So I called Stewart’s this morning to ask about the paint problems they told me the 70 deg 68% humidity was near ideal conditions and they were concerned about the paint not tacking in 20+ minutes especially on first coat. Read them off the lot numbers on the paint I just received and they said they thought it was suspect. They did some checking and found that the resin in that lot of paint was bad. They are sending me two new gallons of paint. It’s a bummer that the paint was messed up however, its great that Stewart’s is such a great company and sent me two new gallons of paint to fix the problem no questions asked. The dehumidifier dropped the basement to 55% humidity which should be better than before and help too.
I have completed the following:
1) Purchased a Hydrometer the basement today was at 70 deg and 68% humidity (not great but not terrible)
2) I shot a test panel of the white it took forever for each coat to tack total paint job took 70 minutes and it still ran (sheeted) because it wasn’t tacked (still slightly stick with some color transfer) 20 secs on the M50 cup
3) Thinking it was the white I shot some metallic silver (20 secs on the M50 cup) I had on a test panel it tacked much much faster still ran and sheeted on me a little but the job was done in 41 minutes about 10-12 minutes for each coat versus 15-20 for each coat with still no where near the tack issues like the white has been doing to me (aka tacked a lot better but I probably should have let it sit a little longer)
4) Thinking it was the humidity I borrowed a de-humidifier and started that process and have the project a rest for the day in 4 hours It had removed 68 Oz of water from the air and had dropped the humidity down to 62%.
I will try another test panel tomorrow after work hopefully the humidity will be way down below 50% or more the lower the better in my mind. I also may try shooting a test panel with the viscosity at 22-23 sec instead of 20. I had been shooting everything at 20 because I was have was having a hard time with the blue flowing out and at 20 sec it really flowed out nice.
Today I decided to take the day off work to paint my upper wing besides it was my Birthday anyhow so what better way to spend day than painting my upper wing. I had a fair bit of cleaning to do to get the upper wing clean mostly just a good wiping and blowing with compressed air then wiping it down with a alcohol damped cloth. I loaded the upper wing into the booth and tacked it down several times to make sure it was ready. I estimated that I would need around 2000 total grams or about 58 ounces of part A to get the wing painted. I was nearly through my first gallon of white paint, so I just dumped the rest into my new gallon of paint. I mixed up the new gallon to get it nice and stirred and and mixed about 65% of my 2000 grams of Part A which ended up at 37 ounces of paint but once you add the catalyst and water you end up with quite a lot of paint, but you need it all for the first 3 coats. I sprayed the first coat and half way through my arm was killing me. Its really a bear to go up and down with so much paint in the hopper. The first coat took almost 20 minutes to tack enough that I was comfortable to move on to the next coat and really it wasn’t as tacky as I like. It also spider webbed on my real bad in places which it hasn’t done before. I just moved on at 20 minutes and sprayed the next coat. It still spider webbed in spots and this coat took nearly 25 minutes to tack. I was starting to get worried about pot life. Anyway I waited as long as I felt comfortable and shot the third coat. This one took nearly 30 minutes to tack. So now we are in almost 70 minutes and it was running and sagging all over the place. I didn’t know what else to do and most of the sags were where I had to put trim colors anyway so i just went with it and mixed up more paint and shot the final coat at 70 minutes. By the time it was all said and done I had runs in places and loads of sags so i tilted the wing up to horizontal to combat that. I came back about 3 hours later to a glossy in places but not really glossy and the areas that spider-webbed looked like strings of yarn in the paint there were other areas that looked like they blushed (a flat soft feel to them) I haven’t had any problems up to this point so this is the list of areas where I could have gone wrong.
1) New gallon of paint
2) New quart of cataylst
3) Possible High Humidity
4) Rushed job not tacking well. (it took nearly a 1hr 30 minutes when it normally takes 50ish minutes)
Well happy birthday to me! Like a giant F’you!
Here is a picture as you can see the wing is dull in places and semi glossy in others it was all over the wing in random places.
Time spent 4 hours
Total time spent 1294 hours
Another two day post here May 1st/2nd. After shooting both the lower wings I decided it was time to work on the upper wing. I pulled it off the wall and got right to work on the sanding it. It takes about 2 hrs per side to get it sanded down properly even with my orbital sander. You also have to hand sand a bunch of it and the easiest way not to damage the rib stitches is to just use the scotch brite around the rib stitches. It took me both days to complete the the sanding.
Time spent on the last two days 4 hours
Total Time spent. 1290 hours
Today. I spent some time prepping the upper ailerons for top coat. I started by cleaning them of all the dust over the last 8 months of sitting around and then I sanded them and scotch-brited them. I also wanted to get some paint on the throttle panel and wobble pump lever so I loaded them into the booth as well. I mixed up paint and shot them to a nice pretty white.
Time spent today 4 hours
Total time spent 1272 hours
Today I spent a bunch of time working on each cowling. I spent most of the time on the cowling that needed an extension to fix the engine (left side) it took several iterations to get the cowling as smooth as I wanted but I eventually did. I also prepped the upper wing by wiping it with 320 sandpaper to get the bumps off from the brush coats of Eko-fill. I then hung it in the paint booth and sprayed it. I found that one cross coat of the upper wing with the 1.3mm tip 23-25 psi at the gun takes approx 2/3 of the hopper of paint. After it was done and dried I did the initial sanding with my orbital sander and scotch brite pad.
Time spent today 8 hours
Total time spent 1198 hours