andretorres89

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All,

I am currently repairing some stress cracks on my dalton's engine cowl and wanted to know what everyone uses on their repairs for both durability and easy to work with?

Andre

combatpigg

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I use plain old bondo automotive type body filler. Summit Racing sells a nice line up of polyester fillers that are a little bit nicer than Bondo brand filler, but they are more expensive.

andretorres89

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I'm really trying to stay away from bondo. This is for a two piece cowl with a da170.

I'm afraid bondo will crack

Any other suggestions?

speedracerntrixie

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I spoke with Andre earlier today and got him pointed in the right direction. I will repeat what I had told him here in hopes it may be of use to someone else as well. The cowl in question is made from epoxy/fiberglass. Putting polyester based fillers onto epoxy can be done in ideal conditions but is not recommended. Epoxy onto a fully cured polyester part is acceptable. That being said, if there are cracks that need to be repaired, the cracks should be opened up into a V notch and filled with a mixture of epoxy and milled fiber. Then after sanding smooth while removing some surface material, a patch of light cloth should be applied over the areas where the cracks were and then feather sanded. Lacquer Based spot putty or polyester based spot putty can be applied over the primer to fill any remaining imperfections. As a rule, Bondo as we have known it for decades is not a good choice for epoxy fiberglass parts.

andretorres89

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Shawn, thanks for going into further detail.

One more question;

-milled fibers for rougher areas such as the "v-notch" work and,

-cobisol for surface areas such as fine surface holes?

JohnFH

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I use epoxy and West System #403 MicroFibers

speedracerntrixie

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Andre, you got it bud. The milled fiber adds structure and strength, Cabosil has no strength but is a great filler. The cloth overlay will make sure the cracks don't come back.

andretorres89

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I get it now.

Thanks for the help.

Hope you been practicing for next season!
Once the Dalton is repaired, I will start to practice advanced to improve my flying skills.

sierratango

Here are two excellent materials for fairing in the repair once the micro fibers and cloth have been used.

Super Fill- Aircraft Spruce and Specialty, epoxy based and suuuuper light and sands well.

Split Second- google it, a polyester fairing compound similar to bondo , but is suuper light and sands well.

andretorres89

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Thank you!