! (tomorrow maybe)
 

kdobson83

Well-known member
#11
Just grab some scrap foam and try on that. That's what I did. Spray it on, let it dry, stick it in a sink full of water. You'll know if it works or not pretty quickly that way. Lol
 

Brett_N

Active member
#13
Just remember - WIPE ON - WIPE OFF!!!

I got a little heavy handed on my otter with the minwax, and the plane decided to dis-assemble itself in mid flight. It ate all the paper and glue joints :black_eyed::black_eyed:

I'll build another one and give it another try.
 

Daniel Kezar

Ultimate Cheap Skate
#14
Just remember - WIPE ON - WIPE OFF!!!

I got a little heavy handed on my otter with the minwax, and the plane decided to dis-assemble itself in mid flight. It ate all the paper and glue joints :black_eyed::black_eyed:

I'll build another one and give it another try.
so did the minwax weaken the paper making it disintegrate and cause the glue joints to fail? how much is needed to make it waterproof while being safe?
 

Brett_N

Active member
#15
If I had to answer either way, I would say yes. But....again I was really heavy with it (think refinishing an antique heavy!) and didn't wipe any off. I gave it 3 hours in Arizona Sun and then spray painted it.

I'd almost say that the "heavy" amount I put on soaked through the paper and ate the foam underneath. The plane was "flyable" but the control surfaces were so gooey that they didn't do anything.

I've got a tradeshow this week so I'll be out of town - but, I pan to run some time-log tests when I'm back.

For now, I'd say go really light, wipe on, wipe off, or just don't do it at all for a week or 2.

Oh - are you using DTFB or some other type of foam? That may cause different results too.
 

Daniel Kezar

Ultimate Cheap Skate
#16
If I had to answer either way, I would say yes. But....again I was really heavy with it (think refinishing an antique heavy!) and didn't wipe any off. I gave it 3 hours in Arizona Sun and then spray painted it.

I'd almost say that the "heavy" amount I put on soaked through the paper and ate the foam underneath. The plane was "flyable" but the control surfaces were so gooey that they didn't do anything.

I've got a tradeshow this week so I'll be out of town - but, I pan to run some time-log tests when I'm back.

For now, I'd say go really light, wipe on, wipe off, or just don't do it at all for a week or 2.

Oh - are you using DTFB or some other type of foam? That may cause different results too.
i am using DTFB. whats this about eating the foam and it being gooey?
 

Daniel Kezar

Ultimate Cheap Skate
#17
Waterproofing of DTFB | spray paint vs spray minwax vs brush minwax

so the results are in. spray paint eats the foam and brush on minwax works better than spray.

the below picture shows how bad just spray paint was. the foam started dissolving on the edges and the paint even leaked through the paper and started eating the foam under it. the paper peeled off at the edges very easily.

IMG_1972.JPG

when you spray paint over the minwax it will still eat the foam on the edges a fair bit and it will cause the paper to stick to the foam even less.

IMG_1976.JPG

in the above picture, the paper that is painted is removed so you can see if there is damage under it. the piece of foam more towards the right and bottom is the spray minwax and the top left ish one is the brush on can of minwax.

for this project i will be using the can or brush on minwax for as much of the plane as i can and i will then use only a small amount of spray paint as markings for orientation and try my best to NOT get the paint on the edges of the foam board.

PS: i have way more pictures and a few videos of this test but it keeps giving me an "image failed to upload" message so i cannot post them. sorry.



the above post is a copy of the one from my Simple Soarer build here
since this test a few weeks ago, i have used the minwax on my simple soarer. there will be a post about that in my simple soarer build thread shortly (a few days probably). i just used a paper towel and did the "wax on, wax off" thing lol.

NOTE: VERY VERY VERY VERY STICKY!!!!!! WEAR GLOVES!!!!! (i didnt it is sticky. very sticky. i washed my hands 6 times and its still sticky. stickystickystickystickysticky

let me know if you think i should make an ft article about this. the ft videos on using minwax are really old and are missing some information that is helpful.