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Building Tips and technical articles. => Building techniques => Topic started by: Allan Perret on April 30, 2008, 05:36:14 PM

Title: Paint lifting off of fillets
Post by: Allan Perret on April 30, 2008, 05:36:14 PM
What causes it and what can you do to prevent it?
Used Sig Nitrate base on balsa fillets, then sanding sealer, and Sig butyrate color coat. The color coat lifted in a couple of small spots and I have not sprayed any clear coats yet..
Title: Re: Paint lifting off of fillets
Post by: Mark Scarborough on April 30, 2008, 06:58:44 PM
A couple things to consider, all Laquer shrinks, and continues to shrink. possible causes, not enough dry time between coats. spraying to dry which will not allow adhesion, laquer must melt into the previous layers to stick and the last thing would be not enough "bite" or sanding.
something has prevented the layers from bonding properly and these are the things I would suspect most commonly could cause that.
my two cents worth
Title: Re: Paint lifting off of fillets
Post by: Leo Mehl on April 30, 2008, 10:21:59 PM
A couple things to consider, all Laquer shrinks, and continues to shrink. possible causes, not enough dry time between coats. spraying to dry which will not allow adhesion, laquer must melt into the previous layers to stick and the last thing would be not enough "bite" or sanding.
something has prevented the layers from bonding properly and these are the things I would suspect most commonly could cause that.
my two cents worth
Two things can cause this to happen. Covering the fillets with silkspan and not waiting long enough between coats. Some colors of paint will not like to stay put either. Make sure your thinner is hot enough so get good bond. Use a good primer on the fillets after you finish the fillets. All of this will help. HB~>
Title: Re: Paint lifting off of fillets
Post by: Bob Reeves on May 01, 2008, 04:26:11 AM
Only one time have I had fillets bubble.. I used nitrate dope instead of my usual butrate.

What works for me on either Epoxlite or Aeropoxy..

Sand fillets with 320.
Put a coat of Brodak white primer over the fillets with a small brush.
Sand with 320
Silkspan/CF and/or butrate clear with filler.
Paint as desired with Brodak butrate, Rustolieum, Lusterkote

What didn't work....

Sand fillets with 320
Coat of Brodak nitrate
Cover with CF strips... more nitrate
Sand and fill with clear nitrate and ZC
Sand with 320-400
Paint with Lusterkote

Next day or two dig and sand everything out then start over with white primer and butrate clear. Result.. no bubbles...