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Question about Minwaxing

#1
I've been looking at the videos on how to seal foam board with Minwax, and would like to do it to my FT3D and upcoming builds, but have a few questions I don't see answers to. Ideally, it seems to make more sense to keep the foam whole while applying (as in the FT video) to ensure i don't miss any spots including tight corners.

1) If we were to apply the minwax to full sheets, how easy do the pieces cut or pop out (if a pre cut kit)? Does the Minwax get in the grooves causing the pieces to stick together?

2) If the sheets have minwax applied how do you crease, bend, or fold the pieces without harming them? it seems to me the coating would harden the surface a bit.

3) Is it safe to assume that the finish is applied to the poster board pieces as well?

Thanks!
 

Tritium

Amateur Extra Class K5TWM
#2
1.. I do not know as I have never done a pre cut kit.

2.. The minwax is a liquid polymer (plastic). All you end up with is a paper reinforced plastic after coating. I have no issues building with pre-coated boards.

3.. It should not matter as the poster board is paper as well.

Thurmond
 

MrGravey

Senior Member
#3
I cut, then minwax the parts.

I will say most of the models I have done turn "someone pee'd in the bed" yellow when everything is said and done. I'm not sure why. I thought I was putting on too much minwax or leaving it too long but changing the way I do things didn't help.

Hot glue and tape also hate sticking to the minwax so be mindful when applying it.
 
#4
1.. I do not know as I have never done a pre cut kit.

2.. The minwax is a liquid polymer (plastic). All you end up with is a paper reinforced plastic after coating. I have no issues building with pre-coated boards.

3.. It should not matter as the poster board is paper as well.

Thurmond
So bending/creasing it after it's coated doesn't crack or break the new coating at all? I'm afraid that after it dries, performing an A or B fold, or even creasing wings would break the "plastic"
 
#5
One important fact to remember, if using hot glue....it will not adhere to a pre-minwaxed piece of foamboard. I typically build and then coat to avoid all this.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#7
Do you coat in sections? I feel like i would miss some hard to reach spots that way
I do the same - assemble then minwax. The humidity here is typically so bad the paper will peal off if you look at it wrong. I want to do anything I can to encourage it to stick, before I make it any easier to peal, which un-dried minwax can do.

Frankly, if it's hard to get to with minwax that's slapped on like wall paint, it's really hard to apply a colored paint for pretty details.
 

Tritium

Amateur Extra Class K5TWM
#9
I see no cracking of the coating as poly is VERY flexible. I also have no issues with hot glue sticking to it (may be related to glue brand or temp or state of Cure of the poly coating).

Thurmond
 
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#10
I see no cracking of the coating as poly is VERY flexible. I also have no issues with hot glue sticking to it (may be related to glue brand or temp).

Thurmond
Really?! Very interesting.....this may require some documented scientific testing....hummmm the gears are a turning.
 

Tritium

Amateur Extra Class K5TWM
#12
For the record I am using Walmart Dual Temp Sticks. The Minwax on my boards was cured for 4 weeks in the summer before I built with it so all the solvent was evaporated which might be why the hot glue stuck well. I almost forgot: Laminate sticks VERY well to my minwaxed boards as well.

Thurmond
 
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#13
All very good information, thanks. I think the simplest and least problematic would be to coat the plane after it's built.

Any tips for knowing when to start wiping off the excess? I'm assuming the color doesn't start yellowing until it begins to dry, and I'd hate to ruin a few hours of work because I waited too long, or not long enough before wiping it down.
 

Tritium

Amateur Extra Class K5TWM
#14
I coat then immediately wipe leaving only what has soaked the paper. Yellowing is just normal for MinWax Polyurethane and most other Polyurethanes as well.

Thurmond
 
#15
wipe immediately....typically break plane into parts...fourths if you will, have found that even the wiping down aids in even distribution of minwax. Just curious, are you minwaxing mainly for paintability or working on a seaplane that requires 100% waterproofing?
 
#16
wipe immediately....typically break plane into parts...fourths if you will, have found that even the wiping down aids in even distribution of minwax. Just curious, are you minwaxing mainly for paintability or working on a seaplane that requires 100% waterproofing?
primarily paintability, and light waterproofing against things like landing in lightly wet grass, etc. would also be nice to be able to keep parts of it from getting quite as dirty as paper does (dust and light dirt).

Also, not sure there's much of a need since foam doesn't react to moisture the same way as paper, but do you also coat the exposed foam or just the areas with paper?
 

xuzme720

Dedicated foam bender
Mentor
#17
Only the paper needs it but people have had success preventing peeling by sealing the edges, ironing the edges, taping the edges or other treatments that I can't recall at the moment...
 

xuzme720

Dedicated foam bender
Mentor
#18
I found a new video for applying PU that you guys might like. The poly is being applied to furniture, but there are a few tips that might help with applying to your foamboard.
Plus, the video thumbnail is awesome!
 

MrGravey

Senior Member
#19
Does anyone air brush their waxed models? I use acrylic Createx paint and have tried cutting it with water, window cleaner (as Chad showed us) and a commercial cutter. All three were problematic on the wax actually. I've tried to change the mixtures and such but I keep getting really bad first coat issues. Things bubble bad and the paint ends up looking pretty rough in the end. Has anyone run into this and solved the issue? I'm sure I'm just doing something a little wrong somewhere but for the time being I'm not waxing models because I can't get them to paint right and once they are waxed color tape doesn't stick either.

To the point of hot glue on wax, I cut away the paper in most of my glue joints anyway. The paper is great for surface tention, but in the end you are only gluing paper to paper with foam in the middle if you don't cut away that paper. I find that removing that little slice of paper in the glue joint means my models stay together longer anyway, so I do this with my waxed models too. I can way them flat, build and glue them by removing the paper with wax on it in my joints.
 

xuzme720

Dedicated foam bender
Mentor
#20
Are you using a paraffin wax or something? This is something I hadn't heard about...The Minwax treatment is polyurethane and if left to cure for a few days to a week, depending on your local weather, should let tape or glue adhere well.