Its time to get to work on buildings and structures. Not being a fan of plastic I plan to build wood kits. I am comfortable with working with wood and already built a little depot that looks pretty good. But painting is an issue. I used rattle can spray paints for the depot and that worked OK, but having to go outside to spray the parts is not at all convenient especially during winter. And then having to "decant" the spray paint for detail work with a brush is a bit of a pain.
So I experimented yesterday with my airbrush and acrylic paints that I could spray inside. I found I could get a nice-looking finish with Model-Master acrylic but as expected the wood really wanted to warp a whole bunch. Before I get back to more experiments- will acrylic paints cover nicely over wood sealed with rattle-can primer? Is there a recommended primer that will seal the wood to reduce warping when painting with acrylics?
I am sure the regulars here have seen my depot in the many pics I've posted, but here it is once again. This is the sort of typical finish I am looking for. I am not looking for heavy weathering for most of my buildings (want to keep my world neat-looking). I just want to figure out how to get there without all the outdoor rattle-can painting.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
I would think using rattle can primer require the outdoor spraying you are trying to avoid. How about brushing on standard sanding sealer? Yes, it is solvent based but if you brush it on you shouldn't have to go outdoors. I do mine in my garage but I could just as well do it next to an open window with a fan blowing outward.
When painting wood parts (rolling stock or structures) I do use acrylic or latex based paints, but mostly of the tube sorts such as Liquitex, but I prefer to use a brush. I do not thin the paint very much, and have not had too much warping.
Did you paint or otherwise seal the other sides of the wood? Some modelers suggest that counter-painting can also help avoid or minimize warping.
Dave Nelson
Primers are not necessary but what is in building wood kits is bracing. You need to brace a lot on the inside or it will warp over time or when you paint. Most wood kits come with some bracing but almost all do not include nearly enough. I have built many wood kits from the new laser types to the old Campbell you cut everything types, in fact I was a test builder for one of the laser kit manufactures. Only time I primed was for a look or a metal part.
HObbyguy So I experimented yesterday with my airbrush and acrylic paints that I could spray inside. I found I could get a nice-looking finish with Model-Master acrylic but as expected the wood really wanted to warp a whole bunch.
So I experimented yesterday with my airbrush and acrylic paints that I could spray inside. I found I could get a nice-looking finish with Model-Master acrylic but as expected the wood really wanted to warp a whole bunch.
I have struggled with that for years. I find my best option is to brace the heck out of the structure from the inside to minimize warping
HObbyguy Before I get back to more experiments- will acrylic paints cover nicely over wood sealed with rattle-can primer? Is there a recommended primer that will seal the wood to reduce warping when painting with acrylics?.
Before I get back to more experiments- will acrylic paints cover nicely over wood sealed with rattle-can primer?
Is there a recommended primer that will seal the wood to reduce warping when painting with acrylics?.
Yes rattle can primer works great but I find that I still have to put weight on the pieces while they dry to keep warping to a minimum. I have also used sanding sealer, smells bad and needs weight as well.
HObbyguy I am sure the regulars here have seen my depot in the many pics I've posted, but here it is once again. This is the sort of typical finish I am looking for. I am not looking for heavy weathering for most of my buildings (want to keep my world neat-looking). I just want to figure out how to get there without all the outdoor rattle-can painting.
Nice Job on the Model.
For scratch building I have moved away from all wood structures and have embraced styrene for the basic shell and walls. Much less issues with painting/warping. Still needs to be braced but not the warping problems you get with wood. I realize that isn't an option with wood kits, I would rattle can primer on warm days and use lots of internal bracing.
Here is a wood kit that has massive internal bracing, sanding sealer was used and then was painted with custom mix acrylic
Here is a scratch built styrene structure. No primer - acrylic on styrene.
Hope this helps,
Guy
see stuff at: the Willoughby Line Site
I built RC model airplanes for years and really got into detailed WWII warbirds which is probably why I feel much more comfortable working with wood- already have the skills, tools, etc. The depot is the Blair Line kit which was pretty simple and probably pretty typical for a laser kit. Building it was very easy- everything fit nicely. And it didn't even have to fly.
I need to paint before assembling to get the detail I want. I played around with some painting methods before I started building and the only thing I tried that worked well was the rattle can primer and enamel spray paint. I kept the primer coat light, just enough to seal it, and hit it on both sides. Doing this I didn't have any problems with warping at all.
Based on my experiments it would have taken a ton of bracing to paint without primer, especially with water-based paints. Even light brushing wanted to make the wood warp a bunch.
I didn't try airbrushing acrylics after the spray primer. If the acrylics work well on the primed sheets, and the primer keeps them from warping then that would be a big improvement. Just one day outside priming all the sheets.
Several mentions of brush-on sanding sealer as an alternative. A quick search tells me there are lots of different types out there. Are they all compatible with acrylics or should I look for something in particular?
Hobbyguy,
You could use, Testors, Dullcote Lacquer,for a sealer,on the wood and it is also safe for Acrylics.You said you built wood Model planes. How about using, DOPE,sealer? Those were the days. If it didn't seal the wood, it sure,got you Dopey.
Cheers,
Frank
In my younger days, I built a 1:1 scale circular bookshelf that rotated on its circular base. It was mostly made of 1/2-inch lumber and dowels. I had finished the initial assembly and staining, and I applied the first coat of polyurethane to the base. In the morning, I was horrified to discover that the 1/2 disk of wood, about 2 feed across, had warped several inches out of plane. I first weighted it down to flatten it as best I could, and then applied polyurethane to the other side, which flattened it out pretty well. So, you can see how much warping force you can get just from applying a coating to only one side of a piece of wood.
It takes an iron man to play with a toy iron horse.
Mr. B,
You are 100% correct, wood breathes, similar to our skin,with pores, sealing the wood grain,will cause it to shrink, causing the warping. So you have to do both sides.
Frank you are showing your age. I built control line airplanes with dope/silkspan for covering the wings but not too many remember those days. I don't even want to say how long ago that was. Is that stuff even available anymore?
Most R/C planes these days are plastic covered (Monocoat). The ones that I did without the plastic covering were sealed with thinned epoxy and painted with 2-stage automotive paint using a full-size detail gun. They were quite a bit bigger than our HO buildings
But, the woodwork was not all that different. Precision is important to final results, and plenty of gussets and braces- only for different reasons. Actually most R/C guys have quit building entirely though. Too many already-built out of the box options available and it seems that nobody wants to take the time anymore.
Yes, sealing both sides is a given to keep the structure stable. But if the first side painted bows it out 1/2" then I expect it would be hard to pull back in again just by painting the other side. So think its best to avoid that.
I got started on my new kit since the last post. Its nothing special but a good test case (company house by BTS.)
Before getting started I gathered together all of the various rattle can primers that I had in the garage and the shop and tested them on a piece of thin balsa sheet. Sprayed the primers, let them dry and then painted with various acrylics using my Pasche H airbrush. All worked OK but I got the best results with Dupli-Color Primer Sealer. The color finish with the others was a bit blotchy (parts flat and parts a bit glossy). The Primer Sealer finish was very uniform and flat. Looking at the label on the can the primer sealer is actually meant to seal primer that is already applied, so it has very little filler in it compared to the others. Another plus is the nozzle- it puts out a very fine mist spray so very uniform, and doesn't want to blow the wood away.
So for the kit, I went outside and sprayed the primer sealer on both sides of the wood sheets, immediately brought them in and let them dry. I used some of my old college textbooks to weigh them down and hold the sheets flat once they were partially dry. No warping at all and in a few hours they were ready for topcoating after knocking down the grain a bit with some fine sandpaper.
I've got most of the parts for the building painted now with the acrylics and had no problems. The etched-in details all look good. And even the very small pieces that have the length oriented across the grain have not warped or bent at all. So I seem to have found a method that works. Eager now to test some weathering methods on the acrylic finish and I will do that on my test balsa sheets before the finished building.
I just finished the company house kit except for the roofing and the steps. The roof is removable and I will put tab shingles on it. And I need to adjust the terrain and length of the legs a bit before installing the steps.
The Dupli-color primer-sealer really worked well- absolutely no problems with warping at all and it did not fill in any of the detail. The acrylic paints went on very nicely and everything is flat and square. This is a very simple structure except for the porch railing assembly- I'll admit building that was a bit of a learning experience but I think it turned out pretty good.
Edit- here are both of the company houses completed and installed on the layout.
zstripe Hobbyguy, You could use, Testors, Dullcote Lacquer,for a sealer,on the wood and it is also safe for Acrylics.You said you built wood Model planes. How about using, DOPE,sealer? Those were the days. If it didn't seal the wood, it sure,got you Dopey. Cheers, Frank
Spray lacquer like dullcoat is a great way to seal. some mention the sanding saelers still warping the wood panels, this is due to the "wet' saturation" of the pieces. Dullcoat is a bit $$$ for this purpose, any cheap lacquer in rattle can will do the job, even a clear acrylic will work and not cause warping. For may years I used Deft sealer fro cabinet interiors, however, this great product is quite pricey these days.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Working on a second company house now and used the primer sealer again without any problems. The downside to most of the cheap primers that I tested is that they go on a bit thick and the nozzles are far from ideal for delicate work.
These structures are small so a bit of warping would not hurt too much which is why they make a good test case. The next building on my list is larger, and looking at the instructions it will need some extra care and bracing. I'll try the primer sealer again and see what happens.
bogp40some mention the sanding sealers still warping the wood panels, this is due to the "wet' saturation" of the pieces
As long as it does not warp the wood when applied it seems to me that some saturation would help long-term stability of the finished strucure. The stuff I am using does seem to penetrate the wood a bit more than a regular primer but I have no idea what is in it. To me it does not smell like a laquer base.
While we are on acrylics and airbrushing, I am quickly learning that darker colors (browns, reds, greens, etc.) are very easy to spray and coat very nicely on the primed parts, while lighter colors (white, tan, gray) tend to load up the airbrush if I stop spraying for more than a few seconds, and they don't go on quite as smoothly. This doesn't seem to have anything to do with the paint brand- Model Master, Tamiya, etc. all seem to act the same. It must have something with the way white pigment (titanium dioxide?) acts in an acrylic base. Starting with a white-base primer instead of gray would probably help with coverage if I could find one that goes on as nicely as the primer sealer. Not a big issue but worth mentioning.
Curious...do you cut the parts from the panels before spraying or cut them out later as you build? If the latter, what do you do about the little un-primed areas?
I really appreciate your reports. I am learning a lot.
Glad you are getting something out of posts- so far, so good but trust me I am learning as I go!
I am priming all of the panels on both sides (except those that are sticky-back) before cutting anything out. This keeps the small pieces from getting blown around by the rattle-can spray. The larger parts on the thick panels could be removed first to get primer on the edges but I haven't bothered. The main reason for the primer-sealer is to stabilize the wood and keep it from warping so its not really necessary to get full coverage on the edges.
After being primed I am finding that the thin pieces can be painted with acrylics using the airbrush without removing them from the panels. Enough paint gets in-between to cover the edges completely. Removing the small thin parts before painting is a mistake (learned that one the hard way.) The airbrush will blow them away unless they are held somehow and that doesn't help the finish. Any unpainted areas on the edge that result from cutting the small parts from the panel can easily be touched up with a small paint brush, but I find that most of the time it isn't really needed.
The thicker parts can be airbrushed on the panels, then removed and the edges touched up using a small brush, or they can be removed and airbrushed while holding them with tweezers in order to get to the edges. Either way seems to work fine. Edges that will show on the finished model require at least two coats of paint, depending on the color, to get complete coverage.
There are some assemblies like the porch railing on the company house that are probably best painted after construction. As small as it is there are literally 25 individual pieces to the porch rail assembly on that kit, and the layer of paint on such small parts made assembling it that much more of a challenge. So for the second kit (already started) I will build the complete railing assembly first, and spray the white paint with the airbrush before gluing it onto the porch. We'll see how well that works- should have it done by the end of the coming weekend.
Yes, learning as I go!
I have always found a good technique for holding or restraining small or lightweight parts for spray painting is to use the blue 3M paint masking tape. Simply take a piece and attach the two ends with the adhesive side being on the outside. Then, using a piece of cardboard, attach one portion of the tape loop to the cardboard, using the cardboard as an anchoring point. Then take whatever part you are painting (wood, metal, plastic, etc.) and press the side that does not require painting onto the outward adhesive side of the tape loop already attached to the cardboard. The tape now provides an anchor for holding the part and will allow you to paint the main surface as well as all of its edges, so the parts can be all trimmed beforehand from sprues, etc.. This is a great technique I have used for years from model building to car restoration projects with equal success. If the part needs to be painted on both sides, simply remove the painted part when dry and stick the painted surface onto the tape and spray the second side. For very small parts, you can attach many to one loop of tape. Try it, it works well. Gary
One of the reasons I like to use Tamiya spray paint cans (besides the much finer spray compared to paint cans from a home supply store) is you can buy small individual jars of the same colors, so you don't have to "decant" the spray paint to do touch ups.
badger1I have always found a good technique for holding or restraining small or lightweight parts for spray painting is to use the blue 3M paint masking tape.
Great idea! I will definitely give it a try.
Acryllic based wood primers (typically a light grey color) help seal out the moisture of acryllic paints. But there is still a high risk for warping. Sooooooo, you brace the backside of the walls with woodstock or plastic I beams/box beams.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!