rubbing compound creates minute white spots / speckles


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fgayford
fgayford
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Yes it is wax and you would not be able to clear on to that. I was just suggesting it if you are as done as you are going to go. Then the black in the wax would hide the tiny pin holes.

Fred   
benet
benet
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this kind of thing 

neilb
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here is a quick video on whotube regarding a homemade degassing chamber, it will all become clear after watching it and you may have things laying around you could use already!

http://www.youtube.com/watch?v=dxVbFwHpg7Q

good luck Smile
benet
benet
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hi  neilb

 I like the sound of making a de-gassing chamber but not having seen what one does i cant quite picture what your describing ...

could you expand a little ..

ben
neilb
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do you heat the resin before mixing or after?

I can recall fred advising another forum user of a technique to remove air bubbles which involves  the resin being pored (when mixed) from a height (around 12-18 inches I think) slowly into another container apparently this causes the air bubbles to pop. worth a try cause its free!

other than that build a degas chamber with some Perspex sheet and tube silicone'd together, make a rubber gasket for the top, piece of Perspex with a small hole in it for the lid and vacuum the air out with a small vacuum cleaner. it just may work!

good luck!
benet
benet
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i dont have access to any vacuum equipment im afraid .. i do stir very slowly and let the resin stand for at least 5 mins before i use it. and i scoop off any collections of bubbles first. also use a heat gun to get rid of bubbles that seems to work very well while im using it  (ie i see tinny bubbles pop) ... Also this is the top coat (brushed on, its synthetic brush and i re-use it , keeping it in acetone between jobs and drying it before use) . its coating resin and im polishing it back to be the top finish. I wonder if what im getting is dust from the surface of the sanded coat below ... i always brush then vacuum ( with a vacuum cleaner) and then brush off with a soft brush, as ive thought it right to steer away from tack cloth of acetone or anything really between coats. Im still a bit miffed ... if anything here sounds or or unnecessary please let me know.

Thanks

Ben 
neilb
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try to de-gas the epoxy before you apply it. do you have access to any form vacuum equipment?
carbonfibreworks
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I have had the same problem in the past and this is my cure, rub over the marks with a black white board marker ( non permanent) and then buff with a cloth and spray with a clear coat. Yes I  know it sounds like a bodge but it could salvage the part.

Chris

http://www.talkcomposites.com/Uploads/Images/97e08777-693c-4af1-a27a-86cf.png
carboncactus
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fgayford (04/05/2013)
neilb (04/05/2013)
I would say that the compound is filling in minute holes in the surface, that is unless these white spots wipe off with your finger?


I agree it is probably pin holes. What I have heard some do is to wash out the pinholes with alcohol and use air to blast out the compound residue.

Take some black boot polish and put a few coats on and buff. The black will fill the pinholes and the rest will be removed when polishing.

Yes its a crude way to make things look good but it works.

Fred    


Boot polish is a wax product, wouldn't that essentially create a repellant film on the top, making a clear coat application a nightmare?

http://www.talkcomposites.com/Uploads/Images/db628ad5-e0e7-47b9-873a-3d84.png
benet
benet
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Thanks , i think your both right but im not sure that boot polish will help as im not doing it on carbon but multi colored patterned cloth. 

and i dont have air tools.

I have previously posted with this issue and found another fix by washing with wd40 but its not perfect and i would dearly love the problem to not occur or at least know what im supposed to try to do to stop it from occurring..

I have just gone back to the surface starting at 320 wet and it took a lot of sanding to get rid of the speckles. and then i did the same process but did the compound and finsh by hand to keep a close eye on what was going on. 

Its better but its still not perfect.

The picure is a BEFOR shot

Here is a picture of what i wahttp://www.talkcomposites.com/Uploads/Images/0c605f08-62d2-4065-ad2c-c9a0.jpgs dealing with...
GO

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