avoiding air bubbles

PressureDrop · #1 06-29-2002, 11:55 AM

as im filling in screw holes and such, i noticed that after sanding my filler has allot of litte air bubbles that make me need to put another coat on, any way to avoid these bubbles? Thanks

Ben

Scott · #2 06-29-2002, 12:56 PM

Hey Ben

Might need a little more info......Sounds like your working with epoxy? Doesnt sound like paint

Are you whipping air into as you mix it??

I've noticed with some of the fairing fillers that they hold air a little more than some of the other fillers......
Also if it is real thick (which it may need to be on vertical surfaces to stop sagging) It will not flow as easily so air trapped will not surface.

For screw holes and such mix in some cabosil/collodial silica/west 406 .... you get the idea. Fill the hole from the bottom .... in other words dont fill it as if you were spackling a wall with plaster by just wiping epoxy over the hole. Force the epoxy deep into the hole and build it out ( If I can I tape the backside of the hole to stop it from dripping out).

As for having to do the second coat ....alot of times I need to go back over hole with more epoxy after fairing.

Hope this helps [img]images/icons/smile.gif[/img]

PressureDrop · #3 06-29-2002, 04:24 PM

scott, its epoxy, west systems infact, ive been using the high density filler though (i beilve its 410?) i think its from whipping air into it. ill just stir less agressively...

Scott · #4 06-30-2002, 10:10 AM

Ben
I have seen small bubbles when I use West 407. More or less similar to the 410 Its a very light very easy too sand filler. I use that stuff after I fill with the High density fillers....to fill in imperfections after the first pass. The 406 is tough to sand but I like how it fills....plus the stuff is rock solid....good for high stress areas.

To get that stuff to the right consistency, as you know, it gets thick and its hard not to get air into it....at the same time making sure its totally mixed.