M L Campbell products finicky

[Alex Horvath]

Hi all,

I have been spraying Ben Moore alkyd SI for quite a while so I have some experience. Of course I thin the BM with mineral spirits and once you get the ratio right it's pretty much trouble free. The problem is that if you are spraying colors that are close to pure white you run the risk of it yellowing in low light areas.

That's why I switched to Campbell pre-cat Magnamax.

The problem I'm having is dry fall and difficulty with flow out.
I solved this by adding the care retarder but I added about 10% based on the severity of the dry fall and that made the finish (satin) dry to at least a semi gloss - way too glossy (adding retarder increases gloss).
It's possible the fast dry is because I'm using a turbine (too hot) and also the CA product is 275 VOC.

Here is my equipment-

Accuspray 10G, 1.8mm nozzle, 4 stage turbine
I'm not thinning the Magnamax as it's about 20 secs on Ford cup.
I added about 10% care retarder.

For my next attempt I'd like to reduce the retarder to about 5% and to improve flow out a 2.0mm tip might help also.
Spraying in the morning to avoid higher temps (it's been about 80 deg in my shop) should help also.

I should have done more testing before spraying the final project but I thought a product made for spraying would be user friendly.

Thanks for any tips.

[Tony Joyce]

I've not used the Magnamax, but have used the Campbell Magnalaq pre-cat lacquer in the past. I use Sherwin Williams(they own ML Campbell) pre-cat now. They are pretty much the same products. When the temps get high I use a retarder(Butyl Cellosolve) plus thinner to slow it down to reduce over-spray. You can get a slower thinner also. I've not had a problem with sheen, but I use a "Dull Rubbed" sheen to begin with. Probably the reason I haven't seen a gloss problem. I also use a very wet coat to help reduce over-spray. Don't let the exhaust fan pull the over-spray across finished areas. I have had some success rubbing the over-spray off with my hand after it flashes. And last but not least I have had to tape off or divide sections if they get too large. Hope something in this will help you out.

Tony

[Rick Mosher]

I have never liked the butyl cellosolve or butyl carbitol type retarders, they are way too oily for my taste and are additives not solvents. I have always used a small amount of MAK (methyl amyl ketone) instead. It is a true solvent, aids flow out and eliminates blushing problems.

[Alex Horvath]

For thinner they gave me a can of Campbell acetone, they said this is the only thinner they will ship to CA.
I thought acetone is a fast drying solvent but not sure. I have googled this issue and for some thinning + 5% retarder + larger nozzle seemed to work well.


I assume you cannot use a mineral spirits thinner with this product. First time shooting this I tried to clean up with paint thinner and I think it activated the catalyzer because the paint instantly cured. I thought I ruined my gun!