Epoxy Wipe for Composite aircraft finishing

Description of the epoxy wipe method to simplify finishing composite aircraft. I provide background and the actual method starts about 6:30. Comments are encouraged. If you like it, give me a thumbs up.
I made the long sanding board from coated shelf material from Lowes. It's nice and straight, but the little piece of angle aluminium helps and gives you a little more to hold on to.
If you used this method, please report back and tell us how it went for you.

[@experimental_av]

I found that if you squirt a bit of color pigment into the resin you can easier spot unwanted build ups and tears compared to transparent resin. West sells them in small bottles and they last forever. They offer 3 colors and you can rotate through them. Also helps with sanding.

[@samhoskins8706]

That is very interesting. If I ever finish another aircraft, I'll have to try the colors.

[@yellowhammer4747]

I KNEW THERE WAS AN EASIER WAY VERSUS THE "FILL AND SAND" METHOD. THANKS FOR TAKING THE TIME TO EDUCATE FOLKS,. I AM GOING TO USE THIS METHOD ON MY PULSAR!

[@samhoskins8706]

Thanks. One of our chapter members tried it on his cowling and he really liked the procedure. He even came up and thanked me after our meeting.

[@yellowhammer4747]

Sam, I tried it on a section of my vertical stab. Looks great!!! Pin hole Killer!

[@RobertTheFriscoSchmid]

I think I didn't wipe enough and now have to sand a bit more epoxy on one side than I would have needed to 😭 ... not sure how many times you emphasized it in the video and it still took me one side to learn plus epoxy is such a pain to sand. Anyhow, amazing time saver from sanding and inhaling micro for days

[@samhoskins8706]

Thanks for your True Confession.

[@cwestw00d]

Thanks for posting this. I think most of us have heard of the epoxy wipe method and know of its benefits, but the step by step explanations are worth their weight in gold!

[@stevesplace7230]

Where in thunder were you 18 years ago when I finished my VariEze!!! Beautiful Carftmanship. I still absolutely looooove your "Plastic Explosive" moniker. Yes, I'm the guy that stole it and put it on my Vari. Sadly that airplane is now a museum relic in some small forgotten town in a flyover state. Oh, well. Since then I've gone to the dark side having completed an RV7 nine years ago - which also involved way too much fiberglass, micro and flox. At this years Oshkosh (I will NOT say airventure!), I walked up and down the flight line about four times looking for your Q200 (I have many photos of it), but, nada. Nothing! Where were you? Your machine still looks awesome, and by the way, I haven't seen it at Phillip Billard Topeka in a long long time. Best. Steve

[@samhoskins8706]

Thanks for the compliments, Steve. I sure I wish I knew about this method myself years ago. That's why I did the video, I was happy enough with the method that I wanted to spread the word. Alas, I didn't make it to Oshkosh this year and maybe not next year. We had planned a driving trip to Alaska, but got waylaid by some non-life threatening health issues, so we weren't able to do either. We're all good though. You may see me at Billard though, my daughter lives in the Topeka area.

[@justinhoffman2236]

Great "how to" lesson on skim coating! I enjoyed it and it's always a pleasure to see another Rutan design...

[@samhoskins8706]

Thanks. I hope it proves useful for you.

[@johncerney8199]

Thanks for putting this together. I have seen a few articles on this technique, but your video really makes it clear.

[@joepolenek503]

Thanks for the video. I had read about the method but it's nice to have it explained with visuals.

[@samhoskins8706]

You know what they say about one picture.

[@jerskip]

Excellent video Sam! I finished my Cozy the same way, and it worked like a charm. This method saves tons-o-time vs. the "Sand and Fill, SaF, SaF, SaF, SAF" method.

[@samhoskins8706]

Thanks Jerry. I kind of got tired trying to describe this method and thought a video would do a better job.

[@daveberenholtz335]

Thanks Sam, really appreciate that you have taken the time to explain this method so clearly. I will try it on a small part exactly as you described. I hope you do one on painting next ;)

[@samhoskins8706]

We better find someone else for the painting part. It's a black art that I haven't mastered yet. The most important part is making sure you are using good equipment. A professional body shop guy is the place to turn to.

[@tonyvaccarella5362]

Further to my previous post about my sandpaper clogging, I contacted West System. They forwarded me a technical leaflet describing a phenomenon called Amine Blush - sometimes called "bloom" that happens when the amines in the hardener react with carbon dioxide and moisture in the air. It's a wax-like substance that clogs sandpaper. Just like I have experienced. The good news is that this Blush is water soluble and can be removed with water after the epoxy has cured hard. Scotch-Brite pads or similar abrasive scouring work well for abrading and dulling the shiny surface. Detergents and solvents are not required, or recommended, for removing blush.

[@samhoskins8706]

That's interesting. I didn't know that.

[@N835CZ]

See the Canard Pusher #77, page 4, for Cory Bird's original writeup on his finishing method.

[@samhoskins8706]

Could you provide a link to that article?

[@N835CZ]

Try this one: www.cozybuilders.org/Canard_Pusher/1994-01_cp-77.pdf

[@delschier1419]

Great video, Thank you, I will try it on repairs

[@besmith51]

How is the final weight comparison between the old method of repeated filling and sanding down to, say, 220 or 320 grit and your recommendation to sand only to 80 grit? I would think filling the coarser grit would necessarily involve some small (negligible?) weight penalty. Second, as a technique, when getting to final sanding, it's useful to use - instead of pencil marks to reveal high and low spots - a fast drying very thin layer of black spray paint, shot from a couple of feet away. But either method works. Thanks for the expertise, time and energy to make this video. These composites are wonderful planes.

[@samhoskins8706]

Unknown Rider How could I know the answer to this question? Don't over think it. When I once did the whole plane I added about 2.5 lbs. Negligible.

[@toddhoskins4196]

Super video Sam - good info. T

[@cwestw00d]

Quick question: I'm working on gear leg fairings. The plane is complete other than the gear leg fairings. The top side of the fairings turned out pretty well (I have definitely discovered that micro a little wet is much better than micro a little dry with regards to pinholes... I steadily increased the micro in 4 batches thinking I hadn't gotten it thick enough (first batch was like warm peanut butter, last was cake frosting) and the first batch had almost no pinholes and the ones that were there were very small and the last batch had hundreds of pinholes with some 1/4-3/8 in size)... back to the question... will this work on the underside of a surface (I can't without a LOT of effort flip the plane over).

[@samhoskins8706]

Not sure that I can answer that question. You got nothing to lose by trying it. I think it will probably work but you may wind up doing additional applications. How about giving it a try and then replying back with your results to share?

[@tonyvaccarella5362]

Thanks for this post - having finished one wing using the old fill and sand method, I think this will save a huge amount of work. I tried it on the lower surface of my other wing. I'm using the West Systems epoxy (as you did in this video) but I have found that once the epoxy is cured and ready for the 240 grit paper, the sandpaper becomes very clogged - using supposedly clog-free sandpaper. Have you had this experience? - if so, can you suggest a solution? Thanks again.

[@samhoskins8706]

So, you were talking about the stage where you are finished with your sanding and you've done the pure epoxy wipe? I really don't know why your sandpaper would be clogging, is your epoxy fresh? Sorry, I really can't help you with that one, since I didn't seem to have the problem myself.

[@samhoskins8706]

I made the long sanding board from coated shelf material from Lowes. It's nice and straight, but the little piece of angle aluminium helps and gives you a little more to hold on to.

[@kansasflying]

Thank you so much for making this video! I am still learning composite methods. During a composite workshop, one of the instructors mentioned after laying down your last fiberglass piece you can place a healthy amount of dry micro over the area. Your objective is to fill the weave of the fiberglass with dry micro throughout the entire surface before the epoxy dries. Once dry, you lightly sand the area and you "should" have a nice smooth finish with minimal sanding. Any thoughts on this, or is this method used for other areas other than a larger surface like the wing? Thanks!

[@samhoskins8706]

I don't like the idea. First, I always like to inspect the surface for imperfections after the epoxy has cured. If you slather micro on top of the epoxy you lose the ability to do that. Second, as I said in the video, there is a sweet spot in timing where it is better to work the dry micro. Frankly, I think your friends idea doesn't hold a candle to the epoxy wipe method I described. This method works for any size part.

[@experimental_av]

Would you say the same is possible with VE resin as a wipe? I have a VE resin fuselage and would like, if possible, stick with one type of resin even though i know you could put epoxy on it if fully cured.

[@samhoskins8706]

Sorry, I have never used VE resins , so I am unqualified to answer the question. My intuition tells me it probably wouldn't be a good idea, but until you try it. We won't know. I do know the West System epoxy worked very well for me. You may have to try something like mixing micro balloons with the resin first, and then adding the hardener once the micro balloons mixed in. But again, I haven't tried it myself.

[@experimental_av]

@@samhoskins8706 Thanks, I will try on the landing gear fairings and report back.

[@experimental_av]

@@samhoskins8706 So it does work with VE resin. Might have to add some styrene as thinner because the VE tends to get sticky when working with it before it hardens. Bit of a different beast. Thanks for the video, now working my way towards the fuselage but this time with epoxy filler and wipe. Easier to sand.

[@wanderlama]

Hi Sam when you do the final wipe do you add micro balloons or is it just pure epoxy?

[@samhoskins8706]

Pure epoxy all the way. Again, I suggest you try a smaller component.

[@MarkSDCA]

Wish you discussed weight of all that fill.

[@samhoskins8706]

Doing the whole aircraft would probably be less than three pounds.

[@avocadoblu]

I've been practicing this method. Is it normal to get streaks from the squeegee in the final epoxy wipes? How smooth should the final product be? Perhaps it just needs finish sanding...

[@samhoskins8706]

There may be just a tad of a ridge, but some 330 grit paper should knock it off. I use the classic Thalco squeegee in new condition.

[@avocadoblu]

@@samhoskins8706 I got some new squeegees and they're much better. Thank you!

[@svetoslavvelev8924]

Great video! Would you say what epoxy resin you used to make the plane itself (brand, type)?

[@samhoskins8706]

Over the years I have used a variety of different epoxies. MGS is one of my favorites and I also used a lot of Aeropoxy.

[@svetoslavvelev8924]

@@samhoskins8706 Thank you!

[@Dynodon64]

Sam, thanks for the details. I have a WAR Corsair project that I just glassed.Check out my channel. I was going to do the micro balloons slurry WAR recommends, at a 50/50 mix, when a follower of mine sent me your video. I will definitely try this one. What I was wondering was, how much micro balloons does this method use? I have two gallons right now. My Lay ups are pretty straight on the wings and most of the fuselage. Don't think that I will need a quarter inch or more to level everything. Any advice will be appreciated. Don

[@samhoskins8706]

Two gallons of microballoons should get you there. Please report back and let us know how it worked for you.