Painting trim - issues

Originally Posted by bowseruni

All trim is stained maple, have coated some of it with Dulux 3 in 1 stain blocker, primer (water based) and then painted over the top with Wash and Wear white high gloss (water based) as instructed by the big green shed.has taken 5 or more coats to get a solid coat and even now a month later the paint is still very soft and flexible.

Wash & wear is acrylic, hence not as hard as an enamel.

I have a similar situation with stained trim and exposed beams in my place. After much trial and error (trying various paints, sequences, etc), here's my current procedure:

1) Give it a coat of straight Penetrol. This stuff penetrates deeply and dries by going hard, not by solvent evaporation. Give it at least a week to go decently hard deep down.

2) Generous coat of slow-drying oil-based primer, such as Taubman's Prep Right, with a little Penetrol added (but not too much). Apply with a small roller and lightly lay off with a foam brush. Don't be too fussy at this stage.

3) Leave it for an extended drying time of 2-3 days. Then decide where filling is necessary -- it's easier to see this after a coat of primer. Fill holes (but not cracks/joins) as necessary with Zinsser Ready Patch. Sand it the next day, wipe clean with a damp cloth, and spot prime.

4) Repeat step (2), possibly twice with at least 2-3 days between coats. Leave it for a week, and then sand with 180g to get a smooth surface. You might have to drop back to 120g in places. Wipe thoroughly clean with a damp cloth.

5) If any bare timber has been re-exposed in step 4, re-prime, sand, etc.

6) Fill any cracks between timber pieces with a flexible product, such as caulk-in-colours, or no more gaps, and smooth quickly with a damp finger. Don't do this if you've still got more oil-based undercoats to do. (An alternative is to use Sikaflex at an earlier stage, which is turps cleanup.) When the caulking is well dried (at least a day for water-based caulks -- 2-3 days is better), give them an acrylic undercoat.

7) At least a week after the last coat of oil-based primer/undercoat, apply 3 coats of Taubmans Endure semi-gloss (or a different gloss level if that's your preference -- personally I think semi-gloss looks better and doesn't show the imperfections quite so much). It might need a very light sanding with 240g or 300g between coats. After the 1st topcoat, re-assess carefully whether any bits need topup filler -- the higher gloss level can make this more obvious than previously. Sand, re-fill, re-undercoat, as necessary before finishing the topcoats.

What prep do I need to do to paint enamel (oil based) over the top of the acrylic (water based) paint?

You'd have to ring the technical help line for the manufacturers in question. Some oil based paints are ok over some acrylics. But note that Aquanamel is water based. I've used Aquanamel in one room, and it's ok, I guess. But I use Taubman's Endure exclusively now.

Thanks for that, I had a look at the big green shed yesterday for some oil based Taubmans paint but they only stocked water based. Ended up getting some Dulux oil based paint, primer and penetrol. Will give your method a try
thanks again

Originally Posted by bowseruni

Thanks for that, I had a look at the big green shed yesterday for some oil based Taubmans paint but they only stocked water based. Ended up getting some Dulux oil based paint, primer and penetrol. Will give your method a try
thanks again

Hi

I think it best you just apply another coat of your water based 3 in 1 to the existing wash and wear gloss, as an undercoat...dont sand ...just paint it on ...then after it dries you can give it a very light sand, just to knock off any imperfections you may have picked up...then apply the oil based gloss.

Good Luck.

Originally Posted by bowseruni

Thanks for that, I had a look at the big green shed yesterday for some oil based Taubmans paint but they only stocked water based. Ended up getting some Dulux oil based paint, primer and penetrol.

If you bought Dulux oil-based 1-Step primer/undercoat, you'll probably find that it's the newer fast-drying formula. It can be more difficult to use, since it dries so fast on the brush or roller. I was so annoyed when Dulux changed their formula -- that's what made me switch to Taubmans who still make a traditional slow-drying oil-based primer. You might want to check whether there's any other outlets in your area that stock a better range of Taubmans. E.g., Bristol decorator centers (some are now called Taubmans decorator centers), or maybe PaintRight? (I've also been told that Haymes oil-based undercoats are good, but haven't tried them myself.)

Also, I've noticed that Penetrol added to these fast-drying oil-based paints doesn't seem to be thoroughly compatible because of the vast difference in their drying times. I experienced some curdling of the mixture.

BTW, I should have mentioned in my earlier post that part of the rationale behind my method is to deal with grain raising that often happens when painting new or stained timber. By this, I mean that when the paint hits the timber, the grain swells and raises, making the surface look much rougher. The Penetrol doesn't cause grain-raising, and once hardened deep down helps to minimize the effect when you apply the oil-based primer. But it doesn't stop it totally, hence my subsequent steps involve extra undercoats and sanding. Anyway, you're the only one who can judge whether the improvement in the final result is worth the extra effort in your case...