Need help selecting gun tip size

[RV7Factory]

Hi all. I am hoping somebody can offer some advice....

I a building an airplane (aluminum) and have been spraying PPG DP48LF on the internal structure as a primer/sealer solely for the sole purpose of corrosion protection (sealing). I have been using a cheap 1.0mm touch-up gun with decent results, but the gun has recently developed bad habits and I am considering the purchase of a new higher quality gun.

A friend said I should consider moving up to a 1.4mm tip for the DP48, which PPG also recommends. However, the 1.4mm guns I have found require around 10cfm or more, and my 5HP compressor is only rated at 6.6cfm @ 40. That being said, I am not sure how much of a factor that should be as my spraying involves a lot of small parts, meaning unlike a car there is a lot of starting and stopping. I also need to be careful to not spray too much primer as it adds a lot of weight. I only need a very light coat of primer as these parts are not getting top-coated.

With all that in mind, would you recommend moving up to a 1.4mm tip or would you recommend staying with a 1.0mm tip?

Thanks,
Brad

[Len]

Brad

When you're applying PAINT to an entire car you should not stop to allow the compressor to catch up. If you do stop you risk creating a dull/dry spot that may be difficult to cure. However when spraying primer you can stop and allow the compressor to catch up because you're usually going to sand and/or recoat the surface. If all you intend to do is use the gun for primer I'd go with the 1.4 tip (or larger) on a large gun because a 1.0 tip is too small for most primer applications.

[RV7Factory]

Thanks Len!