Good filler to paint over??

[sxrchris]

Need help! What filler is everyone using that's easy to sand and leaves a smooth surface? I've used phenolic microballoons in the past but it seems to leave air bubbles/pockets after curing and sanding.

 

[Lm12]

Every filler that i know of needs to be primed before painted.

 

[air blair]

Fairing compound or dabble with microspheres.


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[Vumad]

You can mix anything with epoxy pretty much. Microspheres are light and easy to sand but they are hollow so they leave pin holes. Talc also sands fairly easy but is a solid and will not leave pin holes. The more dense the material, the stronger it fills, the harder it is to sand. Epoxy in general also sands poorly.

Poly bases sand well but wont adhere as well. That's probably okay since I believe almost all high build primers are poly based. They go over epoxy primers in automotive applications after epoxy is applied to seal from rusting. Consult your supplier, but you can probably do okay with fairing compounds and poly high build primers.

I am not a paint expert.

 

[McDog]

Marine tex

 

[sxrchris]

Thanks for the info!

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[Downrange]

Last year I did some different stuff. After doing hull mods with glass and west system epoxies I tried a new approach to finishing prior to paint. I used WS403 micro fibers to fill in any low spots and ensure no fibers got touched when fairing the hull with a 80 grit 4 inch tube. Then switched to a skim coat of 407 light weight filler and faired it with 120 grit 4" tube . This is where I changed it up, wanting a harder surface I decided to apply a thick coat of poly resin over everything. The poly flows way better than any other resin at temp. I read the article on west systems site about there testing of this type of application a decided to try it. I mixed enough to do the entire bottom in one coat. I can't stress enough that you really need to move fast. Anyways used a 4" brush and put it down fast and once everything is coated , don't touch it let it flow out and do its thing . Then crank the heat up so it goes off fast , the faster it goes off the more even the coat will be. Well it turned out perfect as pretty and hard as any gel coat ever was. Like glass!!! Let it cure and a week later sprayed primer. If you want to try it go to the west site and read there testing data and specific surface prep instructions. Have not had any problems with chipping or delam. Just something new I intend on doing again.

 

[jeastes1]

I'm a painter, and I use a thickened epoxy for fairing, but will use polyester putty just to fill pinholes before using a high build primer.

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[Vumad]

I'm a painter, and I use a thickened epoxy for fairing, but will use polyester putty just to fill pinholes before using a high build primer.

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what do you use to thicken?

 

[jeastes1]

West system 407 or 405, or micro balloons.

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[sxrchris]

I went with a few different fillers to experiment with. 3m glass bubbles, q-cells, and sm fairing compound. Thanks for the tips everyone!

 

[b-rad]

Spray Polly or duratec !


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[Nottjbarlow]

I just use cabosil to thicken the epoxy and spread it on with a drywall knife. Works well on large flat surfaces.

 

[McDog]

Cabosil doesn't sand easy at all.

 

[SUPERJET-113]

Ive tried lots of different types of fillers for fairing(west and US composites brand), and the one I like the most that does not leave tiny holes/pores after sanding is the West system 406 Colloidal silica. It also absorbs the resin pretty fast too when mixing.
Nothing is going to sand very easy mixed with any kind of resin. If your just filling pinholes and very minor surface things after final body work, I use Dolphin glaze or Evercoat glaze coat like mentioned above here. That sands easy and leaves a smooth surface for priming ,etc.

 

[michael750x2]

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