I am a noobe to modelling and over the pasts weeks have built,or i should say attemted to build several kits.To be fair i have built them but they are not to my liking but i know i am getting more skilled the more i do.Learning tricks here and there and using less glue!
At first i went for expensive kits thinking these would be the easiest but reading here that is not alwasys the case,I have found the Trumpeter KV tanks to be great to hone my skills on.The one i am doing now(kv large turret) might be a keeper and even get some paint BUT i always have trouble with the barrels in 2 departments.
When i sand or scrape with knife i always seem to get a slight flat spot.I have just got a flexi file,frame kind and this as helped slightly.And secondly the seem always shows.I have tried to glue in two ways.bit by bit using liquid cement down the length and tube glue in one go,i get some plastic to ooze out the seem but i can still see the seem.
Also on the kv large turret the barrel as grooves which need attention.I have tried using a broken knife blade to run round the groove but it is not ideal.Any barrel tips would be cool.
I had the same trouble with them before. What I do with the plastic barrels is when the sand the joints I also sand the sides. I do not concentrate the sanding on the joints alone. But the better solution is to get replacement metal barrels. They’re additional cost but after seeing my first metal barrel I knew it was worth it specially those with grooves.
The flexi-file is the correct tool for getting this done. Typically I give the whole tube a light once over with the coarse(dark gray) grade, just to rough up the whole surface then I do most of the work with the medium(brown) grade. I work all the way around the tube, not just on the seam line. Keep turning the tube as you work. When I’m satisfied with the result I run a few passes with the fine(red) grade and then lay some primer paint to see if the seam is gone if not I touch up and repeat. Work slowly and check what you’re doing regularly that’ll help reduce flat spots. I rarely buy a metal gun tube, but they do require much less work. Like any new skill it takes some practise and a little telling yourself you can do it.
What annoyed me with the latest barrel on the kv kit is that a used adequate tube glue on the join and got some ooze to appear.when i sanded it to my best ability i pushed the barrel onto the manlet stub ,this was a tight fit and it caused the barrel to split/crack at the join.could not use anymore glue.Are all tube/precision glues equal.I was using a shop brand.
To add to the above, I use sponge sanding blocks that I get from the local beauty supply. They come in different grits. They conform to the round barrel. But as above I turn as I sand lightly.
Wet some fine grade sandpaper, wrap it around the tube of the barrel, and spin the barrel with your fingers within the tube of sandpaper. This will sand the seams but also keep the barrel circular, eliminating that dreaded flat spot.
I did this tank, the barrels are annoying, there worse on things like Pattons and more modern kits that have ridges and the like on the cannon.
What I do for them, is the whole, enough glue that it squirts out, but once it does, I run my finger down it after a second. IT doesnt make it smooth, but it makes it easier to sand and work with, plus if it started to melt, it fills the seam right out. After that I just sand it round and apply primer where needed to fill tiny imperfections.
What works for me, is to use a “hot” glue like Tenax 7.R to glue the halves together. Make sure there is a firm bond between the 2 halves. Using a variable speed drill as a “Poorman’s lathe” chuck the barrel and use 320 wet/dry sandpaper for initial sanding. Inspect the seam closely for imperfections. Apply laquer putty and smooth with acetone, if needed, to low spots in the seam and finish sand with 1000 grit for a smooth appearance. While the gun is chucked use a micro chisel to redefine muzzle break seams or other detail.
Have done several 2 piece barrels and even kitbashed one for an Italeri Jagdpanther using the method described and was happy with the results.
Haven’t done any modern weapons with the wrapping on the gun tube or barrles with exposed rifling.
Don’t use tube glues. Use the liquid stuff. Also, you can opt to spend the $5-6 for the metal replacement one if need be. Depends on how you want to use your modelling time.
I just fixed up two Tasca Sherman barrels. Wasn’t that difficult…
i can’t give much more advice on how to deal with the seams in gun tubes,the real experts have already weighed in(great sources of info)however since your new to the hobby keep in mind that patince and practice will help build your skills.also try not to be to critical of your own work,you know where the flawes or weak pionts are however the casual observer may never see them.most of all have fun and ask for help if ya need it.