Tuesday, February 10, 2009

Equinox’s approach to priming models

If I had to rank in order of least favorite to most with regards to the steps that take a model from the blister to painted on the table, I would place priming models just above the bottom of the list. (The bottom is cleaning flash and mold lines.) I wouldn’t hate it so much if there wasn’t the risk of the primer doing something bad and messing up the model. There are many factors that can cause primer to go bad, so I thought I would talk about how I approach the process.

Three Factors

There are three factors that I believe play a direct role in whether a primer will go bad. The first of these factors is the brand of primer. There are many different brands, and while I have not tried them all, I still found the older version of GW’s primer to be the best brand. It rarely flaked when used properly and didn’t require more than one application before prepping (more on prepping below). Sadly, GW decided to change the formula of their primer. The new primer feels like chalk and tends to dry like it. It seems to flake, even with proper application, and doesn’t dry consistent. I’ve heard that GW has recently changed the formula again, but I haven’t tested it. (Maybe something for a future blog.)

The second factor important to priming in my experience is the storage of the primer. I always store my primer inside the house, normally in a closest. What I have found is that if the can gets to hot or cold, the primer doesn’t cover well. The interesting thing is that the outside temperature doesn’t seem to be as important as the actual temp of the primer. I’ve primed on cold and hot days, and while still observing factor three, I have not had any issues with priming models.

The third factor is the humidity in the air. I always avoid priming models if the Weather channel shows the humidity higher than 80%. In my experience, the moisture in the air seems to cause the dreaded flaking more often than not when the meter goes above 80%. Along these lines, I also avoid priming in direct sun or in strong winds, as I believe both can cause flaking due to uneven drying of the primer.

The Basic Process

My basic process for priming is to do the follow.
1. I clean the model, usually with some warm water and dish soap.
2. Once the model is dry, I will get the can of primer and give it a good shake for about a minute. I cannot stress enough how important it is to shake the can. (The directions on the can are not lying about doing it.)
3. Next I place the model onto a large flat surface. I usually use a piece of cardboard placed on a work bench.
4. Once the model is placed, I will give the can another quick shake and then test spray the can onto some cardboard. I’ll actually let the spray run for a few seconds to make sure it is coming out okay and to remove and bad primer that may have been caught in the nozzle.
5. With the primer tested, I then apply a slight level of coverage across the whole model. I don’t sit on any one spot for long and try to cover as much of the model in the first spraying as possible.
6. Once the first layer is applied, I will let the model sit for 15 – 30 minutes. I’ll usually check it once around 10 minutes and make sure there is no flaking. If I see any, I take rag with a little acetone and wipe the bad spot away.
7. After the first layer sets, I will rotate the model to hit the areas I couldn’t get in the first spraying. Again, I will avoid sitting on any single spot and try to keep the coverage light.
8. With the second layer applied, I will give the model another check after 10 minutes and assuming it passes the flake test, I will let it sit for a few hours or overnight.
9. Once the model has sat, I will usually brush over it with diluted primer (I like Vallejo) and let the “wash” dry before I start to paint.

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