R

RV8R999

Well Known Member
Decided to paint the RV8 myself using Stewart Systems. The primer is single part and water soluable so very easy to prepare (just pour through a filter).

I spent a bunch of time filling pin holes in all the glass work and shot and sanded the primer three times now. The technique for painting this system is much different than others and requires some patience in that each coat goes on very light.

my problem now is that I'm seeing fish eyes on a few parts such as the rear half of the wheel pants. At first I thought these were missed pin holes but when I look closely right after shooting the primer I can see the primer is pulling away as if some contaminate is there (like oil and water does). I've sanded these areas down, cleaned with strong detergents, used acetone, cleaned again, used acetone again, sanded, cleaned and acetone again and still when I shoot the paint I see these spots...

Any ideas?

I have a dryer and filter attached in-line and I just ordered a new poly hose made in USA vice the rubber one made in China to eliminate any possibility of hose contamination..hmmmmmm????

Thanks
 
Any chance of the rags you're using being contaminated. I seem to remember reading of dryer sheets causing major fish eye issues.
 
Whu don't you get a small rattle can of self-etching primer, test a small spot in teh same area and see if that does the same? If it doesn't, could it be the primer you're using?
 
the pants have a water soluble release agent that needs to be scrubbed with soap and water Solvents sometimes will not get rid of it all. If that's not the problem start looking at your air supply, etc

RV8R999 said:
Decided to paint the RV8 myself using Stewart S
ystems. The primer is single part and water soluable so very easy to prepare (just pour through a filter).

I spent a bunch of time filling pin holes in all the glass work and shot and sanded the primer three times now. The technique for painting this system is much different than others and requires some patience in that each coat goes on very light.

my problem now is that I'm seeing fish eyes on a few parts such as the rear half of the wheel pants. At first I thought these were missed pin holes but when I look closely right after shooting the primer I can see the primer is pulling away as if some contaminate is there (like oil and water does). I've sanded these areas down, cleaned with strong detergents, used acetone, cleaned again, used acetone again, sanded, cleaned and acetone again and still when I shoot the paint I see these spots...

Any ideas?

I have a dryer and filter attached in-line and I just ordered a new poly hose made in USA vice the rubber one made in China to eliminate any possibility of hose contamination..hmmmmmm????

Thanks
Click to expand...
 
Compressor

Depends on what filter your using but it takes tiny amounts of oil to ruin a paint job. That's why I bought an oil free machine. You either will have to use an activated carbon filter or switch to an oil free unit.. If I'm right you'll have to probably replace the hose again
 
Motorguard

One of the best filters for the DIY'er is made by Motorguard. It holds a filter element that looks like a toilet paper roll (but works much better), and produces really nice clean dry air. Filters last a long time also.
 
thanks for the ideas. I might actually see if I can use my two part epoxy primer as a base and the stewart over top of that. Don't think it is the primer as the entire cowl, top and bottom, came out really nice using the same mix of paint in the same gun. I really think something very difficult to clean in on the part but i'm at a loss as to who to be more thorough than I have been in cleaning.
 
dedgemon said:
One of the best filters for the DIY'er is made by Motorguard. It holds a filter element that looks like a toilet paper roll (but works much better), and produces really nice clean dry air. Filters last a long time also.
Click to expand...

David,

I'd really like to hear more about this. Do you have a part number or a source for this item?

Thanks!
 
Motor Guard M-60

http://www.motorguard.com/air_2_2.html

I like the M-60. You can buy these at a lot of auto paint stores, Grainger, McMaster, Amazon, etc.... Get a couple of their filter elements, they work great.

My setup is a 80 gallon tank oiled compressor from Home Depot followed by about 30 feet of copper tubing with a low point drain. This helps cool the air and drop out some of the water. I then have a centrifugal separator that gets a lot of the water out of the air. Last is M-60. After that I've got a 50' foot hose that I use for nothing but painting. At the base of the gun I have a regulator (only one in the system) to control the air pressure. This assures a repeatable air pressure set right on the gun.

I've painted 2 RV's with this system. Never had the first problem with contamination from the air supply. Its simple, cheap, and effective.

The compressor has enough umph to actually gain pressure while I paint. When shooting clears, its really nice to have unlimited clean air.

I've painted both of my RV's now some I guess I can say I'm getting the hang of it. Lots of different approaches to paint. Most of them can work!

Good Luck
 
Contamination

Contamination can be really really frustrating.

I did something really stupid painting the canopy skirts on the '8. It order to save time I brushed some PPG K36 on with a disposable brush. BIG mistake. I got TONS of fisheye. It dawned on me that those brushes (probably ALL brushes) are lubed during manufacture. I finally cured the problem by wiping all the primer off with MEK and lots of paper towels. Then did it again. Then shot 3 coats of K36 and sanded back to a nice smooth surface, Then primed painted and cleared. Really made a lot extra work.

I'm not familiar with the Stewart paints, primers, but if you're seeing fisheye on the glass parts and not on other parts, I would be really suspicious of the mold release that is used. It really doesn't want to come off with solvents, it is water soluble and will wash off however. Some of it may have gotten trapped in whatever filler you used to smooth the glass.

If you've done that then just be suspicious of you're other components, sandpaper, prep cloths, etc... I've found that for final cleaning of the parts before painting, that a spray bottle with rubbing alcohol and nice new clean paper towels (pure white) works really well. I spray the part and wipe it several times. If its aluminum I want to see perfectly clean towels with no gray. The alcohol is effective, really cheap (grocery store) and is basically what PPG sells for $25/gallon for paint prep.
 
I painted the whole plane in pieces over many different days and the only time I got fish eyes was on the wheel pants. I'd say it's gotta be a mold release deal.
 
Ok so I read the comments about mold release on the wheel pants and took them to heart. I filled a bucket half with water and mixed in a high concentration of Stewart's systems detergent. I used this mixture to completely wet sand the wheel pants with 320 grit paper until all fish eyes where smoothed out and gone. Let them dry and re-primed - no fish eyes this time and they look nearly perfect. I think you guys were right. Thanks!

Ken
 
You must log in or register to reply here.