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I have read of many people using water in their DIY mixes?
Adding water to almost any water-based paint is a necessity when spraying paint through any HVLP or conventional spray system I am familiar with. If the paint is too thick it will either not spray at all or it will spray with a large amount of "spattering" (relatively large globs of paint hitting the target instead of a paint mist). Believe me, you will know it when you see it. BTW, spattering can be a useful artistic technique, but it most definitely shouldn't be used to make projection screens.

Thinning a water-based paint that is to be rolled is another matter. It depends on your own personal rolling technique and the paint being used, some are thicker than others. I'm not a roller so I can only speak in generic terms, but water is generally added to rolled paint to aid in leveling; it helps the rolled paint smooth out better after leaving the roller. The downside is, if the paint is thinned too much it will run.
 

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Discussion Starter #3
Thanks.
I have found that for me, the shorter the nap roller(and most specifically the type of nap on the 3/16" rollers and shorter---not wool) leads to faint lines at rollers edge regardless of pressure or amount of paint used.
 

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Matt when you say 'streaks' in the other thread do you mean roller lines when you over lap each row?

If you are using a good quality paint like Valspar it really should go on smooth as is and level out without leaving roller lines.

My ex brother-in-law was a professional painter for a number of years and he said yes the pros do thin their paint some. Partly so it goes on smooth, but it also extends the paint. Maybe not that much but over the course of a year it adds up and means they don't need as much paint so they have higher profits. Again nothing huge, but every little bit counts.

Here is a big tip, and this comes from my own experience as well as talking to professional house painters- If you buy the best paint out there but the cheapest roller covers you'll have some issues at some point. A person would actually be better off to reverse things and spend their money on a top quality wool roller cover and buy cheaper paint. When the two are combined though, good quality paint and a good quality wool roller, just about anyone can roll a room with professional looking results.

Rolling a screen isn't and shouldn't be any different than painting a room. Maybe I don't have any issues because I've been painting rooms in the various houses I have lived in for over twenty years now. The key is to use good quality products and take your time.

If you continue to have problems rolling, even after getting a good quality wool roller cover, start looking at the actual roller itself. Most people use rollers that came in a $5.99 kit from Walmart. This is a topic I see very few if any others talk about. The roller itself will also make a difference. Those 'kit rollers' often flex and provide uneven pressure across the roller cover. This in turn causes people to apply more pressure and one edge of the roller ends up having more pressure than the other end... which means more paint on that side... and the potential for roller marks.

Now back to the topic of thinning.

If you thin too much and you are rolling you'll have worse problems than if you didn't thin at all. If the paint becomes watery you'll get splatter when you roll and the paint won't go on thick enough to cover evenly. Depending on how much it was thinned, even after several coats it could still look uneven and blotchy in areas.

One of the cool things about Black Widow is we recommend a very good quality paint, that being the Valspar Flat Enamel. With a good quality roller and roller cover this paint should roll out like warm butter and leave a smooth line free surface. The aluminum paint that is added is water based, and it is actually comprised mostly of water. So Black Widow already has eight ounces of a 'thinner' already added in as part of the two step mix. In other words it already has around 20% of a thinning component already added. This is my opinion and experience, but adding more won't make things better, rather it increases the potential for problems, especially as I mentioned if lower quality rollers and roller covers are being used.

Once you get back to a nice smooth surface, spend the little extra on a good quality cover for both your primer coats and your final screen paint coats. I know it sounds like a pain and extra money but in the end it is still a fraction of the cost of a commercial screen.

The end results are well worth it! :bigsmile:
 

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Discussion Starter #5
I think you hit the nail on the head....bad flexing roller that has lived its' life.
The shortest nap I can get at any of the paint stores or hardware stores in 'wool' is 1/4".
I was getting Purdy's and Wooster's.....I didn't have streaks my first couple coats...but after ~8 coats every stroke was showing a line.


I was told that the citrus cleaner will melt my pvc board?
 
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