A Photo & Discussion Forum for Wharram Design Enthusiasts
Hello all,I have done the first coats of the hulls with a roller and had trouble with tiny bubbles appearing on the finish,what i have learnt thru the web is that one needs to follow the roller with a good quality brush after the roller in what is called tipping off,if the brush gets sticky just apply a bit of thinners,they say this works we shall see.
Paul, that is the standard technique for 2-packs. . .Supposed to work even better if you have a competent friend follow along right behind the roller.
The hardest part of the boat building for us was painting using two part paint. We tried hard to master the roller + tipping off with a damp brush technique and never succeeded. Finally we decided the purpose of the paint was to protect the fiberglass and the wood under it, so we just painted it with brushes only and went sailing. Over the past 10 years that has seemed to have been the right decision. Ann and Nev
Truth! Last month I had to replace most of the inner aft hull deck shear, the 19mm x 48mm or so piece that runs along the top of the hull. The deck at the sheer was fine, but the PO had not bedded the oak rub rails sufficiently, and the screws let moisture in under the paint: rot!
At any rate, by the time the top coat of fairing compound went on, I wanted to go sailing more than I wanted to spend time sanding! The paint went on and we went sailing with a sheer that is less than "glass smooth." ;-)
well guys I used the paint brush after the roller and there is a vast improvement,glass smooth though, I am not so sure....
Hi Paul. We've used 2-pack paint on a Cross 24 Tri, a Marples Sea Clipper 18 as well as on 3 sea kayaks .... it's true that practise makes perfect (!!) but to be honest, the finish we achieved would never be called glass smooth. It was pretty good, but not glass smooth. Helpful tips offered are; 1) minimize the amount of bubble you introduce by keeping an even pressure on the roller as you apply the paint 2) Use the best quality brush you can afford for tipping off as the silkiness of the bristles assists the smoothing process and 3) resist the temptation to 'work' the tipping - use long, smooth, even strokes working backwards ie. from the dry area towards the wet area you've just applied. A cold beer often helps! Good luck. Tony, Nannette & Brett
The two part paint which is Linear Polyurethane has "Isocyanate" in it! Methyl Isocyanate is what is still kill and causing birth defects in Bophol, India. When you spray it, it WILL go transderm and get in your body even without breathing it. You need a full moon suit, a full hood with a seperate air supply and lots of ventilation.
Auto body shops in California have spray booths that cost $100,000.00 ! ! ! ! Uh, I don't spray boats any more . . .
When rolling and tiping out, you'll still burn through carbon filters; one to two sets/day. Of course, if you don't want to spend the money on filters, just drink a 6-pack after painting to get some of the solvent out of your system like we did in the old days of pushing glass.
On a positive note, using a really good brush (varnish brush) will give you the best finish. Also, if you have to do repairs down the line, you CAN reproduce the finish. This isn't so true with the spray applied finish. Remenber the "Six Foot Rule": If it looks good from 6' away, its perfect! I thank GOD that I'm 6'2" . . .
I use a second fine foam roller instead of the paintbrush. With soft pressure I take away the excessive paint, which would cause tears. From time to time I have to roll out on a piece of waste paper or ply or in the area which should be painted next. This job would better be done by a second person when painting big areas. I always try this technique during the first coat, then I am used to it when painting the last coat.
The time window to use the second roller is not very long(depending on temperature) and it starts a short while after spreading out the paint with the first roller. When waiting to long you will get a skin like an orange. which sometimes is useful when the underground work is not too smooth and you want to cover this.
The paint will be sanded with 280-320 paper before bringing up the last coat. The surface should be well cleaned.
Before I start painting I sift the 2 pack stuff.
Why thank you for all the helpfull replies.
I repainted a Frances 26 with 2 pot poly from International. I applied with a short pile roller and had someone following with a clean new high-quality brush to get rid of the bubbles. The brusher needed to follow very close behind me. It worked very well, thanks to a tip from a professional painter. He said you need to thin the paint down a bit with solvent, to get the right consistency. It was years ago now, but as far as I can remember we had to thin it quite a lot more than we expected.
Some good tips. But to add;
We used International Interthane 990 (industrial marine range) at about GBP45 per 5l. 11 m/sq per litre. Rolls on well with mohair roller (slight stipple to hide defects and joins in separate panels. Also allows very easy touch up) and tip off with good brush cleaned in acetone. Foam rollers put even less paint on and deteriorate quickly when end of roller loads up(waste paint). We always painted out of wind in cooler temp and always thinned, helping in keeping a wet edge. The tech data sheets say thinning max 5%, but any good spray painter will say more. When we sprayed hulls it was 20% and looks great. No bubbles and happy. Enjoy - but remember a good coat of paint will show up fairing issues. Meet half way, like douglas said 6'.
I have recently painted two hulls with International Perfection. The first was done in summer with temps up to 35 degrees or so. I am just finishing the second hull at around 5 degrees to 10 degrees or more. Less than 4 nothing works. If I could choose a temp it would be about 15 degrees, no wind, clear sky etc etc.
My preferred discovered technique is to put on the first two coats with the undercoat, using bodyfiller for dings where discovered, wet on "wet" ie not sanding between. Then I wetsand with 300 to 400 grit and apply a further two or three coats, the last ones thinned more than they say, maybe 10 to 15%.
Having tried just about every application method bar spraying (sorry, aware of too many industrial victims from that) I now only use a thin foam roller (solvent resistant) followed by A FOAM BRUSH (chuck it after a while, they soften up when they absorb the paint).
This is definitely the best finish I have achieved, but even then, it's hard to eliminate the bubbles. Minimal agitation of the mix seems to help. Working the paint after application is a very bad move.
I am adding this here (also elsewhere already) because there seems little info out there on this very difficult method of finishing, which despite it all, gives good results.
You just have to go like **** at it whatever you do!