Frustration

[Chuck Feldman]

I like most of you am struggling to get better looking models. It is Frustrating! Most recently I stripped an ARF Smoothie to bare wood and cleaned and sanded it. Filled the grain and sanded it smooth. Used finishing resin and fiberglass cloth on the bare wood. Covered the wings with nitrate and polyspan. All this was done with all the care and effort I could muster. Then came the finishing process which I wanted to be the old standard DOPE. Why cause it holds up and seals the plane to prevent fuel soaking. So after putting on more nitrate dope and sanding it was nice and shinny. OK now the silver. It didn't look to bad so I sanded it again fixed the boo boo's and put on the last coat of silver. Next came the color. In this case it was Brodak Orange and a trim done in black. Then after it cured a few days I started to put on Brodak buturate clear to get that high shine that we all like. So after spraying and sanding it had a nice finish and I was happy. Not front row but nice. On to the flying and trimming stage. As I did this I noticed there where some milky looking spots on the finish. These where from fuel spillage. Careful as I was it clearly was from raw fuel. A major disappointment. OK what to do to be rid of them. Sanding was troublesome and not what I wanted to do. But no amount of cleaning or rubbing helped the spots reappeared. So it was a job of sanding it off and then re finshing or repairing the sanded areas. However what good does this do when you know that it will happen again? So how is it that no one mentions that modern buterate dope is not truly fuel proof? The old Aero gloss was as was testers if I recall correctly. So in order to protect the finish I have had to put on auto motive clear. This solves the issue but I think I now have to rethink again my finishing process.

[Bob Reeves]

I feel your pain, I'm not comfortable with the auto clear coats but that may be what I end up with. I like the Nelson water based paint but have to change almost every method of finishing I've been using with dope. I really like dope but it can't take 20% nitro.

I may just go completely to plastic and rustoleum or bite the bullet and spend the money to get geared up for epoxy. Al Rabe can do wonders with epoxy but not sure I can.

Finishing is tough and yes very frustrating...

[Balsa Butcher]

I have found Brodak dope to be not as fuel proof as Sig. I have two airplanes that exhibit the same symptoms that you describe. Both were finished with Brodak dope.  Raw fuel, especially over 10% nitro will cause Brodak clear to blush. Sometimes it can be polished out, often it is there to stay. I do like the coverage I get with Brodak colors though, they cover better than Sig dope especially the lighter colors.  I will use either Sig or Brodak for colors but only Sig lite-coat for the clear overcoats. After curing, it holds up to the 15% nitro blend that most use in my area. No problems with compatability so far.  Every paint system has its challanges. It's a matter of deciding which one you want to go with and trying it 'till you get it right.

[peabody]

On the other hand, Windy uses Brodak dope, especially the clear, and typically flies 1000 flights a season.....his doesn't discolor, blush or anything.....
I think it's the very smooth finishes?
Have fun

[James Mills]

Chuck,

I had the same problem on my Shark 45.  I called and asked John Brodak and he told me you needed to use auto clear to prevent this (it's not fuel proof).

James

[Garf]

On the other hand, Windy uses Brodak dope, especially the clear, and typically flies 1000 flights a season.....his doesn't discolor, blush or anything.....
I think it's the very smooth finishes?
Have fun

I don't think he spills raw fuel on his models.

[Steve Kocher]

I've been watching one of Windy's old videos on dope finishing that he produced when Brodak dope was first introduced.  In the video, he indicated that the dope was only fuel proof for raw fuel at 5% nitro.  He said that he usually used 5%.  So, that may account for why his finishes don't suffer from the raw fuel.  That or he is very careful not to spill any.

Steve.

[Clancy Arnold]

Easy fix!

Electric power.  LOL

Clancy

[john e. holliday]

Like some other finishes, the dope, clear, has not cured long enough.  I have not so far had trouble if I let the plane set for several weeks after the last coat of clear for it to harden up.  Even the auto clear to me need to set for a week or two to be cured.  Otherwise I leave finger prints while handling the plane.  Of course the clear I use is SIG for final coats.  I just finished my Perky Speed which is done in all Brodak dope, start to finish.   

[Chuck Feldman]

Clancy,  Your comment does make a lot of sense!  I think the scale people will be doing electric planes very soon and will incorporate scale actions into the model via the computer. I wonder if AMA and World scale rules would allow that? If not it is time to change it. OK about the comments I have read. Thank you all very much for your input. Interesting to learn that others have the same problem. For me I think I am leaning toward using up all my existing dope supplies and then switching to epoxy. No more dope clear coats just a an auto clear coats. Does the Brodak colored dope with no clear behave the same way as the clear does? Please continue to add to the content of this thread. Thanks again.