PLEASE HELP A GREEN HORN! long story

[Guest]

i have a EW hobby gun and have been doing coating on the side for friends and their motorcycles. i'm having a BIG problem with what i can only describe as what looks and feels like sand particles on some of my finishes. it seems to happen with high gloss black powder although it happens but not as bad with other colors.it also seems to be more prone to happen when a part is shot when it is lying horizontal. i have an air regulater than a filter then a moister filter all in line before the gun. because of the performance of the gun second coats are usualy hot flocked after i sand down the part. i can only think that maybe the gun is loading up and powder is falling a little too much on the part even though i can not see it? any help would be greatly appreiciated. i would like to expand and make some money on the side but i can't with some parts looking like this!! thanks in advance.

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

I took this from your post on the EW forum.
did the clean, blast, clean, outgassed, then hit it with a map gas torch before shooting it.
Now, it's debatable as to which is the best way to go here, I've had success both ways. You need to either clean/degrease or blast/clean again after outgassing.

I agree (it IS debatable), but if you think about it, when you outgas a part, you've used heat to force the substrate to open its pores. Ok, then what happens? That trapped air/grease/dirt/dust/crud (whatever you want to call it) has physically moved from just below the substrate surface TO the surface. You still HAVE to get rid of it by either chemical or mechanical means.

I prefer to blast/clean again after o/g'ing.

And yes, Todd (TNC) and I have had this argument, in public, before. In this case, I honestly believe he is wrong, or maybe just mis-informed.

This forum seems to be hosted/sponsored/monitored AND participated on, by professionals in the p/c industry - what do you guys (gals) say about this one?

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

so you guys are saying it's outgassing thats causeing this "sand grain looking" problem and not a problem with the gun or powder loading up on me? also with the most resent part i did the following: cleaned-blasted-cleaned-outgassed-cleaned again-warmed the part up (about 120f.) and shot it while it was in the horizontal position. also it can happen with steel parts as well as aluminum. it seems to be the worst when a part is shot while it is in the horizontal position too.

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

so you guys are saying it's outgassing thats causeing this "sand grain looking" problem and not a problem with the gun or powder loading up on me? also with the most resent part i did the following: cleaned-blasted-cleaned-outgassed-cleaned again-warmed the part up (about 120f.) and shot it while it was in the horizontal position. also it can happen with steel parts as well as aluminum. it seems to be the worst when a part is shot while it is in the horizontal position too.

You may have 'seeds' in your powder, little chunks of powder that will still spray ok, but give that grainy finish. Try running it thru a flour sifter.

Or your powder may be bad form extreme heat or cold exposure. Ar eyou having this problem with all colors, or just one.

Could also be you're not getting enuff powder on the part. Usually that effect is small patterned orange peel. As opposed to 'normal' (?) orange peel from too much powder.

Is the grainy texture all over and tightly condensed? Or is it like you are getting specks of sand randomly scattered here and there? Got pics?

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

I have to believe with what you have described the part is not complete cleaned, or there is dust in the air that has fallen on your part which cannot be seen with the naked eye. When the part is in the horizontal position there is more surface area to collect this dust and therefore more evident after coating the work piece.Some times those guns do not fluidize well and the particles separate from the fillers but I do not belive this to be the case. I hpe this helps...............................

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

Try this easy test. Other parts are coming out well that are hung a different direction.

Hang the part vertical (THE SAME PART) and see if you have the same issue. This will let you know if its the part or the gun. Take baby steps, do not change everything at once if its working for other items.

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

well after stripping a set of handlebars and risers i decided to cover them with PBTP MIRROR BLACK instead of the EW HIGH GLOSS BLACK that i used and although there are still a few (2 or 3 ) specs on them it is NOTHING like it was useing the EW powder!! i think the gun is not fluidizing the powder that well and the PBTP powder looks finer when i compare the two powders side by side. also after seeing a few videos posted on the web by people i can say that when using the hobby gun with 10 PSI i do not gEt a "cloud" of powder like what i see other people have. could i just not have a good pressure setting at the gun even though i have a gauge and it states 10 PSI? i see more powders from PBTP in my future!!

[wiseguyz]

Re: PLEASE HELP A GREEN HORN! long story

I agree that the majority of PBTP powders seem to be lighter and less prone to clumping than some of the EW powders and shoot as nice as any I've used, but EW also has some (like their black chrome) that are pretty hard to beat.

[Guest]

Re: PLEASE HELP A GREEN HORN! long story

Workin hard to win you over :P :P :P :P