Minwax Polycrylic

[doctormike]

RE: Minwax Polycrylic

I am coating all my foam planes with Polycrylic. I am using gloss or satin, depending on the plane. You must rub down the plane, VERY WELL, with 91% rubbing alcohol first to break down the surface tension. A foam brush works very well. It levels out nicely. Don't over work it and don't apply it too thickly! Check the light reflection for missed spots. If you find that there is still a surface tension problem, you may apply a very thin coat of Polycrylic and then rub it dry with a paper towel. Then it goes on smoothly. Allow it to dry completely before adding coats. This not only improves the appearance of your plane but also cuts down on air resistance. This also makes a very nice primer for spray painting. It protects the foam from melting and spray paint adheres to it. As always, practice on scraps or an old wrecked plane first! The Doctor

[stitch]

RE: Minwax Polycrylic

now i found this stuff here helmsman spar urethane made by minwax for interior exterior has uv protection in it and it is a spray. clear gloss and works great i used it on an old t-28 thats been wrecked well works great dries in 15min no tacking to it,some have a tacky feeling to it after a hour still tacky this stuff no tack. after 15 min dry. says to use 3 light coats let dry recoat within 1 1/2 hrs if u can,t wait 3 days to recoat. going to use it on a dhc-2 beaver then a 1400 t-28 before i put them together. have to do something grass is to hard to wipe off this should make it wipe right off plus it may slice threw the air alittle faster hahaha! or go threw the water alittle faster!
[hr]
oh and i did not wipe off anything just picked it up sprayed it wait 1 hour did it again,so far looks good no side effects at all. tried cabot varnish spar gloss and that caused fish eyes in the foam and wrinkles so don,t use that one.also tried bulls eye shellac for hobbie stuff says so on can clear don,t use that one it turns alittle yellow.all these things i mentioned are found at wal mart.

[Hippie 64]

RE: Minwax Polycrylic

Hey Stitch , the reason for the prewipe with the 91% alcohol is because when the parts are made there is a release agent in molds . This is so the parts come out without damage from the molding process . If you look close or rub your hand across the white unpainted areas you can feel and see the smooth looking shimmer . That's the release agent . The alcohol breaks that down allowing the coatings you want to add stay . If not they will peel off shortly .
Be careful what you use on these foamies because lots of stuff out there will eat and melt the foam .


Bryan

[Wingman]

RE: Minwax Polycrylic

New to foam planes so be gentle. Old school gasser in the past.  I would like to know if anyone has tried Waterborne Polyurethane Varnish.  Just asking because I have some already on bench from another project.  Sherwin Williams brand it says interior.  tried some on foam and at least it didn't melt.

Wingman

[doctormike]

RE: Minwax Polycrylic

Hi, Wingman. I am now using Varathane brand water based polyurethane brushed on with a foam brush. It looks like a spray job! Interior works fine unless you leave your planes out in the weather 24-7. Home Depot seems to be the only place to buy this. Be sure to wipe down unpainted areas with rubbing alcohol to remove mold release and to clean the surface. Funny, I have gone from stick built (60's) to foamies and now back to ARF stick built. What a hobby!!! Have fun! The Doctor

[stu]

RE: Minwax Polycrylic

Hi Guys
I just ordered the waco and was thinking of applying the coating but would like a little advise ...would you give it a coat then add the decals followed by 2 more coats ?? or apply decal first then coat

[OV10]

RE: Minwax Polycrylic

Hello stu,
I used Do It Best brand(you don't need really expensive stuff) water based polyu in satin on my Waco. Applied it after the decals which sealed their edges and only used one coat. Really no need to add multiple coats because your just adding weight. Brushed on with a soft textured bristle brush. It really made the acrylic paint color pop(visual crispness). The poly gives the paint a nice clean look which looks great on civilian planes but I wont do it to my warbirds because I want that dull kinda dingy look.
This is the custom paint job before the poly.
http://www.hobbysquawk.com/thread-1103.html
Best Regards,

[doctormike]

RE: Minwax Polycrylic

Hi, stu. OV10 is right. Decals first, then one clear coat. I do custom paint jobs on my planes. It's a lot of work (masking) but well worth it in the end. A coat of Varathane water based really makes the colors pop out and seals down the pin striping. I usually apply 2 or 3 coats of clear on high wear areas. I found that foam brushes work best for me. It is much easier to clear coat before assembeling your plane. Have fun! Doc

[stu]

RE: Minwax Polycrylic

Hi OV10
Thanks for the info, your waco looks fantastic cant wait to get mine built.i also live upstate and now all the snow has gone looking forward to some sun and calm weather.nice here today but windy.tomorrow looks good so am out of here to go flying lol,i am in Hartsville ny where are you ?...i run camping at the Geneseo warbird airshow and we have a nice strip cut there for flying RC if you ever want to go there...
[hr]
Thanks Doc for all your posts they have help no end,now just waiting on delivery of my waco and will take the advice on coating it and if it turns out good i may do all my other models :)

[doctormike]

RE: Minwax Polycrylic

stu...  Be sure to work under plenty of light so you can see any missed spots. When I have spots of resistance as I'm brushing, I rub the foam brush back and forth over it. This usually makes it go away. Decals, sometimes, resist clear coat. I just do the best I can and when it dries, it's not noticeable. Man, this hobby is so much fun! Doc

[Ben]

RE: Minwax Polycrylic

New to foam planes so be gentle. Old school gasser in the past.  I would like to know if anyone has tried Waterborne Polyurethane Varnish.  Just asking because I have some already on bench from another project.  Sherwin Williams brand it says interior.  tried some on foam and at least it didn't melt.

Wingman

There is thousands of pages all over the internet devoted to different ways to finish a foam plane or different types of protective coats. I have used polyurethane, minwax, foam armour and some things I cant even think of. Now, if you don't mind a brilliant fresh waxed shiny look..the best method bar none is 20 or 30 minute finishing epoxy mixed up and thinned with alcohol and brushed on your plane right out of the box. The weight is no more than the other methods and it will be a actual hard coat around your plane. I have the FMS T-28 Trojan that I brushed on the epoxy. Here is videos of it so you can see how it looks. Toward the end I talk about I added a little weight with the epoxy and its a real clear view of what I am talking about. There is several videos of it on my YT channel and everyone says they like how it looks. Another added bonus is, its a literal hard shell smooth coat that you can wipe off using windex just like you would a good ole nitro/gas plane. Here is a vid of my plane. https://www.youtube.com/watch?v=SPtZ1AB5Mig

Ben

[Flygirl]

RE: Minwax Polycrylic

Does it yellow at all Ben?

[Ben]

RE: Minwax Polycrylic

Does it yellow at all Ben?

Using Z-Poxy I have had no yellowing

[Pheonix]

RE: Minwax Polycrylic

I use hobby coat as a protective covering. I airbrush on several coats and end up with a hard finish, and no added weight. If you have you have trouble with your airbrush clogging, add just a little denatured alcohol as a thinner and this will take care of the clogging.

[SOB8604]

RE: Minwax Polycrylic

Want to toss my name in the ring, if anyone's on the fence about this! Got one can the other day to do my Beaver over, and damn! Looks unbelievable, one word of caution though: do a few nice light coats, I got a bit over enthusiastic with my application and some of the paint started to run, not the end of the world, but required some time touching up.

But I'm going to be stocking up on this stuff, night and day difference!

[8416w]

RE: Minwax Polycrylic

New member first post!

For clarification, I have read that you should use oil based poly not water based. What is the reasoning behind that thought process?

[Hippie 64]

RE: Minwax Polycrylic

First off Welcome to the Forum 8416W !!
 
Some of the oil based have chemicals that will damage the foam . Some instant and some slowly . Use a water based . It will not hurt the foam . The  best options we have found  are , the Minwax , the Hobby Coat , and the brand that Dr Mike has mentioned quite a bit . He has found it and speaks very highly of it sorry I can't recall the name but if you look thru his post you will see it .

I personally have used the Hobby Coat and the Minwax . Both work well . I break the Minwax down with a little water and use thru a airbrush . The Hobby Coat I just brushed on with a foam brush .

All three work really well and my past experience now tells me to always do it . It does protect the finish . I do mine before I assemble the plane .

Hope this helps .

Bryan 

[8416w]

RE: Minwax Polycrylic

Bryan,

Thank you for the clarification on the oil vs water based poly. I will be coating my next airplane with Doc's suggested brand.

Stephen

[doctormike]

RE: Minwax Polycrylic

I use Varathane brand water base clear coat, now. It goes on more smoothly with less bubbles. It is more flexible when dry. It can be found at Home Depot. I use a foam brush and it looks like a spray finish. Read all my posts on this for more instructions. Good luck!!! Doc

[Pheonix]

RE: Minwax Polycrylic

First off Welcome to the Forum 8416W !!
 
Some of the oil based have chemicals that will damage the foam . Some instant and some slowly . Use a water based . It will not hurt the foam . The  best options we have found  are , the Minwax , the Hobby Coat , and the brand that Dr Mike has mentioned quite a bit . He has found it and speaks very highly of it sorry I can't recall the name but if you look thru his post you will see it .

I personally have used the Hobby Coat and the Minwax . Both work well . I break the Minwax down with a little water and use thru a airbrush . The Hobby Coat I just brushed on with a foam brush .

All three work really well and my past experience now tells me to always do it . It does protect the finish . I do mine before I assemble the plane .

Hope this helps .

Bryan 

Do you an problems with your needle clogging when air brushing with Minwax?  When you say a little water, what ratio do you use?  Thanks.