It’s been a frustrating few days
Well, I did ask for it last time…I shouldn’t have mentioned anything about ‘luck’. Anyway, I noticed one of the vertical rubbing rails at the stern end was starting to lift. These are only thin strips of wood, but there is a fair bend in the shape of the hull at that point and I obviously didn’t get sufficient bend ‘set’ into the strip before gluing it down. I thought it best to sort that out now before doing any further painting - that was about the only good thought I had in this little episode!
I decided to glue the end down with some thin CA, using its wicking ability to get back under the timber and then hold it down while it dried. The first problem encountered was that I should have used a fine syringe to apply the glue, but I used an extension nozzle on a new bottle of CA and, when turned upside down, the full bottle gave it enough momentum to inject way too much glue and that came out the other side and over the paintwork…dissolving the acrylic top coat as it went. Then I put a rubber band over top of the piece being glued (around the hull), to let it dry properly before sorting out the paint damage.
This brings me to problem number two…and it’s a bit embarrassing. I thought I’d put the hull back out in the sun for a bit while it dried off (just for a few minutes), and I then went off to do something else. And, you know that feeling you get when you remember something an hour or so later…yes, I’d left it baking in the sun and it was quite hot to touch when I bought it back in. This had allowed the rubber band to cut into the paint work quite badly. A frustrating morning overall…and I only had myself to blame. Unfortunately, I didn’t take any photos of this. Anyway, I’m now back to fixing things prior being able to finish the painting.
First, I removed the worst of both issues by rubbing them back with 600 grit wet & dry, but there were areas that needed a small amount of filler to bring the surface back to a consistent level. Now to problem number three…it turns out that automotive spray primers and putties are solvent rich and that can dissolve dry acrylic paint that is already on the surface…not to the point of wrinkling or peeling, but it does etch the acrylic out to the edges of the applied primer. In my case this was complicated by me using masking tape to try to limit the size of the area I was fixing. This resulted in the primer etching a square of fine lines at the tape edge.
Here (below) is one side after spraying and rubbing back the spray putty, and you can see both the remnants of the masking border, and also a line right around the edge of where the putty was re-sprayed to try and fill the line around the masked area. That wavy, dotted line is actually a line of small cavities in the surface where the solvent has etched the acrylic. At this point I felt this job is getting bigger rather than better!
The small blocks shown near the hull, above, are a couple of thin sanding boards I made up so that I can 600 wet & dry sand between the rubbing bands, they worked well when I got to that stage. The other thing that you can see in that photo is that the fourth band from the left of the photo is also starting to show signs of lifting at the end, probably due to the spray putty softening the paint and Weld-Bond glue below it. Remember the rhyme about the 'old lady who swallowed a fly'...
At this point I decided to re-glue all of the ends that showed even the slightest movement. I used a scalpel blade to carefully slice from the end for a few millimetres and then I used a very small 1ml syringe with a needle point to inject the smallest quantity of thin CA under the timber. This wicked in immediately and each was carefully held in place with a screwdriver blade until dry. The 1ml syringe worked very well, I filled it with a small amount of CA directly from the bottle and it was easily cleaned afterward with acetone…this is how I’ll probably use the thin CA in future.
Finally, I feel as though I’m starting to make progress again. Now the issue that I still have to sort out is filling all those small etched areas around where I had used the spray putty & primer. All of the fillers I have used thus far are not great for this task…the blue Sika 107 is too coarse and the Deluxe Lite does not stick or sand well in very fine applications. I did a bit of research and found another Deluxe product called Perfect Plastic Putty that gets good reviews. And this is close what I was after, it is water based and designed to go on painted surfaces (won’t damage acrylics), it’s very fine in structure, it's a single pack (no mixing), it dries quickly, and importantly it sands well to a hard polished finish for painting. The feathering at the edges is good, but not as good as you get from spray putty or multiple primer coats.
As you can see, below, even though the filled surface looked perfect before painting, once you get the finish coat back on and dry, you can still see remnants of the filled area. Those bright lights make it look worse than it seemed.
At this point I was getting a bit deflated by the whole thing…but I really don’t like giving up! I decided to put it aside for a week or so, and did something else so that I could come back to it with fresh hands.
My last attempt would be…
- sand back with 600 on a rigid board to make sure it was flat
- slightly over-fill a larger area with the new filler to make sure I was getting those nasty edges covered
- dry sand (the filler will dissolve otherwise) at 1000 grit and check it in bright sunlight…I want to get smoothly feathered edges
- re-paint just the local area
- when dry, wet sand the top coat to remove any remaining ‘edges’
- repeat the re-paint/sand process, causing the top coat to act as a fine filler that is repeatedly feathered with each sand and re-coat.
I'm not finished yet, it's had two coats and is looking much better, so I'll show the final product in the next post.
