Three words: Zinsser Cover Stain! Oil base primer in a spray can, and you can find it everywhere. Seals out moisture, covers stains, and makes paint stick like glue to any surface...even shiny packing tape. Use a thin coat so paper doesn't bubble, and a second thin coat a few minutes later when first coat is dry to the touch. Five bucks a can, minutes to waterproof and prime your model, you can even sand it for a smooth finish. You can't beat it!
Where was this 4 days ago? There were lots of other things that went wrong w my project, but it went well enough that I'm not discouraged to try again w lessons learned. This video was exactly what I needed for one of them. Thank you! ♥
Three or four years ago I tried to paint Dollar Tree foam board with a air brush using acrylic paint, this was before I heard about using the Minwax polyurethane to seal the surface, it was an absolute disaster, luckily I tried it on a scrap piece of foam instead of a plane!
Haha, been there myself. Finished an entire new scratch build of a larger Piper low wing RC plane. was so ready to paint it until after the first coat, I returned 10 minutes later to apply second coat of paint to learn that the surface was bubbled up, deformed and melted holes into much of the foam fuselage. distaster. If I only pre treated foam before painting
Hey Jason. Thanks a million for taking the time to create this very informative video. You did a great job of sharing your findings on the benefits of treating our DTFB planes. So far, I have done the FT Explorer. While these planes are very inexpensive to build, the time investment is something to consider. Anything that can be done to extend the life of the plane (especially something this simple) is worth while.
I am preparing to paint a new foam board versawing. I thought to test out the MinWax vs Hot Glue issue. First I used a foam brush to paint a full sheet with Minwax. Initially the foam board weight 113 grams. After wiping off the residual minwax, it weighed 124 grams. After setting and allowing evaporation to do it's wor for two hours, it weighed 117 grams. Not bad over a full sheed of foam board. I allowed it to cure out for one week. After the curing period, I tried several tests. The first three using Masking tape, Packing Tape, and Duck Tape. The tapes stuck to both sides of the board very well, the untreated side, just a little bit better. When pulled off, the treated side showed no damage, while the untreated side showed paper fibers coming off with the tapes. Next Hot glue. I glued two toung depressors to the board exactly oposite to each other allowing handles to extend over the side. Pulling them apart cause the untreated side's paper to seperate somewhat quickly. The treated side took more effort to seperate the paper. Then I tested foam board to foam board gluing and (Treated to Treated, Untreated to Treated, and Untreated to Untreated). In every case where untreated was used in the test, the paper seperated on the untreated side and tore into the foam. The Treated to Treated test was a supprise. No matter how hard I pulled on the two peices, they wouldn't come appart. I bent the heck out of the foam board, but they wouldn't come appart. Try it your self. I intent to minwax my foam board first in all my builds.
+JGZ IFLY How would this work on something like an Experimental Airlines Armin wing where you fold the board over at the leading edge with a sharp crease and no cutting or beveling at the fold? Would bending a treated board like that work OK or would it be better to treat it after assembling the wing?
Dwayne Crow It should work ok treating the board first. The process adds strength to the paper and it's bond to the foam board. In my experiments, the paper maintained it's texture while the foam got bent up. My suggestion is to try a sample first if you are undecided.
Interesting, it's been a couple of years, have you built any planes with pre-treated foam board? The reason I wonder is that Flitetest mentions in a few of their videos not to treat anything that is going to be hot glued because it won't stick.
I did a little test on untreated Dollar Tree foam board, I airbrushed water based acrylic paint on bare foamboard. It was a disaster, the water in the paint caused the foamboard to warp badly as it dried. Some kind of pretreatment like the Minwax polyurethane is needed to prepare foamboard for painting. So far I'm sticking with the tape covering technique as used on the Experimental Airlines planes.
G56AG That's the down side to dollar store foam board, The paper frays and pulls up from the edges. Your better taking the paper off with alcohol from a spray bottle. Letting everything dry then put the Minwax on the foam and re-apply The paper. I've also used foam board without any paper to build my plane then use diluted Elmers white clue and covered it with news paper or phone book paper. Drys hard, sandable and paintable, and adds back the strength.
Just found your vid. Very helpful. Thanks for taking the time to post. I think I'm gonna start using this tip 'after' I do the build, then I know the hot glue will hold... Thanks!!!
Very helpful video. I might just have to get some minwax for some of my EA inspired designs. I was going to ask about the added weight, but I see JGZ IFLY below has answered that one.
I found this material in the spray can. I can't find it in a can. I sprayed it on the foam board just to wet and wiped it off. Before I could get it off, it lifted the paper! Maybe it is something in the spray as that does not work. I dusted it with the spray, not letting it get moist (almost sprayed it on dry) and it seemed to work but the amount of work needed to spray it on dry is not worth it to me. Minwax says it should be available in small amounts in some Cal. stores, can't find it.Thanks
I tried with Saman water based varnish and it worked. I also tried with white glue and it worked too.. The secret seem to be wiping it before the foam begin to wrap. Next thing I want to try is wood sealer it's cheper than varnish it cure in 2 min and it is specialy designed to seal so it might work realy good.
I haven't tested the adhesion of hot glue to the treated surface but my gut tells me that hot glue would stick a little better to the untreated surface. My thinking is that untreated paper would have more 'tooth' to grab on to. However I don't think it would be a huge difference. I also treated a completed airframe, see the link in the description.
My main concern was the peeling off of the paper. For sure, the water based will de-laminate the paper from the foam. When I tried the polyurethane, it did much better, but still, it's easier to peel the treated area than the untreated area. The experimentation method I used was simple. Just paint a piece in zebra stripes. Let dry for at least 24hrs. I did 48 hrs. Then start from the edge peel the paper in the direction so that you would alternately peel the treated and untreated as you go. You will feel the paper "grab" at the untreated area, and not so much in the treated area. This goes against JZG's experiment. His was a year ago. I just did mine, so did the formula change or something? Was it because I didn't wipe off the excess? It seems that the clear will penetrate almost instantly, so wiping the excess may not help. But I will try several light coats and see how that works.
another question I suppose is you painted basically onto the actual foam Paper itself. You treated the foam paper. I noticed in a few of my scratch builds with this foam is when the paper is removed in some areas OR the sides where there is no paper. If I try spray painting this foam without first treating it many or majority of spray paint will bubble on the surface and many will Melt the actual foam destroying the entire build. I wondering if this Miniwax pre treatment will allow me to spray paint directly onto the Foam Board where certain areas of the foam paper was removed. Will this prevent the foam melting and paint from bubbling up? hmmm
Hello and thank you very much for your helpful video. I am planning to paint on a foam core board using Acrylic paints and brush....I need to prime my foam board and in a TH-cam video I got to know that we need to use water-based Minwax or Latex in order to be able to prime the foam board, but here you mentioned to use oil- based....please advice. Appreciate it.
For all the spray paint I've used, yes. Since the minwax sort of merges with the paper once it cures it has a harder surface feel and the paint works very well.
Hi great video!! This is very helpful! Do you know if any other polyurethane products work for this(ex. from Michaels or Hobby Lobby)? Or have you only used Minwax?
Your challenges could be caused by the additional chemicals (propellants, etc) that are in the spray can that are not in the "brush on" can Also, when I went to Home Depot online to check Minwax prices the site said the product cannot be shipped to CA (but did not give a reason). Best of luck!
Have you sen the new Flite Test foam board? New type made by Adams, and supposedly, the glue is bonded to the foam (Have to verify that), so the lifting issue is gone!
How would it work if you treated the board first and then glued things together? Would the treatment work with the hot glue or would it not adhere or stick as well? Thanks
Wondering how this experiment would go with Elmers Foam board? I'm new at this and just finished my FT Spitfire build and wanting to make another with my downloaded plans. The Elmers board is certainly heavier and difficult to cut, but has a rigidity to it that may prohibit warping? Just wondering if it's an alternative... Also, it has a nice smooth finish.
The flight test models are all designed for dollar store foamboard so the rigidity of the elmers is probobly not worth the amount of extra weight it would be adding, also it would cost you quite a bit more to make the models from the elmers brand.
Have you tried PVA? White or wood glue, brushed on thin makes a waterproof, paintable, rock hard surface and won't bother the foam at all. As a surface treatment not as a glue.
That technique only works for a surface that will not be subjected to any flexing. The glues you are mentioning will give a hard smooth finish to paint, but it is also brittle. One flex of the foam and you get all kinds of cracking. I do like to use this technique to seal the edges though. Polyurathane stays flexible and gives good protection. (personal experience)
Terry Peterson I have peeled my foamcore and wasn't happy with the strength. It's not a bad idea if you are going to use tape or stickers, but I wouldn't use it with just paint or even minwax and paint without the paper attached.
You say you shouldn't paint with acrylics, but you don't say why. In my testing, painting acrylic over a poly-treated surface works fine. Just don't do it on untreated foam board, as it warps. Would like to see some justification for your statement, as even your video seems to show it working just fine.
is there an alternative for minwax polyurethane? Because in Germany I could not buy this brand and I do not know what Minwax is. Is it a wax? Oil? Something like a clear coat paint? I guess if it is oil based, no color would stick to it. I hope you can help me. Thank you very much. Kind regards from germany
+RCCarClips check your local paint store, ask them for a "Polyurethan" (german spelling) varnish basically almost any will do. try it on a small scrap piece first. if it contains the wrong solvents it will attack the foam
It doesn't. The way this works is the urethane seeps into the paper and bonds with the fibers. Anytime I've seen urethane dry on the bare foam it just ends up flaking off. There are some spray paints that are 'foam friendly' so if you're looking to paint bare foam, I'd test some scrap foam with these paints.
I am not being critical , sorta, but I 'm not understanding why aircraft builders are leaving the paper on this foam board.. IT IS HEAVY... I use tape to strengthen when needed and acrylic paint( brush or airbrush) on areas needing ID for vision purposes..Over thinking this I believe.. JUSS sayin
+Greg Inman Personally, the 'cheap' Adams brand I get for .99 a sheet has very thin paper, almost like tissue paper. As thin as it is it does offer alot of strength over peeling off the paper. Most times tape over the foam adds more weight and can be a hassle to work with. (cutting the tape, overlaps, tape sticking to itself. etc..) And you can do paint effects pretty easily on the paper. I've even done colored pencil art on them.
+SZretired it was indeed your problem, waterbased solutions works with fiberglassing styrofoam planes, but with the paper cover, you need the polyurethane version.
@@claeswikberg8958 interesting, I just used water based poly on my dollar store foam and it worked great. If the paper is pulled off before it will warp.
Three words: Zinsser Cover Stain! Oil base primer in a spray can, and you can find it everywhere. Seals out moisture, covers stains, and makes paint stick like glue to any surface...even shiny packing tape. Use a thin coat so paper doesn't bubble, and a second thin coat a few minutes later when first coat is dry to the touch. Five bucks a can, minutes to waterproof and prime your model, you can even sand it for a smooth finish. You can't beat it!
Where was this 4 days ago? There were lots of other things that went wrong w my project, but it went well enough that I'm not discouraged to try again w lessons learned. This video was exactly what I needed for one of them. Thank you! ♥
Three or four years ago I tried to paint Dollar Tree foam board with a air brush using acrylic paint, this was before I heard about using the Minwax polyurethane to seal the surface, it was an absolute disaster, luckily I tried it on a scrap piece of foam instead of a plane!
Haha, been there myself. Finished an entire new scratch build of a larger Piper low wing RC plane. was so ready to paint it until after the first coat, I returned 10 minutes later to apply second coat of paint to learn that the surface was bubbled up, deformed and melted holes into much of the foam fuselage. distaster. If I only pre treated foam before painting
Hey Jason. Thanks a million for taking the time to create this very informative video. You did a great job of sharing your findings on the benefits of treating our DTFB planes. So far, I have done the FT Explorer. While these planes are very inexpensive to build, the time investment is something to consider. Anything that can be done to extend the life of the plane (especially something this simple) is worth while.
I am preparing to paint a new foam board versawing. I thought to test out the MinWax vs Hot Glue issue. First I used a foam brush to paint a full sheet with Minwax. Initially the foam board weight 113 grams. After wiping off the residual minwax, it weighed 124 grams. After setting and allowing evaporation to do it's wor for two hours, it weighed 117 grams. Not bad over a full sheed of foam board. I allowed it to cure out for one week.
After the curing period, I tried several tests.
The first three using Masking tape, Packing Tape, and Duck Tape. The tapes stuck to both sides of the board very well, the untreated side, just a little bit better. When pulled off, the treated side showed no damage, while the untreated side showed paper fibers coming off with the tapes.
Next Hot glue.
I glued two toung depressors to the board exactly oposite to each other allowing handles to extend over the side. Pulling them apart cause the untreated side's paper to seperate somewhat quickly. The treated side took more effort to seperate the paper. Then I tested foam board to foam board gluing and (Treated to Treated, Untreated to Treated, and Untreated to Untreated). In every case where untreated was used in the test, the paper seperated on the untreated side and tore into the foam. The Treated to Treated test was a supprise. No matter how hard I pulled on the two peices, they wouldn't come appart. I bent the heck out of the foam board, but they wouldn't come appart. Try it your self. I intent to minwax my foam board first in all my builds.
Really interesting result .
Awesome! thanks for documenting your results, this is very helpful.
+JGZ IFLY How would this work on something like an Experimental Airlines Armin wing where you fold the board over at the leading edge with a sharp crease and no cutting or beveling at the fold? Would bending a treated board like that work OK or would it be better to treat it after assembling the wing?
Dwayne Crow It should work ok treating the board first. The process adds strength to the paper and it's bond to the foam board. In my experiments, the paper maintained it's texture while the foam got bent up. My suggestion is to try a sample first if you are undecided.
Interesting, it's been a couple of years, have you built any planes with pre-treated foam board? The reason I wonder is that Flitetest mentions in a few of their videos not to treat anything that is going to be hot glued because it won't stick.
Nice video. You did a great demo. I have learned from this video something I needed since longtime
I did a little test on untreated Dollar Tree foam board, I airbrushed water based acrylic paint on bare foamboard. It was a disaster, the water in the paint caused the foamboard to warp badly as it dried. Some kind of pretreatment like the Minwax polyurethane is needed to prepare foamboard for painting. So far I'm sticking with the tape covering technique as used on the Experimental Airlines planes.
G56AG That's the down side to dollar store foam board, The paper frays and pulls up from the edges. Your better taking the paper off with alcohol from a spray bottle. Letting everything dry then put the Minwax on the foam and re-apply The paper. I've also used foam board without any paper to build my plane then use diluted Elmers white clue and covered it with news paper or phone book paper. Drys hard, sandable and paintable, and adds back the strength.
Great video man answered some questions I had about painting my foam board models thank you
Awesome man thanks for taking the time to share your discovery
thanks for this. you saved me a bunch of time trying to figure out this issue
Just found your vid. Very helpful. Thanks for taking the time to post. I think I'm gonna start using this tip 'after' I do the build, then I know the hot glue will hold... Thanks!!!
Very helpful video. I might just have to get some minwax for some of my EA inspired designs. I was going to ask about the added weight, but I see JGZ IFLY below has answered that one.
I found this material in the spray can. I can't find it in a can. I sprayed it on the foam board just to wet and wiped it off. Before I could get it off, it lifted the paper! Maybe it is something in the spray as that does not work. I dusted it with the spray, not letting it get moist (almost sprayed it on dry) and it seemed to work but the amount of work needed to spray it on dry is not worth it to me. Minwax says it should be available in small amounts in some Cal. stores, can't find it.Thanks
Did you test to see if packing tape stuck better on the treated side. Packing tape for strenght of course. I'm guessing it did.
I tried with Saman water based varnish and it worked. I also tried with white glue and it worked too..
The secret seem to be wiping it before the foam begin to wrap.
Next thing I want to try is wood sealer it's cheper than varnish it cure in 2 min and it is specialy designed to seal so it might work realy good.
I haven't tested the adhesion of hot glue to the treated surface but my gut tells me that hot glue would stick a little better to the untreated surface. My thinking is that untreated paper would have more 'tooth' to grab on to. However I don't think it would be a huge difference.
I also treated a completed airframe, see the link in the description.
My main concern was the peeling off of the paper. For sure, the water based will de-laminate the paper from the foam. When I tried the polyurethane, it did much better, but still, it's easier to peel the treated area than the untreated area. The experimentation method I used was simple. Just paint a piece in zebra stripes. Let dry for at least 24hrs. I did 48 hrs. Then start from the edge peel the paper in the direction so that you would alternately peel the treated and untreated as you go. You will feel the paper "grab" at the untreated area, and not so much in the treated area. This goes against JZG's experiment. His was a year ago. I just did mine, so did the formula change or something? Was it because I didn't wipe off the excess? It seems that the clear will penetrate almost instantly, so wiping the excess may not help. But I will try several light coats and see how that works.
Very informative, thank you!
another question I suppose is you painted basically onto the actual foam Paper itself. You treated the foam paper. I noticed in a few of my scratch builds with this foam is when the paper is removed in some areas OR the sides where there is no paper. If I try spray painting this foam without first treating it many or majority of spray paint will bubble on the surface and many will Melt the actual foam destroying the entire build. I wondering if this Miniwax pre treatment will allow me to spray paint directly onto the Foam Board where certain areas of the foam paper was removed. Will this prevent the foam melting and paint from bubbling up? hmmm
While I haven't tried it myself, I don't know that the poly would work on the bare foam.
Hello and thank you very much for your helpful video. I am planning to paint on a foam core board using Acrylic paints and brush....I need to prime my foam board and in a TH-cam video I got to know that we need to use water-based Minwax or Latex in order to be able to prime the foam board, but here you mentioned to use oil- based....please advice. Appreciate it.
does the Minwax cover stop it from wrinkling when you spray paint it.??
For all the spray paint I've used, yes. Since the minwax sort of merges with the paper once it cures it has a harder surface feel and the paint works very well.
Hi great video!! This is very helpful! Do you know if any other polyurethane products work for this(ex. from Michaels or Hobby Lobby)? Or have you only used Minwax?
great video. thanks!
Thank you very helpful!
Your challenges could be caused by the additional chemicals (propellants, etc) that are in the spray can that are not in the "brush on" can Also, when I went to Home Depot online to check Minwax prices the site said the product cannot be shipped to CA (but did not give a reason). Best of luck!
Have you sen the new Flite Test foam board? New type made by Adams, and supposedly, the glue is bonded to the foam (Have to verify that), so the lifting issue is gone!
+Vparanormal1 I haven't had a chance to try it yet but I'm looking forward to getting some and making a Polaris/Skipper style float plane.
How would it work if you treated the board first and then glued things together? Would the treatment work with the hot glue or would it not adhere or stick as well?
Thanks
Wondering how this experiment would go with Elmers Foam board?
I'm new at this and just finished my FT Spitfire build and wanting to make another with my downloaded plans. The Elmers board is certainly heavier and difficult to cut, but has a rigidity to it that may prohibit warping? Just wondering if it's an alternative...
Also, it has a nice smooth finish.
The flight test models are all designed for dollar store foamboard so the rigidity of the elmers is probobly not worth the amount of extra weight it would be adding, also it would cost you quite a bit more to make the models from the elmers brand.
Have you tried PVA? White or wood glue, brushed on thin makes a waterproof, paintable, rock hard surface and won't bother the foam at all. As a surface treatment not as a glue.
That technique only works for a surface that will not be subjected to any flexing. The glues you are mentioning will give a hard smooth finish to paint, but it is also brittle. One flex of the foam and you get all kinds of cracking. I do like to use this technique to seal the edges though. Polyurathane stays flexible and gives good protection. (personal experience)
I totally agree. I like the spar urethane (water based) for outdoor stuff, but it needs a lot of layers.
Why would you not remove the paper backing and just coat the foam and then paint? the paper tends to peel away from the foam.
Terry Peterson I have peeled my foamcore and wasn't happy with the strength. It's not a bad idea if you are going to use tape or stickers, but I wouldn't use it with just paint or even minwax and paint without the paper attached.
You say you shouldn't paint with acrylics, but you don't say why. In my testing, painting acrylic over a poly-treated surface works fine. Just don't do it on untreated foam board, as it warps. Would like to see some justification for your statement, as even your video seems to show it working just fine.
have you ever have the paper de-laminate from the foam?
Your first test looked like half a wing to the FT Flyer. lol
is there an alternative for minwax polyurethane? Because in Germany I could not buy this brand and I do not know what Minwax is. Is it a wax? Oil? Something like a clear coat paint?
I guess if it is oil based, no color would stick to it.
I hope you can help me.
Thank you very much.
Kind regards from germany
+RCCarClips check your local paint store, ask them for a "Polyurethan" (german spelling) varnish
basically almost any will do. try it on a small scrap piece first. if it contains the wrong solvents it will attack the foam
is this done with peeled ,or paper still om
thanks for the video man
I purchased a rc airplane foam boulders and it has poly u on it can I paint over it the piant job on it suck???☺
will this work the same on actual foam?
It doesn't. The way this works is the urethane seeps into the paper and bonds with the fibers. Anytime I've seen urethane dry on the bare foam it just ends up flaking off. There are some spray paints that are 'foam friendly' so if you're looking to paint bare foam, I'd test some scrap foam with these paints.
I am not being critical , sorta, but I 'm not understanding why aircraft builders are leaving the paper on this foam board.. IT IS HEAVY... I use tape to strengthen when needed and acrylic paint( brush or airbrush) on areas needing ID for vision purposes..Over thinking this I believe.. JUSS sayin
+Greg Inman Personally, the 'cheap' Adams brand I get for .99 a sheet has very thin paper, almost like tissue paper. As thin as it is it does offer alot of strength over peeling off the paper. Most times tape over the foam adds more weight and can be a hassle to work with. (cutting the tape, overlaps, tape sticking to itself. etc..) And you can do paint effects pretty easily on the paper. I've even done colored pencil art on them.
good stuff!
Ruined my Nutball with it. Wings warped to where aircraft is unusable.
It's $10 now 😭
But mine was water based, so maybe that was the problem................
+SZretired it was indeed your problem, waterbased solutions works with fiberglassing styrofoam planes, but with the paper cover, you need the polyurethane version.
@@claeswikberg8958 interesting, I just used water based poly on my dollar store foam and it worked great. If the paper is pulled off before it will warp.
should have watched the full video. stupid me. oh well.